Radioligand receptor assay for prolactin using chicken and turkey kidney membranes

1. A sensitive and specific radioreceptor assay for measuring prolactin in tissue extracts, culture media and serum has been developed utilizing membrane fractions prepared from either chicken or turkey kidney, and an ovine prolactin standard and tracer. 2. Assay sensitivity was 1.0 +/- 0.1 ng per tube, 50% inhibition of binding occurred with 12.8 +/- 1.2 ng of unlabeled ovine prolactin standard, and intra- and interassay coefficients of variation were 3.9% and 8.8%, respectively. 3. The 47,800 g kidney membrane preparation, which yielded maximum specific binding of 20-40%, offered advantages over current methods including use of an easily available and inexpensive tissue, no need for pretreatment of the donor animal, a high yield of receptor protein, and a simplified method of membrane preparation.