The obese gene is expressed in lean littermates of the genetically obese mouse (C57BL/6J ob/ob).
Some individuals of the mixed group of "lean" littermates (+/ob and +/+) of (C57BL/6J ob/ob) often suggest phenotypic characteristics of ob/ob animals. Therefore, it was of interest to determine whether expression of the ob gene had physiological significance in +/ob animals. Body weight (BW), fasting blood glucose (FBG), and body core temperature (Tr) were monitored between 62 and 364 days of age in +/+ and +/ob mice. Among females but not males, +/ob mice were heavier (P = 0.003) and FBG levels were greater (P = 0.04) than in +/+ animals. Comparison of Tr indicated differences suggesting falling Tr in +/ob but rising Tr in +/+ mice with age in males but not females. Multivariate analysis of variance yielded genotype effects for both males (P = 0.002) and females (P = 0.02). BW, FBG, and Tr alone were sufficient at the 75% level for genotypic characterization and separation of +/? animals as +/ob or +/+; clearly, expression of the ob gene in heterozygotes of the +/ob animal may make the mixed +/? group inappropriate as lean controls.
Haller
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Department of Medical and Molecular Physiology, University of Minnesota, Duluth, Minnesota 55812, USA. ehaller@d.umn.edu
Wittmers
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Haller
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Regal
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D000375:Aging / Q000502:physiology*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D001831:Body Temperature; D001835:Body Weight / Q000235:genetics*; D003433:Crosses, Genetic; D005260:Female; D006580:Genetic Carrier Screening; D005838:Genotype; D006720:Homozygote; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D009765:Obesity / Q000235:genetics*; D012727:Sex Characteristics
D001786:Blood Glucose