Influence of Amorphous Fraction from Adrenal Cortex on Efficiency of Muscle

An extract of the atlrenal cortex which is free from epinephrine and contains the physiologically active steroid derivatives characteristic of the adrenal cortex can he separated into a surprisillgly large number of crystalline compounds and an amorphous fraction. The crystalline compounds A, B, E, and F, which have an atom of oxygen attached to C₁₁, have a nlarked effect on the efficiency of muscle 1 and on carbhidrate metabolism 2 3 , hut relatively large amotmts are recluired to maintain renal function. When large amounts are administered to normal male rats these compounds produce atrophy of the adreiial and thymus glands. 4 , 5 Desoxycorticosterone, which is identical with compound B except that there is no atom of oxygen on C₁₁, has hut little effect on the efficiency of muscle and on carbohydrate metabolism, hut it is from 6 to 10 times more efficient than compound E when renal function is used as a criterion. The amorphous fraction has the greatest effect on renal function aid it protects the adrenalectomized animal against certain forms of stress such as a low environmental temperature, but even 40 times the amount of this fraction which is required to produce these effects does not cause atrophy of the thymus or adrenal glands. It has also heen shown that the amorphous fraction has very little effect on carhohydrate metabolism. 6 It became desirable, therefore, to determine whether this fraction could increase the eficiency of muscle to a degree comparable to compounds A, B, E, and F.

In the present report it will be shown that very small amounts of the amorphous fraction will protect the adrenalectomized rat against a loss in body weight, but that animals so treated are incapable of sustained work.