Prolactin concentrations in mouse milk during lactation

Summary Prolactin levels in mouse milk increased from the day of parturition to give a concentration of 230 ng/ml on days 2 and 3 of lactation. Thereafter, levels dropped to 140 ng/ml by day 6 and were maintained at this concentration until weaning.Acknowledgments. Mouse PRL and its antiserum was the generous gift of Y.N. Sinha (Scripps Clinic and Research Foundation, La Jolla, California). J.M.B. was in receipt of a Liverpool University Studentship.