Arginine vasopressin stimulates 32P labeling of phosphoinositides in rat pineal gland.
The peptidergic innervation of the pineal gland contains arginine vasopressin (AVP) fibers. Since the site and molecular mechanism of AVP action on the pineal signal transduction has not yet been determined, we examined whether the inositol phosphate transduction system is involved. The phosphoinositide signaling system was studied by measuring metabolic turnover of phosphatidylinositol (PI), phosphatidylinositol phosphate (PIP) and phosphatidylinositol bisphosphate (PIP2), which reflects phosphoinositide cycle activation. AVP induced a significant increase in 32P labeling of PI, PIP and PIP2. The V1 receptor site(s) blocker for AVP abolished enhanced 32P labeling of PIP and PIP2. AVP was without effect on cAMP dependent phosphorylation. The data indicate that AVP activates the phosphoinositide signaling system via V1 receptors and is without effect on the cAMP system.
Department of Animal Physiology, Charles University, Prague, Czech Republic.
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R
Novotná
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Z
Zelenková
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R
Krulík
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I
Novotný
D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D008297:Male; D010716:Phosphatidylinositols / Q000378:metabolism*; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D010870:Pineal Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017483:Receptors, Vasopressin / Q000378:metabolism
D065092:Antidiuretic Hormone Receptor Antagonists; D010716:Phosphatidylinositols; D010761:Phosphorus Radioisotopes; D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin; D017868:Cyclic AMP-Dependent Protein Kinases