Müllerian-Inhibiting Activity of Calf Fetal Testes: Relationship to Testosterone and Protein Synthesis

Abstract

Müllerium-inhibiting activity was detected in incubation media of calf fetal testicular tissue. Dialysis of the medium did not modify its biological activity, but testosterone content of dialyzed medium was diminished by 92 percent. Four-fold concentration of incubation medium greatly enhanced its biological activity, which was destroyed by heat and blockage of sulphydryl groups by 0.5 M iodoacetic acid. Addition of cycloheximide to the medium during incubation decreased its biological activity, indicating that part of the activity is due to hormone newly synthesized during the incubation. These results prove that the anti-müllerian hormone is a macromolecule and suggest that it is probably a protein.