Vitamin A stimulation of parathyroid hormone: interactions with calcium, hydrocortisone, and vitamin E in bovine parathyroid tissues and effects of vitamin A in man.

摘要: The effect of vitamin A, a membrane surface-active agent, on parathyroid hormone secretion was studied in vitro, using bovine tissue, and vivo man. Parathyroid tissues were incubated with A (retinol), retinoic acid, calcium, hydrocortisone E, agents that antagonize the effects A. stimulation release by 10(-6) to 10(-9) mol/1 dose time dependent. Retinoic acid did not stimulate secretion. High calcium concentration, hydrocortisone, 10(-5) mol/1, antagonized A-induced Vitamin increased lysosomal cathepsin D activity tissues. In human studies, eleven healthy men received two intramuscular injections palmitate, 25 000 units each, within 24 h. every subject, serum after administration. Our studies indicate that: (1) stimulates possibly through modification cell or granule membrane, proteolytic activity, (2) increases vivo, this may be important clinical states excess.