Plasma renin activity in rats with renal denervation and adrenoreceptor blockers

Plasma renin activity (PRA) was investigated by radioimmunoassay following short-term hypoxic hypoxia (45 min 10 per cent oxygen, 90 per cent nitrogen) or hypovolaemia induced by peritoneal dialysis with isotonic (305 mmol/l) glucose. The effect of the above stimuli was also followed in animals with chronic bilateral kidney denervation, beta-adrenoreceptor blockade with dl-propranolol (3 mg/kg body weight i. p.) and alpha-adrenoreceptor blockade with phentolamine (1.5 mg/kg body weight i. p.). Blood was taken by cardiac puncture ten minutes after Nembutal anaesthesia. It was found that: a) kidney denervation and beta-adrenoreceptor blockade suppressed PRA. b) Short-term general hypoxia activated renin secretion by a reflex mechanism involving the renal nerves and the beta-adrenergic receptors. c) The administration of phentolamine potentiated the effect of hypoxia in respect of PRA. d) Hypovolaemia elevated PRA via a possible intra renal mechanism independent from the beta-adrenoreceptors.