Identification of Ghrelin in Human Saliva: Production by the Salivary Glands and Potential Role in Proliferation of Oral Keratinocytes

Abstract

Background:We investigated whether ghrelin is present in human saliva, is produced by salivary glands, and physiologic consequences of these findings. Methods: Expression of ghrelin and specific receptor mRNA was determined by PCR. Proteins were identified by immunoblotting and size-exclusion fast protein liquid chromatography (FPLC) with consecutive RIA. Specific RIAs were used for quantification of salivary total and bioactive ghrelin. Distribution of ghrelin was investigated by immunohistochemistry in cryosections of the salivary glands. The effect of ghrelin on incorporation of 5-bromo-2-deoxyuridine as a measure of cell proliferation was investigated in primary oral keratinocytes. Results: Ghrelin is produced by the salivary glands. The hormone was identified in saliva and glands by immunoblotting and by FPLC fractionation of saliva. Immunohistochemistry demonstrated ghrelin distribution in the salivary glands. The receptor was also produced by the glands and by oral keratinocytes and was shown to be functional. Comparison of total ghrelin values for healthy individuals (body mass index, 18 -27 kg/m 2 ) showed significantly lower concentrations in saliva than in serum (P <0.01). The correlation between both matrices was r 2 ‫؍‬ 0.56 (P <0.001) with a negative correlation to body mass index (r 2 ‫؍‬ 0.314; P <0.01). Bioactive acylated ghrelin was also present in saliva. Incubation of keratinocytes with ghrelin led to signifi-

Obestatin is present in saliva: alterations in obestatin and ghrelin levels of saliva and serum in ischemic heart disease

“…Another supporting evidence that portions of some of these striated duct protein relased basally into circulation (20). Here we can not rule out the possibility of basal secretion of obestatin, since we do not have evidence of mRNA for obestatin in human salivary glands, but Gröschl and his co-workers have demonstrated ghrelin mRNA expression in the 3 majors' salivary glands (sublingual and submandibular gland, parotid) as well as in oral keratinocytes (22). Ghrelin and obestatin are derived from the same precursor, thus there is a possibility of basal secretion of obestatin.…”

Food Addiction, Obesity and Neuroimaging

“…The vicious obesity cycle begins with excess adipose leading to chronic low grade inflammation that results in insulin resistance (IR) along with hypertension, atherosclerosis, dyslipidemia and type 2 diabetes mellitus (T2DM), which are consistent findings of metabolic syndrome (MetS) (Achike et al, 2011). Studies have shown that obesity can be linked to lower ghrelin concentrations in obese individuals (Groschl et al, 2005). As a result, ghrelin levels have been found to be negatively correlated with body fat and waist circumference (WC) (Fagerberg, Hulten & Hulthe, 2003).…”

The Evaluation of Ghrelin Expression In Oral Leukoplakia And Oral Squamous Cell Carcinoma: An Immunohistochemical Study

“…Ghrelin is produced by the oral epithelium, fibroblasts, salivary glands, oral keratinocytes, teeth, and OSCC in the oral cavity. 10,[19][20][21][22] A major challenge is to determine which oral premalignant lesions will transform into carcinoma. Therefore, this study assessed the expression of ghrelin in normal oral mucosa, oral leukoplakia, and OSCC by immunohistochemistry using formalin-fixed paraffin-embedded tissues.…”