Endocrinology · 1969 · 53 citations · 0 references
Life SciencesEndocrinologyPhysiologyNeuroendocrinologySignal TransductionSteroid BiochemistryAdrenal HormonesHormone ReleaseHormone SecretionHypothalamic-pituitary RegulationNeuroendocrine PhysiologyPituitary HormonesAdrenal Steroid Secretion DynamicsAdrenocortical SecretionAdrenocorticotropic Hormone SecretionCell Membrane PhysiologyHormone Release KineticsHypothalamic Hormone SecretionHypothalamic-releasing HormonesReleasing Hormones
Adenohypophyses were incubated in Krebs-Ringer bicarbonate and the release of ACTH was measured under various conditions. A 5-fold increase in K+ augmented ACTH release. This augmented release was significantly greater from adenohypophyses of adrenalectomized rats than from those of intact animals and was prevented when Ca++ was removed from, or corticosterone was added to, the incubating medium. The increased release of ACTH in the high K+ medium and its prevention when Ca++ was removed were reversible and repeatable. These findings are consistent with the model of “excitation- secretion coupling” which has been proposed to describe the process of hormone release. These findings also suggest that corticosterone may operate directly on releasing mechanisms, possibly in the adenohypophysial cell membrane, to inhibit ACTH release. (Endocrinology85: 1144, 1969)