HYDROCORTISONE INFLUENCES VOLTAGE-DEPENDENT L-TYPE CALCIUM CHANNELS IN CULTURED HUMAN SKELETAL-MUSCLE

The glucocorticoid hydrocortisone (HC), applied for up to 2 weeks to e ither aneurally or innervated cultured human muscle, produced 2-fold i ncrease of the number of dihydropyridine ([H-3]PN200-110) binding site s. The K+-induced, nifedipine-inhibited Ca2+ uptake was increased 40%. The effect of HC was concentration- and time-dependent, [H-3]PN200-11 0 affinity for its receptor was not affected by HC treatment. HC did n ot exert significant influence on the total amount of protein, CK acti vity, and the number of myotubes. These results indicate that voltage- dependent L-type Ca2+ channel expression in human muscle is regulated by glucocorticoid. (C) 1995 Wiley-Liss, Inc.