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Defective insulin secretory response to intravenous glucose in C57Bl/6J compared to C57Bl/6N mice.

Fergusson G, Ethier M, Guévremont M, Chrétien C, Attané C, Joly E, Fioramonti X, Prentki M, Poitout V, Alquier T - Mol Metab (2014)

Bottom Line: However, recent reports comparing Bl/6J to Bl/6N (carrying the wild-type Nnt allele) under normal diet have led to conflicting results using glucose tolerance tests.GSIS was measured using complementary tests (oral and intravenous glucose tolerance tests) and hyperglycemic clamps.Neurally-mediated insulin secretion was measured during central hyperglycemia.

View Article: PubMed Central - PubMed

Affiliation: Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Université de Montréal, Montréal, QC H3T 1J4, Canada ; Rodent Metabolic Phenotyping Core of Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Canada.

ABSTRACT

Objective: The C57Bl/6J (Bl/6J) mouse is the most widely used strain in metabolic research. This strain carries a mutation in nicotinamide nucleotide transhydrogenase (Nnt), a mitochondrial enzyme involved in NADPH production, which has been suggested to lead to glucose intolerance and beta-cell dysfunction. However, recent reports comparing Bl/6J to Bl/6N (carrying the wild-type Nnt allele) under normal diet have led to conflicting results using glucose tolerance tests. Thus, we assessed glucose-stimulated insulin secretion (GSIS), insulin sensitivity, clearance and central glucose-induced insulin secretion in Bl/6J and N mice using gold-standard methodologies.

Methods: GSIS was measured using complementary tests (oral and intravenous glucose tolerance tests) and hyperglycemic clamps. Whole-body insulin sensitivity was assessed using euglycemic-hyperinsulinemic clamps. Neurally-mediated insulin secretion was measured during central hyperglycemia.

Results: Bl/6J mice have impaired GSIS compared to Bl/6N when glucose is administered intravenously during both a tolerance test and hyperglycemic clamp, but not in response to oral glucose. First and second phases of GSIS are altered without changes in whole body insulin sensitivity, insulin clearance, beta-cell mass or central response to glucose, thereby demonstrating defective beta-cell function in Bl/6J mice.

Conclusions: The Bl/6J mouse strain displays impaired insulin secretion. These results have important implications for choosing the appropriate test to assess beta-cell function and background strain in genetically modified mouse models.

No MeSH data available.


Related in: MedlinePlus

Glucose and insulin levels during oral or intravenous glucose tolerance tests. (A) Detection of the mutated Nnt allele by PCR performed on liver DNA from Bl/6J and N mice. The band at 750 bp indicates the truncated form while the band at 570 bp indicates the full-length wild-type form. Glucose (B) and insulin (C) levels during an oral glucose tolerance test (OGTT, 2 g/kg) in 12–14 weeks old Bl/6J and N mice. Glucose (D) and insulin (E) levels during an intravenous glucose tolerance test (IVGTT, 0.75 g/kg) in Bl/6J and N mice. Values are expressed as means ± SEM of 7–9 mice per group. *p < 0.05, **p < 0.01 and ***p < 0.001 compared to Bl/6N mice.
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fig1: Glucose and insulin levels during oral or intravenous glucose tolerance tests. (A) Detection of the mutated Nnt allele by PCR performed on liver DNA from Bl/6J and N mice. The band at 750 bp indicates the truncated form while the band at 570 bp indicates the full-length wild-type form. Glucose (B) and insulin (C) levels during an oral glucose tolerance test (OGTT, 2 g/kg) in 12–14 weeks old Bl/6J and N mice. Glucose (D) and insulin (E) levels during an intravenous glucose tolerance test (IVGTT, 0.75 g/kg) in Bl/6J and N mice. Values are expressed as means ± SEM of 7–9 mice per group. *p < 0.05, **p < 0.01 and ***p < 0.001 compared to Bl/6N mice.

Mentions: As expected, PCR genotyping for the mutation indicates that Bl/6J mice carry the mutated Nnt allele (750 bp band) while Bl/6N mice carry the wild-type allele (570 bp band) (Figure 1A). Body weights were similar in 12–14 weeks old Bl/6J and Bl/6N male mice (26.6 ± 0.4 vs. 26.1 ± 0.5 g, n = 18–21, NS). Blood glucose levels in the fasted (82 ± 3 vs. 86 ± 3 mg/dl, n = 8, NS) and fed states (140 ± 4 vs. 134 ± 3 mg/dl, n = 16, NS) were not different. Insulin levels after an overnight fast were similar (0.26 ± 0.1 vs. 0.20 ± 0.04 ng/ml, n = 8, NS). However, in agreement with the report of Alonso et al. [12], fed insulin levels were significantly lower in Bl/6J compared to Bl/6N (0.42 ± 0.06 vs. 0.73 ± 0.13 ng/ml, n = 14–16, p < 0.05).


