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Title: Measurement of /sup 2/H/sub 2/O by IR absorbance in doubly labeled H/sub 2/O studies of energy expenditure

The energy expenditure of animals in their natural surroundings can be determined by measuring the turnover in body water of isotopes of oxygen and hydrogen. We evaluated the use of infrared spectrophotometry for measuring /sup 2/H/sub 2/O in small (20-microliters) water samples also labeled with 18O. For /sup 2/H/sub 2/O over the enrichment range of 0.1-1 atom%, there was a linear relationship between infrared absorbance and /sup 2/H/sub 2/O enrichment. /sup 2/H/sub 2/O enrichments could be measured with a precision and accuracy of less than or equal to 1%, using this relationship. The presence of /sup 18/O in water samples in enrichments of up to 1 atom% had no significant effect on measurement of /sup 2/H/sub 2/O by infrared absorbance. We measured the simultaneous turnover rates of /sup 2/H/sub 2/O and /sup 3/H in mice and turtles also labeled with 18O. Our results validated the use of infrared absorbance in doubly labeled water measures of energy expenditure and indicated that the fractionation factors in vivo for /sup 2/H/sub 2/O and /sup 3/H do not differ.
Authors:
; ;
Publication Date:
OSTI Identifier:
6902005
Resource Type:
Journal Article
Resource Relation:
Journal Name: Am. J. Physiol.; (United States); Journal Volume: 255
Research Org:
Univ. of Wisconsin, Madison (USA)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; BODY FLUIDS; INFRARED SPECTRA; METABOLISM; MEASURING METHODS; ACCURACY; ALGORITHMS; DEUTERIUM; DOUBLE LABELLING; MICE; OXYGEN 18; TRACER TECHNIQUES; TRITIUM COMPOUNDS; TURTLES; WATER; ANIMALS; BIOLOGICAL MATERIALS; EVEN-EVEN NUCLEI; HYDROGEN COMPOUNDS; HYDROGEN ISOTOPES; ISOTOPE APPLICATIONS; ISOTOPES; LABELLED COMPOUNDS; LABELLING; LIGHT NUCLEI; MAMMALS; MATERIALS; MATHEMATICAL LOGIC; NUCLEI; ODD-ODD NUCLEI; OXYGEN COMPOUNDS; OXYGEN ISOTOPES; REPTILES; RODENTS; SPECTRA; STABLE ISOTOPES; VERTEBRATES 550501* -- Metabolism-- Tracer Techniques