THE BIOASSAY OF PROGESTERONE1

Abstract

The uterine mucosa of 14 control and 49 progesterone-treated immature, estrogen-primed rabbits were analyzed for carbonic anhydrase content and degree of progestational proliferation (G/M ratio). Significant log dose:response relationships of similar degrees of accuracy were obtained with either measurement, but over the range 0-4 mg for carbonic anhydrase and over the range 0-2 mg for the G/M ratio. The increase in mucosal carbonic anhydrase during progesterone administration was not accompanied by any increase in blood carbonic anhydrase. A comparative assay of [DELTA]4-pregnenolone, using progesterone as a standard, indicated a potency ratio to the standard of 1.18 by the carbonic anhydrase method and of 1.16 by the G/M ratio method, suggest-ing the usefulness of the carbonic anhydrase method as a standard assay procedure.