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Key points: Paternal obesity negatively influences metabolic outcomes in adult rat offspring.Maternal voluntary physical activity has previously been reported to improve glucose metabolism in adult rat offspring sired by healthy fathers.Here, we investigated whether a structured programme of maternal exercise training before and during gestation can attenuate the negative impacts that paternal obesity has on insulin sensitivity and secretion in female adult offspring.Exercise before and during pregnancy normalised the lower insulin sensitivity in skeletal muscle and the lower insulin secretion observed in female offspring sired by obese fathers.This paper presents a feasible, low‐cost and translatable intervention strategy that can be applied perinatally to support multifactor interventions to break the cycle of metabolic dysfunction caused by paternal obesity. We investigated whether maternal exercise before and during gestation could attenuate the negative metabolic effects of paternal high‐fat diet‐induced obesity in female adult rat offspring. Fathers consumed a normal chow or high‐fat diet before mating. Mothers exercised on a treadmill before and during gestation or remained sedentary. In adulthood, female offspring were assessed using intraperitoneal insulin and glucose tolerance tests (IPITT and IPGTT, respectively), pancreatic morphology, ex vivo skeletal muscle insulin‐stimulated glucose uptake and mitochondrial respiratory function. Paternal obesity impaired whole‐body and skeletal muscle insulin sensitivity and insulin secretion in adult offspring. Maternal exercise attenuated the lower insulin‐stimulated glucose uptake in offspring sired by obese fathers but distal insulin signalling components (p‐AKT Thr308 and Ser473, p‐TBC1D4 Thr642 and GLUT4) remained unchanged (P > 0.05). Maternal exercise increased citrate synthase activity only in offspring sired by obese fathers. Maternal exercise also reversed the lower insulin secretion in vivo observed in offspring of obese fathers, probably due to an attenuation of the decrease in pancreatic beta cell mass. In summary, maternal exercise before and during pregnancy in rats attenuated skeletal muscle insulin resistance and attenuated the decrease in pancreatic beta cell mass and insulin secretion observed in the female offspring of obese fathers. Key points: Paternal obesity negatively influences metabolic outcomes in adult rat offspring.Maternal voluntary physical activity has previously been reported to improve glucose metabolism in adult rat offspring sired by healthy fathers.Here, we investigated whether a structured programme of maternal exercise training before and during gestation can attenuate the negative impacts that paternal obesity has on insulin sensitivity and secretion in female adult offspring.Exercise before and during pregnancy normalised the lower insulin sensitivity in skeletal muscle and the lower insulin secretion observed in female offspring sired by obese fathers.This paper presents a feasible, low‐cost and translatable intervention strategy that can be applied perinatally to support multifactor interventions to break the cycle of metabolic dysfunction caused by paternal obesity. [ABSTRACT FROM AUTHOR]

Key points: AMP‐activated protein kinase (AMPK) is considered a major regulator of skeletal muscle metabolism during exercise.However, we previously showed that, although AMPK activity increases by 8–10‐fold during ∼120 min of exercise at ∼65% V̇O2peak in untrained individuals, there is no increase in these individuals after only 10 days of exercise training (longitudinal study).In a cross‐sectional study, we show that there is also a lack of activation of skeletal muscle AMPK during 120 min of cycling exercise at 65% V̇O2peak in endurance‐trained individuals.These findings indicate that AMPK is not an important regulator of exercise metabolism during 120 min of exercise at 65% V̇O2peak in endurance trained men.It is important that more energy is directed towards examining other potential regulators of exercise metabolism. AMP‐activated protein kinase (AMPK) is considered a major regulator of skeletal muscle metabolism during exercise. Indeed, AMPK is activated during exercise and activation of AMPK by 5‐aminoimidazole‐4‐carboxyamide‐ribonucleoside (AICAR) increases skeletal muscle glucose uptake and fat oxidation. However, we have previously shown that, although AMPK activity increases by 8–10‐fold during ∼120 min of exercise at ∼65% V̇O2peak in untrained individuals, there is no increase in these individuals after only 10 days of exercise training (longitudinal study). In a cross‐sectional study, we examined whether there is also a lack of activation of skeletal muscle AMPK during 120 min of cycling exercise at 65% V̇O2peak in endurance‐trained individuals. Eleven untrained (UT; V̇O2peak = 37.9 ± 5.6 ml.kg−1 min−1) and seven endurance trained (ET; V̇O2peak = 61.8 ± 2.2 ml.kg−1 min−1) males completed 120 min of cycling exercise at 66 ± 4% V̇O2peak (UT: 100 ± 21 W; ET: 190 ± 15 W). Muscle biopsies