Ghrelin and leptin levels in obese adolescents. Relationship with body fat and insulin resistance.
OBJECTIVE
Ghrelin and leptin levels are influenced by body fat (BF%), pubertal stage and possibly insulin resistance (IR). The aim of our study was: 1) To compare fasting ghrelin and leptin levels between obese and non-obese, adolescents, 2) to investigate possible correlations of these hormones with BF %, as well as IR.


METHODS
Twenty obese insulin resistant (IR) adolescents, twenty obese non IR (NIR) and fifteen healthy non-obese, age-matched adolescents were studied. In all participants, height, weight, body mass index (BMI) and BF % were measured. Fasting glucose, insulin, ghrelin and leptin levels were determined. IR was assessed using HOMA-IR index.


RESULTS
BMI, BF %, insulin and HOMA-IR values were positively correlated with leptin and negatively with ghrelin levels. A negative correlation between circulating leptin and ghrelin levels was found. A suggestive positive correlation between leptin levels and BF %, independent of BMI, was also observed (P=0.075). Ghrelin levels were significantly correlated with insulin levels and HOMA-IR, independent of BMI (P=0.077).


CONCLUSIONS
Obesity and IR may play an important role in the release of ghrelin as well as in the negative correlation between ghrelin and leptin.
4th Department of Pediatrics, Medical School, Aristotle University of Thessaloniki, Greece.
Charilaos
C
Stylianou
Assimina
A
Galli-Tsinopoulou
Dimitrios
D
Farmakiotis
Israel
I
Rousso
Michael
M
Karamouzis
George
G
Koliakos
Sanda
S
Nousia-Arvanitakis
D000273:Adipose Tissue; D000293:Adolescent; D001786:Blood Glucose / Q000032:analysis; D001827:Body Height; D015992:Body Mass Index; D002648:Child; D005215:Fasting; D005260:Female; D054439:Ghrelin / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D020738:Leptin / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood*
D001786:Blood Glucose; D054439:Ghrelin; D007328:Insulin; D020738:Leptin