The intact immature rodent uterotrophic bioassay: possible effects on assay sensitivity of vomeronasal signals from male rodents and strain differences.The vomeronasal organ vomeronasal organ
an organ thought to supplement the olfactory system in receiving pheromonic communication. The sensory part of the organ is in two long, thin sacs, situated on either side of the nasal septum at its base. in rodents is an important social and sexual signaling pathway. We have investigated whether the housing of intact immature females in close proximity to mature males would interfere with the sensitivity of the immature rodent uterotrophic bioassay Bioassay
A method for the quantitation of the effects on a biological system by its exposure to a substance, as well as the quantitation of the concentration of a substance by some observable effect on a biological system. as the result of vomeronasal signals transmitted by male urinary proteins. The hypothesis was that the proximity of males might induce early puberty early puberty Pediatrics The development of signs of sexual maturity before age 8 in ♀ and before age 9 in ♂; some children have changes as early as age 3 or 4; in general there is no identifiable cause in ♀; half of ♂ have underlying , thereby increasing mean uterine uterine /uter·ine/ (u´ter-in) pertaining to the uterus.
Of, relating to, or in the region of the uterus. weight and reducing the responsiveness of the assay. The hypothesis was tested in both rats and mice by housing mature males above immature females, separated only by a wire screen, for 3 days and determining possible changes in uterine weight. The results were negative. Neither the mean uterine weight not the group mean standard deviation In statistics, the average amount a number varies from the average number in a series of numbers.
(statistics) standard deviation - (SD) A measure of the range of values in a set of numbers. of the uterine weights were changed in the uterotrophic bioassay. Given that the timing of sexual maturation may vary with the strain of mouse used, we also evaluated the sensitivity of the immature mouse uterotrophic assay to diethylstilbestrol diethylstilbestrol: see DES. (DES) using four strains of mice. Similar activity was observed for the CD-1, C57B16, and Alpk strains, but [B6CBF CBF Chesapeake Bay Foundation
CBF Cerebral Blood Flow
CBF Cooperative Baptist Fellowship
CBF Confederação Brasileira de Futebol
CBF Core Binding Factor
CBF Chicagoland Bicycle Federation
CBF Coronary Blood Flow
CBF cubic feet .sub.1] mice were marginally less sensitive to DES than were the other strains. These findings, add to earlier data indicating the robustness of the rodent uterotrophic assay protocol. Key words: puberty, sexual development, strain differences, uterine weight, uterotrophic assay, vomeronasal. Environ Health Perspect 111:1568-1570 (2003). doi: 10.1289/ehp.5981 available via http://dx.doi.org/[Online 23 January 2003]
The standardization and validation of the uterotrophic bioassay in immature rodents is of current interest (Kanno et al. 2001, 2003a, 2003b; Odum et al. 1997), especially the level of accuracy in detecting weak estrogen agonists and antagonists. The need is for a responsive assay with a large dynamic range where uterine weights in vehicle control animals are both low and uniform to detect modest changes in uterine weights. For the immature rodent assay, the animals must be prepubertal prepubertal /pre·pu·ber·tal/ (-pu´ber-tal) before puberty; pertaining to the period of accelerated growth preceding gonadal maturity. , that is, before the rise in endogenous estrogen levels that occurs at approximately postnatal postnatal /post·na·tal/ (-na´t'l) occurring after birth, with reference to the newborn.
Of or occurring after birth, especially in the period immediately after birth. day (pnd) 30. The use of animals near puberty may have increased mean uterine weights and greater interindividual variability (leading to increased group mean standard deviations and reduced assay sensitivity (Christian et al. 1998; Schlumpf et al. 2001; Thigpen et al. 1987). Consequently, factors that may affect pubertal timing, and potentially interfere with the assay sensitivity, are worthy of study.
Sexual development and maturity can be modulated by vomeronasal signals in rodents, particularly in mice. The presence of adult females may delay the onset of puberty in prepubertal females and suppress estrous es·trous
Relating to or being in estrus.
pertaining to or emanating from estrus.
estrous cycle cylicity in grouped females [the Lee-Boot effect (van der Lee and Boot 1955)]. Adult males can also induce estrus estrus
Period in the sexual cycle of female mammals, except the higher primates, during which they are in heat (ready to accept a male for mating). Some animals (e.g., dogs) have only one heat during a breeding season; others (e.g. in adult females [the Whitten effect Whitten effect
the introduction of a male into a large group of females results in a synchronization of the estrous cycles of the females. Phenomenon observed in mice. (Whitten 1956)] and accelerate puberty in prepubertal females [the Vandenbergh effect (Vandenbergh 1969)]. The acceleration of puberty may be determined by earlier first estrus or vaginal opening vaginal opening
The narrowest portion of the vaginal canal, located in the floor of the vestibule, behind the urethral orifice. (Vandenbergh 1969) or by increased uterine weight (Price and Vandenbergh 1992).
