Reproductive inhibition and serum prolactin concentrations in laboratory populations of the prairie deermouse

Radioimmunoassay (RIA) of prolactin in the prairie deermouse was established and validated. Serum samples were taken from reproductively inhibited animals grown in experimental populations and compared with reproductively capable control animals of both sexes. At the time of assay, serum prolactin concentrations was unaffected by the length of time a control female was exposed to the olfactory stimulation of bedding soiled by her mate or the stage of the estrous cycle as indicated by vaginal cytology. The reproductively inhibited males and females had significantly reduced reproductive organ weights, body weights, and serum prolactin concentrations compared with their respective controls. Also, the relative mean adenohypophysial weight was greater in the inhibited males. Several significant correlations between prolactin and various gravimetric measures are reported for both males and females. Possible relationships between prolactin and other endocrine systems are discussed.