V. Everett Kinsey

Steady state distribution of free amino acids in the aqueous humours, vitreous body and plasma of the rabbit.

The purpose of this investigation is to provide comparative quantitative data on the composition of amino acids in the intraocular fluids and plasma. The concentration of free amino acids in the aqueous humour of the posterior and anterior chambers, vitreous body and plasma of rabbits has been determined by ion exchange chromatography. Except for glycine, proline and threonine, the concentration of all the amino acids that could reliably be determined is greater in the aqueous humour of the posterior and anterior chambers than in plasma withdrawn at essentially the same time. The concentration of all the amino acids in the posterior and anterior chambers is approximately the same with the exception of glycine, which is present in appreciably higher concentration in the anterior than in the posterior chamber. The concentration of all amino acids, except glutamic acid, is significantly lower in the vitreous body than in the aqueous humour of both chambers and in plasma. The observation that the concentration of most of the free amino acids in the aqueous of the posterior chamber is higher than in plasma leads to the conclusion that at least some of these compounds are transported across the ciliary epithelium by an active process in addition to diffusion. Some evidence is adduced which suggests that there may also be active transport across the iris.

Ion Movement in the Eye

The optical integrity and the metabolism of the eye depend on the exchange of substances between the blood vessels of the eye and the ocular chambers. The present paper considers the exchange of 3 ions in particular, i.e., sodium, chloride and bicarbonate, in the eye, with particular reference to the role of diffusion and active transport in determining the ionic composition of the various ocular fluids.

Studies on the crystalline lens. XIV. Kinetics of alpha-amino isobutyric acid transport.

The magnitude of the transfer coefficients by active transport and the coefficient of diffusion of α-AIB in rabbit lenses cultured at 37°C have been evaluated from data showing both the rate of accumulation and the rate of efflux. Changes in concentration of tracer α-AIB in the media have been compensated for by mathematical treatment using an analog computer to establish fits to data, on the assumption that the lens behaves like a pump-leak system.