title: Enhanced insulin sensitivity mediated by adipose tissue browning perturbs islet morphology and hormone secretion in response to autonomic nervous activation in female mice.
abstract: Insulin resistance results in a compensatory increase in insulin secretion to maintain normoglycemia. Conversely, high insulin sensitivity results in reduced insulin secretion to prevent hypoglycemia. The mechanisms for this inverse adaptation are not well understood. We utilized highly insulin-sensitive mice, due to adipocyte-specific overexpression of the FOXC2 transcription factor, to study mechanisms of the reversed islet adaptation to increased insulin sensitivity. We found that Foxc2TG mice responded to mild hyperglycemia with insulin secretion significantly lower than that of wild-type mice; however, when severe hyperglycemia was induced, Foxc2TG mice demonstrated insulin secretion equal to or greater than that of wild-type mice. In response to autonomic nervous activation by 2-deoxyglucose, the acute suppression of insulin seen in wild-type mice was absent in Foxc2TG mice, suggesting impaired sympathetic signaling to the islet. Basal glucagon was increased in Foxc2TG mice, but they displayed severely impaired glucagon responses to cholinergic and autonomic nervous stimuli. These data suggest that the autonomic nerves contribute to the islet adaptation to high insulin sensitivity, which is compatible with a neuro-adipo regulation of islet function being instrumental for maintaining glucose regulation.
authors.affiliation: Department of Clinical Sciences, Lund University, Lund, Sweden; and bilal.omar@med.lu.se.
authors.forename: Bilal A
authors.initials: BA
authors.lastname: Omar
authors.affiliation: Department of Clinical Sciences, Lund University, Lund, Sweden; and.
authors.forename: Martina
authors.initials: M
authors.lastname: Kvist-Reimer
authors.affiliation: Gothenburg University, Sahlgrenska Hospital, Gothenburg, Sweden.
authors.forename: Sven
authors.initials: S
authors.lastname: Enerbäck
authors.affiliation: Department of Clinical Sciences, Lund University, Lund, Sweden; and.
authors.forename: Bo
authors.initials: B
authors.lastname: Ahrén
mesh_terms: D002001:Adipose Tissue, Brown / Q000502:physiology*; D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology*; D048430:Cell Shape; D054338:Cell Transdifferentiation / Q000502:physiology; D005260:Female; D051858:Forkhead Transcription Factors / Q000235:genetics; D005934:Glucagon / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic
chemical_list: D051858:Forkhead Transcription Factors; D007328:Insulin; C082078:mesenchyme fork head 1 protein; D005934:Glucagon
keywords: glucagon; insulin; parasympathetic nervous system; sympathetic nervous system; white adipose tissue