Growth hormone and ghrelin secretion in severely obese women before and after bariatric surgery.
OBJECTIVE
The objective was to evaluate ghrelin and growth hormone (GH) interactions and responses to a growth hormone-releasing hormone (GHRH)/arginine test in severe obesity before and after surgically-induced weight loss.


METHODS
Our study population included 11 severely obese women 39 +/- 12 years of age, with a mean BMI of 48.6 +/- 2.4 kg/m2, re-studied in a phase of stabilized body weight, with a BMI of 33.4 +/- 1.2 kg/m2, 18 months after having successfully undergone biliopancreatic diversion (BPD). A GHRH/arginine test was performed before and 18 months after BPD to evaluate ghrelin and GH interactions. Active ghrelin, measured by radioimmunoassay (RIA), and GH, measured by chemiluminescence assay, were assayed before and after the GHRH/arginine test.


RESULTS
Fasting serum GH levels and GH area under the curve (AUC) significantly increased from 0.2 +/- 0.05 ng/mL to 1 +/- 0.3 ng/mL (p < 0.05) and from 514.76 +/- 98.7 ng/mL for 120 minutes to 1957.3 +/- 665.1 ng/mL for 120 minutes after bariatric surgery (p < 0.05), respectively. Although no significant change in fasting ghrelin levels was observed (573 +/- 77.9 before BPD vs. 574.1 +/- 32.7 after BPD), ghrelin AUC significantly increased from -3253.9 +/- 2180.9 pg/mL for 120 minutes to 1142.3 +/- 916.4 pg/mL for 120 minutes after BPD (p < 0.05). Fasting serum insulin-like growth factor (IGF)-1 concentration did not change significantly (133.6 +/- 9.9 ng/mL before vs. 153.3 +/- 25.2 ng/mL after BPD).


CONCLUSIONS
Our study demonstrates that the mechanisms involved in ghrelin and GH secretion after the secretagogue stimulus (GHRH/arginine) are consistent with patterns observed in other populations.
Valera Mora
Maria E
ME
Department of Internal Medicine, Metabolic Unit, Università Cattolica S. Cuore, Rome, Italy.
Manco
Melania
M
Capristo
Esmeralda
E
Guidone
Caterina
C
Iaconelli
Amerigo
A
Gniuli
Donatella
D
Rosa
Giuseppina
G
Calvani
Menotti
M
Mingrone
Geltrude
G
D000328:Adult; D001120:Arginine / Q000008:administration & dosage; D015904:Biliopancreatic Diversion / Q000379:methods*; D001786:Blood Glucose / Q000378:metabolism; D005260:Female; D054439:Ghrelin; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000008:administration & dosage; D006801:Humans; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D020738:Leptin / Q000097:blood; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000503:physiopathology* / Q000601:surgery*; D036361:Peptide Hormones / Q000097:blood / Q000378:metabolism*; D015431:Weight Loss / Q000502:physiology*
D001786:Blood Glucose; D054439:Ghrelin; D007328:Insulin; D020738:Leptin; D036361:Peptide Hormones; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D001120:Arginine