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Abstract
The transport of amino acids into the posterior and anterior chambers and lenses of rabbits which have alloxan diabetes tuas studied by measuring the rates of accumulation of nonmetabolized amino acids, cycloleucine, ami α-AIB, and by determining the concentration of amino acids ordinarily present in intraocular fiuids and lenses of normal and diabetic animals. The rate of accumulation of cycloleucine in both aqueous humors and lenses in vivo is decreased significantly in diabetic animals. A similar reduction was found in the concentration of most naturally occurring amino acids in both the anterior aqueous humor and lenses. In cultured lenses removed from animals 48 hours or more after injection of alloxan, the accumulation of α-AIB is decreased to 50 per cent of normal.
The observed reduction in the transport of amino acids into intraocular fluids and lenses in diabetic animals is attributed to an impairment of active transport into both the aqueous humors and lens.
The steady state concentration of cycloleucine in the aqueous of the anterior chamber of normal animals was above that in both the plasma and posterior aqueous; the concentration in the vitreous humor was much lower than that in either of these fluids. These observations suggest that amino acids are actively transported into the anterior chamber across the anterior surface of the iris and unidirectionally moved from the vitreous humor into the blood.