Short Communication: Change in Plasma Ghrelin in Dairy Cows Following an Intravenous Glucose Challenge

• Published in: Journal of dairy science 2008-03, Vol.91 (3), p.1005-1010
• Main Authors: Roche, J.R., Sheahan, A.J., Chagas, L.M., Boston, R.C.
• Format: Article
• Language: English
• Subjects: Animal productions; Animals; Biological and medical sciences; Blood Glucose - analysis; blood plasma; Cattle - blood; dairy cows; Epinephrine - blood; Fatty Acids, Nonesterified - blood; Female; Food industries; Fundamental and applied biological sciences. Psychology; ghrelin; Ghrelin - blood; glucose; glucose challenge; Glucose Tolerance Test - veterinary; Glucose Transporter Type 2 - physiology; Glucose Transporter Type 4 - physiology; Insulin - blood; intake regulation; intravenous glucose challenge; intravenous injection; Kinetics; lipolysis; Milk and cheese industries. Ice creams; neuroendocrine factor; nutrition physiology; Terrestrial animal productions; Vertebrates
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2007-0571

Ghrelin is an endogenous ligand of the growth hormone secretagogue receptor and a potent orexigenic (appetite-stimulating) agent in humans and rodents, but little is known about its effect in dairy cows. Ten multiparous dairy cows 35 d in milk were subjected to an i.v. glucose challenge (300mg of d-glucose/kg of body weight). Before infusion and at regular intervals after infusion, plasma glucose, insulin, nonesterified fatty acids (NEFA), growth hormone, epinephrine, and ghrelin concentrations were monitored. Plasma insulin rose (27.2 mU/L at 10min) and NEFA, epinephrine, and ghrelin declined (nadir=0.22 mmol/L, 22.2μg/L, and 272μg/L at 31, 13, and 22min, respectively) after the glucose infusion. Ghrelin declined for 22min before returning to suprabasal levels at approximately 75min postinfusion. Sequential changes of the hormones and metabolites suggested a glucose transporter, type 2- and glucose transporter, type 4-mediated disposal of glucose, and an insulin-mediated reduction in NEFA. Ghrelin and epinephrine declined after glucose infusion and before the insulin peak, but the effect of insulin as a controlling factor in the hyperglycemic reduction in these hormones cannot be discounted. The post-nadir surge in ghrelin may be regulated by the decline in circulating concentrations of glucose and NEFA (an energy-deficit signal). The profile of change in plasma ghrelin in lactating dairy cows after a glucose challenge was similar to that in monogastric animals.