Saponins from Camellia sinensis Seeds Stimulate GIP Secretion in Mice and STC-1 Cells via SGLT1 and TGR5.

ABSTRACT: Glucose-dependent insulinotropic polypeptide (GIP) is one of the important incretins and possesses lots of physiological activities such as stimulating insulin secretion and maintaining glucose homeostasis. The pentacyclic triterpenoid saponins are the major active ingredients in tea (Camellia sinensis) seeds. This study aimed to investigate the effect of tea seed saponins on the GIP secretion and related mechanisms. Our data showed that the total tea seed saponins (TSS, 65 mg/kg BW) and theasaponin E₁ (TSE1, 2-4 µM) could increase the GIP mRNA and protein levels in mice and STC-1 cells. Phlorizin, the inhibitor of Sodium/glucose cotransporter 1 (SGLT1), reversed the TSE1-induced increase in Ca²⁺ and GIP mRNA level. In addition, TSE1 upregulated the protein exp

SUBMITTER: Zhu H 

PROVIDER: S-EPMC9416400 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature