SEASONAL-CHANGES IN GLUCOSE AND TYROSINE UPTAKE OF ABROTHRIX-ANDINUS (CRICETIDAE) INHABITING THE ANDES RANGE

1. Abrothrix andinus (Rodentia: Cricetidae) is a small mammal active through the year in the Andes mountains, enduring seasonal biotic and abiotic environmental changes. 2. Seasonal changes in diet, in metabolic rate and significant amounts in gastrointestinal dimensions and capacity were found during winter. 3. We tested if seasonal changes in the small intestine morphology were reflected by changes in the transport of D-glucose and L-tyrosine during summer and winter. 4. There is a significant increase (P < 0.05) in nutrients uptake during winter, fluctuating within a range of 52.5-75.1%. 5. Increased metabolic rates, hypertrophy of the gut, and increased transport of these specific nutrients by the small intestine, can be viewed as compensatory mechanisms of the digestive physiological ecology of winter active endotherms.