Energy Metabolism of Spermatozoa During Pronucleus Formation Induced in vitro by Heparin-Reduced Glutathione. I. Glucose Uptake

Abstract

Glycolitic metabolism under basal conditions and its modifications by the combined action of heparin and GSH were studied in human sperm. Respirometric data indicated that the amount of U. L. [¹⁴C]-glucose converted to CO₂ increased with the incubation time, being almost linear for up to 60 min and then leveling off at 120 and 150 min (594 and 620 nmol of [¹⁴C]-glucose/10⁸ spermatozoa, respectively). When spermatozoa were incubated in the presence of heparin-GSH such behavior completely changed, showing a decrease (-50%) in glucose metabolism with values of 254 and 366 nmol of [¹⁴C]-glucose/10 spermatozoa at the same incubation times as the basal consumption. When these results were compared with the kinetic of the swollen nuclei it was seen that at 30 min 44% of the spermatozoa have its nuclei swollen with a glucose uptake value of 91 nmol/10⁸ spermatozoa, and at 150 min when nearly all the spermatozoa nuclei are swollen (95%) the glucose uptake increases fourfold more than the initial rate at 30 min. Therefore, it is possible to suggest the existence of an energy contribution by the sperm to the male pronuclei formation mechanism.

Key Words:

• Glycosaminoglycans
• Glucose uptake
• Pronuclei formation
• Glucose uptake
• Reduced glutathione
• Heparin