Confirmation of Uterotrophic Activity of 3-(4-Methylbenzylidine)camphor in the Immature Rat

• Published in: Environmental health perspectives Vol. 110; no. 5; pp. 533 - 536
• Main Authors: Tinwell, Helen, Lefevre, Paul A., Moffat, Graeme J., Burns, A., Odum, Jenny, Spurway, T. D., Orphanides, George, Ashby, John
• Format: Journal Article
• Language: English
• Published: United States National Institute of Environmental Health Sciences. National Institutes of Health. Department of Health, Education and Welfare 01.05.2002
• Subjects: Administration, Oral; Animals; Body weight; Camphor - administration & dosage; Camphor - adverse effects; Camphor - analogs & derivatives; Cell Division - drug effects; Cell growth; Dosage; Environmental health; Estrogens; Female; Gavage; Injections, Subcutaneous; Rats; Rats, Wistar; Receptors, Estrogen - drug effects; Structure-Activity Relationship; Subcutaneous injections; Sunscreening Agents - administration & dosage; Sunscreening Agents - adverse effects; Transactivation; Uterus - cytology; Uterus - drug effects; Yeasts
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.02110533

In this study we found that the ultraviolet sunscreen component 3-(4-methylbenzylidine)camphor (4MBC) is uterotrophic in immature rats when administered by either subcutaneous injection or oral gavage. These data confirm earlier reports of uterotrophic activity for this agent when administered to immature rats in the diet or by whole-body immersion; however, they are in contrast to negative unpublished immature rat uterotrophic assay results. Data also indicate that 4MBC binds to isolated rat uterine estrogen receptors and shows activity in a human estrogen receptor yeast transactivation assay; however, we considered both of these effects equivocal. In this study, we confirmed the original observation that 4MBC was active as a mitogen to MCF-7 breast cancer cells. We evaluated and discounted the possibility that the estrogenic activity of 4MBC is related to its bulky camphor group, which is of similar molecular dimensions to that of the weak estrogen kepone. Uncertainty remains regarding the mechanism of the uterotrophic activity of 4MBC.