Taurine and other free amino acids in the retina, vitreous, lens, iris-ciliary body, and cornea of the rat eye.

Levels of free amino acids were determined quantitatively in whole ocular tissues of the rat eye with aid of a sensitive amino acid analyzer. The tissues studied were the retina, vitreous, lens, iris-ciliary body, and cornea. The retina and lens contained a more concentrated free amino acid pool than other tissues. The neuroactive amino acids taurine. GABA, glutamic acid, aspartic acid, and glycine were clearly enriched in the retina. Taurine was the most abundant amino acid in all five tissues studied, and its high concentration in non-neural tissues, especially the lens, suggests that it must have other functions as well as neurotransmitter ones in the rat eye.