Anabolic-Androgenic Steroid Administration Causes Hypertrophy of Immobilized and Nonimmobilized Skeletal Muscle in a Sedentary Rabbit Model

Abstract

Although the use of anabolic agents in athletics has generated extensive publicity and controversy, the potential therapeutic benefits of these drugs have not been fully investigated. This randomized, blinded experimental study investigated whether short-term administration of an anabolic-androgenic steroid can limit immobilization-induced muscle atrophy in a rabbit model. We casted one hindlimb each in 48 New Zealand White rabbits and randomly assigned the rabbits to two groups. The treated group received weekly intramuscular injections of the anabolic-androgenic steroid, nandrolone decanoate (15 mg/kg). Immobilization significantly decreased muscle weights in both the treated rabbits and controls. Compared with controls, the body weights of the treated rabbits increased significantly at 2, 4, and 8 weeks. At 4 and 8 weeks, wet weights, dry weights, and contractile forces were significantly greater in both the casted and noncasted tibialis anterior muscle-tendon units of the treated group. Dry weights and casted contractile forces of the extensor digitorum longus muscle unit at 4 weeks and all measures at 8 weeks were greater in the treated rabbits than in controls. These results are contrary to previously accepted views that anabolic-androgenic steroid use leads to muscle hypertrophy only in conjunction with strength training. This study adds to the growing evidence that anabolic-androgenic steroids can produce significant skeletal muscle hypertrophy in sedentary populations.

Effects of nandrolone on recovery after neurotization of chronically denervated muscle in a rat model

“…11 Although we did not evaluate nandrolone levels, we did confirm that the osmotic pump delivery system, which is well validated and considered reliable, 55 did successfully deliver its contents. Likewise, our treatment period of 4 weeks was within the range of other studies (2-8 weeks, 54 5-6 weeks, 10 30 days, 18 28 days, 59 14 days, , although still on the conservative side. Salmons, in particular, reported positive effects of anabolic steroids at 12 weeks but not at 4 weeks.…”

“…Salmons demonstrated improved size and strength in the tibialis anterior muscle of female rabbits following 12 weeks of anabolic steroid administration. 45 Taylor et al found a definite anabolic response in a sedentary rabbit model treated with nandrolone decanoate, 54 and Zhao et al found that nandrolone significantly reduced chronic denervation atrophy (but not acute atrophy) in rats when administered 28 days after nerve transection. 59 In certain types of atrophy, including disuse, HIV infection, and sarcopenia, anabolic steroids have been shown to have a positive effect.…”

“…Some studies, however, used even higher dosages (15 mg/ kg per week 6,54 ), and body builders are reported to use 10-100 times the normal therapeutic dosage of anabolic steroids. 11 Although we did not evaluate nandrolone levels, we did confirm that the osmotic pump delivery system, which is well validated and considered reliable, 55 did successfully deliver its contents.…”

Nandrolone Normalizes Determinants of Muscle Mass and Fiber Type after Spinal Cord Injury

“…Several studies have shown that testosterone or nandrolone reduced muscle atrophy caused by a lack of weight-bearing or immobilization (Taylor et al, 1999;Wimalawansa et al, 1999). In muscle paralyzed by nerve transection, nandrolone slowed atrophy and reduced expression of MAFbx, MuRF1, and FOXO1 (Qin et al, 2010b).…”

Androgens Up-regulate Transcription of the Notch Inhibitor Numb in C2C12 Myoblasts via Wnt/β-Catenin Signaling to T Cell Factor Elements in the Numb Promoter

“…Administration of testosterone promotes the differentiation of mesenchymal stem cells into the myogenic lineage (22). Testosterone is able to increase skeletal muscle mass and strength in elderly men and in many conditions resulting in muscle atrophy, such as cancer and burn-induced cachexia (23), microgravity (24), immobilization (25), and spinal cord injury (26). The precise mechanisms underlying these actions of androgens, however, are poorly understood.…”