Stimulated secretion of pro-opiomelanocortin-related peptides in hypothalamic cells

Although it has been suggested pro-opiomelanocortin (POMC) related peptides in brain may be neurotransmitters or neuromodulators, little is known about their secretion from neurons because it is difficult to study neurosecretion with an in vivo model. To demonstrate the possibility that POMC peptides may be neuroregulators which can be secreted in response to specific stimuli, we studied the secretion of immunoreactive (IR-) adrenocorticotropin (ACTH) and IR-beta-endorphin from dissociated hypothalamic cells during potassium-induced depolarization. Significant increments (p less than 0.025) in secretion of IR-ACTH (267%) and IR-beta-endorphin (88-172%) over basal secretion were stimulated by 60 mM KCl in the presence of calcium.

Stimulated secretion of POMC peptides from hypothalamic cells by potassium and calcium follows classical neurosecretory mechanisms and suggests these neuropeptides could be neuroregulators in brain.