Proteins in the uterine secretions of the cow.

Cows of normal reproductive history were treated with progesterone for periods of 2--3 months. The uterine secretions yielded 5 major fractions of macromolecular components. Two of the fractions comprised serum proteins. In the other 3 fractions at least 9 non-serum proteins were observed, 7 in one fraction, but in only small amounts. Of the remaining 2 non-serum proteins one is an acid phosphatase recoverable in small amounts, and the other is lactoferrin and is the major non-serum protein present in the uterine secretions of progesterone-treated cows.