Effect of Heavy Administration of Viosterol on Metabolism of the Rat

Abstract

In a previous communication 1 it was shown that when large doses of irradiated ergosterol were administered to normal dogs there was a very great increase in metabolic rate. Since it appears that the rat is relatively insensitive to toxic effects of this substance, it seemed advisable to investigate its effect on the metabolism of the rat. Three rats of each sex were selected and trained for several months in a metabolism chamber. They were kept in separate cages and fed on the Wistar normal diet. The cages were kept in the same room where the apparatus was operated during a period of nearly 10 months, and the rats were handled only by the operator. It is believed, therefore, that extraneous factors were eliminated as completely as possible.

The apparatus used consisted of a closed circuit with a motor-driven hydraulic pump that delivered approximately 90 cc. of air each half minute. The respiration chamber consisted of a glass jar. Volume change was recorded on a kymograph by means of a writing needle attached to the bell of a small spirometer cut into the circuit. There was no new principle introduced into the arrangement.

The surface area was calculated by the formula derived by Lee, 2 S = KW^0–60 in which K = 12.54, W = weight in gm, and S = surface area in cm². It was mentioned in the earlier publication that one of the difficulties in calculating the surface area in the dog was the varying weight. Since the rat weight also varied it was thought necessary at first to use Lee's modification of Cowgill's formula, 3 S = KW^0–61 × but comparisons of surface area calculated by the 2 formulae on the same animal made it apparent that for purposes of comparison over a period of time there was not enough difference to justify the use of the more complicated formula.