RESUMO
OBJECTIVE: The aim of the present study was to reveal the expression characteristics of ghrelin in human three major salivary glands and to investigate saliva and serum ghrelin level and the relation with weight and lipid indices in Chinese children. DESIGN: Expression and distribution of ghrelin in parotid, submandibular, and sublingual glands were measured by reverse transcription-polymerase chain reaction and immunohistochemistry. Saliva and serum samples were collected from 194 Chinese children and adolescents (mean age 12.98 years). Ghrelin levels were tested by enzyme-linked immunosorbent assay. Significant differences were estimated by one-way ANOVA. RESULTS: Ghrelin mRNA was expressed in parotid and submandibular glands, but was not detectable in sublingual glands. Ghrelin proteins were widespread in the cytoplasm of striated, intercalated and excretory ducts, as well as in serous acini of parotid and submandibular glands, but not in mucous acinar cells of sublingual glands. Saliva and serum ghrelin levels were increased along with BMI. There was positive correlation between saliva and serum ghrelin levels (r=0.534, P<0.01). Serum and saliva ghrelin levels were both significantly correlated with BMI (r=0.523, r=0.374, P<0.01, respectively), but not with blood lipid levels. CONCLUSIONS: Parotid and submandibular glands were primary sources of ghrelin produced and released in saliva. Although whether salivary ghrelin could be useful in the diagnosis of obesity remains to be determined, salivary ghrelin might be a possible alternative to serum ghrelin for predicting obesity.