RESUMEN
The initial suppression of acid secretion in Insulin Test has been a subject of various interpretaitons. A study of hypothalamic recordings in a patient undergoing sedative neurosurgery for behaviour disorders revealed marked suppression of electrical activity in the lateral hypothalamic nucleus within three minutes after the injection of insulin, followed later by spike formation corresponding to parasympathetic stimulation, when hypoglycaemia is established. It appears that the initial suppression of acid secretion is due to a direct action of insulin, suppressing electrical activities of lateral nucleus, the spike formation occurring later, corresponding to onset of hypoglycaemia with stimulation of the nucleus and consequently gastric secretion.