title: Dietary fat and sex modify heterozygote effects of the rat fatty (fa) allele.
abstract: Rats carrying one copy of the obesity gene fa may exhibit intermediate phenotypes between lean (+/+) and homozygous mutants (fa/fa). Previous data suggested to us that fa heterozygotes may be more sensitive than wild-type rats to high fat diets. To test this hypothesis, we generated +/+ and fa/+ rats and fed them diets containing 12% or 48% energy as fat for 7 wk. Energy efficiency was significantly greater in males than in females and in high fat-fed vs. low fat-fed rats. Perirenal fat pad weights were significantly greater in males than in females, in high fat-vs. low fat-fed rats and in fa/+ vs. +/+ rats. Adipose and soleus plasma membrane calcium-ATPase concentrations were significantly lower in rats fed the high fat diet. This protein was also lower in soleus of fa/+ rats compared with +/+ rats. There were significant diet x genotype interactions such that the high fat diet had the greatest effect on fat pads and calcium-ATPase in fa/+ rats. The results of the present study show heterozygote effects of the fa allele and suggest that these effects may be modulated by both sex-related factors and dietary manipulation.
authors.affiliation: Physiology Program and Department of Nutrition, University of Tennessee, Knoxville 37996-1900, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Maher
authors.forename: W J
authors.initials: WJ
authors.lastname: Banz
authors.forename: G E
authors.initials: GE
authors.lastname: Truett
authors.forename: M B
authors.initials: MB
authors.lastname: Zemel
mesh_terms: D017667:Adipocytes / Q000201:enzymology / Q000648:ultrastructure; D000483:Alleles; D000818:Animals; D000252:Calcium-Transporting ATPases / Q000032:analysis; D002462:Cell Membrane / Q000201:enzymology / Q000648:ultrastructure; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D008297:Male; D009154:Mutation; D009765:Obesity / Q000235:genetics*; D010641:Phenotype; D051381:Rats; D011914:Rats, Inbred BN; D011924:Rats, Zucker; D012727:Sex Characteristics
chemical_list: D004041:Dietary Fats; D000252:Calcium-Transporting ATPases