Stimulation, by vasopressin and other agonists, of inositol-lipid breakdown and inositol phosphate accumulation in WRK 1 cells.
WRK 1 cells were labelled to equilibrium with 2-myo-[3H]inositol and stimulated with vasopressin. Within 3 s of hormone stimulation there was a marked accumulation of 3H-labelled InsP2 and InsP3 (inositol bis- and tris-phosphate), but not of InsP (inositol monophosphate). There was an associated, and rapid, depletion of 3H-labelled PtdInsP and PtdInsP2 (phosphatidylinositol mono- and bis-phosphates), but not of PtdIns (phosphatidylinositol), in these cells. Some 4% of the radioactivity in the total inositol lipid pool of WRK 1 cells was recovered in InsP2 and InsP3 after 10 s stimulation with the hormone. The selectivity of the vasopressin receptors of WRK 1 cells for a variety of vasopressin agonists and antagonists revealed these to be of the V1a subtype. There was no receptor reserve for vasopressin-stimulated inositol phosphate accumulation in WRK 1 cells. The accumulation of inositol phosphates was enhanced in the presence of Li+ions. Half-maximal accumulation of InsP, InsP2 and InsP3 in vasopressin-stimulated cells was observed with 0.9, 3.0 and 3.6 mM-Li+ respectively. Bradykinin and 5-hydroxytryptamine also provoked inositol phosphate accumulation in WRK 1 cells. The effects of sub-optimal concentrations of bradykinin and vasopressin upon inositol phosphate accumulation were additive, but those of optimal concentrations of the hormones were not.
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002460:Cell Line; D005260:Female; D007295:Inositol Phosphates / Q000378:metabolism*; D008094:Lithium / Q000494:pharmacology; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D013268:Stimulation, Chemical; D013403:Sugar Phosphates / Q000378:metabolism*; D014667:Vasopressins / Q000494:pharmacology*
D007295:Inositol Phosphates; D010455:Peptides; D010716:Phosphatidylinositols; D013403:Sugar Phosphates; D014667:Vasopressins; D008094:Lithium; D001920:Bradykinin