Implications of prolactin abnormalities on the male reproductive tract and male factor infertility

Abstract

INTRODUCTION: A significant proportion of male population suffer from Male Factor Infertility (MFI) due to prolactin abnormalities. OBJECTIVE: To establish the role of prolactin on the male reproductive system. METHODOLOGY: A case control study was carried out to determine the effects of prolactin abnormalities in otherwise normal 297 males with infertility after obtaining an informed written consent. Each of the participants was subjected to a Basic Seminal Fluid Analysis(BSA) and an endocrine profile (Follicular Stimulating Hormone, Luteinizing Hormone, Testosterone and Prolactin levels). An age, Sex, height and weight matched voluntary control group was recruited for comparison. None of the cases had any medical or surgical disorder or occupational hazardous exposure which related to infertility. RESULTS: Among the controls mean age 33.2 years+/-5.2, body mass index 21.4+/- 1.39Kgm-2, sperm count 34 x 106, number of children fathered 2+/-1, Serum prolactin level 6.78+/- 2.92mg/ml. Of the case group 28/297 were hyperprolactinemic while 1/297 was hypoprolactinaemia. All the hyperprolactinemic patients had oligospermia, abnormal morphology of sperms, with reduced viability of the sperms. 26/28 Subjects with hyperprolactinaemia had markedly low testosterone levels. The only subject with hypoprolactinaemia had normal testosterone levels. FSH and LH levels were normal in all the participants. 29 subjects with abnormal prolactin levels were followed up for 12 months. 28 patients with hyperprolactinaemia were given oral bromocriptine (2.5mg twice daily). The response with bromocriptine was assessed with repeated Basic Semen Analysis. After 3 months of therapy 19/29 cases showed an improved response to the drug while 4/28 responded after 6 months of treatment. 1/28 took 1 year to show a response. 2 of the cases showed some improvement which fell short of normal BSA parameters. CONCLUSIONS: Prolactin abnormalities affects male reproductive system and semen parameters. Further studies should be carried out to find the exact mechanism of prolactin on the male reproductive system.