The vomeronasal system is not a true olfactory olfactory /ol·fac·to·ry/ (ol-fak´ter-e) pertaining to the sense of smell.
Of, relating to, or contributing to the sense of smell. organ. Rather, it is a blind cavity in the nasal epithelium that may require direct sniffing to capture particles or droplets or oral licking to transfer sufficient compounds into the vomeronasal organ (Greene and Kipen 2002). The literature indicates that the female responses are due to a class of major urinary proteins (MUPs) produced by the male that are members of the lipocalin protein family (Flower 1994; Sansom et al. 1994). The MUPs appear to be species, sex, and strain specific and may include individual polymorphisms (Clissold and Bishop 1982; Johnson et al. 1995). The MUPs bind to vomeronasal receptors in the female. The binding first leads to molecular events in the vomeronasal organ and the generation of neural signals that must be transmitted along intact nerve pathways to brain centers to impact behavior or neuroendocrine neuroendocrine /neu·ro·en·do·crine/ (-en´do-krin) pertaining to neural and endocrine influence, and particularly to the interaction between the nervous and endocrine systems.
adj. function (Brennan et al. 1999; Dudley et al. 1996; Mucignat-Caretra et al. 1995; Vandenbergh et al. 1975). These reports (Brennan et al. 1999; Dudley et al. 1996; Mucignat-Caretta et al. 1995; Vandenbergh et al. 1975) suggest that the female vomeronasal system is unlikely to be sensitive to highly volatile compounds that might come from males in the same facility, or even housed in the same room. Rather, the female must be in contact with a sufficient amount of contaminated contaminated,
v 1. made radioactive by the addition of small quantities of radioactive material.
2. made contaminated by adding infective or radiographic materials.
3. an infective surface or object. bedding or the male himself.
Another factor that may affect the timing of puberty is the strain of animal used (Nelson et al. 1990). Different strains may also show differing responses to treatment. For example, Spearow et al. (1999) detected a 16-fold difference in susceptibilityto disruption of male sexual development in four strains of male mice exposed to estradiol.
In this study, we have investigated the possible effects of vomeronasal signals and strain differences on the performance of the uterotrophic assay. To test the effect of vomeronasal signals, we housed mature males in dose proximity to immature females and determined the effects on uterine weight after 3 days. We used both rats and mice in these experiments. The mature males were housed directly above the immature females with only a wire screen separating the sexes. This would allow any vomeronasal signals in male urine to be transmitted to the females. We also used standard uterotrophic assays to investigate the sensitivity of four strains of immature mice to diethylstilbestrol (DES).
Materials and Methods
Chemicals. DES (> 99% pure) and arachis oil were obtained from Sigma Chemicals (Poole, Dorset, UK).
Animals. Alpk (Alpk:ApfSD, Wistar-derived) rats and Alpk (Alpk:A[P.sub.f]CD-1, Swiss-derived) and B6CB[F.sub.1] (C57BL/6J-Alpk X CBA/Ca-Alpk) mice were obtained from the AstraZeneca breeding unit (Alderley Park, Macclesfield, Cheshire, UK). CD-1 [CD-1 Crl:CD-1 (ICR (Intelligent Character Recognition or Image Character Recognition) The machine recognition of hand-printed characters as well as machine printing that is difficult to recognize. ) BR] mice were obtained from Charles River UK (Margate, Kent, UK). C57BL6J (C57BL/6JolaHsd) mice were obtained from Harlan UK (Bicester, Oxon, UK). Female rats were 18-19 days of age on arrival (body weights [less than or equal to] 45 g); male rats were 10-12 weeks of age. Female mice were 19-20 or 20-21 days of age on arrival, and male mice were 10-12 weeks of age. Immature animals were selected randomly from a large number of litters by the suppliers and were already weaned wean
