Water balance and kidney function in the least shrew (Cryptotis parva).
We assessed renal function in least shrews (Cryptotis parva, body mass 4.7 g) within the context of overall water balance. The glomerular filtration rate (GFR) of shrews with unlimited food and water was 2.4 ml/h, about 60% of the rate predicted from body mass. Of this, about 3% (0.075 ml/h) was excreted as urine with an osmolality of 1944 mmol/kg, 5.5 times plasma osmolality. Shrews had a total water turnover (5 ml/day) two to three times higher than expected from allometry for a small mammal of this size. Water influx was partitioned among preformed water from food (65%), drinking (16%), and metabolic water (20%). Water efflux was divided among urine flow (35%), fecal water loss (estimated as 23%), and evaporation (by difference, 42%). Least shrews had a high water turnover rate and relatively high urine flow rate (UFR); this likely reflects a combination of factors, including high metabolism, active lifestyle, and wet diet.
Goldstein
David L
DL
Department of Biological Sciences, Wright State University, Dayton, OH 45435, USA. david.goldstein@wright.edu
Newland
Stacy
S
D000821:Animal Feed; D000818:Animals; D004231:Diuresis; D005260:Female; D005919:Glomerular Filtration Rate; D007668:Kidney / Q000378:metabolism / Q000502:physiology*; D007671:Kidney Concentrating Ability; D009994:Osmolar Concentration; D012788:Shrews / Q000033:anatomy & histology / Q000502:physiology*; D014867:Water / Q000378:metabolism*
D014867:Water