With the interest in somatostatin as an inhibitory regulator of nutrient absorption, this study was designed to investigate changes in gastrointestinal somatostatin after a voluntary shift in diet towards increased carbohydrates and sucrose in otherwise normal rats. In the first experiment a complex 'cafeteria style' high-sucrose diet was offered to experimental animals (n = 5) for one month as an additional option to the usual lab chow and water of controls (n = 5). In the second experiment rats were offered the added option of a 32% sucrose solution for five months (n = con-24, exp-26) and thirteen months (n = con-4, exp-6). A significant increase in daily caloric intake was demonstrated with the sucrose-solution diet, where approximately two-thirds of their caloric intake was taken as sugar water. A 14% and 33% weight increase due to increased adiposity was observed in the 5 and 13 month groups respectively. Insulin response to I.V. glucose was significantly correlated to weight at sacrifice in controls but unrelated in experimental animals and was significantly lower (53-63%) in older animals. Significant increases in tissue somatostatin-like immunoreactivity (SLI) were observed in the pancreas after one and five months, and in the antral stomach after five and thirteen months. No diet effect was observed in whole brain, duodenal, jejunal or ileal SLI. Portal plasma SLI was significantly decreased after I.V. glucose relative to basal (64%) and controls (59%) in the 5m experimental rats. Multiple regression analysis was used to see which of the measured factors were predictive of the final weight of the 5m rats. While variability in insulin response plays a dominant role in the prediction of the final weight of control animals, other factors such as pancreatic and brain SLI, gain importance in animals consuming sucrose solutions. These relationships are consistent with, but do not prove, a functional role of insulin and these other factors in the regulation of weight. It is concluded that chronic high-sucrose diets can increase pancreatic and stomach SLI and decrease portal plasma SLI and a mechanism of decreased somatostatin release is postulated / acase@tulane.edu
| Identifer | oai:union.ndltd.org:TULANE/oai:http://digitallibrary.tulane.edu/:tulane_27465 |
| Date | January 1985 |
| Contributors | Luciano, Mark Gregory (Author) |
| Publisher | Tulane University |
| Source Sets | Tulane University |
| Language | English |
| Detected Language | English |
| Rights | Access requires a license to the Dissertations and Theses (ProQuest) database., Copyright is in accordance with U.S. Copyright law |
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