Starvation reduces hyaluronan synthesis by suppressing TGF-β1/IGF-I signaling in rat skin.

Although starvation has been reported to influence the functions of various tissues, its effects on the skin are not well understood. In this study, we investigated the effect of starvation on hyaluronan synthesis in rat skin. Starvation reduced hyaluronan synthesis in the skin. Starvation also decreased the skin mRNA expression of transforming growth factor (TGF)-β1, which enhances the gene expression of rhas2 and rhas3. The serum levels of insulin-like growth factor (IGF)-I, which enhances rhas2, rhas3, and TGF-β1 mRNA expression, in the starvation group were considerably lower than those in the control (CO) group. IGF-IR phosphorylation was substantially lower in the starvation group compared with the CO group. These findings suggest that starvation reduces hyaluronan synthesis in the skin by suppressing TGF-β1/IGF-I signaling. Abbreviations: HAS: hyaluronan synthase; IGF-I: insulin-like growth factor-I; IGFBP-1: insulin-like growth factor binding protein-1; TGF-β1: transforming growth factor-β1; TBST: tris buffered saline containing 0.5% (v/v) Tween 20; HABP: hyaluronic acid binding protein; GAPDH: glyceraldehyde-3-phosphate dehydrogenase.