Sensitivity of locally regenerated testicular vessels to cadmium

The conditions under which capillaries and venules within the testes of most scrotum-bearing mammals become sensitive and/or resistant to cadmium are not clearly elucidated. Localized heat lesions were produced within the testes of rats to allow regrowth from surrounding Cd-sensitive vessels into the damaged areas. After 2, 4, or 8 weeks rats were given a subcutaneous injection of CdCl2 in saline (5 mg/kg) and were sacrificed 6 h later. Tissue samples were examined by both light and electron microscopy. No evidence of Cd sensitivity in regenerated vessels was present after 2 weeks, but the surrounding normal tissue did show typical Cd-related damage. By 8 weeks, vessels within the lesioned areas responded to Cd in a manner similar to those in the surrounding tissue. Newly grown testicular vessels do not demonstrate Cd sensitivity, but they develop it between 4 and 8 weeks.