Prolactin and LH release in response to vasoactive intestinal peptide (VIP) administration in spontaneously hypertensive and normotensive rats.
Vasoactive intestinal peptide (VIP) was injected intravenously at a dose of 10 micrograms in spontaneously hypertensive and normotensive Wistar-Kyoto rats. In order to evaluate the hemodynamic and hormonal effects of this peptide, the mean arterial pressure, heart rate as well as a serum rLH and rPRL levels, the contents of LH-RH in hypothalamus and the content of LH in pituitary tissue were determined. The same procedure was applied in rats receiving placebo. Serum rPRL concentration was measured additionally after combined administration of VIP+dopamine. VIP injection produced a decrease in mean arterial pressure and an increase in heart rate in both spontaneously hypertensive and normotensive rats. Serum rPRL concentration was significantly increased at 10 minutes after injection. The combined therapy (VIP+dopamine) partially inhibited this response. Serum rLH concentration, the content of LH-RH in hypothalamic tissue as well as the content of pituitary LH after VIP injection in spontaneously hypertensive and normotensive rats did not differ from the values obtained for the control group.


CONCLUSIONS
1. VIP injection produced the dramatic hypotensive effects in hypertensive rats; 2. A marked increase in PRL concentration in response to VIP was partially inhibited by dopamine in hypertensive and normotensive rats; 3. VIP injection did not change LH-RH and LH release in both hypertensive and normotensive rats.
Department of Neuroendocrinology, Institute of Physiology and Animal Nutrition of the Polish Academy of Science, Jabłonna.
B
B
Baranowska
M
M
Radzikowska
E
E
Wasilewska-Dziubińska
E
E
Staff-Zielińska
K
K
Kochman
D000818:Animals; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis; D006439:Hemodynamics / Q000502:physiology; D006973:Hypertension / Q000378:metabolism*; D007031:Hypothalamus / Q000737:chemistry; D007986:Luteinizing Hormone / Q000032:analysis / Q000378:metabolism*; D010902:Pituitary Gland / Q000737:chemistry; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D014660:Vasoactive Intestinal Peptide / Q000502:physiology*
D007987:Gonadotropin-Releasing Hormone; D014660:Vasoactive Intestinal Peptide; D011388:Prolactin; D007986:Luteinizing Hormone