Immunocytochemical detection of luteinizing hormone in epididymis of mature mouse.

Luteinizing hormone (LH) binds to the Leydig cells of several mammalian species where it stimulates steroidogenesis, protein synthesis and protein phosphorylation. In the present study, standard immunoperoxidase (PAP) and avidin-biotin complex (ABC) techniques were used to detect the binding of endogenous and exogenous LH to the epididymis of the mature mouse. Throughout the epididymal duct, a positive reaction for peroxidase, indicating LH binding, occurred in the Golgi area of principal cells. In segment 1, positive reactions were also visualized in the perinuclear area and in the region located between the Golgi area and the apical surface of the principal cells (supra-Golgi area). In the corpus and cauda epididymidis, scattered entire principal cells were also positive. Throughout the epididymal duct, the reactions indicating the binding of exogenous LH were more intense than those of endogenous LH. The significance of LH binding to the epididymis is uncertain but LH may perform the same functions in epididymal principal cells as it does in Leydig cells.