were obtained at rest and following 30 and 120 min of exercise. Muscle glycogen was significantly (P < 0.05) higher before exercise in ET and decreased similarly during exercise in the ET and UT individuals. Exercise significantly increased calculated skeletal muscle free AMP content and more so in the UT individuals. Exercise significantly (P < 0.05) increased skeletal muscle AMPK α2 activity (4‐fold), AMPK αThr172 phosphorylation (2‐fold) and ACCβ Ser222 phosphorylation (2‐fold) in the UT individuals but not in the ET individuals. These findings indicate that AMPK is not an important regulator of exercise metabolism during 120 min of exercise at 65% V̇O2peak in endurance trained men. Key points: AMP‐activated protein kinase (AMPK) is considered a major regulator of skeletal muscle metabolism during exercise.However, we previously showed that, although AMPK activity increases by 8–10‐fold during ∼120 min of exercise at ∼65% V̇O2peak in untrained individuals, there is no increase in these individuals after only 10 days of exercise training (longitudinal study).In a cross‐sectional study, we show that there is also a lack of activation of skeletal muscle AMPK during 120 min of cycling exercise at 65% V̇O2peak in endurance‐trained individuals.These findings indicate that AMPK is not an important regulator of exercise metabolism during 120 min of exercise at 65% V̇O2peak in endurance trained men.It is important that more energy is directed towards examining other potential regulators of exercise metabolism. [ABSTRACT FROM AUTHOR]

Key points: Increased insulin action is an important component of the health benefits of exercise, but its regulation is complex and not fully elucidated.Previous studies of insulin‐stimulated GLUT4 translocation to the skeletal muscle membrane found insufficient increases to explain the increases in glucose uptake.By determination of leg glucose uptake and interstitial muscle glucose concentration, insulin‐induced muscle membrane permeability to glucose was calculated 4 h after one‐legged knee‐extensor exercise during a submaximal euglycaemic–hyperinsulinaemic clamp.It was found that during submaximal insulin stimulation, muscle membrane permeability to glucose in humans increases twice as much in previously exercised vs. rested muscle and outstrips the supply of glucose, which then becomes limiting for glucose uptake.This methodology can now be employed to determine muscle membrane permeability to glucose in people with diabetes, who have reduced insulin action, and in principle can also be used to determine membrane permeability to other substrates or metabolites. Increased insulin action is an important component of the health benefits of exercise, but the regulation of insulin action in vivo is complex and not fully elucidated. Previously determined increases in skeletal muscle insulin‐stimulated GLUT4 translocation are inconsistent and mostly cannot explain the increases in insulin action in humans. Here we used leg glucose uptake (LGU) and interstitial muscle glucose concentration to calculate insulin‐induced muscle membrane permeability to glucose, a variable not previously possible to quantify in humans. Muscle membrane permeability to glucose, measured 4 h after one‐legged knee‐extensor exercise, increased ∼17‐fold during a submaximal euglycaemic–hyperinsulinaemic clamp in rested muscle (R) and ∼36‐fold in exercised muscle (EX). Femoral arterial infusion of NG‐monomethyl l‐arginine acetate or ATP decreased and increased, respectively, leg blood flow (LBF) in both legs but did not affect membrane glucose permeability. Decreasing LBF reduced interstitial glucose concentrations to ∼2 mM in the exercised but only to ∼3.5 mM in non‐exercised muscle and abrogated the augmented effect of insulin on LGU in the EX leg. Increasing LBF by ATP infusion increased LGU in both legs with uptake higher in the EX leg. We conclude that it is possible to measure functional muscle membrane permeability to glucose in humans and it increases twice as much in exercised vs. rested muscle during submaximal insulin stimulation. We also show that muscle perfusion is an important regulator of muscle glucose uptake when membrane permeability to glucose is high and we show that the capillary wall can be a significant barrier for glucose transport. Key points: Increased insulin action is an important component of the health benefits of exercise, but its regulation is complex and not fully elucidated.Previous studies of insulin‐stimulated GLUT4 translocation to the skeletal muscle membrane found insufficient increases to explain the increases in glucose uptake.By determination of leg glucose uptake and interstitial muscle glucose concentration, insulin‐induced muscle membrane permeability to glucose was calculated 4 h after one‐legged knee‐extensor exercise during a submaximal euglycaemic–hyperinsulinaemic clamp.It was found that during submaximal insulin stimulation, muscle membrane permeability to glucose in humans increases twice as much in previously exercised vs. rested muscle and outstrips the supply of glucose, which then becomes limiting for glucose uptake.This methodology can now be employed to determine muscle membrane permeability to glucose in people with diabetes, who have reduced insulin action, and in principle can also be used to determine membrane permeability to other substrates or metabolites. [ABSTRACT FROM AUTHOR]