tr.v. weaned, wean·ing, weans
1. To accustom (the young of a mammal) to take nourishment other than by suckling.
2. at delivery. Animals were allowed 24 hr acclimatization acclimatization
Any of numerous gradual, long-term responses of an individual organism to changes in its environment. The responses are more or less habitual and reversible should conditions revert to an earlier state. before the start of the uterotrophic assays. Female animals were housed (up to five per cage) in metal cages with wire mesh bases and were supplied with shredded paper bedding. Males were not supplied with beddingto allow the females maximum contact with the male urine. Rat and Mouse No. 1 diet (Special Diet Services Ltd., Witham, Essex, UK) and water were available ad libitum ad libitum
ad libitum feeding
food available at all times with the quantity and frequency of consumption being the free choice of the animal. . Animal care and procedures were conducted according to in-house standards as described previously (Odum et al. 1999).
Uterotrophic assays. Immature rat and mouse uterotrophic assays were conducted in an identical manner.
The effect of the dose proximity of mature males on female uterine growth was tested in Alpk rats and Alpk mice that were 19-20 days of age (pnd 19-20) and 20-21 days of age (pnd 20-21), respectively, at the start of treatment. Untreated females were housed for 3 days in groups of three in a cage placed directly under a cage containing a mature (untreated) male. The base of the male's cage was open wire mesh, thus allowing direct contact with the male's urine. Control untreated animals were housed for 3 days in a separate room containing no male animals. DES (5 [micro]g/kg) or vehicle (arachis oil) were administered by subcutaneous (sc) injection (dosing volumes for rats and mice were 2.5 and 5 mL/kg, respectively) daily for 3 days to two additional groups of animals housed in the same room as the control untreated animals (i.e., in the absence of males).
The impact of strain on the sensitivity of the mouse uterotrophic assay was tested in Alpk, C57BL6J, B6CB[F.sub.1], and CD-1 mice. C57BL6J and B6CB[F.sub.1] mice were 20-21 days of age (pnd 20-21) at the start of treatment, whereas the CD-1 mice were 21-22 days of age (pnd 21-22) at the start of treatment (animals 20-21 days of age were unavailable). Three experiments were carried out in which Alpk mice were tested alongside C57BL6J, B6CB[F.sub.1], or CD-1 mice. Alpk mice were present in each experiment and of the same age as the strain against which they were being compared. DES (1 or 10 [micro]g/kg) or vehicle (arachis oil) were administered by sc injection (dosing volume 5 mL/kg) daily for 3 days.
In all cases, on the fourth day animals were killed by an overdose of halothane halothane /hal·o·thane/ (hal´o-than) an inhalational anesthetic used for induction and maintenance of general anesthesia.
n. (AstraZeneca plc), followed by cervical dislocation. The abdomen was opened and the uterus removed. The cervix and ovaries Ovaries
The female sex organs that make eggs and female hormones.
Mentioned in: Choriocarcinoma
ovaries (ō´v were then removed, and the uterus was trimmed free of fat. Blotred uterine weights and dried uterine weights were determined as described earlier for the immature rat uterotrophic assay (Odum et al. 1997).
The data from two studies to investigate female uterine growth in the presence of mature males are shown in Table 1; the first study was conducted in rats and the second in mice. Each study was performed with four groups of animals: untreated immature females with mature males housed directly above and separated only by a wire screen to allow exposure to MUPs and other possible vomeronasal signals; untreated immature females with no males housed in the same room; a vehicle control group; and a positive control group treated with DES. For animal welfare considerations, the vehicle control and DES groups were limited to three animals. For power, the groups housed in proximity to mature males and with males absent were enlarged to 9 or 10 animals. Blotted and oven-dried uterine weights were recorded, as well as body weight at termination.
In both studies, the DES-treated group had significantly increased uterine weights and the vehicle control group had uterine weights consistent with previous results in each species (Odum et al. 2002; Tinwell et al. 2000). As shown in Table 1, the mean blotted and dry uterine weights of females in dose proximity to males were similar to those of untreated females in the absence of males and those of the vehicle controls. Further, the standard deviations of females in dose proximity to males were also similar to the controls. Therefore, we detected no impact of mature males in close proximity in immature females in the uterotrophic bioassay using either rats or mice.
