Transplantable Leydig Cell Tumors in Fischer Rats: Hormone Responsivity and Hormone Production

Summary

Spontaneous testicular interstitial (Leydig) cell tumors arising in our colony of inbred Fischer rats proved to be readily transplantable. The hormone production and hormone responsivity of 8 of these Leydig cell tumors are reported. The tumors showed a wide range of morphologic and functional characteristics. All produced some androgen and/or estrogen. Some grew only in castrate recipients while others grew in intact and hypophysectomized hosts. Hormone production continued in one tumor when growing in hypophysectomized hosts. Hormone production, hormone responsivity, and the morphologic appearance of the tumors appear to be characteristics manifested independently of each other. The similarity of these tumors to estrogen-induced tumors of the mouse is discussed.