What They Did Back Then
* Master of Science completed 2003, University of Guelph
Advisors: Dr. John F. Leatherland and Professor Richard D. Moccia
Nutritional regulation of the somatotrophic axis in the Arctic charr (Salvelinus alpinus)
The effects of energy intake on the somatotropic axis in the Arctic charr (Salvelinus alpinus) were investigated by feeding fish at 3 different ration levels for 5 weeks. After 5 weeks, plasma growth hormone (GH) and insulin-like growth factor-I (IGF-I) concentrations were positively correlated to ration level, and levels of both hormones were significantly lower in fasted fish. Plasma IGF-I concentrations were also positively correlated to individual body weight. The reduced plasma GH concentrations in food-deprived fish may represent a species difference in the response of the somatotropic axis to fasting in the Arctic charr.
Somatostatin-14 (SRIF-14) and human IGF-I (hIGF-I) inhibited GH secretion from Arctic charr pituitary tissue in vitro after 18 hours in static hemipituitary culture, as well as after acute exposure in a pituitary fragment perifusion system. Nutritional status did not influence the sensitivity of the Arctic charr pituitary gland to either SRIF-14 or hIGF-I.
Cameron C, Moccia R, Azevedo PA, Leatherland JF. 2007. Effect of diet and ration on the relationship between plasma GH and IGF-1 concentrations in Arctic charr, Salvelinus alpinus (L.). Aquaculture Research 38: 877-886.
Cameron C, Moccia RD, Leatherland JF. 2005. Growth hormone secretion from the Arctic charr (Salvelinus alpinus) pituitary gland in vitro: effects of somatostatin-14, insulin-like growth factor-I, and nutritional status. General and Comparative Endocrinology 141: 93-100.
Cameron C, Gurure R, Reddy K, Moccia R, Leatherland J. 2002. Correlation between dietary lipid:protein ratios and plasma growth and thyroid hormone levels in juvenile Arctic charr, Salvelinus alpinus (Linnaeus). Aquaculture Research 33: 383-394.
Where They Are Now
Colin is currently nearing the end of a PhD degree at the University of Ottawa. He has been studying the function of fibrate pharmaceutical receptors (peroxisome proliferator-activated receptors) in goldfish gonadal steroidogenesis. The objective is to determine the potential effects of environmental exposure to these pharmaceuticals, and other pollutants activating the same receptors, on steroid production and the reproductive axis of wild fish.