Obestatin is not elevated or correlated with insulin in children with Prader-Willi syndrome.
BACKGROUND
Obestatin is a peptide hormone derived from the proteolytic cleavage of ghrelin preprohormone. In Prader-Willi syndrome (PWS), the levels of total ghrelin (TG) and acylated ghrelin (AG) are increased, and these hormones are regulated by insulin.


OBJECTIVE
Our objective was to analyze the changes in the obestatin levels after glucose loading and to characterize the correlations of obestatin with TG, AG, and insulin.


METHODS
Plasma obestatin, TG, AG, and insulin levels were measured in PWS children (n = 15) and controls (n = 18) during an oral glucose tolerance test.


METHODS
All subjects were admitted to the Samsung Medical Center.


METHODS
An oral glucose tolerance test was performed after an overnight fast.


METHODS
The plasma levels of obestatin, TG, AG, and serum insulin were measured at 0, 30, 60, 90, and 120 min after glucose challenge, and areas under the curves (AUCs) were calculated.


RESULTS
No significant difference in AUC of the plasma obestatin was found between the PWS children and normal obese controls (P = 0.885), although AUC of AG (P = 0.002) and TG (P = 0.003) were increased in the PWS children. Moreover, There was a negative correlation between the AUC of AG and AUC of insulin both in PWS (r = -0.432; P = 0.049) and in controls (r = -0.507; P = 0.016). However, AUC of obestatin was not significantly correlated with AUC of insulin (in PWS, r = 0.168 and P = 0.275; in controls, r = -0.331 and P = 0.09).


CONCLUSIONS
Our results indicate that plasma obestatin is not elevated in PWS children and is not regulated by insulin both in PWS children and in obese controls.
Park
Won Hah
WH
Department of Orthopedic Sports Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 135-710 Seoul, Korea.
Oh
Yoo Joung
YJ
Kim
Gae Young
GY
Kim
Sang Eun
SE
Paik
Kyung-Hoon
KH
Han
Sun Ju
SJ
Kim
An Hee
AH
Chu
Su Hyun
SH
Kwon
Eun Kyung
EK
Kim
Seon Woo
SW
Jin
Dong-Kyu
DK
D019540:Area Under Curve; D015992:Body Mass Index; D002648:Child; D005260:Female; D054439:Ghrelin; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D036361:Peptide Hormones / Q000097:blood*; D011218:Prader-Willi Syndrome / Q000097:blood*; D014280:Triglycerides / Q000097:blood
D054439:Ghrelin; D007328:Insulin; D036361:Peptide Hormones; D014280:Triglycerides; C505799:obestatin, human