In normal weight humans:

Three-day fasting in six lean men, abolished the meal-related secretory pattern of Ghrelin without increasing 24-h Ghrelin levels with reduction of leptin levels without major changes in fat mass. J Clin Endocrinol Metab. 2004 Jan;89(1):335-43

In Obese humans:

A 3-month energy deficit-imposing diet and exercise intervention  in 22 healthy normal-weight women resulted in increased Ghrelin levels which correlated negatively  with weight changes. J Clin Endocrinol Metab. 2004 Jun;89(6):2659-64. A 3-week integrated body weight reduction program in 10  obese subjects significantly reduced weight, BMI and leptin levels, without significant changes in fasting Ghrelin or the Ghrelin response to a meal. The degree of non-surgically induced weight loss that might normalise fasting Ghrelin levels and restore normal meal-induced Ghrelin suppression in severely obese subjects remains unknown. J Endocrinol Invest. 2003 Aug;26(8):723-7 Weight loss produced over 6 months by a low calorie diet in 13 obese subjects resulted in an  increase in plasma Ghrelin levels N Engl J Med 346:1623–1630, while weight loss over 12 weeks induced by fat restriction on adlibitum diet  in 16 obese subjects did not result in compensatory Ghrelin rise J Clin Endocrinol Metab. 2003 Apr;88(4):1577-86
 

Ghrelin and Weight loss by Gastric Surgery

In the rat, Ghrelin seems to occur in the X/A-like cells. The Ghrelin-IR cells in the antrum were distinct from the gastrin cells, the serotonin-containing enterochromaffin cells and the D cells.  The concentration of Ghrelin in the circulation was lowered by about 80% following the surgical removal of the acid-producing part of the stomach. Regul Pept. 2001 Jun 15;99(2-3):141-50 The oxyntic mucosa is thus probably the  major source of Ghrelin. Ghrelin levels have been shown to be proportional to the degree of gastric fundus resection in rats. Scand J Gastroenterol. 2002 Apr;37(4):437-43

 Total gastrectomy in man results in reduction of Ghrelin levels by 65%. J Biol Chem. 2003 Jan 3;278(1):64-70 This is proposed as one of the mechanisms facilitating weight loss in patients undergoing gastric bypass surgery; N Engl J Med. 2002 May 23;346(21):1623-30. Ghrelin levels fell dramatically post gastric bypass surgery in man with abolition of the "normal", meal-related fluctuations and diurnal rhythm of Ghrelin. Removal of stomach and part of duodenum is thought to be responsible for the lack of Ghrelin rise in response to weight loss in these patients. After gastrectomy, plasma Ghrelin level is reduced only by 65% emphasizing the contribution from other sites (pancreas and small and large intestines). Proceedings of the 83rd Annual Meeting of The Endocrine Society, Denver, CO, 2001, p 336. Interestingly, a study in 10 obese women has demonstrated that Ghrelin levels rise (rather than fall) post roux-en-Y gastric bypass surgery  in keeping with weight loss, compared to 10 non-operated BMI matched obese women.  J Clin Endocrinol Metab. 2003 Jul;88(7):3177-83,  although further studies seem to be consistent with a lack of compensatory Ghrelin rise post bypass surgery. J Clin Endocrinol Metab. 2005 Jan;90(1):359-65.

A study comparing 17 BMI-matched weight stable patients who had undergone laparoscopic adjustable gastric banding with optimal or  suboptimal band restriction demonstrated no difference of Ghrelin, leptin or insulin levels in the two groups despite the fact that optimal band restriction was associated with significantly greater fasting and post-prandial satiety levels than with reduced restriction. J Clin Endocrinol Metab. 2004 Dec 7

 In another study, 8 patients who lost weight by gastric banding demonstrated a significant rise in Ghrelin levels (377 +/- 201 pg/mL) following weight loss compared to 5 patients who underwent gastric bypass.  Plasma Leptin decreased in both these groups. Obes Res. 2004 Feb;12(2):346-50. Yet another study has demonstrated a decrease in Ghrelin levels in both laparoscopic gastric bypass and laparoscopic banding. Not surprisingly, there was a more marked decrease in Ghrelin levels in laparoscopic gastric bypass as opposed to laparoscopic gastric banding. J Clin Endocrinol Metab. 2003 Sep;88(9):4227-31.

Ghrelin levels have also been shown to be low in patients with the short bowel syndrome. Eat Weight Disord. 2003 Sep;8(3):207-11.

  .

    This page was last updated on: 07/03/2007

 Copyright and Terms of use