Studies On the Glomerular Filtration Rate of Rainbow Trout (Salmo Gairdneri)*

Abstract

1. Variations in the glomerular filtration rate (G.F.R.) and the renal tubular reabsorption of water are probably important factors in the homoiostatic mechanisms associated with the euryhalinity of the rainbow trout (Salmo gairdneri). 2. The observed reduction in urine flow after the adaptation of rainbow trout to sea water can be largely accounted for on the basis of the reduced G.F.R. 3. Intraperitoneal injections of mammalian preparations of vasopressin, oxytocin and vasopressin/oxytocin into freshwater trout significantly increased the G.F.R. 4. The intraperitoneal injection of aldosterone into freshwater fish had no detectable effect on G.F.R. 5. The similar administration of corticosterone significantly reduced the G.F.R. to 73% of the intact freshwater control value.