The second series of experiments was designed to investigate the response of different strains of mice to DES. All strains showed a highly significant uterotrophic response to DES at 10 [micro]g/kg/day, although the uterine weight increase varied from 64 mg in the Alpk to 35 mg in the B6CB[F.sub.1] strain (Table 2). DES at 1 [micro]g/kg/day produced a significant uterine weight increase in the Alpk and C57BL6J mice but a nonsignificant non·sig·nif·i·cant
1. Not significant.
2. Having, producing, or being a value obtained from a statistical test that lies within the limits for being of random occurrence. increase in the other two strains. In the case of the CD-1 strain, this may have been due to the high uterine weight in controls (21 mg compared with ~10 mg in the other strains). The CD-1 mice were 1 day older than the other strains at the start of dosing, which may have contributed to the increased uterine weight in controls, although Alpk mice of this age showed a similar response to mice that were 1 day younger.
Discussion and Conclusions
The rodent uterotrophic assay is currently undergoing validation by the Organisation for Economic Co-operation and Development The Organisation for Economic Co-operation and Development (OECD), (in French: Organisation de coopération et de développement économiques; OCDE) is an international organisation of thirty countries that accept the principles of representative democracy and a free market (OECD OECD: see Organization for Economic Cooperation and Development. ) as a tier 1 screening bioassay to identify estrogen agonists and antagonists that may warrant testing for adverse effects (Kanno et al. 2001, 2003a, 2003b). The gravimetric weight of the uterus in response to chemical administration can be assayed in sexually immature or ovariectomized rodents, and either rats or mice can be used. Recently, several experiments have been conducted on the possible influence of several variables on the responsiveness of the bioassay, including the age of immature animals (Yamasaki et al. 2001), diet (Ashby et al. 2000, 2001; Degen et al. 2002; Owens et al. 2003; Yamasaki et al. 2002), and vehicle (Yamasaki et al. 2001). One interest here was to define whether certain animal husbandry animal husbandry, aspect of agriculture concerned with the care and breeding of domestic animals such as cattle, goats, sheep, hogs, and horses. Domestication of wild animal species was a crucial achievement in the prehistoric transition of human civilization from conditions may lead to early puberty and decreased assay responsiveness. A second interest was to determine possible strain differences in the response to estrogen agonists such as DES.
Both the group mean of blotted and dry uterine weights and the standard deviations of these group means were unaffected by proximity of males for either rats or mice. These data, therefore, provide no evidence that the presence of mature males will alter the results of the uterotrophic bioassay or lead to conditions that will interfere with the responsiveness of the bioassay. The absence of an effect in these studies is probably due to the young age of the animals (24 days of age at termination). Colby and Vandenberg (1974) showed accelerated first estrus in mice 24-29 days of age at the time of exposure to male urine, an effect that is absent in younger animals.
Strain differences were not a major variable in the OECD validation of the rat uterotrophic assay. No differences were observed between Sprague-Dawley and Wistar rat strains among several laboratories using ethinyl estradiol eth·i·nyl estradiol
A synthetic estrogen derivative commonly used in oral contraceptives.
Ethinyl estradiol as a potent reference and also five weak estrogen agonists (Kanno et al. 2001, 2003a, 2003b). However, strain differences in response to estrogen receptor estrogen receptor A protein of a superfamily of nuclear receptors for small hydrophilic ligands–eg, steroid hormones, thyroid hormone, vitamin D, retinoids; the presence of ERs in breast CA generally is associated with a better prognosis, as they respond to agonists have been observed with male mice exposed to estradiol, where marked differences in the effects on testes testes
Male reproductive organs (see reproductive system). Humans have two oval-shaped testes 1.5–2 in. (4–5 cm) long that produce sperm and androgens (mainly testosterone), contained in a sac (scrotum) behind the penis. and sperm were evident (Spearow et al. 1999). Strain distances in the response of rats to bisphenol A (Long et al. 2000) have also been reported, with F344 rats more sensitive than Sprague-Dawley rats, although we found no difference in the magnitude of the uterotrophic effect of nonylphenol in Sprague-Dawley and Alpk rats (Odum et al. 1999). The work of Thigpen et al. (1987) and Schlumpf et al. (2001) dearly demonstrate the impact of the early events of prepuberty pre·pu·ber·ty
The period of life immediately before puberty, often marked by accelerated physical growth. in mice and rats, respectively. In both species, an increase in mean uterine weight and a rapid increase in the standard deviations of a group occurs. Thus, the timing of puberty must be taken into account with each species and each strain. In this investigation, B6CB[F.sub.1] mice were less sensitive to the action of DES, and control CD-1 mice had relatively high uterine weights. However, in each of the strains, DES was dearly detected as an estrogen. Although the possibility remains that the response to vomeronasal signals may differ with strain, the age of the immature animals appears to be the primary determinant of sensitivity, in agreement with others (Thigpen et al. 1987; Schlumpf et al. 2001). Our chosen strain was unaffected.
