Comparative effects of a low-carbohydrate diet and exercise plus a low-carbohydrate diet on muscle sarcoplasmic reticulum responses in males

2006 ◽  
Vol 291 (4) ◽  
pp. C607-C617 ◽  
Author(s):  
T. A. Duhamel ◽  
H. J. Green ◽  
J. G. Perco ◽  
J. Ouyang

We employed a glycogen-depleting session of exercise followed by a low-carbohydrate (CHO) diet to investigate modifications that occur in muscle sarcoplasmic reticulum (SR) Ca2+-cycling properties compared with low-CHO diet alone. SR properties were assessed in nine untrained males [peak aerobic power (V̇o2 peak) = 43.6 ± 2.6 (SE) ml·kg−1·min−1] during prolonged cycle exercise to fatigue performed at ∼58% V̇o2 peak after 4 days of low-CHO diet (Lo CHO) and after glycogen-depleting exercise plus 4 days of low-CHO (Ex+Lo CHO). Compared with Lo CHO, Ex+Lo CHO resulted in 12% lower ( P < 0.05) resting maximal Ca2+-ATPase activity ( Vmax = 174 ± 12 vs. 153 ± 10 μmol·g protein−1·min−1) and smaller reduction in Vmax induced during exercise. A similar effect was observed for Ca2+ uptake. The Hill coefficient, defined as slope of the relationship between cytosolic free Ca2+ concentration and Ca2+-ATPase activity, was higher ( P < 0.05) at rest (2.07 ± 0.15 vs. 1.90 ± 0.10) with Ex+Lo CHO, an effect that persisted throughout the exercise. The coupling ratio, defined as the ratio of Ca2+ uptake to Vmax, was 23–30% elevated ( P < 0.05) at rest and during the first 60 min of exercise with Ex+Lo CHO. The ∼27 and 34% reductions ( P < 0.05) in phase 1 and phase 2 Ca2+ release, respectively, observed during exercise with Lo CHO were not altered by Ex+Lo CHO. These results indicate that when prolonged exercise precedes a short-term Lo CHO diet, Ca2+ sequestration properties and efficiency are improved compared with those during Lo CHO alone.

2006 ◽  
Vol 101 (3) ◽  
pp. 695-706 ◽  
Author(s):  
T. A. Duhamel ◽  
H. J. Green ◽  
J. G. Perco ◽  
J. Ouyang

The effects of exercise and diet on sarcoplasmic reticulum Ca2+-cycling properties in female vastus lateralis muscle were investigated in two groups of women following four different conditions. The conditions were 4 days of a low-carbohydrate (Lo CHO) and glycogen-depleting exercise plus a Lo CHO diet (Ex + Lo CHO) ( experiment 2) and 4 days of normal CHO (Norm CHO) and glycogen-depleting exercise plus Norm CHO (Ex + Norm CHO) ( experiment 1). Peak aerobic power (V̇o2peak) was 38.1 ± 1.4 (SE); n = 9 and 35.6 ± 1.4 ml·kg−1·min−1; n = 9, respectively. Sarcoplasmic reticulum properties measured in vitro in homogenates (μmol·g protein−1·min−1) indicated exercise-induced reductions ( P < 0.05) in maximal Ca2+-ATPase activity (0 > 30, 60 min > fatigue), Ca2+ uptake (0 > 30 > 60 min, fatigue), and Ca2+ release, both phase 1 (0, 30 > 60 min, fatigue) and phase 2 (0 > 30, 60 min, fatigue; 30 min > fatigue) in Norm CHO. Exercise was without effect in altering the Hill slope ( nH), defined as the slope of relationship between Ca2+-ATPase activity and Ca2+ concentration. No differences were observed between Norm CHO and Ex+Norm CHO. Compared with Norm CHO, Lo CHO resulted in a lower ( P < 0.05) Ca2+ uptake, phase 1 Ca2+ release (30 min), and nH. Ex + Lo CHO resulted in a greater ( P < 0.05) Ca2+ uptake and nH compared with Lo CHO. The results demonstrate that Lo CHO alone can disrupt SR Ca2+ cycling and that, with the exception of Ca2+ release, a glycogen-depleting session of exercise before Lo CHO can reverse the effects.


