title: Insulinotropic and antidiabetic effects of 17β-estradiol and the GPR30 agonist G-1 on human pancreatic islets.
abstract: We have recently shown that 17β-estradiol (E2) and the synthetic G protein-coupled receptor 30 (GPR30) ligand G-1 have antiapoptotic actions in mouse pancreatic islets, raising the prospect that they might exert beneficial effects also in human islets. The objective of the present study was to identify the expression of GPR30 in human islets and clarify the role of GPR30 in islet hormone secretion and β-cell survival. GPR30 expression was analyzed by confocal microscopy, Western blot, and quantitative PCR in islets from female and male donors. Hormone secretion, phosphatidylinositol hydrolysis, cAMP content, and caspase-3 activity in female islets were determined with conventional methods and apoptosis with the annexin-V method. Confocal microscopy revealed GPR30 expression in islet insulin, glucagon, and somatostatin cells. GPR30 mRNA and protein expression was markedly higher in female vs. male islets. An amplifying effect of G-1 or E2 on cAMP content and insulin secretion from isolated female islets was not influenced by the E2 genomic receptor (ERα and ERβ) antagonists ICI 182,780 and EM-652. Cytokine-induced (IL-1β plus TNFα plus interferon-γ) apoptosis in islets cultured for 24 h at 5 mmol/liter glucose was almost abolished by G-1 or E2 treatment and was not affected by the nuclear estrogen receptor antagonists. Concentration-response studies on female islets from healthy controls and type 2 diabetic subjects showed that both E2 and G-1 displayed important antidiabetic actions by improving glucose-stimulated insulin release while suppressing glucagon and somatostatin secretion. In view of these findings, we propose that small molecules activating GPR30 could be promising in the therapy of diabetes mellitus.
authors.affiliation: Department of Clinical Science, Skåne Universitetssjukhus, Division of Islet Cell Physiology, Clinical Research Center, Building 91, Plan 11, Entrance 72, S-205 02 Malmö, Sweden.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Kumar
authors.forename: Alexander
authors.initials: A
authors.lastname: Balhuizen
authors.forename: Stefan
authors.initials: S
authors.lastname: Amisten
authors.forename: Ingmar
authors.initials: I
authors.lastname: Lundquist
authors.forename: Albert
authors.initials: A
authors.lastname: Salehi
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003517:Cyclopentanes / Q000494:pharmacology*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D004958:Estradiol / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D058990:Molecular Targeted Therapy; D020411:Oligonucleotide Array Sequence Analysis; D009924:Organ Culture Techniques; D011804:Quinolines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D015290:Second Messenger Systems / Q000187:drug effects; D012727:Sex Characteristics
chemical_list: C517943:1-(4-(6-bromobenzo(1,3)dioxol-5-yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta(c)quinolin-8-yl)ethanone; D003517:Cyclopentanes; D004965:Estrogen Antagonists; C109584:GPER1 protein, human; D007004:Hypoglycemic Agents; D007328:Insulin; D011804:Quinolines; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled; D004958:Estradiol