The postprandial response of adiponectin to a high-fat meal in normal and insulin-resistant subjects.
OBJECTIVE
Adiponectin is an adipose-specific protein with short-term effects in vivo on glucose and fatty acid levels. We studied the plasma concentration and the proteolytic activation status of adiponectin following the consumption of a high-fat, low-carbohydrate meal.


METHODS
Analysis of adiponectin concentration and polypeptide structure after consumption of a fat meal.


METHODS
Normal subjects (n=24) and first-degree relatives of patients with type II diabetes (n=20).


METHODS
All subjects had a normal fasting plasma glucose and glucose tolerance. Blood was collected for the determination of plasma insulin, adiponectin, triglyceride, and free fatty acids. Body composition was assessed with dual-energy X-ray absorptiometry and whole-body insulin sensitivity with a euglycaemic, hyperinsulinaemic clamp. Postprandial response over 6 h was determined for plasma adiponectin, glucose, insulin, triglyceride, and free fatty acids. Adiponectin was measured by commercial RIA and its polypeptide structure examined by Western blotting.


RESULTS
The relatives were more insulin resistant and had increased adiposity compared with control subjects. There was no significant difference in postprandial response in fatty acids, triglyceride, or insulin between the groups. Postprandial levels of adiponectin measured by radioimmunoassay were not significantly different from fasting levels, and no breakdown products of adiponectin were detectable in postprandial samples by Western blotting.


CONCLUSIONS
Levels of circulating adiponectin do not alter in response to a fat meal, despite evidence in mice that acute changes in adiponectin significantly affect postprandial fatty acid flux. Moreover, a fat meal challenge did not lead to significant activation of adiponectin by proteolytic conversion.
Peake
P W
PW
Division of Medicine, Prince of Wales Hospital, Randwick, NSW, Australia. p.peake@unsw.edu.au
Kriketos
A D
AD
Denyer
G S
GS
Campbell
L V
LV
Charlesworth
J A
JA
D052242:Adiponectin; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D015153:Blotting, Western; D004041:Dietary Fats / Q000008:administration & dosage / Q000097:blood*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D011506:Proteins / Q000378:metabolism*; D014280:Triglycerides / Q000097:blood
D052242:Adiponectin; D001786:Blood Glucose; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D014280:Triglycerides