Effect of 9-Fluoroprednisolone Acetate and Transplanted Pituitaries on Milk Synthesis 1

Summary

A daily dose of 50 μg of 9-fluoroprednisolone acetate (Predef), from days 16 to 32 of lactation, retarded the normal decline in litter weight gain and maintained rat mammary gland DNA and RNA content. A delay in the onset of injections until day 24, or injections of 50 μg of Predef daily from days 16 to 23 and 100 μg of Predef daily from 24 to 32 days of lactation maintained litter weight gain and increased mammary gland nucleic acid content. Predef injections for 16 days increased the ability of in vitro liver preparations to metabolize cortisol into polar metabolites while formation of nonpolar metabolites was reduced. Chronic secretion of rat prolactin from five isotrans-planted pituitaries under the kidney capsule did not increase litter weight gain. However, marginal increases in mammary gland DNA and RNA content and RNA/DNA ratio were detected.