The first goal of my thesis is to develop a double catheterization method allowing simultaneous infusion of labeled compounds and blood sampling, and to quantify glucose fluxes in resting rainbow trout by continuous infusion of 6-$\sp3$H-glucose (Chapter 2). The new cannulation technique consists of placing both sampling and infusing catheters in the dorsal aorta. Continuous isotope infusion results show that resting glucose turnover is 9.5 $\pm$ 0.8 $\mu$mol $\rm kg\sp{-1}\ min\sp{-1},$ a value 4 to 9 times higher than most rates measured with bolus injection technique. Consequently, the second goal is to quantify the accuracy of the continuous infusion technique in estimating glucose turnover rate. Trout are hepatectomizad and liver glucose production is artificially replaced by a pump infusing unlabelled glucose. Glucose flux measured with the continuous infusion technique using either plasma or whole blood is not significantly different from artificial pump glucose entry rate. Therefore, this result suggests that the bolus injection method widely used in previous trout studies strongly underestimates true glucose flux. Using the continuous infusion technique, my third goal is to investigate the effects of two environmental disturbances namely acute hypoxia and cold exposure, on the rates of glucose and NEFA (non-esterified fatty acids) turnover. My hypotheses are that: (1) during hypoxia, a fuel preference for carbohydrates would lead to an increase in glucose flux and a decrease in NEFA flux; (2) during cold exposure, both glucose and NEFA fluxes would decrease in proportion to metabolic rate depression. The results suggest that no fuel preference is occurring during cold exposure. However, while glucose concentration only shows a slight overall decrease, NEFA concentration increases by 30% after 100 minutes at 6$\sp\circ$C. (Abstract shortened by UMI.)
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/9901 |
| Date | January 1996 |
| Creators | Haman, François. |
| Contributors | Weber, Jean-Michel, |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 149 p. |
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