The effects of neurohypophysial nonapeptides and their analogs on magnesium excretion in rat kidney

The effects of vertebrate neurohypophysial nonapeptides (vasopressin, vasotocin and their synthesized analogs) on urinary magnesium excretion were studied in rats. Neurohypophysial hormones and their analogs at doses stimulating V2-receptors (0.0001–0.001 nmol/100 g BM) exerted antidiuretic effect and reduced urinary magnesium excretion. At higher doses, activating V2 and V1a-receptors (0.025–0.1 nmol/100 g BW), vasotocin and its analogs (deamino-vasotocin (dAVT), deamino-Thr4-vasotocin, deamino-hArg8-vasotocin, deamino-monocarbo-vasotocin) enhanced excretion of magnesium and sodium ions. A direct relationship was revealed between the enhanced renal excretion of sodium and magnesium ions under these conditions. After the V1a-receptor antagonist injection, dAVT caused a 10-fold lower increase in magnesium excretion. The V2-receptor antagonist did not affect dAVT-induced magniuresis. The data obtained suggest that V-receptors are involved in magnesium transport regulation in the rat kidney.