Some acute metabolic effects of parathyroid hormone in sheep.

PERSSON, J. and J. LUTHMAN: Acta vet. scand. 1974, , 381–397. — It is now well established that calcium ions play a key role in the activation of many different cell systems. Parathyroid hormone (PTH) causes a shift of calcium into bone cells, and lipolytic hormones have little or no effect in calcium-free media. In the present investigation sheep were used to study the acute effects of intravenous injection of bovine PTH on mineral and lipid metabolism. A significant initial hypocalcaemia was found in all groups of animals. The subsequent rise in plasma calcium was most pronounced in rams. Thyroid-ectomized animals showed a greater calcium response than did intacts. PTH was found to have a strong lipolytic effect, comparable to that of catecholamines, and a slight hyperglycaemic effect. The rise in plasma NEFA was blocked by nicotinic acid, while the hyper-glycaemia was potentiated. Hypophosphataemia was obtained in young rams but not in young ewes, and in elder ewes a slight increase in the plasma phosphate level was found. Plasma magnesium decreased in all groups after PTH injection, while PTH + nicotinic acid caused a rise in magnesium concentration. The results are discussed in the view of current knowledge of mineral and lipid metabolism. parathyroid hormone; hypocalcaemia; lipolysis; sheep.