Experimental Studies on the Insulin-requirement of Alloxan-Diabetic Rabbit and the Effect of Pituitary & Adrenal Cortical Hormones on this Requirement

Abstract

The effects of pituitary and adrenal cortical hormones on the metabolism of carbohydrate have been discussed by many workers. As to the actions of these hormones on carbohydrate metabolism, one claimed as related to insulin effect, while the other proved it as contra-insulin.An attemt has been undertaken by the present author to solve this problem from the standpoint of what effects these hormones will have on the metabolism of carbohydrate when injected into rabbits treated with insulin on one hand and without insulin on the other. And in order to solve this controversial problem clearly, the author developed this experimental study as follows:a) Determination of the insulin-requirement in alloxan rabbits.b) Estimation of effects of these hormones on the fasting blood sugar levels and on the output of urine sugar in alloxan rabbits.c) Estimation of effects of these hormones on insulin requirement in alloxan rabbits treated with insulin.The results obtained are summarized as follows:1. In estimating insulin-glucose equivalent of alloxan diabetic animals, it is found that insulin-glucose equivalent for one unit of insulin is 1.10 gm.2. The action of insulin on fasting blood sugar is not so direct as on urinary sugar, but in alloxan diabetic rabbit one unit of insulin has brought about an average lowering of 23mg.% in the early morning specimen of blood sugar.3. In order to examine the influence of continued parenteral administration of these hormones of pituitary-adrenal system upon the output of urinary sugar in experimental rabbits, a fixed dosage of administration was given three times a day.It is found that the quantity of urinary sugar has increased with the use of cortisone and adrenocorticotropic hormone (ACTH), but with desoxycorticosterone acetate (DOCA), there is a decrease. To convert this increased or decreased urinary sugar into insulin-glucose equivalent of alloxan diabetic rabbit, the increase in insulin requirement for cortisone is 3.2 units a day, 2.7 units for ACTH and 0.4 unit for DOCA which is much lower in insulin requirement.4. The influence of continued administration of pituitary adrenal hormone on fasting blood sugar in these experimental animals has revealed the fact that there are an average increase of 13 mg.% with cortisone and 38mg.% with ACTH respectively, but with DOCA there is a decrease of 36mg. percent.5. When these hormones are given to insulin treated alloxan rabbits the output of urinary sugar increases in cortisone and ACTH but decreases in DOCA. To convert it into daily insulin requirement of experimental rabbits the dosage increased is 3.16 units for cortisone and 2.87 for ACTH, and for DOCA the decrease is 0.65 unit.6. When observing the effect of pituitary adrenal hormone on insulin requirement or that of insulin on the sugar metabolism control of alloxan diabetic rabbit it can positively be demonstrated that either cortisone or ACTH has contra-insulin while DOCA has insulin effect.