These findings add to earlier data (Kanno et al. 2001, 2003a, 2003b) indicating the robustness of the rodent uterotrophic assay protocol, and they raise the possibility that some strains of animal or the conditions under which they are used may lead to differences in sensitivity to the action of estrogens Estrogens
Hormones produced by the ovaries, the female sex glands.
Mentioned in: Acne, Polycystic Ovary Syndrome
n. . This supports the efforts of Kanno et al. (2001, 2003a, 2003b) to standardize the age of their animals and of Owens et al. (2003) to investigate the influence of dietary phytoestrogens Phytoestrogens
Compounds found in plants that can mimic the effects of estrogen in the body.
Mentioned in: Premenstrual Syndrome
n.pl plant-derived estrogen analogs. .
Table 1. The effect of males on uterine weight of immature females (mean [+ or -] SD) in Alpk rats and Alpk mice. Uterine blotted Treatment/condition No. weight (mg) Rats (a) Untreated females, close proximity to males 9 21.3 [+ or -] 2.3 Untreated females (males absent) 10 22.8 [+ or -] 1.7 Arachis oil, 5 mL/kg/ day (males absent) 3 23.6 [+ or -] 5.8 DES, 5 pg/kg/day (males absent) 3 107.2 [+ or -] 7.6 * Mice (b) Untreated females, close proximity to males 9 11.7 [+ or -] 2.9 Untreated females (males absent) 10 10.8 [+ or -] 3.6 Arachis oil, 5 mL/kg/ day (males absent) 3 12.2 [+ or -] 3.7 DES, 5 pg/kg/day (males absent) 3 70.8 [+ or -] 11.5 * Uterine dry Body weight at Treatment/condition weight (mg) termination (g) Rats (a) Untreated females, close proximity to males 4.1 [+ or -] 0.5 49.2 [+ or -] 5.9 Untreated females (males absent) 4.5 [+ or -] 0.4 48.3 [+ or -] 6.1 Arachis oil, 5 mL/kg/ day (males absent) 4.4 [+ or -] 1.1 48.0 [+ or -] 4.6 DES, 5 pg/kg/day (males absent) 18.6 [+ or -] 0.9 * 51.5 [+ or -] 4.6 Mice (b) Untreated females, close proximity to males 2.5 [+ or -] 0.6 16.1 [+ or -] 2.4 Untreated females (males absent) 2.4 [+ or -] 0.6 15.9 [+ or -] 2.8 Arachis oil, 5 mL/kg/ day (males absent) 2.8 [+ or -] 0.61 16.3 [+ or -] 2.8 DES, 5 pg/kg/day (males absent) 11.3 [+ or -] 1.6 * 17.9 [+ or -] 2.9 (a) 19-20 days of age at the start of dosing. (b) 20-21 days of age at the start of dosing. * Significantly different from the appropriate vehicle control group (p < 0.01). Table 2. Uterine weight (mean [+ or -] SD) of different strains of immature female mice exposed to DES. Age (days) at start Uterine blotted Experiment/strain/compound of dosing weight (mg) Experiment 1 Alpk Arachis oil, 5 mL/kg/day 20-21 11.0 [+ or -] 2.8 DES, 1 [micro]g/kg/day 25.7 [+ or -] 8.6 * DES, 10 [micro]g/kg/day 64.2 [+ or -] 8.1 * C57BL6J Arachis oil, 5 mL/kg/day 20-21 8.8 [+ or -] 1.3 DES, 1 [micro]g/kg/day 20.3 [+ or -] 8.0 * DES, 10 [micro]g/kg/day 45.7 [+ or -] 6.2 * Experiment 2 Alpk Arachis oil, 5 mL/kg/day 20-21 9.6 [+ or -] 3.2 DES, 1 [micro]g/kg/day 16.3 [+ or -] 3.1 * DES, 10 [micro]g/kg/day 51.7 [+ or -] 7.4 * B6CB[F.sub.1] Arachis oil, 5 mL/kg/day 20-21 8.8 [+ or -] 1.6 DES, 1 [micro]g/kg/day 11.7 [+ or -] 2.6 DES, 10 [micro]g/kg/day 34.6 [+ or -] 5.0 * Experiment 3 Alpk Arachis oil, 5 mL/kg/day 21-22 10.9 [+ or -] 1.9 DES, 1 [micro]g/kg/day 26.8 [+ or -] 5.9 * DES, 10 [micro]g/kg/day 45.1 [+ or -] 8.6 * CD-1 Arachis oil, 5 mL/kg/day 21-22 21.0 [+ or -] 6.8 DES, 1 [micro]g/kg/day 29.6 [+ or -] 7.3 DES, 10 [micro]g/kg/day 60.9 [+ or -] 9.0 * Body weight at Experiment/strain/compound termination (g)a Experiment 1 Alpk Arachis oil, 5 mL/kg/day 16.0 [+ or -] 1.7 DES, 1 [micro]g/kg/day 16.6 [+ or -] 1.5 DES, 10 [micro]g/kg/day 17.1 [+ or -] 1.7 C57BL6J Arachis oil, 5 mL/kg/day 11.3 [+ or -] 1.1 DES, 1 [micro]g/kg/day 11.2 [+ or -] 1.0 DES, 10 [micro]g/kg/day 11.7 [+ or -] 1.6 Experiment 2 Alpk Arachis oil, 5 mL/kg/day 17.4 [+ or -] 0.7 DES, 1 [micro]g/kg/day 17.4 [+ or -] 1.5 DES, 10 [micro]g/kg/day 18.5 [+ or -] 1.5 B6CB[F.sub.1] Arachis oil, 5 mL/kg/day 10.3 [+ or -] 0.9 DES, 1 [micro]g/kg/day 10.6 [+ or -] 1.6 DES, 10 [micro]g/kg/day 10.7 [+ or -] 1.0 Experiment 3 Alpk Arachis oil, 5 mL/kg/day 15.4 [+ or -] 1.2 DES, 1 [micro]g/kg/day 16.0 [+ or -] 1.1 DES, 10 [micro]g/kg/day 15.6 [+ or -] 2.2 CD-1 Arachis oil, 5 mL/kg/day 15.4 [+ or -] 1.2 DES, 1 [micro]g/kg/day 14.9 [+ or -] 1.8 DES, 10 [micro]g/kg/day 15.1 [+ or -] 1.5 (a) n = 10 animals per group. * Significantly different from the appropriate vehicle control group (p < 0.01).
Ashby J, Tinwell H, Odum J. 2000. Uterotrophic activity of a "phytoestregen-free" rat diet [Letter]. Environ Health Perspect 108:A12-A13.
--. 2001. DNA adducts, estrogenicity and rodent diets. Mutat Res 483:105-106.
Brennan PA, Schellinck HM, Keverne EB, 1999, Patterns of expression of the immediate early gene egr-1 in the accessory olfactory bulb olfactory bulb
The bulblike distal end of the olfactory lobe where the olfactory nerves begin.
olfactory bulb (olfak´t of female mice exposed to pheromonal constituents of male urine. Neuroscience 60:1463-1470.
Christian MS, Hoberman AM, Bachmann S, Hellwig J. 1998. Variability in the uterotrophic response essay (an in vivo in vivo /in vi·vo/ (ve´vo) [L.] within the living body.
Within a living organism.
in vivo adv. estrogenic response assay) in untreated control and positive control (DES-DP, 2.5 [micro]g/kg, bid) Wistar and Sprague-Dawley rats. Drug Chem Toxicol 21(suppl 1):51-100.
Clissold PM, Bishop JO, 1982. Variation in the mouse major urinary protein (MUP MUP - Multiple Universal naming convention Provider ) genes isolated from a single inbred in·bred
1. Produced by inbreeding.
2. Fixed in the character or disposition as if inherited; deep-seated.
said of offspring produced by inbreeding. line. Gene 18:221-230.
Colby DR, Vandenberg JG. 1974. Regulatory effects of urinary pheromones pheromones, any of a variety of substances, secreted by many animal species, that alter the behavior of individuals of the same species. Sex attractant pheromones, secreted by a male or female to attract the opposite sex, are widespread among insects. on puberty in the mouse. Biol Reprod 11:268-279.
Degen GH, Janning P, Diel P, Bolt HM. 2002, Estrogenic isoflavones isoflavones (īˑ·sō·flāˈ·vōnz),
n.pl phytoestrogenic compounds found in various plants, including red clover and soy. in rodent diets. Toxicol Lett 128:145-157.
