Meeting Abstract
P1.90 Jan. 4 Mechanisms of nitrogen conservation in a small mammal hibernator during periods of protein scarcity and hibernation GRELLER, K.A.; Univ. of Wyoming greller@uwyo.edu
Mammals experiencing fasting during winter or drought undergo significant urinary nitrogen and water losses. Remarkably, many hibernators minimize these losses by reducing or ceasing urine elimination. This reduction is partially due to their ability to recycle urea nitrogen. Urea recycling is probably accomplished through a symbiotic relationship with ureolytic gut microbes that use endogenous urea transported into the gut. I investigated the potential functional adaptations of urea hydrolysis associated with dietary protein intake and state of hibernation in the Wyoming ground squirrel. Specifically, I confirmed and quantified the expression of urea transporters in bladder and intestinal tissues using Western blots. I also determined the ureolytic activity of intestinal microbes with urease assays on gut digesta. Finally, I verified that recycled urea was used to synthesize amino acids. I measured the amount of 15N incorporated into specific body tissues after a dose of [13C15N15N]-urea. My study elucidates the extent of the impact that urea hydrolysis has on animal nitrogen balance under protein deficient conditions such as fasting or hibernation.
