title: Nutritional status induces divergent variations of GLUT4 protein content, but not lipoprotein lipase activity, between adipose tissues and muscles in adult cattle.
abstract: Metabolic adaptations to variations in food supply are incompletely understood in ruminant animal adipose tissue (AT) and muscle. To explore this, we studied lipid metabolism and glucose transport potential in one internal and one external AT, as well as in one oxidative and one glycolytic muscle from control, 7 d underfed and 21 d refed adult cows. Refeeding increased (+79 to +307 %) the activities of enzymes involved in de novo lipogenesis (fatty acid synthase, malic enzyme, glucose-6-phosphate dehydrogenase) in perirenal and subcutaneous AT; underfeeding did not modify these variables. Underfeeding decreased the activities of lipoprotein lipase (LPL) in perirenal AT (-70 %) and cardiac muscle (-67 %), but did not modify the activities in subcutaneous AT and longissimus thoracis. Refeeding increased LPL activities in all tissues (+40 to +553 %) to levels comparable with (cardiac muscle) or greater than (AT, longissimus thoracis) those observed in control cows. Such variations in perirenal and cardiac muscle LPL activities did not result from variations in LPL mRNA levels, but suggest a post-transcriptional regulation of LPL in these nutritional conditions. Underfeeding did not modify GLUT4 contents in perirenal AT and muscles, while refeeding increased it only in perirenal AT (+250 %). Our present results contrast with previous results in rats, where LPL is regulated in opposite directions in AT and muscles, and GLUT4 is generally increased by fasting and decreased by refeeding in skeletal muscles. The present results highlight the bovine specificity of the response, which probably arises in part from peculiarities of ruminant animals for nutrient digestion and absorption.
authors.affiliation: INRA, Unité de Recherches sur les Herbivores, Theix, 63122 Saint-Genès-Champanelle, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Bonnet
authors.forename: Yannick
authors.initials: Y
authors.lastname: Faulconnier
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Hocquette
authors.forename: François
authors.initials: F
authors.lastname: Bocquier
authors.forename: Christine
authors.initials: C
authors.lastname: Leroux
authors.forename: Patrice
authors.initials: P
authors.lastname: Martin
authors.forename: Yves
authors.initials: Y
authors.lastname: Chilliard
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D001835:Body Weight; D002417:Cattle / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D051275:Glucose Transporter Type 4; D008055:Lipids / Q000096:biosynthesis; D008071:Lipoprotein Lipase / Q000235:genetics / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D009752:Nutritional Status / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D051275:Glucose Transporter Type 4; D008055:Lipids; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; D008071:Lipoprotein Lipase