Section of the pituitary stalk in the rhesus monkey: morphological and endocrine observations.

The effect of sectioning the pituitary stalk on the hypothalamic magnocellular system of the rhesus monkey was studied by specific immunocytochemical techniques. Regeneration of the proximal stump with reconstitution of a "new" neurohypophysis occurred as early as three weeks after operation, illustrating the remarkable regenerative ability of the system. The functional capacity of the newly formed neurovascular units was also tested, and the results indicate that they not only resume basal secretion of posterior pituitary hormones, but are also able to increase their output in response to a variety of challenges.