The effects of hyperprolactinemia on the testis, epididymis and prostate are not fully understood. The aim of this study was to determine the influence of hyperprolactinemia induced with metoclopramide (MCP) on expression of the androgen receptor (AR) in the testis, epididymis and the lateral and dorsal lobes of the prostate in rats. Male, sexually mature, inbred Wistar rats were divided into two groups of ten rats each. Hyperprolactynemia was induced in the study group with metoclopramide intraperitoneally at 2.2 mg/kg b. w. for 14 days. Rats of the control group were given saline. Prolactin (PRL) levels in serum were measured with an enzyme immunoassay. Serum levels of testosterone (T) were measured with a radioimmunoassay. The testis, epididymis and lateral and dorsal lobes of the prostate were obtained for light and electron microscopy. The immunohistochemical reaction to AR was assessed by optical density measurements with a computer image analyzer. Ultrastructural studies of androgen receptor expressing cells were carried out with transmission and scanning electron microscopes.
Results: PRL concentrations in MCP rats were increased by more than twice, while T concentrations were reduced by half. The intensity of the immunohistochemical reaction to AR in the testis, epididymis and lateral and dorsal lobes of the prostate differed significantly in the study and control groups. Hyperprolactinemia produced structural changes in cells expressing the androgen receptor in the testis, epididymis and the lateral and dorsal lobes of prostate.