Treatment with hCG increases the size of Leydig cells and testicular macrophages in unilaterally cryptorchid rats.

Adult, unilaterally cryptorchid rats were treated with a single injection of 200 i.u. human chorionic gonadotrophin (hCG). The morphological response of Leydig cells and testicular macrophages at 24 and 72 h after treatment was quantified using morphometry. Treatment with hCG induced an increase in the volume density of Leydig cells and macrophages, as well as in the average cell profile area of individual Leydig cells and macrophages in both scrotal and abdominal testes. However, the relative response was considerably larger in abdominal than in scrotal testes, and there was a strong positive correlation between the response of Leydig cells and macrophages. It is suggested that hCG, probably via effects on Leydig cells, also influences the function of testicular macrophages.