Neurophysins

Neurophysins are carrier proteins which transport the hormones oxytocin and vasopressin to the posterior pituitary from the paraventricular and supraoptic nucleus of the hypothalamus, respectively.

[1] Stabilizing neurophysin-hormone complexes that are formed within neurosecretory granules located in the posterior pituitary gland aid in intra-axonal transport.

[2] During intra-axonal transport, the neurophysin's are believed to prevent the bound hormone from leaking into the cytoplasmic space and proteolytic digestion via enzymes.

The disulfide-rich neurophysin protein is suggested to be congruent with the synthesis of insulin in which a precursor molecule of higher molecular weight is proteolytically cleaved and forms disulfide linkages.

[2] Neurophysins are acidic proteins with a molecular weight of approximately 10,000 Da that are rich in cysteine, glycine, and proline residues .