A Sensitive Bioassay for Prolactin Based on H 3 -Methyl-Thymidine Uptake by the Pigeon-Crop Mucous Epithelium

Summary

A simple, sensitive, and entirely objective bioassay for prolactin is described, using H³-thymidine uptake by the pigeon crop-epithelial tissue only. Doses as low as 1-100 mU of highly purified ovine prolactin (NIH-P-S-7, 24.3 IU/mg), dissolved in 0.5% agar solution and intradermally injected as a gel over one side of the pigeon crop resulted in highly significant increase in H³-thymidine uptake ranging between 59% and 905% as compared to the control sides. A good dose response curve was established. The sensitivity and the objectivity of the method are discussed.