β₂-Adrenergic agonist salbutamol augments hypertrophy in MHCIIa fibers and sprint mean power output but not muscle force during 11 weeks of resistance training in young men

Abstract

In this study, we examined the effect of beta2-agonist salbutamol at oral doses during a period of resistance training on sprint performance, quadriceps contractile function, skeletal muscle hypertrophy, fiber-type composition, maximal activity of enzymes of importance for anaerobic energy turnover, and sarcoplasmic reticulum Ca2+-handling in young men. Twenty-six men (23±2 years;mean±SD) were randomized to daily intake of oral salbutamol (16 mg/d;RES+SAL) or placebo (RES) during 11 weeks full-body resistance training 3 times/week. Mean power output during 10s maximal cycling increased more (P=0.027) in RES+SAL (+12%) than in RES (+7%), whereas peak power output increased similarly (RES+SAL:+8%;RES:+7%;P=0.400). Quadriceps dynamic peak torque and maximal voluntary isometric torque increased by 13 and 14% (P≤0.001) in RES+SAL and 13 and 13% (P≤0.001) in RES, respectively. Myosin heavy chain (MHC) isoform distribution transitioned from MHCI and MHCIIx towards MHCIIa in RES+SAL (P=0.002), but not in RES (P=0.323). MHCIIa cross-sectional-area increased more (P=0.040) in RES+SAL (+35%) than RES (+21%). Sarcoplasmic reticulum Ca2+-release rate increased in both groups (RES+SAL:+9%,P=0.048;RES:+13%,P=0.008), whereas Ca2+-uptake rate increased only in RES (+12%,P=0.022) but not different from the non-significant change in RES+SAL (+2%,P=0.484). Maximal activity of lactate dehydrogenase increased only in RES+SAL (+13%,P=0.008). Muscle content of the dihydropyridine receptor, ryanodine receptor 1, and sarcoplasmic reticulum Ca2+-ATPase isoform 1 and 2 did not change with the intervention in either group (P≥0.100). These observations suggest that salbutamol is a muscle anabolic drug, which induces greater sprint mean power output, without affecting peak power output and muscle strength when ingested during a period of resistance training.

The beta2‐adrenergic receptor – a re‐emerging target to combat obesity and induce leanness?

“…The endurance-training group receiving terbutaline experienced a weight loss of 1.9 kg compared with placebo, whereas the resistance-training group receiving terbutaline had a 1 kg greater gain of muscle mass than placebo but not a greater reduction of fat mass (Jessen et al 2018). The latter observation corresponds with studies showing an additive effect of salbutamol on muscle power and hypertrophy in young men subjected to a period of resistance training (Caruso et al 2005;Jessen et al 2021). Hence, beta 2 -agonists may exert some beneficial effects on body composition when taken concomitantly with training as demonstrated for terbutaline (Fig.…”

“…2005; Jessen et al . 2021). Hence, beta 2 ‐agonists may exert some beneficial effects on body composition when taken concomitantly with training as demonstrated for terbutaline (Fig.…”

Prevalence of Prohibited Substance Use and Methods by Female Athletes: Evidence of Gender-Related Differences

“…After short-term oral salbutamol administration, maximal anaerobic power but not capacity was improved, irrespective of the gender or training status, with no change in body composition (Le Panse et al, 2005 , 2006 ). Other studies performed only in men showed various results after salbutamol or terbutaline inhalation or intake, with change or no change in aerobic (Collomp et al, 2000 ) and anaerobic performances, coupled or not to anabolic effects (Hostrup et al, 2014 ; Jessen et al, 2021 ). Women may have greater sensitivity to beta-2 receptor stimulation (Kneale et al, 2000 ), but in view of the same TUE prevalence for beta-2 agonists in female and male athletes (Vernec and Healy, 2020 ) and the lack of studies on the pharmacokinetics and the ergogenic, physiological, and psychological terbutaline effects in women, it is difficult to speculate on the higher number of terbutaline cases found in female athletes.…”

Beta2‐agonist increases skeletal muscle interleukin 6 production and release in response to resistance exercise in men

“…The study employed a randomized double‐blinded placebo‐controlled crossover design and is part of a larger project investigating beta 2 ‐adrenergic effects on skeletal muscle hypertrophy and metabolism induced by selective beta 2 ‐agonist. A part pertaining to beta 2 ‐adrenergic‐induced changes in muscle protein turnover rates, 35 glucose metabolism, 36 and hypertrophy 37 have been described elsewhere. The outcome measures for the present part are arterial and venous IL‐6 concentrations, a‐v IL‐6 difference, IL‐6 release, and mRNA levels of IL‐6 and TNF‐α.…”