Distributions of the activities of aspartate aminotransferase isoenzymes in rat retinal layers.

Distributions of the activities of the cytosolic (cAAT) and mitochondrial (mAAT) isoenzymes of aspartate aminotransferase were determined in rat retinal layers. cAAT was highest in the photoreceptor inner segments, inner nuclear layer and inner plexiform layer; mAAT was highest in the inner segments. The high activity in the inner segments indicates that both isoenzymes are involved in energy metabolism in addition to a possible role in neurotransmission.