THE FUNCTIONAL RELATIONSHIP BETWEEN THE HYPOTHALAMUS AND THE ANTERIOR PITUITARY-ADRENAL SYSTEM

Abstract

1) Stimulation of the posterior part of the hypothalamus caused increase of Ch. C. content in the adrenal vein blood and decrease of sudanophile substance in the adrenal cortex. In hypophysectomized cat, these changes were not obtained.2) Catechol content in the adrenal vein blood was remarkably increased by stimulation of the middle part of the hypothalamus in most cases.3) On the influence of the hypothalamic stimulation upon the potassium content in the blood serum, from the anterior and middle parts of the hypothalamus, remarkable increase was obtained, and from the posterior part the tendency to decrease was generally observed. In hypophysectomized or adrenalectomized rabbits, the response from the posterior part reversed, namely potassium content markedly increased.4) Direct electrical stimulation of the anterior pituitary gland did not cause increase of Ch. C. content in the adrenal vein blood. Local application of minimal doses of acetylcholine (0.15mg.) into the anterior pituitary gland caused the increase of Ch. C. content and decrease of potassium content, but the application of adrenaline (10γ) did not cause the change.From the above results it may be considered that acetylcholine-like substance liberated at nerve ending by excitation of nerve cells in the posterior part of the hypothalamus reaches the anterior pituitary cells as a neuro-chemical transmitter via the portal vessels and causes increase of secretion of ACTH, and consequentely increace of Ch. C. content in the adrenal vein blood and decrease of serum potassium content occurs.