Ghrelin is a 28 amino acid peptide predominantly produced by the stomach that has been discovered to be a natural ligand of the orphan growth hormone (GH) secretagogue (GHS) receptor (GHS-R) type 1a. Like synthetic GHS, ghrelin possesses a strong GH-releasing effect provided that the molecule is acylated in serine3 and it is thought to be a natural GHS of major importance in the control of soma...

Ingestion of food affects secretion of hormones from enteroendocrine cells located in the gastrointestinal mucosa. These hormones are involved in the regulation of various gastrointestinal functions including the control of food intake. One cell in the stomach, the X/A-like has received much attention over the past years due to the production of ghrelin. Until now, ghrelin is the only known ore...

OBJECTIVE The dorsomedial hypothalamus (DMH) has been considered an orexigenic nucleus, since the DMH lesion reduced food intake and body weight and induced resistance to diet-induced obesity. The DMH expresses feeding regulatory neuropeptides and receptors including neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART), cholecystokinin (CCK), leptin receptor, and melanocor...

We studied the long term effects of a single exposure to immobilization stress (IS) (1 h) on the expression of anorexigenic (Pro-opiomelanocortin: POMC and cocaine amphetamine related transcript: CART) and orexigenic (neuropeptide Y:NPY, Agouti related peptide: AgRP) factors in hypothalamus and dorso vagal complex (DVC). We showed, by using RT-PCR that in the hypothalamus, that the mRNAs of POM...

Activation of mammalian target of rapamycin 1 (mTORC1) by nutrients, insulin and leptin leads to appetite suppression (anorexia). Contrastingly, increased AMP-activated protein kinase (AMPK) activity by ghrelin promotes appetite (orexia). However, the interplay between these mechanisms remains poorly defined. The relationship between the anorexigenic hormones, insulin and leptin, and the orexig...

The goldfish (Carassius auratus) has a number of merits as a laboratory animal, and we have extensively identified the mechanisms by which ghrelin regulates food intake in this species. For the first time, we have purified and characterized 11 molecular variants of ghrelin that are present in goldfish intestine and shown that 17-residue ghrelin, the predominant form with n-octanoyl modification...

Previously, we reported that exogenous administration of ghrelin ameliorates glucose metabolism in a neonate streptozotocin (STZ)-induced diabetic rat model through enhancement of β-cell proliferation. However, it was not clear whether the observed β-cell proliferation was a direct or indirect effect (e.g., via orexigenic or growth hormone-stimulated pathways) of ghrelin activity. Here, we aime...

NPY is a potent orexigenic signal and represents a key component of targets through which leptin exerts a regulatory restraint on body adiposity. Part of the orexigenic effects of NPY are mediated by hypothalamic NPY-Y(1) receptors. Here we studied the effect of fasting, leptin, and glucose administration on Y(1) receptor gene expression using a transgenic mouse model carrying a mouse Y(1) rece...