Aqueous flow and entry of cycloleucine into the aqueous humor of vervet monkeys (Cercopithecus ethiops).

A buffer solution containing I-albumin was washed to and fro through the anterior chamber of vervet monkeys gioen I-albumin systemically. The rate of outward flow of I-albumin and the accumulation of 'I-albumin in the solution were determined. In 5 monkeys the concentration of 'I-albumin in the newly formed aqueous was calculated to be an average 3 per cent of that in plasma for several hours. In a sixth monkey it ivas about 6 per cent after 9 hours of perfusion. The entry of H-cycloleucine from the blood into the anterior chamber and the rate of aqueous humor formation were then studied in vervets. H-cycloleucine was given parenterally; the steady-state concentration of H-cycloleucine in the anterior aqueous humor was 1.11 of that in plasma water. The anterior chamber was perfused with a buffer solution containing 'I-albumin or >C-inulin. The rate of aqueous humor formation was calculated from dilution data. The flow determined toith I-albumin in one eye was practically the same as that determined toith *C-inulin in the other eye. In experiments with 9 hours of perfusion, the rate of aqueous humor formation calculated from C-inulin data increased from 2.0 to 2.3 nL per minute. The simultaneously measured mean concentration of H-cycloleucine in the anterior chamber fluid increased from 14.7 to 17.4 per cent of that in plasma (perfusion rate: 22 nL per minute). With these concentrations of cycloleucine in the anterior chamber fluid, about 2/3 of the amount of cycloleucine entered the chamber with the newly formed aqueous, and 1/3 entered mainly by diffusion across the anterior surface of the iris. The rate of entry of C-AIB was about 2/3 of that of H-cycloleucine. As a rule rabbit eyes tolerated the procedure for only one hour.