Title

Testicular and prostatic cyclic amp metabolism following chronic cadmium treatment and subsequent withdrawal

Document Type

Article

Department

Brain and Mind Institute

Abstract

Daily intraperitoneal injection of cadmium chloride (1 mg/kg) for 45 days decreased prostatic and testicular weights of mature male rats. In the prostate gland, chronic treatment with cadmium reduced cyclic AMP levels to 57% of normal values which appeared to be due to the decrease in adenyl cyclase activity since cyclic AMP metabolism by phosphodiesterase was not significant altered. Cyclic AMP binding to prostatic protein kinase was increased following cadmium administration, as was the activity of the cyclic AMP dependent form of protein kinase. In contrast to the prostate, testicular adenyl cyclase was stimulated by cadmium treatment. However, the endogenous cyclic AMP levels remained unaffected since the increase in testicular adenyl cyclase was offset by a concomitant increase in the activity of phosphodiesterase. Although the activities of the cyclic AMP dependent and the independent forms of testicular protein kinase were significantly depressed, the binding of cyclic AMP to protein kinase from testes of cadmium treated rats was not affected. Discontinuation of treatment for 28 days in rats that had previously been given the heavy metal for 45 days resulted in a reversal of several of the cadmium induced changes in cyclic AMP metabolism of the prostate gland. However, the weight of the prostate glands remained essentially in the same ranges as that seen in the 45 day 'treated group'. In the case of testes, cessation of cadmium treatment restored adenyl cyclase and protein kinase (the cyclic AMP dependent form) activities back to normal. However, endogenous cyclic AMP levels, the cyclic AMP binding capacity of protein kinase, as well as testicular phosphodiesterase and the cyclic AMP independent form of protein kinase were still significantly reduced in the 'withdrawal group'. ata suggest that cyclic AMP metabolism in both the primary and the secondary reproductive organs of the male rat is altered following chronic cadmium treatment and that the metabolic changes persist even 28 days following the termination of daily exposure to the heavy METAL.

Comments

This work was published before the author joined Aga Khan University.

Publication

Environmental Physiology & Biochemistry

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