Chicken eggshell porphyrins and the glyoxalase pathway: its possible physiological role.

1. The plasma 4,5-dioxovaleric acid (DOVA) levels of two different breeds of chicken were determined and found to be higher in the group with a higher porphyrin eggshell content. 2. The erythrocyte and uterus glyoxalase II activity, investigated by means of a new spectrophotometric method, was found to be significantly higher in the group with a low porphyrin eggshell content. 3. A comparative genetic study of two chicken populations, one with white and one with dark eggshells, showed different gene frequencies for the glyoxalase I polymorphism. 4. An interpretation of these data suggests that the glyoxalase pathway may be involved in the metabolism of early porphyrin precursors.