PROLACTIN GENE-EXPRESSION AND PROLACTIN PROTEIN IN PREMENOPAUSAL AND POSTMENOPAUSAL HUMAN OVARIES

Objective: To investigate intraovarian prolactin and prolactin-recepto r gene expression and to assess local prolactin synthesis with emphasi s on possible differences between premenopausal and postmenopausal sta tus. Design: The RNA extracted from human premenopausal and postmenopa usal tissues was subjected to reverse transcription and polymerase cha in reaction by using prolactin-specific intron- and exon-spanning prim ers. Prolactin-receptor expression was investigated accordingly. The a mplified complementary DNA fragments were analyzed by gel electrophore sis and restriction enzyme mapping. Local prolactin hormone synthesis was verified by a time-resolved immunofluorometric assay based on our monoclonal antibodies. Result(s): Prolactin and prolactin-receptor gen e expression was observed in all analyzed human ovaries (n = 18). Seve ral other human tissue specimens, such as lung and kidney, served as n egative control tissues. Significantly elevated concentrations of prol actin were detected in cytosolic extracts of premenopausal (n = 6; mea n +/- SD; 20.6 +/- 3.3 ng/g tissue wet weight) versus postmenopausal ( n = 6; 3.6 +/- 3.0 ng/g tissue wet weight) ovaries. Conclusion(s): The human ovary not only serves as a target for endocrine prolactin actio n but also as a site of local prolactin hormone production. In agreeme nt with previous reports on extrapituitary sources of prolactin, we co nsider prolactin as a hormone as well as an autocrine or paracrine gro wth or regulatory factor. Significantly increased concentrations of pr olactin in premenopausal ovarian tissue verifies its role in human rep roduction. (C) 1997 by American Society for Reproductive Medicine.