Luteinizing hormone-releasing hormone and function of the magnocellular vasopressinergic system.
Mechanisms by which luteinizing hormone-releasing hormone (LHRH) affects vasopressin secretion were investigated using the isolated rat hypothalamo-neurohypophysial explants. LHRH in a concentration of 4 x 10(-7)M inhibited both the basal and K(+)-stimulated vasopressin release from explants isolated from euhydrated rats. When, however, the tissue was obtained from animals previously salt-loaded, the inhibitory effect of LHRH was completely abolished, thus implying a decrease in the sensitivity to LHRH. LHRH did not affect vasopressin secretion under conditions of generalized blockade of synaptic inputs by 15 mM MgSO(4), suggesting the indirect action of this neurohormone on the hypothalamic magnocellular system. It is concluded that LHRH may play the role of a neuromodulator of vasopressinergic neurones in the rat.
Bojanowska
E
E
Department of Pathophysiology, Medical University of Lodz, 60 Narutowicza St, Pl-90-136, Lodz, Poland.
Guzek
J W
JW
Dabrowski
R
R
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000166:cytology / Q000378:metabolism*; D066298:In Vitro Techniques; D008278:Magnesium Sulfate / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride / Q000494:pharmacology; D013268:Stimulation, Chemical; D009435:Synaptic Transmission / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014667:Vasopressins / Q000378:metabolism*; D014883:Water-Electrolyte Imbalance / Q000139:chemically induced / Q000378:metabolism
D014662:Vasoconstrictor Agents; D014667:Vasopressins; D000804:Angiotensin II; D007987:Gonadotropin-Releasing Hormone; D012965:Sodium Chloride; D008278:Magnesium Sulfate; D011188:Potassium