Lactate and pyruvate utilization by the spermatozoa of infertile human males.
In studying the metabolic pathway of lactate and pyruvate in human spermatozoa from fertile and infertile subjects, pyruvate 1-C14 and lactate 1-C14 were used as substrates in a radiorespirometry system. Spermatozoa from patients with 20 +/- 2.0/10(6) spz/ml and decreased motility (group B) showed a more active decarboxylation of both pyruvate 1-C14 and lactate 1-C14 with a higher production of lactate C14, oxaloacetate, citrate, and isocitrate than those from fertile normal subjects (group A). Spermatozoa from fertile patients with normal counts but low motility (35 +/- 2.0% +++ motility) showed a similar rate of decarboxtlation of pyruvate 1-C14 but a greater rate of decarboxylation of lactate 1-C14 than those from fertile subjects. The low utilization of pyruvate by the spermatozoa from group C infertile patients, with intermediate counts and motility could be explained by a metabolic failure similar to that produced by some inhibitors of the respiratory chain. We do not have an explanation for the metabolic behavior observed in spermatozoa from group B patients, and further research on this point is desirable.
Lactate and pyruvate utilization by the spermatozoa of infertile human males. In studying the metabolic pathway of lactate and pyruvate in human spermatozoa from fertile and infertile subjects, pyruvate 1-C14 and lactate 1-C14 were used as substrates in a radiorespirometry system. Spermatozoa from patients with 20 +/- 2.0/10(6) spz/ml and decreased motility (group B) showed a more active decarboxylation of both pyruvate 1-C14 and lactate 1-C14 with a higher production of lactate C14, oxaloacetate, citrate, and isocitrate than those from fertile normal subjects (group A). Spermatozoa from fertile patients with normal counts but low motility (35 +/- 2.0% +++ motility) showed a similar rate of decarboxtlation of pyruvate 1-C14 but a greater rate of decarboxylation of lactate 1-C14 than those from fertile subjects. The low utilization of pyruvate by the spermatozoa from group C infertile patients, with intermediate counts and motility could be explained by a metabolic failure similar to that produced by some inhibitors of the respiratory chain. We do not have an explanation for the metabolic behavior observed in spermatozoa from group B patients, and further research on this point is desirable.