Regulation of carbohydrate metabolism by exogenous glucagon in lactating cows
- Resource Type
- Authors
- Pengxiang She
- Source
- Subject
- chemistry.chemical_classification
endocrine system
medicine.medical_specialty
Glycogenolysis
Glycogen
Increased Lipolysis
Chemistry
digestive, oral, and skin physiology
Carbohydrate metabolism
Glucagon
Amino acid
chemistry.chemical_compound
Endocrinology
NEFA
Internal medicine
medicine
Urea
hormones, hormone substitutes, and hormone antagonists
- Language
Twenty cows were assigned at parturition into two groups to study metabolic effects of continuous infusions of glucagon. Groups were normal controls and normal cows treated with glucagon at 10 mg/d for 14 d starting at 21 d postpartum. Daily blood samples and nine periodic liver biopsies were tziken from d 7 to d 49 postpartum. Plasma glucagon increased 6to 7-fold during infusions into treated cows. Plasma insulin increased during wk 1 of glucagon infusions. Plasma glucose increased by 11.5 and 9.0 mg/dl during wk I and wk 2 of glucagon infusions. Neither plasma NEFA. BHBA. nor urea N were affected by glucagon infusions. Liver glycogen decreased by d 2 of glucagon infusions, but it was restored by d 7 of infusions and had increased to 169% of the preinfusion baseline at 3 d after cessation of glucagon infusions. Milk production was less during glucagon infusions. Both milk protein yield and milk protein percentage decreased during glucagon infusions, which implies a decreased availability of amino acids for milk protein synthesis. Feed intakes did not increase during glucagon infusions, which was in contrast to the control group. The results indicate that glucagon infusions cause a net hepatic glycogenolysis initially and enhance plasma glucose concentrations, but there is no evidence for increased lipolysis from