The effect of beta -adrenoceptor stimulation on skeletal muscle protein turnover and intracellular signalling is insufficiently explored in humans, particularly in association with exercise. In a randomized, placebo-controlled, cross-over study investigating 12 trained men, the effects of beta -agonist (6 × 4 mg oral salbutamol) on protein turnover rates, intracellular signalling and mRNA response in skeletal muscle were investigated 0.5-5 h after quadriceps resistance exercise. Each trial was preceded by a 4-day lead-in treatment period. Leg protein turnover rates were assessed by infusion of [ C ]-phenylalanine and sampling of arterial and venous blood, as well as vastus lateralis muscle biopsies 0.5 and 5 h after exercise. Furthermore, myofibrillar fractional synthesis rate, intracellular signalling and mRNA response were measured in muscle biopsies. The mean (95% confidence interval) myofibrillar fractional synthesis rate was higher for salbutamol than placebo [0.079 (95% CI, 0.064 to 0.093) vs. 0.066 (95% CI, 0.056 to 0.075%) × h ] (P < 0.05). Mean net leg phenylalanine balance 0.5-5 h after exercise was higher for salbutamol than placebo [3.6 (95% CI, 1.0 to 6.2 nmol) × min × 100 g ] (P < 0.01). Phosphorylation of Akt2, cAMP response element binding protein and PKA substrate 0.5 and 5 h after exercise, as well as phosphorylation of eEF2 5 h after exercise, was higher (P < 0.05) for salbutamol than placebo. Calpain-1, Forkhead box protein O1, myostatin and Smad3 mRNA content was higher (P < 0.01) for salbutamol than placebo 0.5 h after exercise, as well as Forkhead box protein O1 and myostatin mRNA content 5 h after exercise, whereas ActivinRIIB mRNA content was lower (P < 0.01) for salbutamol 5 h after exercise. These observations suggest that beta -agonist increases protein turnover rates in skeletal muscle after resistance exercise in humans, with concomitant cAMP/PKA and Akt2 signalling, as well as modulation of mRNA response of growth-regulating proteins.

Selective β-adrenoceptor agonism effectively increases metabolic rate and fat oxidation in overweight individuals. The potential for weight loss induced by β-agonists may be greater for R-enantiopure formulations.

PURPOSE To analyze the risk of cardiovascular disease (CVD) after treatment of male germ cell cancer (GCC). METHODS Clinical data were extracted from the Danish Testicular Cancer database. For each patient, 10 men matched on date of birth were identified in the Danish normal population by risk-set sampling. Cardiovascular risk factors, CVD, and associated deaths were identified in Danish registries. The association between treatment and outcomes was analyzed by separate Cox models for each outcome. Cancer treatment was included as a time-varying covariate. RESULTS We included 5,185 patients with GCC and 51,850 men in the normal population. Median follow-up was 15.8 years. Treatment with bleomycin-etoposide-cisplatin (BEP; n = 1,819) was associated with increased risks of hypertension and hypercholesterolemia. Hazard ratios (HRs) of CVD < 1 year after initiation of BEP treatment were as follows: myocardial infarction (HR, 6.3; 95% CI, 2.9 to 13.9), cerebrovascular accident (HR, 6.0; 95% CI, 2.6 to 14.1), and venous thromboembolism (HR, 24.7; 95% CI, 14.0 to 43.6). One year after BEP treatment, the risk of CVD decreased to normal levels, but after 10 years, increasing risks were found for myocardial infarction (HR, 1.4; 95% CI, 1.0 to 2.0) and cardiovascular death (HR, 1.6; 95% CI, 1.0 to 2.5). Radiotherapy (n = 780) increased the risk of diabetes at long-term follow-up (HR, 1.4; 95% CI, 1.0 to 2.0) but not that of other outcomes. With surveillance (n = 3,332), cardiovascular risk factors, CVD, and cardiovascular death data were comparable to that of the normal population. CONCLUSION Treatment with BEP was associated with highly increased risks of CVD < 1 year after treatment start and mildly increased risks after 10 years of follow-up. Radiotherapy increased the risk of diabetes but not incident CVD. The risk of CVD in patients followed in a surveillance program was comparable to that of the normal population.

No abstract