Hydrolytic capacity of trehalase in Bufo arenarum

CALERO, I.; CIMINARI, M. E.; ENRIQUE CAVIEDES VIDAL

Mendoza

Congreso; Reunión Anual de la Sociedad de Biología de Cuyo; 2005

HYDROLYTIC CAPACITY OF TREHALASE IN Bufo arenarum. Calero I, Ciminari ME, Caviedes- Vidal E. Lab Biol., Univ Nac San Luis, 5700 San Luis. E-mail: ivana.calero@gmail.com Several studies in endotherms examined how digestive capacity is adapted to different life conditions, such as dietary switch, hibernation or growth. This problem has not received enough attention in ectotherms. Consequently, this work aimed at assessing the enzymatic activity of an intestinal carbohydrase - trehalase - in an insectivore amphibian. This enzyme is important since it breaks down trehalose, a sugar present in insects. In this study, we explored if trehalase activity scales with body size. We captured 30 toads (14 males and 16 females; body weight range: 63.13 to 158.358) in Rio Cuarto (C6rdoba) and La Florida (San Luis). We assayed trehalase activity in homogenates of small intestines. Total trehalase activity scaled with body weight (p < 0.01). A tissue specific activity pattern is apparent along the small intestine (proximal > medial > distal, p < 0.05); the same profile was also found for other carbohydrases. Thus, during growth the digestive capacity of trehalose increases as a result of the growth of the small intestine, while tissue-specific trehalase activity remains constant. These results suggest that the increment in hydrolytic capacity needed for matching increased energy requirements is provided by enlargement of the intestine.