Genistein may act as an endocrine disruptor due to its structural similarity to estradiol. Exposure to genistein during development has been shown to alter neuromorphology and G protein-coupled estrogen receptor (GPER) expression in the arcuate nucleus in adult rats. In this study, we investigated the long-term effects of genistein exposure in the ventromedial nucleus of the hypothalamus (VMH) during the second week of life. Rats of both sexes were injected daily (s.c.) from postnatal day 6 to 13, with the following treatments: I) corn oil vehicle (control group); II) 10μg/g of genistein (G10); and III) 50μg/g of genistein (G50). Morphometric analyses of the VMH in Nissl-stained and GPER-immunostained brain sections were performed at P90 using ImageJ software. In males, the low dose of genistein provoked a significant increase of GPER-ir neurons in the dorsomedial, central and ventrolateral subdivisions and in the medial division, as well as in the total VMH, while in females no effects in GPER-ir neurons were observed. In females, the high dose of genistein produced a significant decrease of Nissl-stained neurons in the ventrolateral subdivision and medial division, but no effect was detected in males. Early exposure to genistein may differentially alter the VMH in the long-term depending on the sex, dose, and subdivision studied.
Primo et al. (2026) studied this question.