Potential detrimental effects of a phytoestrogen-rich diet on male fertility in mice.

Soy and soy-based products are widely consumed by infants and adult individuals. There has been speculation that the presence of isoflavone phytoestrogens in soybean cause adverse effects on the development and function of the male reproductive system. The purpose of this study was to examine the influence of dietary soy and phytoestrogens on testicular and reproductive functions. Male mice were fed from conception to adulthood with either a high soy-containing diet or a soy-free diet. Although adult mice fed a soy-rich diet exhibited normal male behaviour and were fertile, we observed a reduced proportion of haploid germ cells in testes correlating with a 25% decrease in epididymal sperm counts and a 21% reduction in litter size. LH and androgens levels were not affected but transcripts coding for androgen-response genes in Sertoli cells and Gapd-s, a germ cell-specific gene involved in sperm glycolysis and mobility were significantly reduced. In addition, we found that dietary soy decreased the size of the seminal vesicle but without affecting its proteolytic activity. Taken together, these studies show that long-term exposure to dietary soy and phytoestrogens may affect male reproductive function resulting in a small decrease in sperm count and fertility

Desenvolvimento pós-natal e potencial teratogênico da prole de ratos Wistar no estudo da toxicidade reprodutiva de duas preparações fitoterápicas contendo soja Glycine max (L.) Merr

Avaliou-se o efeito de duas preparações fitoterápicas comerciais que continham soja sobre o desenvolvimento geral e sexual da progênie de ratos Wistar e sobre o potencial teratogênico das preparações fitoterápicas durante um estudo de toxicidade reprodutiva. Para tanto, observaram-se, diariamente, as características de desenvolvimento dos filhotes e analisou-se o comportamento em campo aberto, e, para avaliar o potencial teratogênico, realizou-se diafanização dos fetos removidos por cesariana. Inferiu-se que o tratamento dos pais não comprometeu o desenvolvimento de sua progênie e também não determinou efeitos teratogênicos aos fetos de ratos Wistar