EFFECT OF CHORIONIC-GONADOTROPIN AND FLUTAMIDE ON LEYDIG-CELL AND MACROPHAGE POPULATIONS IN THE TESTOSTERONE-ESTRADIOL-IMPLANTED ADULT-RAT

The objective of this study was to investigate the role of androgens a nd nonandrogenic Leydig cell products in maintaining Leydig cell and m acrophage numbers in the testis of the adult rat. Adult male Sprague-D awley rats received Silastic implants containing testosterone and estr adiol (T-E) in order to suppress endogenous luteinizing hormone (LH) f or 9 weeks. After T-E treatment, Leydig cell and macrophage numbers, q uantified using the optical disector approach, were reduced by 40 and 60%, respectively, compared with controls. Administration of human cho rionic gonadotropin (hCG) for a period of 10 days restored Leydig cell numbers to control levels, and macrophage numbers were partially rest ored. Administration of the antiandrogen, flutamide, in combination wi th hCG treatment in T-E implanted animals prevented the restoration of Leydig cell numbers but did not prevent the recovery of macrophage nu mbers, in the T-E-implanted animals, there was a decrease in testicula r macrophage nuclear size, which was not restored by either hCG or hCG plus flutamide treatment. The results of this study support the hypot hesis that LH is the main pituitary regulator of both Leydig cell and macrophage number in the adult rat testis and further indicate that an drogens are responsible for maintaining Leydig cell numbers and/or dif ferentiation, but nonandrogenic Leydig cell factors are primarily resp onsible for controlling macrophage numbers. Testicular macrophage func tion, as indicated by nuclear size, does not appear to be influenced b y LH or testosterone in the adult rat.