Separation of non-melatonin antiovulatory substances from bovine pineal powder by ultrafiltration

An attempt was made to partially separate substances which inhibit the induced ovulation by PMS and hCG in immature mice from the sodium borate buffer extract of bovine pineal powder by means of ultramembrane filtration. The antiovulatory activities were concentrated in fractions which possess materials of a molecular weight greater than 10,000 and also in fractions containing substances of a molecular weight less than 1000. The proteinaceous large inhibitor was thermostable while the small inhibitor, which is different from melatonin or arginine vasotocin, was inactivated by heating.