title: Insulin-dependent glucose metabolism in dairy cows with variable fat mobilization around calving.
abstract: Dairy cows undergo significant metabolic and endocrine changes during the transition from pregnancy to lactation, and impaired insulin action influences nutrient partitioning toward the fetus and the mammary gland. Because impaired insulin action during transition is thought to be related to elevated body condition and body fat mobilization, we hypothesized that over-conditioned cows with excessive body fat mobilization around calving may have impaired insulin metabolism compared with cows with low fat mobilization. Nineteen dairy cows were grouped according to their average concentration of total liver fat (LFC) after calving in low [LLFC; LFC <24% total fat/dry matter (DM); n=9] and high (HLFC; LFC >24.4% total fat/DM; n=10) fat-mobilizing cows. Blood samples were taken from wk 7 antepartum (ap) to wk 5 postpartum (pp) to determine plasma concentrations of glucose, insulin, glucagon, and adiponectin. We applied euglycemic-hyperinsulinemic (EGHIC) and hyperglycemic clamps (HGC) in wk 5 ap and wk 3 pp to measure insulin responsiveness in peripheral tissue and pancreatic insulin secretion during the transition period. Before and during the pp EGHIC, [(13)C6] glucose was infused to determine the rate of glucose appearance (GlucRa) and glucose oxidation (GOx). Body condition, back fat thickness, and energy-corrected milk were greater, but energy balance was lower in HLFC than in LLFC. Plasma concentrations of glucose, insulin, glucagon, and adiponectin decreased at calving, and this was followed by an immediate increase of glucagon and adiponectin after calving. Insulin concentrations ap were higher in HLFC than in LLFC cows, but the EGHIC indicated no differences in peripheral insulin responsiveness among cows ap and pp. However, GlucRa and GOx:GlucRa during the pp EGHIC were greater in HLFC than in LLFC cows. During HGC, pancreatic insulin secretion was lower, but the glucose infusion rate was higher pp than ap in both groups. Plasma concentrations of nonesterified fatty acids decreased during HGC and EGHIC, but in both clamps, pp nonesterified fatty acid concentrations did not reach the ap levels. The study demonstrated a minor influence of different degrees of body fat mobilization on insulin metabolism in cows during the transition period. The distinct decrease in the glucose-dependent release of insulin pp is the most striking finding that explains the impaired insulin action after calving, but does not explain differences in body fat mobilization between HLFC and LLFC cows.
authors.affiliation: Institute of Nutritional Physiology ("Oskar Kellner"), 18196 Dummerstorf, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Weber
authors.affiliation: Institute of Nutritional Physiology ("Oskar Kellner"), 18196 Dummerstorf, Germany.
authors.forename: C T
authors.initials: CT
authors.lastname: Schäff
authors.affiliation: Institute of Nutritional Physiology ("Oskar Kellner"), 18196 Dummerstorf, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Kautzsch
authors.affiliation: Institute of Nutritional Physiology ("Oskar Kellner"), 18196 Dummerstorf, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Börner
authors.affiliation: Institute of Nutritional Physiology ("Oskar Kellner"), 18196 Dummerstorf, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Erdmann
authors.affiliation: Institute of Nutritional Physiology ("Oskar Kellner"), 18196 Dummerstorf, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Görs
authors.affiliation: Institute of Muscle Biology and Growth, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Röntgen
authors.affiliation: Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, 53113 Bonn, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Sauerwein
authors.affiliation: Veterinary Physiology, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland.
authors.forename: R M
authors.initials: RM
authors.lastname: Bruckmaier
authors.affiliation: Institute of Nutritional Physiology ("Oskar Kellner"), 18196 Dummerstorf, Germany.
authors.forename: C C
authors.initials: CC
authors.lastname: Metges
authors.affiliation: Institute of Nutritional Physiology ("Oskar Kellner"), 18196 Dummerstorf, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Kuhla
authors.affiliation: Institute of Nutritional Physiology ("Oskar Kellner"), 18196 Dummerstorf, Germany. Electronic address: hammon@fbn-dummerstorf.de.
authors.forename: H M
authors.initials: HM
authors.lastname: Hammon
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002417:Cattle; D004032:Diet / Q000662:veterinary; D004734:Energy Metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000097:blood*; D007774:Lactation / Q000378:metabolism; D008892:Milk / Q000378:metabolism; D036801:Parturition; D011247:Pregnancy
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D005947:Glucose
keywords: endogenous glucose production; glucose metabolism; insulin responsiveness; insulin secretion