Intracellular free calcium in rat anterior pituitary cells monitored by fura-2.
Rat anterior pituitary cells, loaded with the calcium indicator dye fura-2 after primary culture, were challenged with prolactin and growth hormone secretagogues and inhibitory hormones. To initially validate the technique, the calcium channel activator maitotoxin effectively increased intracellular free calcium [( Ca++]i). Various concentrations of the secretagogues thyrotropin releasing hormone or angiotensin II induced peak increases in [Ca++]i within 15 sec, followed by a lower and prolonged plateau phase. The inhibitory hormones dopamine and somatostatin maximally reduced [Ca++]i by 15-20 sec, followed by a spontaneous return to baseline over 5-10 min. The receptor antagonists saralacin and spiperone blocked the angiotensin II and dopamine effects, respectively. Thus, fura-2 appears to be an adequate probe for resolving second-to-second changes in [Ca++]i induced by hormone receptor activation in anterior pituitary cells.
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004298:Dopamine / Q000494:pharmacology; D005456:Fluorescent Dyes; D016257:Fura-2; D007700:Kinetics; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000494:pharmacology; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D001572:Benzofurans; D005456:Fluorescent Dyes; D000804:Angiotensin II; D014660:Vasoactive Intestinal Peptide; D013004:Somatostatin; D013973:Thyrotropin-Releasing Hormone; D002118:Calcium; D016257:Fura-2; D004298:Dopamine