2005 ◽  
Vol 99 (3) ◽  
pp. 836-843 ◽  
Author(s):  
G. P. Holloway ◽  
H. J. Green ◽  
T. A. Duhamel ◽  
S. Ferth ◽  
J. W. Moule ◽  
...  

The repetition-dependent effects of a repetitive heavy exercise protocol previously shown to alter muscle mechanic behavior (Green HJ, Duhamel TA, Ferth S, Holloway GP, Thomas MM, Tupling AR, Rich SM, and Yau JE. J Appl Physiol 97: 2166–2175, 2004) on muscle sarcoplasmic reticulum (SR) Ca2+-transport properties, measured in vitro, were examined in 12 untrained volunteers [peak aerobic power (V̇o2 peak) = 44.3 ± 0.66 ml·kg−1·min−1]. The protocol involved 6 min of cycle exercise performed at ∼91% V̇o2 peak once per hour for 16 h. Tissue samples were obtained from the vastus lateralis before (B) and after (A) exercise at repetitions 1 (R1), 2 (R2), 9 (R9), and 16 (R16). Reductions ( P < 0.05) in maximal Ca2+-ATPase activity ( Vmax) of 26 and 12% with exercise were only observed at R1 and R16, respectively. Vmax remained depressed ( P < 0.05) at R2 (B) but not at R9 (B) and R16 (B). No changes were observed in two other kinetic properties of the enzyme, namely the Hill coefficient (defined as the slope of the relationship between Ca2+-ATPase activity and free Ca2+ concentration) and the Ca50 (defined as the free Ca2+ concentration needed to elicit 50% Vmax). Changes in Ca2+ uptake (measured at 2,000 nM) with exercise and recovery generally paralleled Vmax. The apparent coupling ratio, defined as the ratio between Ca2+ uptake and Vmax, was unaffected by the intermittent protocol. Reductions ( P < 0.05) in phase 1 Ca2+ release (32%) were only observed at R1. No differences were observed between B and A for R2, R9, and R16 or between B and B for R1, R2, R9, and R16. The changes in phase 2 Ca2+ release were as observed for phase 1 Ca2+ release. It is concluded that the SR Ca2+-handling properties, in general, display rapid adaptations to repetitive exercise.


2003 ◽  
Vol 94 (5) ◽  
pp. 2034-2042 ◽  
Author(s):  
H. J. Green ◽  
C. S. Ballantyne ◽  
J. D. MacDougall ◽  
M. A. Tarnopolsky ◽  
J. D. Schertzer

In this study, we employed single-leg submaximal cycle training, conducted over a 10-wk period, to investigate adaptations in sarcoplasmic reticulum (SR) Ca2+-regulatory proteins and processes of the vastus lateralis. During the final weeks, the untrained volunteers (age 21.4 ± 0.3 yr; means ± SE, n = 10) were exercising 5 times/wk and for 60 min/session. Analyses were performed on tissue extracted by needle biopsy ∼4 days after the last training session. Compared with the control leg, the trained leg displayed a 19% reduction ( P < 0.05) in homogenate maximal Ca2+-ATPase activity (192 ± 11 vs. 156 ± 18 μmol · g protein−1 · min−1), a 4.3% increase ( P < 0.05) in pCa50, defined as the Ca2+ concentration at half-maximal activity (6.01 ± 0.05 vs. 6.26 ± 0.07), and no change in the Hill coefficient (1.75 ± 0.15 vs. 1.76 ± 0.21). Western blot analysis using monoclonal antibodies (7E6 and A52) revealed a 13% lower ( P < 0.05) sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) 1 in trained vs. control in the absence of differences in SERCA2a. Training also resulted in an 18% lower ( P < 0.05) SR Ca2+ uptake and a 26% lower ( P < 0.05) Ca2+ release. It is concluded that a downregulation in SR Ca2+ cycling in vastus lateralis occurs with aerobic-based training, which at least in the case of Ca2+ uptake can be explained by reduction in Ca2+-ATPase activity and SERCA1 protein levels.


Nutrients ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1357
Author(s):  
Buthaina E. Alathari ◽  
Dhanasekaran Bodhini ◽  
Ramamoorthy Jayashri ◽  
Nagarajan Lakshmipriya ◽  
Coimbatore Subramanian Shanthi Rani ◽  
...  

