Periparturient dairy cows do not exhibit hepatic insulin resistance, yet adipose-specific insulin resistance occurs in cows prone to high weight loss
| Autor: | Sigalit Boura-Halfon, M. Zachut, H. Honig, Uzi Moallem, Yehiel Zick, S. Striem |
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| Rok vydání: | 2013 |
| Předmět: |
Blood Glucose
medicine.medical_specialty medicine.medical_treatment Adipose tissue Ice calving Biology Real-Time Polymerase Chain Reaction Insulin resistance Pregnancy Internal medicine Weight Loss Peripartum Period Genetics medicine Animals Insulin Protein kinase B reproductive and urinary physiology Pyruvate Carboxylase Glucose tolerance test medicine.diagnostic_test Gluconeogenesis Glucose Tolerance Test medicine.disease Insulin receptor Endocrinology Adipose Tissue Liver Basal (medicine) biology.protein Cattle Female Phosphoenolpyruvate Carboxykinase (GTP) Animal Science and Zoology Insulin Resistance Phosphoenolpyruvate Carboxykinase (ATP) Food Science |
| Zdroj: | Journal of Dairy Science. 96:5656-5669 |
| ISSN: | 0022-0302 |
| DOI: | 10.3168/jds.2012-6142 |
| Popis: | The periparturient period in dairy cows is associated with alterations in insulin action in peripheral tissues; however, the molecular mechanism underlying this process is not completely understood. The objective was to examine the response to a glucose tolerance test (GTT) and to analyze insulin signaling in liver and adipose tissues in pre- and postpartum dairy cows. Liver and adipose tissue biopsies were taken before and after GTT, at 17d prepartum and again at 3 to 5d postpartum from 8 high-yielding Israeli Holstein dairy cows. Glucose clearance rate after GTT was similar pre- and postpartum. Basal insulin concentrations and the insulin response to GTT were approximately 4-fold higher prepartum than postpartum. In accordance, phosphorylation of the hepatic insulin receptor after GTT was higher prepartum than postpartum. Across periods, a positive correlation was observed between the basal and peak plasma insulin and phosphorylated insulin receptor after GTT in the liver. Hepatic phosphorylation of protein kinase B after GTT was elevated pre- and postpartum. Conversely, in adipose tissue, phosphorylation of protein kinase B after GTT pre- and postpartum was increased only in 4 out of 8 cows that lost less body weight postpartum. Our results demonstrate that hepatic insulin signaling is regulated by plasma insulin concentrations as part of the homeorhetic adjustments toward calving, and do not support a model of hepatic insulin resistance in periparturient cows. Nevertheless, we suggest that specific insulin resistance in adipose tissue occurs pre- and postpartum only in cows prone to high weight loss. The different responses among these cows imply that genetic background may affect insulin responsiveness in adipose tissue pre- and postpartum. |
| Databáze: | OpenAIRE |
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