Abstract
Summary
High levels of adenine nucleotides are present in sperm taken from the caput segment of the guinea pig epididymis. This level declines progressively in the corpus and cauda segments where there is also a progressive increase in in vitro glycolysis. Nucleotide control of glycolysis is suggested by the observation that the depletion of nucleotide pools by incubation in the absence of substrate leads to increased glycolytic rates. This is particularly pronounced in caput sperm. Sperm motility in different segments, however, is not enhanced by lowering nucleotide levels in this manner.
Sperm motility and metabolism are markedly increased in all segments of the epididymis and vas deferens by caffeine and dibutyryl cyclic AMP. High rates of glycolysis in treated cells occur, however, without any significant differences from controls in energy charge and ATP levels, suggesting that the glycolytic apparatus as well as the mechanisms involved in motility are stimulated. Although metabolism in sperm from all segments increased about fourfold in treated cells, the glycolytic rate of sperm taken from segments increasingly distal to the caput segment shows the same pattern of increasing glycolytic capacity as observed in controls. This suggests that other mechanisms, in addition to changes in adenyl cyclase activity, are apparently involved in the changes in sperm metabolism that occur during epididymal transit.
The authors gratefully acknowledge the technical assistance of Miss Cecil Miller and Miss Ollie Brown.
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