PHOSPHORUS METABOLISM OF THE ADRENAL GLAND EFFECT OF HYPOPHYSECTOMY AND ADMINISTRATION OF ACTH ON INCORPORATION OF P32 INTO INORGANIC PHOSPHATE

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Abstract
In confirmation of the work of others, the concn. of inorganic phosphate (P) in the plasma of hypophysectomized rats was less than that in the plasma of control animals. Hypophysectomy caused no significant change in concn. of inorganic P in adrenal gland or liver. A single intraperitoneal injn. of each of 2 prepns. of ACTH failed to cause significant change in concns. of inorganic P in plasma, adrenal, or liver. The specific activity of the inorganic P in the plasma of hypophysectomized rats after an intraperitoneal injn. of inorganic P labelled with p32 was greater than that in the control animals. Hypophysectomy caused a decrease in specific activity of inorganic P of the adrenal gland relative to that of inorganic P of the plasma. Each of the 2 prepns. of ACTH, given to the hypophysectomized animals as a single intraperitoneal injn. 20 hr. before killing, restored the relative specific activity of the inorganic P of the adrenals to normal values. When the ACTH was administered 6 hrs. before killing, one of the prepns. (ACTH A) caused an increase in the relative specific activity of the inorganic P of the adrenals, but a 2d prepn. (ACTH C) was without effect. The increase in specific activity of the inorganic P of the plasma comes on slowly (quite small 2 days after hypophysectomy), whereas the decrease in the relative specific activity of the inorganic P of the adrenal gland comes on rapidly (maximal 2 days after hypophysectomy). At longer time intervals after hypophysectomy (greater than 6 days) the absolute activity of acid-soluble P of the adrenal, i.e., activity not referred to that of the inorganic P of the plasma, was greater in hypophysectomized animals, and not less, as reported by other workers. The activity of this fraction is less in hypophysectomized animals only if the observations are made at short time intervals after pituitary removal. Evidence is presented for the view that increase in specific activity of the inorganic P of the plasma is the result of changes brought about by a deficiency of growth hormone, whereas decrease in the relative specific activity of the adrenal is due to a deficiency of ACTH.