Effect of progesterone on the testosterone and estradiol levels in the hypothalamus of neonatal rats.
Pregnant female rats were injected with progesterone or oil from 18.5 up to 21.5 days of gestation. Rat pups were delivered by caesarean section, and pups delivered from progesterone-treated mothers were injected with 100 micrograms of progesterone and pups from oil-treated mothers were injected with oil. Two hours after delivery, pups were killed and hypothalamic testosterone and estradiol were determined by RIA. Control males had substantially higher concentrations of testosterone and estradiol in hypothalamus than control females. Treatment with progesterone did not affect the accumulation of testosterone in the hypothalamic tissue of neonatal males, but completely prevented the formation of estradiol in hypothalamic tissue. This result suggests that progesterone can inhibit hypothalamic aromatase activity in the neonate and may explain why progesterone can protect against some of the neural defeminizing effects of neonatally administered androgens.
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D005333:Fetus / Q000187:drug effects; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D011247:Pregnancy; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D013739:Testosterone / Q000378:metabolism*
D013739:Testosterone; D011374:Progesterone; D004958:Estradiol