The inhibitory effects of D-600 and cobalt on theophylline-mediated calcitonin secretion and calcium distribution in porcine thyroid slices.
Theophylline (5mM) produced a two-fold rise in calcitonin release from porcine thyroid slices; however, tissue uptake of 45Ca was not affected by theophylline. The calcium antagonists D-600 (5mM) and cobalt (5mM) which reduced the total tissue and cell associated 45Ca spaces in this incubation system were found to reduce theophylline-stimulated calcitonin release. Cobalt produced a greater reduction in tissue uptake of 45Ca and also reduced basal calcitonin secretion. The results suggest that calcium is necessary for theophylline-mediated calcitonin secretion.
D000818:Animals; D002116:Calcitonin / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D003035:Cobalt / Q000494:pharmacology*; D005711:Gallopamil / Q000494:pharmacology*; D066298:In Vitro Techniques; D008353:Mannitol / Q000378:metabolism; D013552:Swine; D013806:Theophylline / Q000037:antagonists & inhibitors*; D013961:Thyroid Gland / Q000378:metabolism*; D014700:Verapamil / Q000031:analogs & derivatives*
D005711:Gallopamil; D003035:Cobalt; D008353:Mannitol; D002116:Calcitonin; D013806:Theophylline; D014700:Verapamil; D002118:Calcium