REDUCING SUBSTANCES IN THE BLOOD OF NORMAL AND ALLOXAN-TREATED FISH.

Blood sugar changes in fish, after the intravenous injection of alloxan, were determined by a modified Folin method and by an enzymatic method using glucose oxidase. The rest reduction was calculated as the difference between the two methods. The blood rest reduction levels were normally 15 mg% in toadfish and 11 mg% in bullheads (glucose 19 and 22 mg% respectively). One hour after alloxan administration, the rest reduction had increased on the average several times while the glucose level was only slightly above normal. From a maximum at 1 hour the rest reduction level dropped while the glucose level began to rise. Considerable variation in the response to alloxan occurred.The reducing substances in the blood were studied by paper chromatography. In normal blood, glucose and another compound (Rf value approximately one-half that of glucose) were detected by alkaline silver nitrate. No increase in reducing material in alloxan-treated samples could be shown on the chromato-grams by the methods used.