Obestatin is a recently discovered
peptide hormone that appears to be involved in reducing food intake, gut motility and
body weight.
Obestatin is a product of the preproghrelin gene and appears to oppose several physiological actions of
ghrelin. This study investigated the acute effects of
obestatin (1-23) and the truncated form,
obestatin (11-23), on feeding activity,
glucose homeostasis or insulin secretion. Mice received either intraperitoneal
obestatin (1-23) or (11-23) (1 micromol/kg) 4h prior to an allowed 15 min period of feeding.
Glucose excursions and
insulin responses were lowered by 64-77% and 39-41%, respectively, compared with saline controls. However this was accompanied by 43% and 53% reductions in food intake, respectively. The effects of
obestatin peptides were examined under either basal or
glucose (18 mmol/kg) challenge conditions to establish whether effects were independent of changes in feeding. No alterations in plasma
glucose or
insulin responses were observed. In addition,
obestatin peptides had no effect on
insulin sensitivity as revealed by hypoglycaemic response when co-administered with
insulin. Our observations support a role for
obestatin in regulating metabolism through changes of appetite, but indicate no direct actions on
glucose homeostasis or insulin secretion.