Key points: A paternal high‐fat diet/obesity before mating can negatively influence the metabolism of offspring.Exercise only early in life has a remarkable effect with respect to reprogramming adult rat offspring exposed to detrimental insults before conception.Exercise only early in life normalized adult whole body and muscle insulin resistance as a result of having a high‐fat fed/obese father.Unlike the effects on the muscle, early exercise did not normalize the reduced adult pancreatic beta cell mass as a result of having a high‐fat fed/obese father.Early‐life exercise training may be able to reprogram an individual whose father was obese, inducing long‐lasting beneficial effects on health. A paternal high‐fat diet (HFD) impairs female rat offspring glucose tolerance, pancreatic morphology and insulin secretion. We examined whether only 4 weeks of exercise early in life could reprogram these negative effects. Male Sprague–Dawley rats consumed a HFD for 10 weeks before mating with chow‐fed dams. Female offspring remained sedentary or performed moderate intensity treadmill exercise (5 days week−1, 60 min day−1, 20 m min−1) from 5 to 9 weeks of age. Paternal HFD impaired (P < 0.05) adult offspring whole body insulin sensitivity (i.p. insulin sensitivity test), as well as skeletal muscle ex vivo insulin sensitivity and TBC1D4 phosphorylation. It also lowered β‐cell mass and reduced in vivo insulin secretion in response to an i.p. glucose tolerance test. Early‐life exercise in offspring reprogrammed the negative effects of a paternal HFD on whole body insulin sensitivity, skeletal muscle ex vivo insulin‐stimulated glucose uptake and TBC1D4 phosphorylation and also increased glucose transporter 4 protein. However, early exercise did not normalize the reduced pancreatic β‐cell mass or insulin secretion. In conclusion, only 4 weeks of exercise early in life in female rat offspring reprograms reductions in insulin sensitivity in adulthood caused by a paternal HFD without affecting pancreatic β‐cell mass or insulin secretion. Key points: A paternal high‐fat diet/obesity before mating can negatively influence the metabolism of offspring.Exercise only early in life has a remarkable effect with respect to reprogramming adult rat offspring exposed to detrimental insults before conception.Exercise only early in life normalized adult whole body and muscle insulin resistance as a result of having a high‐fat fed/obese father.Unlike the effects on the muscle, early exercise did not normalize the reduced adult pancreatic beta cell mass as a result of having a high‐fat fed/obese father.Early‐life exercise training may be able to reprogram an individual whose father was obese, inducing long‐lasting beneficial effects on health. [ABSTRACT FROM AUTHOR]

Key points People with insulin resistance or type 2 diabetes can substantially increase their skeletal muscle glucose uptake during exercise and insulin sensitivity after exercise., Skeletal muscle nitric oxide (NO) is important for glucose uptake during exercise, although how prior exercise increases insulin sensitivity is unclear., In the present study, we examined whether NO is necessary for normal increases in skeletal muscle insulin sensitivity after contraction ex vivo in mouse muscle., The present study uncovers, for the first time, a novel role for NO in the insulin sensitizing effects of ex vivo contraction, which is independent of blood flow., Abstract The factors regulating the increase in skeletal muscle insulin sensitivity after exercise are unclear. We examined whether nitric oxide (NO) is required for the increase in insulin sensitivity after ex vivo contractions. Isolated C57BL/6J mouse EDL muscles were contracted for 10 min or remained at rest (basal) with or without the NO synthase (NOS) inhibition ( NG-monomethyl- l-arginine; l-NMMA; 100 μ m). Then, 3.5 h post contraction/basal, muscles were exposed to saline or insulin (120 μU ml−1) with or without l-NMMA during the last 30 min. l-NMMA had no effect on basal skeletal muscle glucose uptake. The increase in muscle glucose uptake with insulin (57%) was significantly ( P < 0.05) greater after prior contraction (140% increase). NOS inhibition during the contractions had no effect on this insulin-sensitizing effect of contraction, whereas NOS inhibition during insulin prevented the increase in skeletal muscle insulin sensitivity post-contraction. Soluble guanylate cyclase inhibition, protein kinase G (PKG) inhibition or cyclic nucleotide phosphodiesterase inhibition each had no effect on the insulin-sensitizing effect of prior contraction. In conclusion, NO is required for increases in insulin sensitivity several hours after contraction of mouse skeletal muscle via a cGMP/PKG independent pathway. [ABSTRACT FROM AUTHOR]