Glycerol and water balance in a near-isosmotic teleost, winter-acclimatized rainbow smelt
- 1 September 1993
- journal article
- Published by Canadian Science Publishing in Canadian Journal of Zoology
- Vol. 71 (9) , 1849-1854
- https://doi.org/10.1139/z93-263
Abstract
Rainbow smelt, Osmerus mordax, have previously been shown to produce high concentrations of glycerol in winter to avoid freezing, becoming almost isosmotic in a marine environment when temperatures reach the freezing point of seawater. Here it is shown that osmotic water losses, as shown by drinking rate, decrease dramatically in winter as a result of the increased osmolality. Urine flow also appears to decrease in winter in response to reduced drinking. Glycerol is lost through the skin and gills, and probably through intestinal discharge, at total rates ranging from 3.5 to 9.5 mg∙100 g−1∙h−1. Combined permeabilities to glycerol of the gills and skin in the head were in the range 0.9–2.6 × 10−7 cm∙s−1. Glycerol concentrations, efflux, and permeability of the gills were comparable to those for urea in marine elasmobranchs. However, mechanisms for conserving the two osmolytes may differ.Keywords
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