NEONATAL EXPOSURE TO COUMESTROL, A PHYTOESTROGEN, DOES NOT ALTER SPERMATOGENIC POTENTIAL IN RATS

The objective of this study was to determine the effects of neonatal e xposure to phytoestrogens on male reproductive function as adults. Mal e rats were injected either with 100 mu g coumestrol or DMSO (controls ) daily during their first 5 d of life. Pituitary gland, testes, sex a ccessory organs, and blood were collected on d 60 of life. Serum testo sterone, LH, and FSH levels were determined by RIA. Levels of steady-s tate mRNA for gonadotrophin subunits (LH beta and FSH beta were determ ined by Northern blot analysis and quantified by a scanning densitomet er. Coumestrol had no effect on weights of testes and sex accessory or gans, or sperm count. Similarly, there were no significant differences among serum concentrations of testosterone, LH beta and FSH of coumes trol-treated vats and those of controls. Whereas steady state levels o f LH beta mRNA in coumestrol-treated rats did not differ from those of controls, steady state levels of FSH beta mRNA increased (37%) in tre ated animals. However, the augmented FSH beta mRNA expression in coume strol-treated rats did not negatively affect reproductive potential in male rats. We conclude that neonatal exposure to coumestrol does not alter reproductive organ structure or spermatogenic potential in male rats.