Influence of Temperature on Lactate Utilization by Round Spermatids from Rat Testes. (Temperature/lactate/spermatids/rat/oxidative phosphorylation)

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Abstract
Rotenone-sensitive 14CO2 formation from [14C]lactate and O2 consumption by round spermatids were greater at elevated temperatures than at 34.degree. C. More than 96% of the total radioactivity of the metabolized [14C]lactate was recovered in the released CO2 and the acid soluble fraction of the cells. There was practically no incorporation of [14C]lactate into the lipid, nucleic acid and protein fractions. Intracellular level of ATP in spermatids was enhanced in the presence of lactate (20 mM) at 34.degree. C (scrotal temperature), while it was decreased at 37.degree. C (body temperature). This was reversible when the cells were transferred from the elevated temperature to 34.degree. C. O2 consumption and CO2 production were increased at 34.degree. C by 2,4-dinitrophenol (DNP), but decreased by oligomycin. Oligomycin and DNP had no effect on O2 consumption and 14CO2 formation at the elevated temperature. Lactate utilization by spermatids is coupled with oxidative phosphorylation at scrotal temperature, but becomes uncoupled at elevated temperature, although more lactate is consumed.