title: Time-resolved metabolomics analysis of β-cells implicates the pentose phosphate pathway in the control of insulin release.
abstract: Insulin secretion is coupled with changes in β-cell metabolism. To define this process, 195 putative metabolites, mitochondrial respiration, NADP+, NADPH and insulin secretion were measured within 15 min of stimulation of clonal INS-1 832/13 β-cells with glucose. Rapid responses in the major metabolic pathways of glucose occurred, involving several previously suggested metabolic coupling factors. The complexity of metabolite changes observed disagreed with the concept of one single metabolite controlling insulin secretion. The complex alterations in metabolite levels suggest that a coupling signal should reflect large parts of the β-cell metabolic response. This was fulfilled by the NADPH/NADP+ ratio, which was elevated (8-fold; P<0.01) at 6 min after glucose stimulation. The NADPH/NADP+ ratio paralleled an increase in ribose 5-phosphate (>2.5-fold; P<0.001). Inhibition of the pentose phosphate pathway by trans-dehydroepiandrosterone (DHEA) suppressed ribose 5-phosphate levels and production of reduced glutathione, as well as insulin secretion in INS-1 832/13 β-cells and rat islets without affecting ATP production. Metabolite profiling of rat islets confirmed the glucose-induced rise in ribose 5-phosphate, which was prevented by DHEA. These findings implicate the pentose phosphate pathway, and support a role for NADPH and glutathione, in β-cell stimulus-secretion coupling.
authors.affiliation: Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Scania University Hospital, 205 02 Malmö, Sweden. peter.spegel@med.lu.se
authors.forename: Peter
authors.initials: P
authors.lastname: Spégel
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Sharoyko
authors.forename: Isabel
authors.initials: I
authors.lastname: Goehring
authors.forename: Anders P H
authors.initials: AP
authors.lastname: Danielsson
authors.forename: Siri
authors.initials: S
authors.lastname: Malmgren
authors.forename: Cecilia L F
authors.initials: CL
authors.lastname: Nagorny
authors.forename: Lotta E
authors.initials: LE
authors.lastname: Andersson
authors.forename: Thomas
authors.initials: T
authors.lastname: Koeck
authors.forename: Geoffrey W G
authors.initials: GW
authors.lastname: Sharp
authors.forename: Susanne G
authors.initials: SG
authors.lastname: Straub
authors.forename: Claes B
authors.initials: CB
authors.lastname: Wollheim
authors.forename: Hindrik
authors.initials: H
authors.lastname: Mulder
mesh_terms: D000818:Animals; D019069:Cell Respiration / Q000502:physiology; D002478:Cells, Cultured; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000737:chemistry / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism; D008297:Male; D055442:Metabolome; D055432:Metabolomics / Q000379:methods*; D008928:Mitochondria / Q000378:metabolism / Q000502:physiology; D010427:Pentose Phosphate Pathway / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D055571:Secretory Pathway / Q000187:drug effects
chemical_list: D007328:Insulin; D005947:Glucose