Effects of Anterior Pituitary and Adrenal Cortical Extracts on Metabolism of Adrenalectomized Rats Fed Glucose

Abstract

Whole anterior pituitary extracts given to normal rats fed glucose prevent the usual elevation of R.Q. and increase deposition of muscle glycogen. 1 , 2

Adrenal cortical extracts, 3 corticosterone, and certain adrenotropic anterior pituitary extracts have now also been shown to diminish the rise in R.O. and to promote glycogen deposition. These findings suggested that part or all of the action of the anterior pituitary extract in fed animals might be mediated through the adrenal cortex. A study has therefore been made of the relative effects of anterior pituitary extract and of adrenal cortical extract (CE) on the disposition of fed glucose in the absence of the adrenal glands.

The experiments were carried out as described previously: 2 young male rats were fasted 18 hours, then fed known amounts of glucose, the respiratory data was obtained during the 4-hour period after feeding, and terminal analyses were made of liver and muscle glycogen, blood glucose and glucose remaining in the gastro-intestinal tracts. Recovery and oxidation of the fed glucose are presented here, calculated as percent of the absorbed amounts. The figures are averages of 9 or 10 experiments in each group.

The rats were adrenalectomized from 3 to 20 days before the experiments and were maintained in good condition in the interim by the administration of saline drinking water. All carbohydrate levels were low in the fasted adrenalectomized rats; the muscle glycogen values, however, were still much above those of fasted hypophysectomized rats. The glucose absorption rates under these conditions were also reduced moderately, but again not to the same extent as in hypophysectomized rats.

The extracts used in these experiments were a 2% saline extract of beef anterior lobes clarified by Sharples centrifugation, and Upjohn's cortical extract from which the alcohol had been removed by vacuum distillation.