TY - JOUR
T1 - The effects of dietary weight loss on indices of norepinephrine turnover
T2 - Modulatory influence of hyperinsulinemia
AU - Straznicky, Nora E.
AU - Lambert, Elisabeth A.
AU - Grima, Mariee T.
AU - Eikelis, Nina
AU - Richards, Katrina
AU - Nestel, Paul J.
AU - Dawood, Tye
AU - Masuo, Kazuko
AU - Sari, Carolina I.
AU - Dixon, John B.
AU - Esler, Murray D.
AU - Paul, Eldho
AU - Schlaich, Markus P.
AU - Lambert, Gavin W.
PY - 2014
Y1 - 2014
N2 - Objectives This study was conducted to examine 1) the effects of dietary weight loss on indices of norepinephrine (NE) turnover and 2) whether baseline hyperinsulinemia modulates sympathetic neural adaptations. Methods Obese individuals aged 56 ± 1 year, BMI 32.5 ± 0.4 kg/m2, with metabolic syndrome, underwent a 12-week hypocaloric diet (HCD, n = 39) or no treatment (n = 26). Neurochemical measurements comprised arterial dihydroxyphenylalanine (DOPA), 3,4-dihydroxyphenylglycol (DHPG), and NE concentrations, the steady-state ratio of [3H]-DHPG to [ 3H]-NE, as an index of neuronal uptake, and calculated whole-body plasma NE clearance and spillover rates. Results Body weight decreased by -7.4 ± 0.5% in HCD group (P < 0.001) and was accompanied by reductions in DOPA, NE, and DHPG averaging -14 ± 5% (P = 0.001), -23 ± 4% (P <0.001), and -5 ± 4% (P = 0.03), respectively. NE spillover rate decreased by -88 ± 39 ng/min (P = 0.01), whereas neuronal uptake and NE plasma clearance were unchanged. Despite similar weight loss, hyperinsulinemic subjects exhibited greater reductions in NE and NE spillover rate, compared to normoinsulinemic subjects (group by time interaction P < 0.05). Conclusions Weight loss is associated with down-regulation of sympathetic nervous activity but no overall alteration in disposition indices. Hyperinsulinemic subjects derive a greater sympathoinhibitory benefit during weight loss.
AB - Objectives This study was conducted to examine 1) the effects of dietary weight loss on indices of norepinephrine (NE) turnover and 2) whether baseline hyperinsulinemia modulates sympathetic neural adaptations. Methods Obese individuals aged 56 ± 1 year, BMI 32.5 ± 0.4 kg/m2, with metabolic syndrome, underwent a 12-week hypocaloric diet (HCD, n = 39) or no treatment (n = 26). Neurochemical measurements comprised arterial dihydroxyphenylalanine (DOPA), 3,4-dihydroxyphenylglycol (DHPG), and NE concentrations, the steady-state ratio of [3H]-DHPG to [ 3H]-NE, as an index of neuronal uptake, and calculated whole-body plasma NE clearance and spillover rates. Results Body weight decreased by -7.4 ± 0.5% in HCD group (P < 0.001) and was accompanied by reductions in DOPA, NE, and DHPG averaging -14 ± 5% (P = 0.001), -23 ± 4% (P <0.001), and -5 ± 4% (P = 0.03), respectively. NE spillover rate decreased by -88 ± 39 ng/min (P = 0.01), whereas neuronal uptake and NE plasma clearance were unchanged. Despite similar weight loss, hyperinsulinemic subjects exhibited greater reductions in NE and NE spillover rate, compared to normoinsulinemic subjects (group by time interaction P < 0.05). Conclusions Weight loss is associated with down-regulation of sympathetic nervous activity but no overall alteration in disposition indices. Hyperinsulinemic subjects derive a greater sympathoinhibitory benefit during weight loss.
UR - http://www.scopus.com/inward/record.url?scp=84895797900&partnerID=8YFLogxK
U2 - 10.1002/oby.20614
DO - 10.1002/oby.20614
M3 - Article
C2 - 23997009
AN - SCOPUS:84895797900
SN - 1930-7381
VL - 22
SP - 652
EP - 662
JO - Obesity
JF - Obesity
IS - 3
ER -
