Vasoactive intestinal peptide stimulates gonadotropin-releasing hormone release from rat hypothalamus in vitro.
The effects of vasoactive intestinal peptide (VIP) on the releases of LH and GnRH were examined in a sequential double chamber perifusion system by perfusing the medio-basal hypothalamus and/or pituitary excised from normal female rats in diestrus or ovariectomized rats. When the medio-basal hypothalamus and pituitary from normal rats in series were perifused with VIP (10(-6) mol/l), the concentration of LH in the efflux was increased by 59-181% above that before the injection (P less than 0.05), VIP having a dose-dependent effect. VIP had no effect on LH release from the pituitary perifused alone. Infusion of VIP at 10(-6) mol/l induced a significant release (84-159% increase, P less than 0.05) of GnRH from the medio-basal hypothalamus. Infusion of 10(-6) mol/l VIP induced a significant release (41-99% increase, P less than 0.05) of LH in ovariectomized rats. These findings suggest that VIP induces GnRH release from the medio-basal hypothalamus, resulting in LH release from the pituitary, and that this process does not require ovarian estrogen.
Ohtsuka
S
S
Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
Miyake
A
A
Nishizaki
T
T
Tasaka
K
K
Tanizawa
O
O
D000818:Animals; D005260:Female; D007031:Hypothalamus / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000378:metabolism; D010477:Perfusion; D010902:Pituitary Gland / Q000378:metabolism; D010906:Pituitary Hormone-Releasing Hormones / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D010906:Pituitary Hormone-Releasing Hormones; D014660:Vasoactive Intestinal Peptide; D007986:Luteinizing Hormone