Activity of hepatic but not skeletal muscle carnitine palmitoyltransferase enzyme is depressed by intravenous glucose infusions in lactating dairy cows

Al-Trad, B., Wittek, T., Gäbel, G., Fürll, M., Reisberg, K. and Aschenbach, J.R. (2010) Activity of hepatic but not skeletal muscle carnitine palmitoyltransferase enzyme is depressed by intravenous glucose infusions in lactating dairy cows. Journal of Animal Physiology and Animal Nutrition, 94(6), pp. 685-695. (doi: 10.1111/j.1439-0396.2010.00993.x)

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Abstract

A positive energy balance in dairy cows pre-partum may decrease hepatic carnitine palmitoyltransferase (CPT) enzyme activity, which might contribute to disturbances of lipid metabolism post-partum. The purpose of this study was to investigate whether skeletal muscle CPT activity can also be downregulated during positive energy balance. Mid-lactating dairy cows were maintained on intravenous infusion of either saline (control) or glucose solutions that increased linearly over 24 days, remained at the 24-day level until day 28 and were suspended thereafter. Liver and skeletal muscle biopsies, as well as four diurnal blood samples, were taken on days 0, 8, 16, 24, and 32, representing infusion levels equivalent to 0%, 10%, 20%, 30% and 0% of the net energy for lactation (NEL) requirement respectively. Glucose infusion increased serum insulin concentrations on day 16 and 24 while plasma glucose levels were increased at only a single time point on day 24. Serum beta-hydroxybutyric acid concentrations decreased between day 8 and 24; whereas changes in non-esterified fatty acids were mostly insignificant. Total lipid contents of liver and skeletal muscle were not affected by treatment. Hepatic CPT activity decreased with glucose infusion (by 35% on day 24) and remained decreased on day 32. Hepatic expression levels of CPT-1A and CPT-2 mRNA were not significantly altered but tended to reflect the changes in enzyme activity. In contrast to the liver, no effect of glucose infusion was observed on skeletal muscle CPT activity. We conclude that suppression of CPT activity by positive energy balance appears to be specific for the liver in mid-lactating dairy cows.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Wittek, Dr Thomas
Authors: Al-Trad, B., Wittek, T., Gäbel, G., Fürll, M., Reisberg, K., and Aschenbach, J.R.
Subjects:S Agriculture > SF Animal culture > SF600 Veterinary Medicine
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Journal of Animal Physiology and Animal Nutrition
ISSN:1439-0396
ISSN (Online):0931-2439
Published Online:09 June 2010

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