Studies on Müllerian Inhibitors in Rats and Pigs by Semiquantitative Bioassay

In the first half of this study, attempts have been made to establish a new score which was designated Mullerian-Inhibition Score (M.I. Score) in order to represent quantitatively the grades of regression of the Mullerian duct. The Mullerian-Inhibiting activities expressed as M.I. Score were analyzed in the testes of fetal rats and in those of fetal and adult pigs by means of organ culture, in which they were cultured for 3 days in close proximity to the primitive Mullerian duct from female rat fetuses. It was revealed that the fetal testes had significantly high M.I. Score. In the latter half of the study, isolation of Mullerian Inhibitor of fetal pig testes was attempted. They were incubated in Eagle's minimum essential medium. The medium was collected, concentrated using a collodion bag and fractionated on a Sephadex G-200 column. The fractions with molecular weight in the range between 190,000 and 280,000 had specifically high M.I. Score.