Carbohydrate metabolism of the lens depending on age

Abstract

For investigations on age-dependent changes of lens metabolism, longitudinal studies are requisite. Graphic representation of such findings should be based on a proper arithmetic age scale. Using the lens weight for representing the age leads to distortion of the curves, whereby certain periods of life are liable to be overemphasized. In longitudinal studies, data on concentrations should never be given per unit weight, but rather for the whole lens. Absolute values of the whole, intact lens may be referred to a reference value, a percental representation of the curves is possible. With regard to the expectancy of life of test animals one may already state that longitudinal studies including the senile phase will only be feasible with rats.

Oxidative Denaturation of Lens Protein: Prevention by Pyruvate

“…Since pyruvate is a normal tissue metabo lite capable of exerting an antioxidant effect, the findings are also in accord with the con cept that adequate activity of lens metabolism is crucial for the maintenance of lens trans parency [15][16][17][18]. Although the variation in the concentration of pyruvate in lens as a function of age is not known at present, it is highly probable that it decreases due to the age-related decline in the tissue glycosis.…”

“…Although the variation in the concentration of pyruvate in lens as a function of age is not known at present, it is highly probable that it decreases due to the age-related decline in the tissue glycosis. This is evident by the slow glycolysis [ 15] and high er concentration of hexose monophosphates in the older lenses [17,18], indicating a block in their further metabolism towards the trioses. The functional significance of accu mulation of hexose phosphate is also reflected by a corresponding decrease in the lactate content.…”