Oxandrolone and fat burning
Oral anabolic steroid treatment, but not parenteral androgen treatment, decreases abdominal fat in obese, older men.
Lovejoy JC, Bray GA, Greeson CS, Klemperer M, Morris J, Partington C, Tulley R.
Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808-4124, USA.
OBJECTIVE: To compare the effects of testosterone enanthate (TE), anabolic steroid (AS) or placebo (PL) on regional fat distribution and health risk factors in obese middle-aged men undergoing weight loss by dietary means. DESIGN: Randomized, double-blind, placebo-controlled clinical trial, carried out for 9 months with primary assessments at 3 month intervals. Due to adverse blood lipid changes, the AS group was switched from oral oxandrolone (ASOX) to parenteral nandrolone decaoate (ASND) after the 3 month assessment point. SUBJECTS: Thirty healthy, obese men, aged 40-60 years, with serum testosterone (T) levels in the low-normal range (2-5 ng/mL). MAIN OUTCOME MEASURES: Abdominal fat distribution and thigh muscle volume by CT scan, body composition by dual energy X-ray absorptiometry (DEXA), insulin sensitivity by the Minimal Model method, blood lipids, blood chemistry, blood pressure, thyroid hormones and urological parameters. RESULTS: After 3 months, there was a significantly greater decrease in subcutaneous (SQ) abdominal fat in the ASOX group compared to the TE and PL groups although body weight changes did not differ by treatment group. There was also a tendency for the ASOX group to exhibit greater losses in visceral fat, and the absolute level of visceral fat in this group was significantly lower at 3 months than in the TE and PL groups. There were significant main effects of treatment at 3 months on serum T and free T (increased in the TE group and decreased in the ASOX group) and on thyroid hormone parameters (T4 and T3 resin uptake significantly decreased in the ASOX group compared with the other two groups). There was a significant decrease in HDL-C, and increase in LDL-C in the ASOX group, which led to their being switched to the parenteral nandrolone decanoate (ASND) after 3 months. ASND had opposite effects on visceral fat from ASOX, producing a significant increase from 3 to 9 months while continuing to decrease SQ abdominal fat. ASND treatment also decreased thigh muscle area, while ASOX treatment increased high muscle. ASND reversed the effects of ASOX on lipoproteins and thyroid hormones. The previously reported effect of T to decrease visceral fat was not observed, in fact, visceral fat in the TE group increased slightly from 3 to 9 months, although SQ fat continued to decrease. Neither TE nor AS treatment resulted in any change in urologic parameters. CONCLUSIONS: Oral oxandrolone decreased SQ abdominal fat more than TE or weight loss alone and also tended to produce favorable changes in visceral fat. TE and ASND injections given every 2 weeks had similar effects to weight loss alone on regional body fat. Most of the beneficial effects observed on metabolic and cardiovascular risk factors were due to weight loss per se. These results suggest that SQ and visceral abdominal fat can be independently modulated by androgens and that at least some anabolic steroids are capable of influencing abdominal fat.
It has been postulated that Oxandrolone is especially good at reducing visceral fat due to its high AR binding affinity. It appears to be better at binding to the AR (at even amounts) then Test or deca. It would make sense if it is working through the AR if it also increases AR expression in adipose tissue as well (upregulating the AR in adipose tissue adding to lipolytic effects), which the following study seems to show:
Short-term oxandrolone administration stimulates net muscle protein synthesis in young men.
Sheffield-Moore M, Urban RJ, Wolf SE, Jiang J, Catlin DH, Herndon DN, Wolfe RR, Ferrando AA.
Department of Surgery, University of Texas Medical Branch, and Shriners Burn Hospital for Children, Galveston 77550, USA.
melmoore@utmb.edu Short term administration of testosterone stimulates net protein synthesis in healthy men. We investigated whether oxandrolone [Oxandrin (OX)], a synthetic analog of testosterone, would improve net muscle protein synthesis and transport of amino acids across the leg. Six healthy men [22+/-1 (+/-SE) yr] were studied in the postabsorptive state before and after 5 days of oral OX (15 mg/day). Muscle protein synthesis and breakdown were determined by a three-compartment model using stable isotopic data obtained from femoral arterio-venous sampling and muscle biopsy. The precursor-product method was used to determine muscle protein fractional synthetic rates. Fractional breakdown rates were also directly calculated. Total messenger ribonucleic acid (mRNA) concentrations of skeletal muscle insulin-like growth factor I and androgen receptor (AR) were determined using RT-PCR. Model-derived muscle protein synthesis increased from 53.5+/-3 to 68.3+/-5 (mean+/-SE) nmol/min.100 mL/leg (P < 0.05), whereas protein breakdown was unchanged. Inward transport of amino acids remained unchanged with OX, whereas outward transport decreased (P < 0.05). The fractional synthetic rate increased 44% (P < 0.05) after OX administration, with no change in fractional breakdown rate. Therefore, the net balance between synthesis and breakdown became more positive with both methodologies (P < 0.05) and was not different from zero. Further, RT-PCR showed that OX administration significantly increased mRNA concentrations of skeletal muscle AR without changing insulin-like growth factor I mRNA concentrations. We conclude that short term OX administration stimulated an increase in skeletal muscle protein synthesis and improved intracellular reutilization of amino acids. The mechanism for this stimulation may be related to an OX-induced increase in AR expression in skeletal muscle.