Urinary Gonadotrophin (ICSH)-Inhibiting Substance During the Normal Menstrual Cycle

Abstract

In 72-hr pooled urine specimens from 4 normal menstruating women, varying “gonadotrophin inhibitor” activity was found throughout the cycle, with the exception of days 7–9 when significant reduction in urinary inhibitor activity was observed. The possible relationship between this reduction in inhibitor and the mid-cycle rise in ICSH is discussed.