Regional distribution of glutathione peroxidase and Glutathione-S-transferase in adult and premature human retinas.

The activities of glutathione peroxidase (GSH-Px) and glutathione-S-transferase (GSH-S-tase) were investigated in adult and premature human retinas. The measurements were done in the vascular and avascular regions of premature retinas at gestational age of 22-33 weeks and in the central, mid-peripheral, and far peripheral regions of mature retinas from the age of 1 month to 73 years. Among the premature infants, those who survived for greater than 24 hours were supplemented with alpha-tocopherol (vitamin E) on a periodic basis. The vascular and avascular regions of premature retinas had higher activities of GSH-Px when compared to the central and far peripheral regions of mature retinas. Infants surviving more than 24 hr had higher activities of GSH-S-tase in the avascular region than infants who survived less than 24 hr. Survival did not affect either enzyme activity in the vascular regions. Mature retinas showed a decrease in GSH-Px specific activity with age, but no age-related changes in GSH-S-tase were observed. These data demonstrate that premature infants are born with relatively high levels of GSH-Px and GSH-S-tase.