Defective insulin secretory response to intravenous glucose in C57Bl/6J compared to C57Bl/6N mice.

Fergusson G, Ethier M, Guévremont M, Chrétien C, Attané C, Joly E, Fioramonti X, Prentki M, Poitout V, Alquier T - Mol Metab (2014)

Glucose and insulin levels during oral or intravenous glucose tolerance tests. (A) Detection of the mutated Nnt allele by PCR performed on liver DNA from Bl/6J and N mice. The band at 750 bp indicates the truncated form while the band at 570 bp indicates the full-length wild-type form. Glucose (B) and insulin (C) levels during an oral glucose tolerance test (OGTT, 2 g/kg) in 12–14 weeks old Bl/6J and N mice. Glucose (D) and insulin (E) levels during an intravenous glucose tolerance test (IVGTT, 0.75 g/kg) in Bl/6J and N mice. Values are expressed as means ± SEM of 7–9 mice per group. *p < 0.05, **p < 0.01 and ***p < 0.001 compared to Bl/6N mice.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4264561&req=5

fig1: Glucose and insulin levels during oral or intravenous glucose tolerance tests. (A) Detection of the mutated Nnt allele by PCR performed on liver DNA from Bl/6J and N mice. The band at 750 bp indicates the truncated form while the band at 570 bp indicates the full-length wild-type form. Glucose (B) and insulin (C) levels during an oral glucose tolerance test (OGTT, 2 g/kg) in 12–14 weeks old Bl/6J and N mice. Glucose (D) and insulin (E) levels during an intravenous glucose tolerance test (IVGTT, 0.75 g/kg) in Bl/6J and N mice. Values are expressed as means ± SEM of 7–9 mice per group. *p < 0.05, **p < 0.01 and ***p < 0.001 compared to Bl/6N mice.
Mentions: As expected, PCR genotyping for the mutation indicates that Bl/6J mice carry the mutated Nnt allele (750 bp band) while Bl/6N mice carry the wild-type allele (570 bp band) (Figure 1A). Body weights were similar in 12–14 weeks old Bl/6J and Bl/6N male mice (26.6 ± 0.4 vs. 26.1 ± 0.5 g, n = 18–21, NS). Blood glucose levels in the fasted (82 ± 3 vs. 86 ± 3 mg/dl, n = 8, NS) and fed states (140 ± 4 vs. 134 ± 3 mg/dl, n = 16, NS) were not different. Insulin levels after an overnight fast were similar (0.26 ± 0.1 vs. 0.20 ± 0.04 ng/ml, n = 8, NS). However, in agreement with the report of Alonso et al. [12], fed insulin levels were significantly lower in Bl/6J compared to Bl/6N (0.42 ± 0.06 vs. 0.73 ± 0.13 ng/ml, n = 14–16, p < 0.05).

Bottom Line: However, recent reports comparing Bl/6J to Bl/6N (carrying the wild-type Nnt allele) under normal diet have led to conflicting results using glucose tolerance tests.GSIS was measured using complementary tests (oral and intravenous glucose tolerance tests) and hyperglycemic clamps.Neurally-mediated insulin secretion was measured during central hyperglycemia.

View Article: PubMed Central - PubMed

Affiliation: Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Université de Montréal, Montréal, QC H3T 1J4, Canada ; Rodent Metabolic Phenotyping Core of Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Canada.

ABSTRACT

Objective: The C57Bl/6J (Bl/6J) mouse is the most widely used strain in metabolic research. This strain carries a mutation in nicotinamide nucleotide transhydrogenase (Nnt), a mitochondrial enzyme involved in NADPH production, which has been suggested to lead to glucose intolerance and beta-cell dysfunction. However, recent reports comparing Bl/6J to Bl/6N (carrying the wild-type Nnt allele) under normal diet have led to conflicting results using glucose tolerance tests. Thus, we assessed glucose-stimulated insulin secretion (GSIS), insulin sensitivity, clearance and central glucose-induced insulin secretion in Bl/6J and N mice using gold-standard methodologies.

Methods: GSIS was measured using complementary tests (oral and intravenous glucose tolerance tests) and hyperglycemic clamps. Whole-body insulin sensitivity was assessed using euglycemic-hyperinsulinemic clamps. Neurally-mediated insulin secretion was measured during central hyperglycemia.

Results: Bl/6J mice have impaired GSIS compared to Bl/6N when glucose is administered intravenously during both a tolerance test and hyperglycemic clamp, but not in response to oral glucose. First and second phases of GSIS are altered without changes in whole body insulin sensitivity, insulin clearance, beta-cell mass or central response to glucose, thereby demonstrating defective beta-cell function in Bl/6J mice.

Conclusions: The Bl/6J mouse strain displays impaired insulin secretion. These results have important implications for choosing the appropriate test to assess beta-cell function and background strain in genetically modified mouse models.

No MeSH data available.


Related in: MedlinePlus