Induction of ovulation by endothelin-3 in rats.
Endothelins vary in their biological activity. We therefore examined the effects of endothelin-3 (ET-3) on ovulation and secretion of LH, FSH and prolactin in rats in which naturally occurring ovulation was blocked by the administration of sodium pentobarbital (40 mg/kg, i.p.) prior to the critical period (1330 h) on the day of pro-oestrus. ET-3 (10 nmol/kg) was given via the jugular vein under pentobarbital anaesthesia from 1600 to 1800 h on the day of pro-oestrous and induced ovulation in all rats whether given by venous injection or by infusion but the number of ova in rats injected with ET-3 was less than that in normally cycling control rats. Infusion of ET-3 stimulated the secretion of LH but caused a lower than expected rate of secretion of FSH. It would therefore appear that ET-3 causes release of the total amount of LH that is required for induction of ovulation. Our findings strongly suggest that ET-3 has a physiologically significant role in the regulation of anterior pituitary hormone secretion.
Furudate
S
S
Department of Laboratory Animal Science, Kitasato University School of Medicine, Kanagawa, Japan.
Masaki
Y
Y
Muto
T
T
D000818:Animals; D016232:Endothelins / Q000494:pharmacology*; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D010062:Ovulation Induction / Q000379:methods*; D010903:Pituitary Gland, Anterior / Q000187:drug effects; D011388:Prolactin / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D016232:Endothelins; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone