New RIA kit for the determination of progesterone in cows' milk

A new, single-step, specific, simple, economical, and ready to use RIA test for the determination of progesterone in cow's milk was developed. Tubes coated with the specific polyclonal anti-progesterone antibody and progesterone-CMO-I-125-histamine as the tracer were used. Progesterone in buffer and fat-free cow's milk, without progesterone were the matrix for the standard curve preparation. Fifty mu L of milk and 500 mu L of tracer were incubated in the tube for 2 h at room temperature, decanted, and coated. Assay range was 0-270 nmol of progesterone (.) l(-1); sensitivity, < 1 nmol (.) l(-1); recovery, 94-104%; precision as CV%, 2.44-6%.