RENIN STIMULATION CAUSED BY BLOOD COLLECTION TECHNIQUES IN THE RAT

SUMMARY 1. Experiments were conducted in rats to determine the effects of various methods of blood collection upon plasma renin concentration (PRC). 2. Either restraint or anaesthesia during blood sampling resulted in PRC levels up to five times higher than in samples collected after decapitation. 3. A similar difference was observed in adrenalectomized rats, indicating that the PRC increase did not depend upon liberation of adrenal catecholamines. 4. In contrast, administration of propranolol abolished the difference in PRC between decapitated rats, and those sampled during ether anaesthesia, suggesting involvement of a β‐adrenoreceptor mechanism in the stimulation of renin release by anaesthesia. 5. Despite high starting levels of PRC in ether‐anaesthetized rats, the PRC response to water deprivation was proportionally the same (a 7‐fold increase), whether sampling was carried out during ether anaesthesia or after decapitation.