Rat hypothalamic extract inhibits vasopressin-stimulated Na+-K+-ATPase activity in the rat renal medulla.
Arginine vasopressin stimulates Na+-K+-ATPase activity located in the rat thick ascending limb of Henle's loop. mammalian hypothalamus appears to produce a factor capable of inhibiting Na+-K+-ATPase activity in a variety of tissues. The effect of a purified rat hypothalamic extract with and without AVP on rat renal Na+-K+-ATPase activity was evaluated by a cytochemical technique. The hypothalamic extract alone failed to affect basal Na+-K+-ATPase activity throughout renal segments after 10 min exposure. Na+-K+-ATPase activity stimulated by AVP (1-10 fmol l-1) for 10 min was inhibited by rat hypothalamic extract over the concentration range 10(-7)-10(-3) U ml-1 in a dose-dependent manner. Complete inhibition of AVP-stimulated Na+-K+-ATPase activity occurred at a hypothalamic extract concentration of 10(-3) U ml-1. Only Na+-K+-ATPase activity located in the renal medullary thick ascending limb was influenced by the rat hypothalamic extract.
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D005260:Female; D007031:Hypothalamus / Q000502:physiology*; D007679:Kidney Medulla / Q000201:enzymology*; D007684:Kidney Tubules / Q000201:enzymology*; D007700:Kinetics; D008138:Loop of Henle / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014020:Tissue Extracts / Q000494:pharmacology*
D014020:Tissue Extracts; D001127:Arginine Vasopressin; D000254:Sodium-Potassium-Exchanging ATPase