Release of alpha-MSH from the in vitro superfused neuro-intermediate lobe of the pituitary of the rat by antidiuretic hormone.

The effect of antidiuretic hormone (ADH) on the release of immunoreactive alpha-melanocyte stimulating hormone (alpha-MSH) from the superfused neurointermediate lobe of the pituitary of the normal Wistar and Brattleboro (diabetes insipidus) rat was studied in vitro. In control experiments, there was usually an initial peak, after which alpha-MSH release fell exponentially over the course of the perfusion. Following the addition of ADH, the levels of alpha-MSH in the superfusate showed a significant rise. It is suggested that ADH is normally involved in the secretion of alpha-MSH by the pars intermedia of the rat, especially in response to osmotic stimuli.