Studies in Asian Indians have examined the association of metabolic traits with vitamin D status. However, findings have been quite inconsistent. Hence, we aimed to explore the relationship between metabolic traits and 25-hydroxyvitamin D [25(OH)D] concentrations. We investigate whether this relationship was modified by lifestyle factors using a nutrigenetic approach in 545 Asian Indians randomly selected from the Chennai Urban Rural Epidemiology Study (219 normal glucose tolerant individuals, 151 with pre-diabetes and 175 individuals with type 2 diabetes). A metabolic genetic risk score (GRS) was developed using five common metabolic disease-related genetic variants. There was a significant interaction between metabolic GRS and carbohydrate intake (energy%) on 25(OH)D (Pinteraction = 0.047). Individuals consuming a low carbohydrate diet (≤62%) and those having lesser number of metabolic risk alleles (GRS ≤ 1) had significantly higher levels of 25(OH)D (p = 0.033). Conversely, individuals consuming a high carbohydrate diet despite having lesser number of risk alleles did not show a significant increase in 25(OH)D (p = 0.662). In summary, our findings show that individuals carrying a smaller number of metabolic risk alleles are likely to have higher 25(OH)D levels if they consume a low carbohydrate diet. These data support the current dietary carbohydrate recommendations of 50%–60% energy suggesting that reduced metabolic genetic risk increases 25(OH)D.


2001 ◽  
Vol 281 (4) ◽  
pp. E867-E877 ◽  
Author(s):  
R. Tupling ◽  
H. Green ◽  
G. Senisterra ◽  
J. Lepock ◽  
N. McKee

To investigate the hypothesis that ischemia and reperfusion would impair sarcoplasmic reticulum (SR) Ca2+ regulation in skeletal muscle, Sprague-Dawley rats ( n = 20) weighing 290 ± 3.5 g were randomly assigned to either a control control (CC) group, in which only the effects of anesthetization were studied, or to a group in which the muscles in one hindlimb were made ischemic for 4 h and allowed to recover for 1 h (I). The nonischemic, contralateral muscles served as control (C). Measurements of Ca2+-ATPase properties in homogenates and SR vesicles, in mixed gastrocnemius and tibialis anterior muscles, indicated no differences between groups on maximal activity, the Hill coefficient, and Ca50, defined as the Ca2+concentration needed to elicit 50% of maximal activity. In homogenates, Ca2+ uptake was lower ( P < 0.05) by 20–25%, measured at 0.5 and 1.0 μM of free Ca2+ ([Ca2+]f) in C compared with CC. In SR vesicles, Ca2+ uptake was lower ( P < 0.05) by 30–38% in I compared with CC at [Ca2+]f between 0.5 and 1.5 μM. Silver nitrate induced Ca2+ release, assessed during both the initial, early rapid ( phase 1), and slower, prolonged late ( phase 2) phases, in homogenates and SR vesicles, indicated a higher ( P < 0.05) release only in phase 1in SR vesicles in I compared with CC. These results indicate that the alterations in SR Ca2+ regulation, previously observed after prolonged ischemia by our group, are reversed within 1 h of reperfusion. However, the lower Ca2+ uptake observed in long-term, nonischemic homogenates suggests that altered regulation may occur in the absence of ischemia.


2020 ◽  
Vol 14 (2) ◽  
pp. 47-54
Author(s):  
Habib Yarizadeh ◽  
Leila Setayesh ◽  
Moein Askarpour ◽  
Seyed Ali Keshavarz ◽  
Khadijeh Mirzaei ◽  
...  

2019 ◽  
Vol 2 (S1) ◽  
pp. 34-37
Author(s):  
Tugrul I

Diet is one of the main therapies for patients with type 2 diabetes mellitus (T2DM). Many studies have investigated the relationship and risks between diet lifestyle, carbohydrate intake, and diabetes. It is not known exactly how diets, along with medication, affect medication during the treatment of diabetes mellitus. The purpose of this review is to summarize studies investigating the interaction of low-carbohydrate diets (LCD) and diabetes mellitus medication.


Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 731-P
Author(s):  
JIAN ZHOU ◽  
LINGLI CAI ◽  
JUN YIN ◽  
XIAOJING MA ◽  
YIFEI MO ◽  
...  

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