Changes in expression of appetite-regulating hormones in the cunner (Tautogolabrus adspersus) during short-term fasting and torpor

Babichuk, Nicole Allen (2012) Changes in expression of appetite-regulating hormones in the cunner (Tautogolabrus adspersus) during short-term fasting and torpor. Masters thesis, Memorial University of Newfoundland.

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Abstract

Feeding in vertebrates is controlled by a number of appetite stimulating (orexigenic) and appetite suppressing (anorexigenic) hormones, whose levels respectively increase and decrease following fasting. Cunners (Tautogolabrus adspersus) survive the winter in shallow coastal waters by entering a torpor-like state. In order to better understand the mechanisms regulating appetite/fasting in these fish, quantitative real-time PCR was used to measure transcript expression levels of four appetite-regulating hormones: cholecystokinin (CCK) in the gut, and neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART) and orexin in the forebrain (hypothalamus and telencephalon) of fed, short-term fasted, induced summer torpor and natural torpor cunners. All hormone mRNA levels decreased during fasting and during natural torpor, but during induced summer torpor brain NPY and orexin mRNA expression levels increased, and CART brain mRNA and CCK gut mRNA expression levels decreased. These results clearly indicate that the cunner has different physiological responses to fasting and torpor.

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