The effects of interstitial cell-stimulating hormone, prolactin, and bovine growth hormone on the transplantable Leydig cell tumor in the mouse.

The effects of ovine interstitial cell-stimulating hormone (ICSH), ovine prolactin, or bovine growth hormone (BGH) on the growth and fine structure of transplantable Leydig cell tumors have been investigated. The Leydig cell tumor was capable of growth in the hypophysectomized mouse as well as in the intact mouse treated with rabbit antisera to ICSH. The ultrastructure of the Leydig cell was also greatly changed following the malignant transformation. Although the tumor Leydig cell shows growth in the absence of ICSH, daily administrations of 200 ßgICSH, 1 mg prolactin, or l mg BGH were all clearly effective, enhancing the tumor growth to 176, 179, and 185%, respectively, in comparison to those in the control. These hormones also exerted a significant effect on the growth of seminal vesicles. The agranular endoplasmi reticulum, which normally is abundant in the active Leydig cell, was sparse in the tumor cells growing in the intact mouse. ICSH treatment produced a significant increase in the agranular reticulum of the tumor cells, although similar morphological change was not observed following prolactin or BGH administration. There was an increase in intracellular ß-glycogenparticles following prolactin or BGH treatments, but not with ICSH treatment.