Inositol hexakisphosphate stimulates 45Ca2+ uptake in anterior pituitary cells in culture.
Inositol hexakisphosphate (InsP6) is thought to act as an intracellular signal molecule in the central nervous system. We report that InsP6 stimulates 45Ca2+ uptake in cultured anterior pituitary cells. This effect is concentration-dependent, is mimicked by inositol-pentakis phosphate (InsP5) but not by inositol-tetrakis phosphate (InsP4), is present after 2 min of incubation, is independent of extracellular Na+ and insensitive to nifedipine and verapamil. These results suggest that InsP6, a putative metabolite of the inositol cycle, may regulate transmembrane mechanism in the pituitary.
Sortino
M A
MA
Institute of Pharmacology, University of Catania, School of Medicine, Italy.
Nicoletti
F
F
Canonico
P L
PL
D000818:Animals; D002118:Calcium / Q000493:pharmacokinetics*; D002132:Calcium Radioisotopes; D002478:Cells, Cultured; D005260:Female; D007295:Inositol Phosphates / Q000494:pharmacology; D010833:Phytic Acid / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical
D002132:Calcium Radioisotopes; D007295:Inositol Phosphates; C013571:inositol pentaphosphate; D010833:Phytic Acid; D002118:Calcium