Sex and Organ Specificity in the Response of β-Glucuronidase to Extrinsic Agents

Abstract

IT was considered that the correlation shown to exist between the β-glucuronidase activity of a tissue and the amount of cell proliferation in progress¹ could explain the rise in uterine glucuronidase found by Fishman and Fishman² to follow æstrogen administration to ovariectomized mice. In a preliminary kinetic study of the enzyme in mouse uterus, the pH-activity curve for the hydrolysis of phenol β-d-glucuronide was found to be almost symmetrical about pH 4·5. This is in contrast to the curves previously found for liver and spleen glucuronidase in the normal mouse³, With peaks at pH. 5·2 as well as at 4·5. Mills⁴ has shown that beef spleen glucuronidase can be separated into two fractions, A and B, with slightly different pH. optima for the hydrolysis of menthol glucuronide. Since it seemed probable that mouse uterus lacked a glucuronidase fraction present in liver and spleen, it was considered necessary to investigate the possibility that differences between A and B in distribution and response to extrinsic agents might in some way explain the selective actions of such substances as carbon tetrachloride and æstrone on liver and uterine tissue respectively.