INVIVO URINARY-BLADDER FUNCTION IN RATS FOLLOWING PROLONGED DIABETIC AND NONDIABETIC DIURESIS

Changes in urinary bladder function are present in animal models of diabetes mellitus. In vivo cystometry in diabetic rats shows a bladder with increased capacity and a raised threshold for initiation of the micturition reflex. At sacrifice, diabetic rats have bladder hypertrophy, resulting in approximately a doubling of the bladder weight. This study was designed to characterize the effects of diabetes on micturition in the streptozotocin‐diabetic rat. For comparative purposes, two different control groups were examined: 1) age‐matched control rats and 2) age‐matched rats which were given 5% sucrose to drink. Sucrose‐fed rats consumed large volumes of fluid resulting in diuresis and bladder hypertrophy. Fluid consumption and excretion were significantly increased in diabetic and sucrose‐drinking rats. In addition, the diabetic rats both drank and excreted more than the sucrose‐drinking rats. Control rats had twice as many micturitions during the dark cycle than during the light cycle, but the volume micturition during the dark cycle was less than one‐half the volume per micturition during the light cycle. Sucrose drinking rats had the same number of micturitions as control rats during the light cycle. but the volumes per micturition were significantly increased. During the dark cycle, the number of micturitions increased four‐fold and the volume per micturition was significantly increased compared to controls. The diabetic rats, in contrast to the two control groups, had a significant increase in the number of micturitions during the light and dark cycles. Similar to the sucrose drinking rats, the volumes excreted per micturition were significantly greater than the normal controls. The data are discussed with regard to the effects of prolonged diuresis on bladder function and hypertrophy. Copyright © 1990 Wiley‐Liss, Inc., A Wiley Company