Cadmium-induced changes in luminal fluid pH in testis and epididymis of the rat in vivo.

The effects of a single low subcutaneous dose of cadmium chloride (CdCl2) (2.7 mg/kg body weight) on in situ pH in the rat testis and epididymis, plasma testosterone, and testis and epididymis weights were investigated in this study. Values for in situ pH in seminiferous tubules (6.97 +/- 0.01), proximal caput (6.62 +/- 0.01), middle caput (6.59 +/- 0.01), and proximal cauda epididymidis (6.84 +/- 0.01) of sham-treated rats were significantly more acid than systemic arterial blood pH (7.41 +/- 0.01). Cadmium (Cd) administration was associated with significant alkalinization of luminal fluid in seminiferous tubules (7.17 +/- 0.02) and in proximal (7.02 +/- 0.04) and middle caput (6.99 +/- 0.03), but not in proximal cauda epididymidis (6.88 +/- 0.02), after 1 d. Eleven days after Cd administration, marked alkalinization of luminal fluid was observed in all segments studied including proximal cauda epididymidis (7.21 +/- 0.02). Plasma testosterone concentration in sham-treated rats was 1.93 +/- 0.30 ng/ml and was reduced significantly after 1 d (0.56 +/- 0.06 ng/ml) and persisted after 11 d postexposure (0.57 +/- 0.07 ng/ml). Testis and epididymis weights were not altered 1 d after Cd exposure but were significantly reduced after 11 d. These studies suggest that the alkalization observed in luminal fluid of seminiferous tubules and epididymal duct of the rat after subcutaneous CdCl2 administration may be the result of structural degeneration of the testis associated with inhibition of Leydig-cell androgen production.