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Gene expression basis for flexibility of intestinal maltase activity in young house sparrows
Author(s) -
Karasov William,
GaticaSosa Claudia,
Brzandęk Pawel,
CaviedesVidal Enrique
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.lb617
Subject(s) - maltase , biology , carbohydrate , starch , small intestine , medicine , endocrinology , biochemistry , enzyme
House sparrows ( Passer domesticus ) undergo a natural diet switch from insects to starch‐containing seed diet during development. Correlated with that is an increase in intestinal maltase activity that is partly genetically programmed (occurs even in absence of dietary carbohydrate) and partly diet induced (activity doubled by inclusion of 25% dietary starch) (Brzek et al. 2009 J. Exp. Biol. 212:1284) and completely reversible (Kohl et al 2009 Integ. and Comp. Biol. 49:e93). To test if the observed maltase flexibility has a gene expression basis we assessed using RT‐qPCR the maltase‐glucoamylase (MG) mRNA of mid‐intestine samples. Nestlings were raised from day 4 after hatch on either a starch free or a 25% starch diet. At age 12 days some were switched to the alternate diet and others remained on the original diet (hence 4 diet groups). Birds at ages 12 days and 30 days were tested for maltase activity and MG mRNA. Cq values normalized to β ‐actin and GDPH showed that the up‐ and down‐regulation of maltase activity by dietary carbohydrate correlated with a significant increase and decrease in MG mRNA ( P <0.05), which is consistent with transcriptional regulation as found in rodents. These changes seem specific, because in the same tissues mRNA for SGLT1, the active glucose transporter, was not increased on 25% starch diet. Funded by NSF IOS 0615678 to WHK and UNSL‐CyT 22Q751 & FONCYT 25561 to EC‐V.