Dudley CA, Rajendren G, Moss RL. 1996. Signal processing in the vomeronasal system: modulation of sexual behavior sexual behavior A person's sexual practices–ie, whether he/she engages in heterosexual or homosexual activity. See Sex life, Sexual life. in the female rat. Crit Rev Neurobiol 10:265-290.
Flower DR. 1994. The lipcalin protein family: a role in cell regulation. FEBS FEBS Federation of European Biochemical Societies Left 354:7-11.
Greene GJ, Kipen HM. 2002. The vomeronasal organ and chemical sensitivity: a hypothesis. Environ Health Perspect 110(suppl 4):655-661.
Johnson D, Al-Shawi R, Bishop JO. 1995. Sexual dimorphism Sexual dimorphism
Any difference, morphological or behavioral, between males and females of the same species. In many animals, the sex of an individual can be determined at a glance. and growth hormone growth hormone or somatotropin (sōmăt'ətrō`pən), glycoprotein hormone released by the anterior pituitary gland that is necessary for normal skeletal growth in humans (see protein). induction of murine murine /mu·rine/ (mur´en) pertaining to, derived from, or characteristic of mice or rats.
adj. pheromone binding proteins. J Mol Endocrinol 14:21-34.
Kanno J, Onyon L, Haseman J, Fenner-Crisp P, Ashby J, Owens W. 2001. The OECD program to validate the rat uterotrophic bioassay to screen compounds for in vivo estrogenic responses: phase 1. Environ Health Perspect 109:785-794.
Kanno J, Onyon L, Peddada S, Ashby J, Jacob E, Owens W. 2003a. The OECD program to validate the rat uterotrophic bioassay. Phase 2: coded single-dose studies. Environ Health Perspect 111:1530-1549.
--. 2003b. The OECD program to validate the rat uterotrophic bioassay. Phase 2: dose-response studies. Environ Health Perspect 111:1530-1549.
Long X, Steinmetz R, Ben-Jonathan N, Caperell-Grant A, Young PCM (1) See phase change memory.
(2) (Plug Compatible Manufacturer) An organization that makes a computer or electronic device that is compatible with an existing machine. , Nephew KP, et al. 2000. Strain differences in vaginal responses to the xenoestrogen bisphenol A. Environ Health Perspect 108:243-247,
Mucignat-Caretta C, Caretta A, Cavaggioni A. 1995. Acceleration of puberty onset in female mice by male urinary proteins. J Physiol 486:517-522.
Nelson JF, Karelus K, Felicio LA, Johnson TE, 1990. Genetic influences on the timing of puberty in mice. Blot Reprod 42:649-655.
Odum J, Lefevre PA, Tinwell H, Van Miller JP, Joiner join·er
1. A carpenter, especially a cabinetmaker.
2. Informal A person given to joining groups, organizations, or causes. RL, Chapin RE, et al. (2002). Comparison of the developmental and reproductive toxicity reproductive toxicity Any adverse effect attributable to exposure to a chemical, directed against the reproductive and/or related endocrine systems Adverse effects Altered sexual behavior, fertility, pregnancy outcomes, or modifications in other functions that of diethylstilbestrol administered to rats in utero in utero (in u´ter-o) [L.] within the uterus.
In the uterus.
in utero adv. , lactationally, pre-weaning or post weaning weaning,
n the period of transition from breast feeding to eating solid foods.
the act of separating the young from the dam that it has been sucking, or receiving a milk diet provided by the dam or from artificial sources. Toxicol Sci 68:147-163.
Odum J, Lefevre PA, Tittensor S, Paton D, Routledge EJ, Sumpter JP, et al. 1997. The rodent uterotrophic assay: critical protocol features, studies with nonylphenols, and comparison with a yeast estrogenicity assay. Regul Toxicol Pharmacol 25:176-188.
0dum J, Pyrah ITG ITG In the Groove
ITG Investment Technology Group
ITG Information Technology Group
ITG International Trumpet Guild
ITG Instituut Voor Tropische Geneeskunde (Dutch: Institute of Tropical Medicine; Antwerp, Belgium) , Soames AR, Foster JR, Van Miller JP, Joiner RL, et al. 1999. Effects of p-nonylphenel (NP) and diethylstilboestrol Noun 1. diethylstilboestrol - a potent estrogen used in medicine and in feed for livestock and poultry
DES, diethylstilbestrol, stilbestrol, stilboestrol (DES) on the Alderley Park (Alpk) rat: comparison of mammary gland mammary gland, organ of the female mammal that produces and secretes milk for the nourishment of the young. A mammal may have from 1 to 11 pairs of mammary glands, depending on the species. Generally, those mammals that bear larger litters have more glands. and uterus sensitivity following oral garage or implanted minipumps. J Appl Toxicol 19:367-378
Owens W, Ashby J, Odum J, Onyon L 2003. The DECD DECD Deceased
DECD Department of Economic and Community Development (State of Connecticut and Maine)
DECD Digital Expandable Color Display program to validate the rat uterotrophic bioassay. Phase 2: dietary phytoestrogen phytoestrogen /phy·to·es·tro·gen/ (-es´tro-jen) any of a group of weakly estrogenic, nonsteroidal compounds widely occurring in plants.
