Protein intake during aggressive calorie restriction in obesity determines growth hormone response to growth hormone-releasing hormone after weight loss.
OBJECTIVE
We evaluated the influence of two types of calorie restriction, total fast or very low calorie diet, on GH responsiveness to GHRH in severely obese patients.


METHODS
Twenty patients with massive obesity underwent one of two types of calorie restriction, total fast (10 patients) or very low calorie diet (10 patients).


METHODS
Fasting GH, IGF-I, glucose, insulin and GH secretion after GHRH (100 ug i.v.) were assessed in all patients before and after diet therapy.


RESULTS
Both types of diet produced similar weight reduction (total fast, 5.6 +/- 1.6 kg/m2 vs very low calorie diet, 5.6 +/- 1.5 kg/m2 mean +/- SD). A significant increase in the integrated GH secretion was observed after weight loss with very low calorie diet (17 +/- 9 vs 27 +/- 12 mU/l min; P < 0.05). However, no change was found in GH response after weight loss with total fast (13 +/- 5 vs 15 +/- 7 mU/l min). Glucose, insulin and IGF-I levels showed a significant decrease with weight reduction which was similar for both groups.


CONCLUSIONS
These findings suggest that the type of dietary manipulation during calorie restriction in obese patients may influence the changes in GH response to GHRH after weight loss.
Megia
A
A
Endocrinology Department, Hospital La Paz, Madrid, Spain.
Herranz
L
L
Luna
R
R
Gómez-Candela
C
C
Pallardo
F
F
Gonzalez-Gancedo
P
P
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake / Q000502:physiology*; D005260:Female; 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 / Q000032:analysis; D008297:Male; D009765:Obesity / Q000097:blood / Q000178:diet therapy*; D015431:Weight Loss / Q000502:physiology
D001786:Blood Glucose; D004044:Dietary Proteins; D007328:Insulin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone