title: Broiler chickens (Ross strain) lack insulin-responsive glucose transporter GLUT4 and have GLUT8 cDNA.
abstract: Identification of insulin-responsive glucose transporter proteins, GLUT4 and GLUT8, was attempted in chickens that characteristically are hyperglycemic and insulin resistant. Northern blot analysis using rat GLUT4 cDNA probe and RT-PCR using primers designed against the conserved regions in mammalian GLUT4 cDNA were not successful in identifying GLUT4 homologue(s) in various chicken tissues. Furthermore, GLUT4 homologues could not be detected in chicken tissues by genomic Southern blot analyses using a rat GLUT4 cDNA probe. These data, therefore, suggest that the GLUT4 homologous gene is deficient in chicken tissues. However, GLUT8, another insulin-responsive glucose transporter in the blastocyst, was identified with the aid of RACE (rapid amplification of cDNA ends) reactions in the chicken testis. Chicken GLUT8 was composed of 1449 bp with a coding region for a 482 amino acid protein. The deduced amino acid sequence was 58.8, 56.3, and 56.8% identical with human, rat, and mouse GLUT8, respectively. By RT-PCR, GLUT8 mRNA expressions were detected in chicken brain, kidney, adrenal, spleen, lung, testis, and pancreas; and barely detectable in skeletal muscle, liver, adipose tissue, and heart. Here we firstly report that GLUT8 was identified in chickens, while GLUT4, a major insulin-responsive transporter in mammals, is deficient in these animals. We propose the hypothesis that the hyperglycemia and insulin resistance observable in chickens is associated with their possible deficiency of GLUT4.
authors.affiliation: Animal Nutrition, Division of Life Sciences, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Seki
authors.forename: Kan
authors.initials: K
authors.lastname: Sato
authors.forename: Tatsuyoshi
authors.initials: T
authors.lastname: Kono
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Abe
authors.forename: Yukio
authors.initials: Y
authors.lastname: Akiba
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D015139:Blotting, Southern; D002645:Chickens / Q000378:metabolism*; D004247:DNA / Q000235:genetics; D018076:DNA, Complementary / Q000378:metabolism*; D016678:Genome; D051275:Glucose Transporter Type 4; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000172:deficiency* / Q000235:genetics* / Q000378:metabolism; D009124:Muscle Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
chemical_list: D018076:DNA, Complementary; D051275:Glucose Transporter Type 4; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D004247:DNA