In adult rats, reducing Leydig cell function by inhibition of gonadotropin secretion with T-implants led to a decrease in resident testicular macrophages 3 wk later, similar to the decline observed at the same time point after ablation of the Leydig cells with EDS, providing further confirmation of the importance of functional Leydig cells for maintaining normal resident testicular macrophage numbers. The decline in macrophage numbers was observed even when seminiferous tubule function was preserved by the use of high-dose T-implants, while disruption of seminiferous tubule function through depletion of the spermato-genic cells by experimental bilateral cryptorchidism had no influence on testicular macrophage numbers or subsets. buy ortho tri-cyclen online
Altogether, these data indicate that maintenance of macrophage numbers by the Leydig cells is not mediated via the seminiferous epithelium, and most likely involves a direct mechanism. However, neither testosterone nor MIF, a cytokine recently found to be produced by the Leydig cell, appeared to be primarily responsible for maintaining resident macrophage numbers. These data also indicate that resident macrophage numbers in the rat testis are not affected by raising the temperature of the testis to normal body temperature or large experimentally induced changes in testicular and/or interstitial tissue volume.