n. analyses. Environ Health Perspect 111:1559-1567.
Price MA, Vandenbergh JG. 1992. Analysis of puberty-accelerating pheromones. J Exp Zool 264: 42-45.
Sansom CE, North ACT, Sawyer L. 1994. Structural analysis and classification of lipocalins and related proteins using a profile-search method. Biochem Biophys Acta 1208:247-255.
Schlumpf M, Berger L, Cotton B, Conscience-Egli M, Durrer S, Fleichmann I, et al. 2001. Estrogen active UV screens, Seifen-Ole-Fette-Wachse 127:10-18.
Spearow JL, Doemeny P, Sera R, Leffler R, Berkley M. 1999. Genetic variation in susceptibility to endocrine disruption by estrogen in mice. Science 285:1250-1261.
Thigpen JE, Li L-A, Richter CB, Lebetkin EH, Jameson CW. 1987. The mouse bioassay for the detection of estrogenic activity in rodent diets. I. A standardized method for conducting the mouse bioassay. Lab Anim Sci 37:596-601.
Tinwell H, Joiner R, Pate I, Ashby J. 2000. Uterotrophic activity of bisphenol A (BPA BPA British Paediatric Association. ) in the immature mouse. Regul Toxicol Pharmacol 32:118-126.
Vandenbergh JG. 1969. Male odor accelerates female sexual maturation in mice. Endocrinology 84:658-660.
Vandenbergh JG, Whitsett J, Lombardi JR. 1975. Partial isolation of a pheromone pheromone
Any chemical compound secreted by an organism in minute amounts to elicit a particular reaction from other organisms of the same species. Pheromones are widespread among insects and vertebrates (except birds) and are present in some fungi, slime molds, and algae. accelerating puberty in female mice. J Reprod Fertil 43:515-523.
van der Lee S, Boot LM. 1955. Spontaneous pseudopregnancy pseudopregnancy /pseu·do·preg·nan·cy/ (-preg´nan-se)
1. false pregnancy.
2. the premenstrual stage of the endometrium; so called because it resembles the endometrium just before implantation of the blastocyst. in mice. Acta Physiol Pharmacol Neural 4:442-443.
Whitten WK. 1956. Modification of oestrous cycle of the mouse by external stimuli associated with the male. J Endocrinol 13:399-404.
Yamasaki K, Sawaki M, Noda S, Takatuki M. 2001. Effects of age and weaning on the immature rat uterotrophic assay using ethinylestradiol. Exp Anim 50:87-89.
Yamasski K, Sawaki M, Noda S, Wada T, Hara T, Takatsuki M. 2002. Immature uterotrophic assay of estrogenic compounds in rats given diets of different phytoestrogen content and the ovarian changes in the immature rat uterotrophic of estrogenic compounds with ICI (language) ICI - An extensible, interpretated language by Tim Long with syntax similar to C. ICI adds high-level garbage-collected associative data structures, exception handling, sets, regular expressions, and dynamic arrays. 182,780 or antide. Arch Toxicol 76:613-620.
John Ashby, (1) William Owens, (2) Jenny Odum, (1) Helen Tinwell (1)
(1) Syngenta Central Toxicology Laboratory, Cheshire, United Kingdom; (2) Central Product Safety, The Procter & Gamble Company, Cincinnati, Ohio, USA
This article is part of the mini-monograph "The OECD Validation of the Uterotrophic Bioassay."
Address correspondence to J. Ashby, Syngenta Central Toxicology Laboratory, Alderley Park, Macclesfield, Cheshire, SK10 4TJ, UK, Telephone: 44 0 1625 512833. Fax: 44 0 1625 590249. E-mail: email@example.com
The authors declare they have no conflict of interest.
Received 5 September 2002; accepted 9 January 2003.