title: Age and body weight effects on glucose and insulin tolerance in colony cats maintained since weaning on high dietary carbohydrate.
abstract: High dietary carbohydrate is suggested to promote development of diabetes mellitus in cats. Glucose tolerance, insulin sensitivity, and insulin secretion were assessed in young [0.8-2.3 (median = 1.1) years, n = 13] and mature [4.0-7.0 (median 5.8) years, n = 12] sexually intact females of a large (n ≅ 700) feline colony in which only dry-type diets (35% metabolizable energy as carbohydrate) were fed from weaning. Insulin sensitivity was assessed from the 'late-phase' (60-120 min) plasma insulin response of intravenous glucose tolerance tests (IVGTTs) and from fractional change in glycaemia from baseline 15 min after an insulin bolus (0.1 U/kg, i.v.). Insulin secretion was assessed from the 'early-phase' (0-15 min) plasma insulin response of IVGTTs. Compared to the young cats, the mature cats had greater body weights [2.3-3.8 (median = 2.9) vs. 3.0-6.3 (median = 4.0) kg, p < 0.01], greater late-phase insulin responses (p < 0.05), lower insulin-induced glycaemic changes (p = 0.06), lower early-phase insulin responses (p < 0.05), and non-significantly different rates of glucose disposal. The late-phase insulin response was correlated with body weight and age (p < 0.05). When group assignments were balanced for body weight, the age-group differences and correlations became non-significant. The findings indicate that body weight gain is more likely than dry-type diets to induce the pre-diabetic conditions of insulin resistance and secretion dysfunction.
authors.affiliation: Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA. backusr@missouri.edu
authors.forename: R C
authors.initials: RC
authors.lastname: Backus
authors.forename: N J
authors.initials: NJ
authors.lastname: Cave
authors.forename: V K
authors.initials: VK
authors.lastname: Ganjam
authors.forename: J B M
authors.initials: JB
authors.lastname: Turner
authors.forename: V C
authors.initials: VC
authors.lastname: Biourge
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001786:Blood Glucose / Q000502:physiology*; D001835:Body Weight / Q000502:physiology*; D002415:Cats / Q000097:blood / Q000502:physiology*; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D005260:Female; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism; D005951:Glucose Tolerance Test / Q000662:veterinary; D007262:Infusions, Intravenous; D007333:Insulin Resistance / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D005947:Glucose