Metabolic and digestive response to food ingestion in a binge-feeding lizard, the Gila monster (Heloderma suspectum)
Open Access
- 1 October 2007
- journal article
- Published by The Company of Biologists in Journal Of Experimental Biology
- Vol. 210 (19), 3430-3439
- https://doi.org/10.1242/jeb.004820
Abstract
The gastrointestinal tract possesses the capacity to change in form and function in response to fasting and feeding. Such plasticity can be dramatic for species that naturally experience long episodes of fasting between large meals (e.g. sit-and-wait foraging snakes, estivating anurans). By contrast, for active foraging species that feed more frequently on smaller meals, gastrointestinal responses are more modest in magnitude. The Gila monster Heloderma suspectum is an active foraging lizard that feeds infrequently on meals weighing up to one-third of its body mass. Additionally, Gila monsters possess a species-specific salivary peptide, exendin-4, which may be involved in the regulation of metabolic and digestive performance. To investigate the adaptive postprandial response of Gila monsters and the potential regulatory role of exendin-4, we measured metabolic and intestinal responses to feeding in the presence or absence of circulating exendin-4. Following the consumption of rodent or egg meals equivalent to 10% of lizard body mass, metabolic rates peaked at 4.0- to 4.9-fold of standard metabolic rates and remained elevated for 5–6 days. Specific dynamic action of these meals (43–60 kJ) was 13–18% of total meal energy. Feeding triggered significant increases in mucosal mass, enterocyte width and volume, and the upregulation of d-glucose uptake rates and aminopeptidase-N activity. Total intestinal uptake capacity for l-leucine, l-proline and d-glucose were significantly elevated within 1–3 days after feeding. Whereas the absence of circulating exendin-4 had no impact on postprandial metabolism or the postprandial response of intestinal structure and nutrient uptake, it significantly increased intestinal aminopeptidase-N activity. Within the continuum of physiological responses to feeding and fasting, Gila monsters occupy an intermediate position in experiencing moderate, though significant, regulation of intestinal performance with feeding.Keywords
This publication has 31 references indexed in Scilit:
- Adaptive regulation of digestive performance in the genusPythonJournal Of Experimental Biology, 2007
- Metabolic Response to Feeding inTupinambis merianae: Circadian Rhythm and a Possible Respiratory ConstraintPhysiological and Biochemical Zoology, 2006
- Physiological responses to feeding, fasting and estivation for anuransJournal Of Experimental Biology, 2005
- Regulation of Gut Function Varies with Life‐History Traits in Chuckwallas (Sauromalus obesus: Iguanidae)Physiological and Biochemical Zoology, 2005
- Evolutionary and Cellular Mechanisms Regulating Intestinal Performance of Amphibians and ReptilesIntegrative and Comparative Biology, 2005
- Temperature and Meal Size Effects on the Postprandial Metabolism and Energetics in a Boid SnakePhysiological and Biochemical Zoology, 2003
- Effects of Meal Size, Meal Type, Body Temperature, and Body Size on the Specific Dynamic Action of the Marine Toad,Bufo marinusPhysiological and Biochemical Zoology, 2002
- Maintenance of Digestive Performance in the Turtles Chelydra serpentina, Sternotherus odoratus, and Trachemys scriptaIchthyology & Herpetology, 1999
- Water, Energy, and Electrolyte Balance in Captive Namib Sand-Dune Lizards (Angolosaurus skoogi)Ichthyology & Herpetology, 1994
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976