Master's Theses



Degree Name

Master of Science (MS)


Food intake regulation is a complex neural process that involves the coordination of multiple mechanisms. O-linked N-acetylglucosamine transferase (OGT) is a neural nutrient sensor that aids in regulating satiety in mammals. Compared to mammals, little is known about function and regulation of OGT expression in fish. It was hypothesized changes in food intake are associated with changes in OGT expression in channel catfish. The objectives of this study were to examine tissue distribution of OGT mRNA and determine the possible relationship between food intake and OGT mRNA in channel catfish. Screening of the catfish genome database yielded four highly homologous transcript variants. The predicted amino acid sequence of channel catfish OGT variants was highly homologous ( > 90%) to those of other fish and mammals. Expression of OGT was detected in many tissues including the heart, liver, spleen, kidney, and muscle, but was most readily detectable in the brain. Prolonged fasting, as well as fasting followed by refeeding, decreased expression of total OGT in the brain. In contrast, prolonged fasting increased expression of total OGT in the liver, and refeeding fish after fasting restored total OGT expression in the liver to a level similar to that of fish that received food daily. Additionally, a correlation between increased feeding and increased expression of total OGT was observed in the brain of channel catfish. Compared to total OGT, expression of OGT variant X1 and X3 was not affected by changes in food intake. These results suggest that OGT expression appears to be influenced by the nutritional status of channel catfish. The results of this study also indicate that changes in OGT expression are not associated with the expression of OGT variant X1 and X3.


Dr. Yasuhiro Kobayashi

Date of Award

Spring 2018

Document Type



© The Author(s)


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