title: Impaired glucose homeostasis in insulin-like growth factor-binding protein-3-transgenic mice.
abstract: Glucose homeostasis was examined in male transgenic (Tg) mice that overexpressed the human insulin-like growth factor (IGF)-binding protein (IGFBP)-3 cDNA, driven by either the cytomegalovirus (CMV) or the phosphoglycerate kinase (PGK) promoter. The Tg mice of both lineages demonstrated increased serum levels of human (h) IGFBP-3 and total IGF-I compared with wild-type (Wt) mice. Fasting blood glucose levels were significantly elevated in 8-wk-old CMV-binding protein (CMVBP)-3- and PGK binding protein (PGKBP)-3-Tg mice compared with Wt mice: 6.35 +/- 0.22 and 5.22 +/- 0.39 vs. 3.99 +/- 0.26 mmol/l, respectively. Plasma insulin was significantly elevated only in CMVBP-3-Tg mice. The responses to a glucose challenge were significantly increased in both Tg strains: area under the glucose curve = 1,824 +/- 65 and 1,910 +/- 115 vs. 1,590 +/- 67 mmol. l(-1). min for CMVBP-3, PGKBP-3, and Wt mice, respectively. The hypoglycemic effects of insulin and IGF-I were significantly attenuated in Tg mice compared with Wt mice. There were no differences in adipose tissue resistin, retinoid X receptor-alpha, or peroxisome proliferator-activated receptor-gamma mRNA levels between Tg and Wt mice. Uptake of 2-deoxyglucose was reduced in muscle and adipose tissue from Tg mice compared with Wt mice. These data demonstrate that overexpression of hIGFBP-3 results in fasting hyperglycemia, impaired glucose tolerance, and insulin resistance.
authors.affiliation: Department of Physiology, University of Manitoba, Winnipeg R3E 0W3, Canada.
authors.forename: Josef V
authors.initials: JV
authors.lastname: Silha
authors.forename: Yaoting
authors.initials: Y
authors.lastname: Gui
authors.forename: Liam J
authors.initials: LJ
authors.lastname: Murphy
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D015870:Gene Expression / Q000502:physiology; D006706:Homeostasis / Q000502:physiology; D006729:Hormones, Ectopic / Q000235:genetics; D006801:Humans; D006943:Hyperglycemia / Q000235:genetics; D007333:Insulin Resistance / Q000235:genetics*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics*; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D020932:Nerve Growth Factor; D011506:Proteins; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000235:genetics; D052243:Resistin; D047488:Retinoid X Receptors; D014157:Transcription Factors / Q000235:genetics
chemical_list: D001786:Blood Glucose; D006729:Hormones, Ectopic; D018972:Insulin-Like Growth Factor Binding Protein 3; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; C499624:RETN protein, human; C486574:RETNLB protein, human; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D052243:Resistin; D047488:Retinoid X Receptors; C499623:Retn protein, mouse; C413576:Retnla protein, mouse; D014157:Transcription Factors; D020932:Nerve Growth Factor