The effects of age on glutathione peroxidase and glutathione reductase activities in lenses of Old World simians and prosimians.

The effects of age on the activities of the two enzymes of the glutathione redox cycle, glutathione peroxidase and glutathione reductase, were studied in lenses of primates. Three species were Old World simians (orangutan, olive baboon and pigtail monkey) and two were prosimians (galago and mouse lemur). Glutathione peroxidase activity of the olive baboon lens increased steadily with age while that of the pigtail monkey increased during the first 6-8 years and then plateaued. Enzyme activity in the orangutan increased steadily from 9 months to 28 years. This enzyme activity decreased steadily in the galago but increased only slightly in the mouse lemur lens. The lenticular glutathione reductase activity profiles showed decreases with age for all three simian species. Enzyme activity in the galago decreased gradually from birth to the age of 16.5 years. The enzyme activity values of the mouse lemur lens did not yield a comprehensible pattern. Lens weight increased with age in all five primate species, particularly in the infant and juvenile years and leveled off in adulthood. The current investigation demonstrated that the responses of these enzyme activities to aging were very different in Old World simians as compared to prosimians. These studies are consistent with earlier enzyme activity and thermolability data and are indicative of probable critical differences in the primary structures of the enzymes between the two primate groups.