Tu2037 Food Intake Associated Gene Expression Profiles in the Stomach of Genetically Targeted Mice Deficient in CCK1 Receptor and/or CCK2 Receptor

Abstract

Background: Ghrelin is the only known peripherally produced and centrally acting peptide hormone that stimulates food intake in animals and humans. Recently, the ghrelin acylating enzyme ghrelin-O-acyltransferase (GOAT) has been identified in mice and humans. Besides the expected expression in the stomach we also detected GOAT in the circulation of rats and mice and its expression was dependent on the metabolic status with an increase under fasting conditions. Aims: To investigate whether GOAT is also present in human plasma and whether expression levels are affected under different conditions of body weight. Methods: Normal weight (body mass index, BMI 19-25 kg/m2, n=4 women and 5 men, age 48.4 ± 3.8 years), anorexic (BMI 30 kg/m2, n=4 women and 5 men, age 46.2 ± 4.4 years) hospitalized patients were recruited from the Division of Psychosomatic Medicine and gave informed consent to participate in the study. Blood was withdrawn in overnight fasted subjects between 07:00 and 08:00 am, collected in EDTA tubes containing aprotinin and plasma was formed by centrifugation, processed for Western blot and stained with an anti-human-GOAT polyclonal antibody (Phoenix Pharmaceuticals). Semiquantitative analysis of pixel intensity was performed using Scion Image 4.0.3. Results: GOAT protein expression was detected in human plasma as indicated by a strong band at the expected size of 50 kDa. In normal weight patients (mean BMI 22.7 ± 0.8 kg/m2) the intensity of the 50 kDa band was 28361.2 ± 849.6. The expression was significantly lower in anorexic patients (mean BMI 12.6 ± 0.6 kg/m2, intensity: 20733.3 ± 1732.0, P<0.001), while it was significantly higher in the plasma of obese patients (mean BMI 68.9 ± 2.7 kg/m2, intensity: 32532.3 ± 1822.9, P<0.05). Plasma GOATprotein expression showed a significant positive correlationwith BMI (r=0.59, P<0.01). Conclusions: These data show that GOAT protein is also present in human plasma and that GOAT protein levels depend on the metabolic condition with decreased levels in anorexic and increased levels in morbidly obese patients. These data may point towards a contributing role of GOAT in the development or maintenance of these diseases as it is the only enzyme known to acylate ghrelin.