Further studies on gonadotropin-inhibiting substances excreted in human urine

Partial separtion of human urinary substances which have properties to suppress the ovulation induced by PMS and HCG in mice was attempted by gel filtration on Sephadex G-100 and ultrafiltration using the Amicon Diaflo membranes UM-2 and UM-10. In addition to a thermostable inhibitor which has a molecular weight more than 10,000, the presence of heat-labile inhibitor with a molecular weight less than 1,000 was newly demonstrated.