Biology of Reproduction, Vol 10, 69-73, Copyright © 1974 by Society for the Study of Reproduction

Pyruvate Dehydrogenase Activity in the Normal and Cryptorchid Rat Testis

¹ Biology Department, Battelle, Pacific Northwest Laboratories, Richland, Washington 99352
² Department of Biological Science, California State University, Hayward, California 94542

Studies were carried out to determine the active and total levels of pyruvate dehydrogenase (PDH) in normal rat testis tissue homogenates and PDH activity in 2-, 4-, and 8-h and 14-, 16-, and 120-day sham-operated and cryptorchid rat testis homogenates. It was confirmed that the inactive-active interconversion of PDH does take place in rat testicular homogenates, that 7 mM Mg²⁺ was sufficient for maximal activation of the inactive form, and that approximately 40% of total PDH was in the active form. PDH activity increased by 50% 4 h after abdominal translocation of the testes compared with zero time or sham-operated controls (P < 0.001). By 8 h, PDH activity was 30% lower than controls (P < 0.01). Longer term translocation resulted in 70, 60, and 60% reductions in PDH activity at 14, 16, and 120 days, respectively.