Insulin resistance of hind-limb tissues in vivo in lactating sheep.
1. The effects of varying the plasma insulin concentration by infusion while maintaining euglycaemia by infusion of glucose on nutrient arterio-venous differences across the hind-limb and mammary gland in lactating and non-lactating sheep were investigated. 2. Insulin infusion increased the glucose arterio-venous difference across the hind-limb; this effect of insulin was decreased by lactation, suggesting that lactation induces insulin resistance in skeletal muscle. 3. Lactation increased but insulin infusion decreased the plasma concentrations of acetate, beta-hydroxybutyrate and non-esterified fatty acids. 4. Insulin infusion decreased the arterio-venous differences of acetate and hydroxybutyrate across the hind-limb; this effect of insulin is probably indirect, resulting from the decrease in plasma concentrations of these metabolites. 5. Infusion of insulin had no effect on the glucose arterio-venous difference across the mammary gland, but did decrease the oxygen arterio-venous difference. 6. The results suggest that lactation results in insulin resistance in skeletal muscle, at least with respect to glucose utilization; this should facilitate the preferential utilization of glucose by the mammary gland.
Vernon
R G
RG
Hannah Research Institute, Ayr, Scotland, U.K.
Faulkner
A
A
Hay
W W
WW
Calvert
D T
DT
Flint
D J
DJ
D000085:Acetates / Q000378:metabolism; D000818:Animals; D005947:Glucose / Q000378:metabolism*; D006614:Hindlimb; D006885:Hydroxybutyrates / Q000378:metabolism; D007328:Insulin / Q000502:physiology*; D007333:Insulin Resistance; D007773:Lactates / Q000378:metabolism; D007774:Lactation; D008321:Mammary Glands, Animal / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D012756:Sheep
D000085:Acetates; D006885:Hydroxybutyrates; D007328:Insulin; D007773:Lactates; D005947:Glucose; D010100:Oxygen