FIG. 2.

Leydig cell hyperplasia and reduced numbers of sperm in Ink4cd doubly deficient mice. Hematoxylin and eosin staining of sections of testes from 3-month-old (A) and 6-month-old (C) wild-type (WT) mice show normal seminiferous tubule architecture and interstitial Leydig cells. In the testes of 3-month-old (B) and 6-month-old (D) Ink4cd double-null males, Leydig cell hyperplasia is apparent. Although the 6-month-old wild-type epididymis (E) was replete with mature spermatozoa, the epididymis of the 6-month-old Ink4cd double-null mouse (F) had few mature spermatozoa. Magnification, ×200.