Effects of the infusion of non-selective beta-, and selective beta1- or beta2-adrenergic agonists, on body fat mobilisation in underfed or overfed non-pregnant heifers.
The aim of this study was to analyse the effects of the intravenous infusion of a non-selective beta-agonist (beta-A) (isoproterenol, ISO), and selective beta1-A (dobutamine, D) or beta2-A (terbutaline, T) on body fat mobilisation in non-pregnant heifers, in a 2 x 2 crossover design with two treatments (underfeeding or overfeeding) and two periods. The effect of the duration of submission to each energy level on basal and ISO-induced fat mobilisation was also studied. ISO had a high and significant lipolytic effect whatever the energy level. Nevertheless, the response area of non-esterified fatty acids (NEFA) to ISO in underfed cows was 1.7 times greater than that in overfed cows. T had a slight but significant lipolytic effect on NEFA plasma response in the underfed group. D had no lipolytic effect. Basal and ISO-stimulated plasma NEFA levels were similar after 1 or 4 weeks of underfeeding.
Ferlay
A
A
Laboratoire sous-nutrition des ruminants, Inra, Theix, Saint-Genès-Champanelle, France. ferlay@clermont.inra.fr
Chilliard
Y
Y
D000273:Adipose Tissue / Q000378:metabolism*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004032:Diet; D004280:Dobutamine / Q000494:pharmacology; D002149:Energy Intake; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D008066:Lipolysis / Q000187:drug effects; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D013726:Terbutaline / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D011943:Receptors, Adrenergic, beta; D004280:Dobutamine; D007545:Isoproterenol; D013726:Terbutaline