title: Increased plasma leptin attenuates adaptive metabolism in early lactating dairy cows.
abstract: Mammals meet the increased nutritional demands of lactation through a combination of increased feed intake and a collection of adaptations known as adaptive metabolism (e.g., glucose sparing via insulin resistance, mobilization of endogenous reserves, and increased metabolic efficiency via reduced thyroid hormones). In the modern dairy cow, adaptive metabolism predominates over increased feed intake at the onset of lactation and develops concurrently with a reduction in plasma leptin. To address the role of leptin in the adaptive metabolism of early lactation, we asked which adaptations could be countered by a constant 96-h intravenous infusion of human leptin (hLeptin) starting on day 8 of lactation. Compared to saline infusion (Control), hLeptin did not alter energy intake or milk energy output but caused a modest increase in body weight loss. hLeptin reduced plasma glucose by 9% and hepatic glycogen content by 73%, and these effects were associated with a 17% increase in glucose disposal during an insulin tolerance test. hLeptin attenuated the accumulation of triglyceride in the liver by 28% in the absence of effects on plasma levels of the anti-lipolytic hormone insulin or plasma levels of free fatty acids, a marker of lipid mobilization from adipose tissue. Finally, hLeptin increased the plasma concentrations of T4 and T3 by nearly 50% without affecting other neurally regulated hormones (i.e., cortisol and luteinizing hormone (LH)). Overall these data implicate the periparturient reduction in plasma leptin as one of the signals promoting conservation of glucose and energy at the onset of lactation in the energy-deficient dairy cow.
authors.affiliation: Departments of Animal Science and Large Animal Clinical SciencesMichigan State University, East Lansing, Michigan, USA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Ehrhardt
authors.affiliation: Institute of Biological, Environmental and Rural SciencesAberystwyth University, Aberystwyth, UK.
authors.forename: Andreas
authors.initials: A
authors.lastname: Foskolos
authors.affiliation: Department of Animal ScienceCornell University, Ithaca, New York, USA.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Giesy
authors.affiliation: University of Colorado School of MedicineAurora, Colorado, USA.
authors.forename: Stephanie R
authors.initials: SR
authors.lastname: Wesolowski
authors.affiliation: Department of Animal ScienceCornell University, Ithaca, New York, USA.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Krumm
authors.affiliation: Department of Animal ScienceCornell University, Ithaca, New York, USA.
authors.forename: W Ronald
authors.initials: WR
authors.lastname: Butler
authors.affiliation: Department of Animal ScienceCornell University, Ithaca, New York, USA.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Quirk
authors.affiliation: Department of Animal ScienceCornell University, Ithaca, New York, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Waldron
authors.affiliation: Department of Animal ScienceCornell University, Ithaca, New York, USA yrb1@cornell.edu.
authors.forename: Yves R
authors.initials: YR
authors.lastname: Boisclair
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002417:Cattle; D004435:Eating; D005260:Female; D013006:Growth Hormone / Q000378:metabolism; D006801:Humans; D007262:Infusions, Intravenous; D007774:Lactation / Q000378:metabolism*; D020738:Leptin / Q000008:administration & dosage / Q000097:blood*; D050356:Lipid Metabolism / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008112:Liver Glycogen / Q000378:metabolism; D007986:Luteinizing Hormone / Q000378:metabolism; D011247:Pregnancy; D013963:Thyroid Hormones / Q000097:blood
chemical_list: D001786:Blood Glucose; D020738:Leptin; D008112:Liver Glycogen; D013963:Thyroid Hormones; D007986:Luteinizing Hormone; D013006:Growth Hormone
keywords: glucose metabolism; lipid metabolism; liver; thyroid hormone