Neonatal glucocorticoid administration: effect on the diurnal rhythm of serum concentrations of corticosterone, progesterone and LH, and the response to pregnant mare serum gonadotrophin in immature female rats.
The effects of neonatal cortisol acetate administration on diurnal changes in serum corticosterone, progesterone and LH and on the response to pregnant mare serum gonadotrophin (PMSG) were examined in immature female rats. Neonatal cortisol treatment (250 micrograms/rat) abolished the diurnal rhythm of serum progesterone in rats at 27-29 days of age, and lowered overall the serum progesterone response to PMSG. Neonatal cortisol also reduced the number of animals ovulating on day 28 after PMSG injection 48 h earlier. This dosage of cortisol did not alter the diurnal rhythm of serum corticosterone in these animals. Serum LH concentrations in control rats at 27-29 days of age did not differ between 09.00 and 18.00 h, and prior treatment with cortisol acetate did not significantly influence serum concentrations of this hormone. Our data suggest that ovarian production of progesterone contributes significantly to diurnal fluctuations of this steroid in the circulation of immature rats. Perinatal exposure to cortisol acetate abolishes the diurnal rhythm of serum progesterone and impairs the ovarian response of the immature female rat to PMSG. The mechanism(s) by which cortisol acetate alters these processes remains to be determined.
D000818:Animals; D000831:Animals, Newborn / Q000097:blood*; D002940:Circadian Rhythm / Q000187:drug effects; D003345:Corticosterone / Q000097:blood*; D005260:Female; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000097:blood*; D010060:Ovulation / Q000187:drug effects; D011374:Progesterone / Q000097:blood*; D051381:Rats; D011919:Rats, Inbred Strains; D014621:Vagina / Q000187:drug effects
D006064:Gonadotropins, Equine; C021650:hydrocortisone acetate; D011374:Progesterone; D007986:Luteinizing Hormone; D003345:Corticosterone; D006854:Hydrocortisone