A major component of neurohypophysial tissue associated with antidiuretic activity

Synthesis, transport, and release of posterior pituitary hormones

Vasopressin and oxytocin are made and released by neurons of the hypothalamo-neurohypophysial system. Pulse labeling these neurons with radioactive amino acid indicates that the two hormones and their respective neurophysin carrier proteins are synthesized as parts of separate precursor proteins. The precursors seem to be processed into smaller, biologically active molecules while they are being transported along the axon.

Histochemical and immunohistochemical properties of the CRF-granules and other "Gomori-positive" substances of the rat

In adrenalectomized rats, histochemical and immunohistochemical properties of the following secretion products have been investigated: 1. CRF-granules in the outer layer of the median eminence; 2. neurosecretory material (NSM) in the supraoptico-hypophysial system of the hypothalamus; 3. secretory granules in the TSH-cells of the anterior lobe of the hypophysis; 4. secretory granules in the ependymal cells of the subcommissural organ (SCO); 5. beta-cell-granules in the islets of Langerhans in the pancreas. All these substances are characterized by their stainability with the so-called "Gomori method". The experiments have included studies into: a) the extractability of the substances by various solvents; b) the digestability of the substances by pepsin or trypsin; c) their histochemically detectable content of disulfide groups, arginine and periodic acid-Schiff (PAS) reactive carbohydrates; d) their reaction with porcine-neurophysin-II-antibodies. All substances exhibited a positive reaction for disulfide groups. Based on their solubility properties, their resistance to pepsin or trypsin, their respective content of PAS-reactive carbohydrates and their failure to react with anti-neurophysin serum the "Gomori-positive" granules in TSH-, SCO- and pancreatic beta-cells can be distinguished from one another and from CRF- and neurosecretory granules. In contrast, CRF-granules and NSM showed identical properties. Taking into consideration data from the biochemical and histochemical literature, the present findings suggest that CRF-granules and NSM consist of closely related biochemical substances.