[Mechanism of the hypotensive effect of parathyroid hormone]

Intravenous injection of parathyroidine to intact rats in a dose of 2 Units/100 g bw provoked a hypotensive effect. The blockade of alpha-adrenoreceptors did not change the effect of parathyroid hormone. The stable analog of leu-enkephalin inhibited the parathyroidine-induced increase in cAMP level in the vascular wall with no influence on the hypotensive action of parathyroid hormone. Since the hypotensive action of parathyroidine was blocked with isoptin, it is concluded that parathyroid hormone primarily influences sodium-calcium metabolism in the vascular wall.