Institute of Endocrinology, Belgrade, Serbia and Montenegro.
Ghrelin is the brain-gut peptide with growth hormone (GH)- releasing and appetite-inducing activities. Reviewed experimental evidence confirms the role of endogenous ghrelin in regulating GH secretion while studies in humans still fail to pinpoint the exact role of ghrelin in GH secretion. Accumulating evidence supports that ghrelin/GH secretagogue receptor (GHS-R) axis contributes to the maintenance of body weight. Evidence suggest the role of environmental factors modulating ghrelins activity, the role of constitutive activation of the GHS-R, polymorphisms in the GHS-R gene together with dysregulation of postpranidal ghrelin suppression in obesity. New important psychiatric issue is the role of ghrelin in the weight gain, insulin resistance and diabetes type 2 associated with the use of atypical antipsychotics.The novel role of ghrelin is in the adaptive response to caloric restriction and loss of body fat by inducing tissue-specific changes in lipid metabolism favoring triglyceride deposition in liver over skeletal muscle. New insights into the ghrelins effects on pancreas and liver, gives enough evidence for its role in glucose metabolism. In summary recent studies confirm the role of ghrelin as a marker of changes in energy balance and GHS-R as a modest amplifier of biological function. A ghrelin antagonist may provide answers in regard to ghrelin physiology or its involvement in the etiology of obesity. One of the crucial questions will be which side effects might be to watch for during blocking endogenous ghrelin action.