The purpose of this study is do determine the functional significance of the G protein-coupled receptor TGR5 in the secretion of GI satiation peptides by using natural bile acids and oleanolic acid (triterpenoid compound of plant origin) as TGR5 agonists.
TGR5 is expressed in GLP-1-secreting cell lines and L cells from mice; gain- and loss-of-function models suggest a physiological role for TGR5 activation on GLP-1 secretion in rodents. TGR5 signaling showed improved postprandial glucose tolerance in obese mice, associated with marked postprandial GLP-1 release and insulin secretion. In contrast, TGR5-/- mice exhibited reduced glucose tolerance. In animals, TGR5 activation has been shown for natural bile acids (BAs) and triterpenoid compounds of plant origin, such as oleanolic acid (OA), suggesting a role for postprandial BAs in modulating nutrient-induced GLP-1 secretion. We therefore hypothesized that intraduodenal (ID) perfusions of TGR5 agonists (BAs and OA) stimulate the secretion of GLP-1 with respective changes in the glucose metabolism of healthy humans.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
QUADRUPLE
Enrollment
12
University Hospital Basel, Phase 1 Research Unit
Basel, Switzerland
Gastrointestinal satiation peptide secretion
Assessment of plasma GLP-1, PYY and CCK release to BA and OA stimulation
Time frame: 3 hours blood sampling
Serum bile acids
Assessment of serum bile acids levels to BA and OA stimulation
Time frame: 3 hours blood sampling
Appetite perceptions during 3 hours using visual analogue scales
Assessment of the following appetite perceptions markers: feelings of hunger, feelings of prospective food consumption, feelings of fullness and feelings of satiety using validated visual analogue scales
Time frame: 3 hours
Glucose and insulin secretion
Assessment of plasma glucose and insulin levels to BA and OA stimulation
Time frame: 3 hours blood sampling
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intraduodenal perfusion