Norgestimate increases pituitary and hypothalamic concentrations of immunoreactive beta-endorphin.
Progesterone is a potent hormone acting on the female reproductive tract and influencing a series of other functions. Recent studies revealed a correlation between progesterone and brain neurotransmitters and neuropeptides. Our study evaluated the possible effect of norgestimate, a new progestin, on hypothalamic and pituitary beta-endorphin (B-EP) concentration in castrated female rats. Ovariectomy was performed under ethyl ether anesthesia. Treatment was started 3 weeks after surgery. Norgestimate, estradiol benzoate or norgestimate plus estradiol benzoate were administered. The two steroids were dissolved in sesame oil and injected (s.c.) every day for 2 weeks. Pituitary and hypothalamus B-EP concentrations were measured by radioimmunoassay. Our studies showed that norgestimate increases the pituitary and hypothalamic B-EP concentration in female rats, reaching values higher than controls and estrogen-treated rats. Because B-EP has an important role in reproductive function, both modulating gonadotropin secretion and sexual behavior, the present results lead to the hypothesis that norgestimate affecting B-EP concentrations may influence central functions.
Genazzani
A R
AR
Department of Obstetrics and Gynecology, University of Modena School of Medicine, Italy.
Petraglia
F
F
Cleva
M
M
Brilli
G
G
Mercuri
N
N
De Ramundo
B M
BM
Volpe
A
A
D000818:Animals; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D007031:Hypothalamus / Q000378:metabolism*; D009644:Norgestrel / Q000031:analogs & derivatives* / Q000494:pharmacology; D010902:Pituitary Gland / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D001615:beta-Endorphin / Q000276:immunology / Q000378:metabolism*
D009644:Norgestrel; D004958:Estradiol; D001615:beta-Endorphin; C010452:estradiol-17 beta-benzoate; C017576:norgestimate