Spinal cord and ACTH release in adrenalectomized rats following electrical stimulation.

Rapid ACTH release following stimulation of an extremity has been proposed to occur by mediation through vascular and neural paths. The vascular paths presumably involve release of substances into the blood at the site of stimulation which subsequently release ACTH from the pituitary. Blood ACTH levels in adrenalectomized rats were measured by the adrenal ascorbic acid method in hypophysectomized rats. The contribution of the vascular path to the mediation of ACTH release was estimated by assaying aortic blood for ACTH content after electrical stimulation of the hindlegs of 3-hour and 48-hour cord-sectioned rats. No response to the flow of electric current through the hindlegs was observed. It was concluded that no contribution to ACTH release was rendered by the vascular path. In contrast electrical stimulation of the intact neural paths in the forelegs of cord-sectioned rats resulted in ACTH release equivalent to that observed in intact cord rats. This indicated that absence of ACTH release in response ...