Arginine and ‘Neurosecretory’ Material in the Pituitary Gland of the Pig

Abstract

IN a previous publication¹, the distribution of arginine as demonstrated histoehemically by an improved Sakaguchi reaction² was examined in sections of rat pituitary gland. The results were discussed in relation to present knowledge of the origin and chemical nature of the hormones of the pituitary gland, with particular reference to the correlation between the stainable ‘neurosecretory’ material of the pars nervosa and the octapeptide antidiuretic-vasopressor hormone (ADH-vasopressin). It was further suggested that a similar examination of the neurohypophysis of the pig would be of interest since the ADH-vasopressin extracted from the posterior lobe of the pituitary of this animal contains lysine in place of arginine. Unfortunately, there does not appear to be a specific histochemical method for lysine; nevertheless, some information may be derived by applying the reaction for arginine, for if the stainable ‘neurosecretory’ material represents the hormones oxytocin and ADH-vasopressin, as postulated by the neurosecretory theory, then it might be expected to give no reaction for arginine in the case of the pig.