Lactate dehydrogenase isozymes of chick embryo: response to variations of ambient oxygen tension.

Incubation of chick embryos in an hypoxic environment causes an ncrease in the proportion of tissue lactate dehydrogenase (LDH) made up of subunit M, whereas incubation in aerobic conditions decreases the proportional amount of subunit M. The variation of ambient oxygen tension does not change the total LDH activity. These results support the hypothesis that oxygen or oxidative metabolites have an effect on the synthesis of the subunit peptides.