Serum levels of testosterone, cortisol, prolactin and bioactive luteinizing hormone in adult male rhesus monkeys following cage-restraint or anaesthetizing with ketamine hydrochloride.

The present studies were carried out to characterize and compare the acute effects of cage-restraint or administration of a mild anaesthetic on serum levels of testosterone (T) cortisol (C), prolactin (Prl) and bioactive luteinizing hormone (LH) in adult male rhesus monkeys. Serum T levels declined progressively while C levels increased in the 3 sequential blood samples obtained at 20 min intervals from restrained monkeys. Prl and LH levels in the serum remained unaltered. Following single or multiple injections of ketamine hydrochloride (10 mg/kg) serum T levels did not decline progressively as seen in the blood samples obtained from the cage-restrained, conscious monkeys. Serum C and Prl levels showed a progressive rise following anaesthetization. LH levels were not affected by the anaesthetic. The findings reported here are of pertinent relevance to the evaluation of acute effects of any experimental procedure aimed at altering circulating levels of the hormones studied.