The effects of rosiglitazone on fatty acid and triglyceride metabolism in type 2 diabetes.
OBJECTIVE
We investigated the effects of rosiglitazone on NEFA and triglyceride metabolism in type 2 diabetes.


METHODS
In a double-blind, placebo-controlled, cross-over study of rosiglitazone in diet-treated type 2 diabetic subjects, we measured arteriovenous differences and tissue blood flow in forearm muscle and subcutaneous abdominal adipose tissue, used stable isotope techniques, and analysed gene expression. Responses to a mixed meal containing [1,1,1-(13)C]tripalmitin were assessed.


RESULTS
Rosiglitazone induced insulin sensitisation without altering fasting NEFA concentrations (-6.6%, p=0.16). Postprandial NEFA concentrations were lowered by rosiglitazone compared with placebo (-21%, p=0.04). Adipose tissue NEFA release was not decreased in the fasting state by rosiglitazone treatment (+24%, p=0.17) and was associated with an increased fasting hormone-sensitive lipase rate of action (+118%, p=0.01). Postprandial triglyceride concentrations were decreased by rosiglitazone treatment (-26%, p<0.01) despite unchanged fasting concentrations. Rosiglitazone did not change concentrations of triglyceride-rich lipoprotein remnants. Adipose tissue blood flow increased with rosiglitazone (+32%, p=0.03). Postprandial triglyceride [(13)C]palmitic acid concentrations were unchanged, whilst NEFA [(13)C]palmitic acid concentrations were decreased (p=0.04). In muscle, hexokinase II mRNA expression was increased by rosiglitazone (+166%, p=0.001) whilst the expression of genes involved in insulin signalling was unchanged. Adipose tissue expression of FABP4, LPL and FAT/CD36 was increased.


CONCLUSIONS
Rosiglitazone decreases postprandial NEFA and triglyceride concentrations. This may represent decreased spillover of NEFAs from adipose tissue depots. Decreased delivery of NEFAs to the liver may lead to lowered postprandial triglyceride concentrations. Upregulation of hexokinase II expression in muscle may contribute to insulin sensitisation by rosiglitazone.
Tan
G D
GD
Oxford Centre for Diabetes Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, OX3 7LJ, UK. garry.tan@oxlip.ox.ac.uk
Fielding
B A
BA
Currie
J M
JM
Humphreys
S M
SM
Désage
M
M
Frayn
K N
KN
Laville
M
M
Vidal
H
H
Karpe
F
F
D000273:Adipose Tissue / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism*; D000328:Adult; D000368:Aged; D001706:Biopsy; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000097:blood; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism*; D010919:Placebos; D012039:Regional Blood Flow / Q000187:drug effects; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology*; D014280:Triglycerides / Q000097:blood / Q000378:metabolism*
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007004:Hypoglycemic Agents; D007328:Insulin; D010919:Placebos; D045162:Thiazolidinediones; D014280:Triglycerides; D000077154:Rosiglitazone