Document Type

Thesis - Open Access

Award Date

1984

Degree Name

Master of Science (MS)

Department

Biology and Microbiology

Abstract

Dehydroepiandrosterone (DHEA) is a non-competitive inhibitor in vitro of glucose-6-phosphate dehydrogenase (G6PDH), the rate controlling enzyme in the pentose-phosphate shunt. This pathway produces NADPH, a necessary co-factor for the synthesis of fatty acids and ribo- and deoxyribonucleotides. Some researchers believe that by decreasing G6PDH activity, DHEA produces an anti-obesity and anticarcinogenic effect in laboratory mice and rats genetically inclined toward obesity and cancer. It is DHEA's anti-obesity effect which lends it to the study of the yellow obese (AY/-) mouse with its peculiar pleiotropic syndrome. Yellow obese AY/AW mice were found to be more susceptible to dietary DHEA's effects than their agouti (AW/AW) littermates. They lost significantly more weight while consuming the same or greater amounts of food (P<0.01), their urinary output seemed to increase, and their G6PDH activities (U/1012 RBC) (P < 0.05) were significantly higher. G6PDH activity in red blood cell lysates at 340 nm also increased significantly (P < 0.01) in both mouse genotypes as the percent of DHEA in the mouse chow increased. This increase in activity may be a compensatory effect in response to DHEA's action. However, this explanation neither explains the observed anti-obesity effects nor the differential effects in G6 PDH activity between AY/AW and AW/AW littermates. This research centered on the physiological and metabolic effects that the steroid dehydroepiandrosterone (DHEA) has on the lethal yellow (AY/AW) mouse. The AY allele is a genetic mutation which is of particular interest because of the multiple effects it produces in heterozygotes (AY/-). Homozygotes (AY/AY) never survive longer than the sixth day of gestation. Yellow heterozygotes display a yellow coat color, stimulation of normal body growth, obesity, operation of unusual metabolic pathways (i.e. greater efficiency in the conversion of food to fat), sterility, diabetes-like syndrome, and increased cancer susceptibility. The obesity and the operation of unusual metabolic pathways were investigated in this research.

Library of Congress Subject Headings

Mice -- Physiology
Steroid horomones -- Physiological effect

Format

application/pdf

Number of Pages

230

Publisher

South Dakota State University

Rights

No Copyright - United State
http://rightsstatements.org/vocab/NoC-US/1.0/

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