Serum ghrelin levels in response to glucose load in obese subjects post-gastric bypass surgery.
OBJECTIVE
We sought to elucidate further the mechanisms leading to weight loss after gastric bypass (GBP) surgery in morbidly obese individuals. Ghrelin is a gastroenteric appetite-stimulating peptide hormone, fasting levels of which decrease with increasing adiposity and increase with diet-induced weight loss. In addition, ghrelin levels rapidly decline postprandially.


METHODS
We measured serum ghrelin responses to a 75-g oral glucose tolerance test (OGTT) in 6 subjects who had undergone GBP surgery 1.5 +/- 0.7 years before testing and compared these responses with 6 obese subjects about to undergo GBP surgery, 6 obese nonsurgical subjects (matched for BMI to the post-GBP surgical group), and 5 lean subjects.


RESULTS
Despite weight loss induced by the GBP surgery, fasting serum ghrelin levels were significantly lower in the post-GBP surgery group than in the lean subject (by 57%) or pre-GBP surgery (by 45%) group. Serum ghrelin levels during the OGTT were significantly lower in postoperative than in lean, obese pre-GBP surgical, or obese nonsurgical subjects. The magnitude of the decline in serum ghrelin levels between 0 and 120 minutes post-OGTT was significantly smaller in postoperative (by 62%), obese pre-GBP surgical (by 80%), or obese nonsurgical (by 69%) subjects in comparison with lean subjects.


CONCLUSIONS
Serum ghrelin levels in response to OGTT are lower in subjects post-GBP surgery than in either lean or obese subjects. Tonically low serum ghrelin levels may be involved in the mechanisms inducing sustained weight loss after GBP surgery.
Tritos
Nicholas A
NA
Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA.
Mun
Edward
E
Bertkau
Anne
A
Grayson
Rebecca
R
Maratos-Flier
Eleftheria
E
Goldfine
Allison
A
D000328:Adult; D005260:Female; D015390:Gastric Bypass; D054439:Ghrelin; D005947:Glucose / Q000008:administration & dosage*; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000601:surgery; D036361:Peptide Hormones / Q000097:blood*; D011184:Postoperative Period; D015431:Weight Loss / Q000502:physiology*
D054439:Ghrelin; D007328:Insulin; D036361:Peptide Hormones; D005947:Glucose