Endocrine Influences on Rat Ovarian Proteinase Activity

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Abstract
Lyophilized ovaries collected from intact rats were shown to possess proteolytic activity in both acid and alkaline pH ranges, with apparent optima at about pH 4 and 8. Administration of ovine FSH (folliclestimulating hormone) and HCG (human chorionic gonadotropin) resulted in a decrease in the level of proteolytic activity at pH's more acid than pH 5, and an increased level of proteolytic activity at pH's alkaline to pH 5, with a maximum increase around pH 8. Treatment of intact rats with partially purified ovine FSH alone, as well as with partially purified ovine TSH (thyroid-stimulating hormone) or partially purified ovine LH (luteinizing hormone), resulted in increased levels of activity of the pH 8 enzyme. HCG alone does not produce this effect. Hypophysectomy is followed by a decrease in the level of the pH 8 enzyme, with no change being observed in the level of the pH 4 enzyme. The activity of the pH 8 proteinase can be increased to levels above those in intact controls by treatment with partially purified ovine FSH, either by itself or with HCG. Purified bovine growth hormone also exerts a stimulatory effect, whereas HCG alone does not. Partially purified ovine LH and TSH have slight stimulatory effects on the pH 8 ovarian proteinase. The pH 8 active enzyme is not inhibited significantly by EDTA (ethylenediaminetetraacetate), KCN or cysteine at 10−2m, but is decreased about 50% by 10−4m parahydroxy mercuribenzo ate.