Straznicky NE, Guo L, Corcoran SJ, Esler MD, Phillips SE, Sari CI, Grima MT, Karapanagiotidis S, Wong CY, Eikelis N, Mariani JA, Kobayashi D, Dixon JB, Lambert GW, Lambert EA. Norepinephrine transporter expression is inversely associated with glycaemic indices: a pilot study in metabolically diverse persons with overweight and obesity.
Obes Sci Pract 2016;
2:13-23. [PMID:
27812376 PMCID:
PMC5066670 DOI:
10.1002/osp4.20]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 10/04/2015] [Accepted: 10/09/2015] [Indexed: 01/20/2023] Open
Abstract
Objective
The objective of this study was to examine the cross‐sectional relationship between the expression of norepinephrine transporter (NET), the protein responsible for neuronal uptake‐1, and indices of glycaemia and hyperinsulinaemia, in overweight and obese individuals.
Methods
Thirteen non‐medicated, non‐smoking subjects, aged 58 ± 1 years (mean ± standard error of the mean), body mass index (BMI) 31.4 ± 1.0 kg m−2, with wide‐ranging plasma glucose and haemoglobin A1c (HbA1c, range 5.1% to 6.5%) participated. They underwent forearm vein biopsy to access sympathetic nerves for the quantification of NET by Western blot, oral glucose tolerance test (OGTT), euglycaemic hyperinsulinaemic clamp, echocardiography and assessments of whole‐body norepinephrine kinetics and muscle sympathetic nerve activity.
Results
Norepinephrine transporter expression was inversely associated with fasting plasma glucose (r = −0.62, P = 0.02), glucose area under the curve during OGTT (AUC0–120, r = −0.65, P = 0.02) and HbA1c (r = −0.67, P = 0.01), and positively associated with steady‐state glucose utilization during euglycaemic clamp (r = 0.58, P = 0.04). Moreover, NET expression was inversely related to left ventricular posterior wall dimensions (r = −0.64, P = 0.02) and heart rate (r = −0.55, P = 0.05). Indices of hyperinsulinaemia were not associated with NET expression. In stepwise linear regression analysis adjusted for age, body mass index and blood pressure, HbA1c was an independent inverse predictor of NET expression, explaining 45% of its variance.
Conclusions
Hyperglycaemia is associated with reduced peripheral NET expression. Further studies are required to identify the direction of causality.
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