Confirmation of uterotrophic activity for 4-MBC in the immature rat. (Correspondence).Schlumpf et al. (1,2) reported that the ultraviolet (UV) sunscreen sunscreen /sun·screen/ (-skren) a substance applied to the skin to protect it from the effects of the sun's rays. sun·screen n. component 3-(4-methylbenzylidine)camphor camphor (kăm`fər), C10H16O, white, crystalline solid ketone with a characteristic pungent odor and taste. It melts at 176°C; and boils at 204°C;. (4-MBC) is uterotrophic when administered either in diet to immature Long-Evans rats or by whole body immersion of immature hairless hr/hr rats into an oil solution of 4-MBC. Subsequently, Bolt et al. (3) questioned the validity of those data and referred to two negative unpublished immature rat uterotrophic assays of 4-MBC (4,5). When the discussion between Bolt et al. (3) and Schlumpf et al. (6) appeared, we had already studied the uterotrophic activity of 4-MBC in immature rat uterotrophic assays using both oral gavage gavage /ga·vage/ (gah-vahzh´) [Fr.] 1. forced feeding, especially through a tube passed into the stomach. 2. superalimentation. ga·vage n. 1. and subcutaneous injection Noun 1. subcutaneous injection - an injection under the skin injection, shot - the act of putting a liquid into the body by means of a syringe; "the nurse gave him a flu shot" as the route of administration. The report on these studies has been submitted for publication (7). Of particular relevance to the recent discussion (3,6), we found 4-MBC to be clearly positive in our standard immature rat uterotrophic assay (8). Activity was apparent in the oral study at 500 and 800 mg/kg/day and in the subcutaneous injection study at 500 and 1,000 mg/kg/day. In the oral gavage study (7), uterine uterine /uter·ine/ (u´ter-in) pertaining to the uterus. u·ter·ine adj. Of, relating to, or in the region of the uterus. weights were 22.0 [+ or -] 2.5 for controls and 32.5 [+ or -] 6.5 and 42.4 [+ or -] 6.0 for 500 and 800 mg/kg 4-MBC, respectively (mean + SD; p < 0.01 by analysis of variance and analysis of covariance Covariance A measure of the degree to which returns on two risky assets move in tandem. A positive covariance means that asset returns move together. A negative covariance means returns vary inversely. with terminal body weight). John Ashby Syngenta Central Toxicology Laboratory Alderley Park, Cheshire, United Kingdom E-mail: john.ashby@syngenta.com REFERENCES AND NOTES (1.) Schlumpf M, Cotton B, Conscience M, Haller V, Steinmann B, Lichtensteiger W. In vitro in vitro /in vi·tro/ (in ve´tro) [L.] within a glass; observable in a test tube; in an artificial environment. in vi·tro adj. In an artificial environment outside a living organism. and in vivo in vivo /in vi·vo/ (ve´vo) [L.] within the living body. in vi·vo adj. Within a living organism. in vivo adv. estrogenicity of UV screens. Environ Health Perspect 109:239-244 (2001). (2.) Schlumpf M, Berger L, Cotton B, Conscience-Egli M, Durrer S, Flelschmann I, Haller V, Maerkel K, Lichtensteiger W. Estrogen active UV screens. Seifen-Ole-Fette-Wachse 127:10-18 (2001). (3.) Bolt HM, Guhe C, Degen GH. Comments on "In vitro and in vivo estrogenicity of UV screens" [Letter]. Environ Health Perspect 109:A358-359 (2001). (4.) Comotto L, Bussi R. Unpublished data. (5.) Bachmann S, Hellwig J. Unpublished data. (6.) Schlumpf M, Lichtensteiger W. "in vitro and in vivo estrogenicity of UV screens": Response [Letter]. Environ Health Perspect 109:A359-360 (2001). (7.) Tinwell H, Lefevre PA, Moffat GJ, Burns A, Odum J, Ashby J. Unpublished data. (8.) Ashby J, Tinwell H. Uterotrophic activity of bisphenol A in the immature rat. Environ Health Perspect 106:719-720 (1998). |
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