THE EFFECT OF PENTOBARBITAL (NEMBUTAL, MEBUMAL NFN) ON CORTICOTROPHIN RELEASE IN THE RAT

Abstract

The effects of high doses of pentobarbital sodium (Nembutal sodium, Mebumalnatrium NFN) on endogenous corticotrophin release were investigated. Under the stage of anaesthesia endogenous corticotrophin release was almost totally blocked, whereas under the stage of awakening from anaesthesia the secretion of corticotrophin exceeded the "resting level". In normal, non-anaesthetized rats, subcutaneous or intraperitoneal injections did not per se affect circulating free plasma steroid levels. In pentobarbital-anaesthetized rats neither subcutaneous, intraperitoneal, nor intravenous injections influenced the plasma steroid levels. Minor surgical procedures, e.g. cutaneous incisions or cutting the tail tip of the rats did not immediately affect endogenous corticotrophin secretions under pentobarbital anaesthesia. The findings and their application for the simplification of corticotrophin assays and their limitations are discussed.