Dose-Dependent Effects of an Anabolic Steroid, Nandrolone Phenylpropionate (Durabolin), on Body Composition and Muscle Protein Metabolism in Female Rats

Abstract

The effects of three doses (1,4 and 10 mg/kgbody weight) of an anabolic steroid, nandrolone phenylpropionate (NPP), on body weight and composition, and muscle protein metabolism were investigated in female rats. Daily injections of 1 mg/kg of NPP for 10 days caused a significant increase in weight gain which was associated with an increase in body protein (9%) without affecting body fat. At higher doses this effect on body weight was attenuated, resulting in no change in body weight at 10 mg/kg. However body protein content was still increased (9%) whereas body fat content was significantly reduced (32%). NPP did not affect metabolizable energy intake at any dose tested. Body energy gain and gross energetic efficiency were both significantly reduced in animals treated with a dose of 10 mg/ kg. The mass and protein content of gastrocnemius muscle were significantly increased in animals injected with NPP at all doses. Muscle protein synthesis measured in vivo was also significantly stimulated at 1 and 4 mg/kg but was not affected at 10 mg/kg. These data confirm an anabolic action of NPP and suggest highly dose-dependent effects on other parameters such as body weight, fat deposition and muscle protein synthesis.

Physiologic effects of nutritional support and anabolic steroids in patients with chronic obstructive pulmonary disease. A placebo-controlled randomized trial.

“…Despite a similar weight gain as the group with nutrition alone, measurements of body composition indicated a favorable distribution of the body weight gain towards a larger increase of FFM in the group additionally treated with a short course of anabolic steroids. These findings are in agreement with studies in rats in which nandrolone decanoate induced muscle hypertrophy not attributable to fluid retention or changes in body weight (36,37). Because women are more susceptible to androgenic anabolic steroids (37), they received half the dose given to the men, and we carefully monitored possible side effects such as indicated in METHODS.…”

“…These findings are in agreement with studies in rats in which nandrolone decanoate induced muscle hypertrophy not attributable to fluid retention or changes in body weight (36,37). Because women are more susceptible to androgenic anabolic steroids (37), they received half the dose given to the men, and we carefully monitored possible side effects such as indicated in METHODS. This treatment scheme induced similar body compositional and functional effects in both sexes, and no side effects were seen.…”

Short-Term Modulation of the Androgen Milieu Alters Pulsatile, But Not Exercise- or Growth Hormone (GH)-Releasing Hormone-Stimulated GH Secretion in Healthy Men: Impact of Gonadal Steroid and GH Secretory Changes on Metabolic Outcomes1

“…6. The anabolic action on lean body mass was largely ascribable to an increase in muscle and was observed in hypogonadal male and female animals or eugonadal men given high dose testosterone or anabolic steroids (1,3,5,21,26,34,(43)(44)(45). Tertiles run from low (ϭ1) to high (ϭ3) hormone levels.…”

“…Triaxial display of urinary nitrogen excretion (normalized for creatinine) segregated by tertiles of serum testosterone concentrations and 24-h pulsatile GH production rate. Although some studies suggested that androgens increased protein mass via decreases in proteolysis (46), most investigations have reported that androgens augment muscle mass through increases in muscle protein synthesis without affecting degradation (5,21,43,45,(47)(48)(49). Movement from low to high serum testosterone tertiles discloses significant changes in urinary nitrogen excretion, whereas a similar pattern is not observed between the low and high GH production tertiles (by ANCOVA) .…”

Exogenous testosterone treatment decreases diaphragm neuromuscular transmission failure in male rats

“…PREVIOUS STUDIES ON THE EFFECT of pharmacological anabolic-androgenic steroid (AAS) levels on neuromuscular systems in animal models have principally focused on their modulation of skeletal muscle properties (7,11,12,13,15,27,28,33,34). Because both final components of neuromuscular systems (i.e., motoneurons and skeletal muscle fibers) express the androgen receptor (6,18,22,35), AAS-induced alterations in muscle function may be mediated by either component.…”