Adiponectin receptors gene expression and insulin sensitivity in non-diabetic Mexican Americans with or without a family history of Type 2 diabetes.
OBJECTIVE
The recent discovery of two adiponectin receptors (AdipoR1 and AdipoR2) will improve our understanding of the molecular mechanisms underlying the insulin-sensitising effect of adiponectin. The aim of this study was to determine for the first time whether skeletal muscle AdipoR1 and/or AdipoR2 gene expression levels are associated with insulin resistance.


METHODS
Using RT-PCR and northern analysis we measured AdipoR1 and AdipoR2 gene expression in skeletal muscle from healthy Mexican Americans with normal glucose tolerance who had (n=8) or did not have (n=10) a family history of Type 2 diabetes.


RESULTS
Gene expression profiling indicated that the AdipoR1 and AdipoR2 isoforms are highly expressed in human skeletal muscle, unlike in mice where AdipoR2 expression was highest in the liver, and AdipoR1 was highest in skeletal muscle. In the study subjects, the expression levels of AdipoR1 (p=0.004) and AdipoR2 (p=0.04), as well as plasma adiponectin concentration (p=0.03) were lower in people with a family history of Type 2 diabetes than in those with no family history of the disease. Importantly, the expression levels of both receptors correlated positively with insulin sensitivity (r=0.64, p=0.004 and r=0.47, p=0.048 respectively).


CONCLUSIONS
Collectively, these data indicate that both isoforms of the adiponectin receptor play a role in the insulin-sensitising effect of adiponectin.
Civitarese
A E
AE
Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
Jenkinson
C P
CP
Richardson
D
D
Bajaj
M
M
Cusi
K
K
Kashyap
S
S
Berria
R
R
Belfort
R
R
DeFronzo
R A
RA
Mandarino
L J
LJ
Ravussin
E
E
D052242:Adiponectin; D000328:Adult; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood; D008297:Male; D017058:Mexican Americans; D012333:RNA, Messenger / Q000235:genetics; D054419:Receptors, Adiponectin; D011956:Receptors, Cell Surface / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013781:Texas
C475418:ADIPOR1 protein, human; C475420:ADIPOR2 protein, human; D052242:Adiponectin; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D054419:Receptors, Adiponectin; D011956:Receptors, Cell Surface