Genistein affects ER beta- but not ER alpha-dependent gene expression in the hypothalamus.
Isoflavone phytoestrogens are growing increasingly popular because of their reported cardiovascular and anticarcinogenic properties, but the effects of these compounds in the brain are largely unknown. In a previous study, we found that an isoflavone supplement, containing a mixture of soy phytoestrogens, inhibited estrogen-dependent female sexual behavior and was antiestrogenic for both ER alpha- and ER beta-dependent gene expression in the hypothalamus. Here we examined the impact of the soy isoflavone genistein, a major component of the supplement, on estrogen-dependent female sexual behavior and ER alpha- and ER beta-dependent gene expression in the rat brain. Genistein, at a dietary concentration of 100 or 500 ppm had no effect on lordosis behavior in rats. However, at 500 ppm genistein had differential activity through ER alpha and ER beta in the hypothalamus. Genistein had no effect, in either the presence or absence of 17 beta-E2, on oxytocin receptor density in the ventromedial nucleus of the hypothalamus, an estrogen-dependent action thought to be regulated via ER alpha. However, genistein increased ER beta mRNA expression in the paraventricular nucleus of the hypothalamus by 24%, whereas 17 beta-E2 decreased ER beta mRNA expression by 26%, a process likely mediated by ER beta itself. These results suggest that at this dose, genistein has antiestrogenic action through ER beta in the paraventricular nucleus but negligible activity through ER alpha in the brain.
Patisaul
Heather B
HB
Center for Behavioral Neuroscience, Emory University, Atlanta, Georgia 30329, USA. hbeaupr@emory.edu
Melby
Melissa
M
Whitten
Patricia L
PL
Young
Larry J
LJ
D000818:Animals; D001345:Autoradiography; D001923:Brain Chemistry / Q000187:drug effects; D004032:Diet; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens / Q000097:blood; D004968:Estrogens, Non-Steroidal / Q000097:blood / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D019833:Genistein / Q000097:blood / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis; D011863:Radioimmunoassay; D051381:Rats; D020318:Rats, Long-Evans; D011960:Receptors, Estrogen / Q000096:biosynthesis / Q000235:genetics*; D018045:Receptors, Oxytocin / Q000187:drug effects / Q000378:metabolism; D012726:Sexual Behavior, Animal / Q000187:drug effects; D012741:Sexual Maturation / Q000502:physiology; D014599:Uterus / Q000187:drug effects / Q000254:growth & development
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D004968:Estrogens, Non-Steroidal; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D018045:Receptors, Oxytocin; D019833:Genistein