Inhibitory Effects of Diclofenac on Steroid Glucuronidation In Vivo Do Not Affect Hair-Based Doping Tests for Stanozolol

In vitro studies show that diclofenac inhibits enzymatic steroid glucuronidation. This study was designed to investigate the influence of diclofenac on the excretion of stanozolol and 3′-hydroxystanozolol via analyses in hair, blood and urine in vivo in a rat study. Brown Norway rats were administered with stanozolol (weeks 1–3) and diclofenac (weeks 1–6). Weekly assessment of steroid levels in hair was complemented with spot urine and serum tests. Levels of both stanozolol and 3′-hydroxystanozolol steadily increased in hair during stanozolol treatment and decreased post-treatment, but remained readily detectable for 6 weeks. In contrast, compared to control rats, diclofenac significantly reduced urinary excretion of 3′-hydroxystanozolol which was undetectable in most samples. This is the first report of diclofenac altering steroid metabolism in vivo, detrimentally affecting detection in urine, but not in hair, which holds considerable advantages over urinalysis for anti-doping tests.

Pharmacokinetics of boldenone and stanozolol and the results of quantification of anabolic and androgenic steroids in race horses and nonrace horses

Anabolic steroids (ABS) boldenone (BL; 1.1 mg/kg) and stanozolol (ST; 0.55 mg/kg) were administered i.m. to horses and the plasma samples collected up to 64 days. Anabolic steroids and androgenic steroids (ANS) in plasma were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The limit of detection of all analytes was 25 pg/mL. The median absorption (t1/2 partial differential) and elimination (t1/2e) half-lives for BL were 8.5 h and 123.0 h, respectively, and the area under the plasma concentration-time curve (AUCho) was 274.8 ng.h/mL. The median t1/2e for ST was 82.1 h and the was 700.1 ng.h/mL. Peak mean (X+/-SD) plasma concentrations (Cmax) for BL and ST were 1127.8 and 4118.2 pg/mL, respectively. Quantifiable concentrations of ABS and ANS were found in 61.7% of the 988 plasma samples tested from race tracks. In 17.3% of the plasma samples two or more ABS or ANS were quantifiable. Testosterone (TES) concentrations mean (X+/-SE) in racing and nonracing intact males were 241.3+/-61.3 and 490.4+/-35.1 pg/mL, respectively. TES was not quantified in nonracing geldings and female horses, but was in racing females and geldings. Plasma concentrations of endogenous 19-nortestosterone (nandrolone; NA) from racing and nonracing males were 50.2+/-5.5 and 71.8+/-4.6 pg/mL, respectively.

A decreasing CD4+/CD8+ ratio after one month of treatment with stanazolol in postmenopausal women

Androgens influence some immunological processes, including the differentiation of T-cells in CD4+ (helpers) or CD8+ (suppressors/cytotoxic) phenotype. In nine postmenopausal osteoporotic women the effect of stanazolol on lymphocyte counts, CD3+ and the immunoregulatory index (CD4+/CD8+) were investigated. In the placebo group, ten postmenopausal osteoporotic women of similar age were included. The means of the investigated indices after stanazolol as compared with the values before treatment were as follows: lymphocyte counts (cells/microL +/- SEM) 2974 +/- 225 versus 2313 +/- 166, CD3+ (%) 54.3 +/- 5.5 versus 70.9 +/- 1.6 (P < 0.05); CD4+/CD8+ ratio 1.8 +/- 0.02 versus 2.5 +/- 0.28 (P < 0.05). The values after placebo as compared with the values before placebo were: 2558 +/- 201 versus 2370 +/- 256, 62.9 +/- 2.1 versus 64.8 +/- 1.7 and 1.6 +/- 0.2 versus 1.6 +/- 0.1 in sequence. The treatment was controlled by the serum stanazolol levels before and after steroid administration (unmeasurable versus 20.8 +/- 3.4 nmol/L, P < 0.01). The good compliance of the therapy was confirmed by a decline of serum LH (U/L; 30.1 +/- 3.1 versus 24.7 +/- 2.8, P = 0.014), FSH (U/L; 108.9 +/- 13.1 versus 93.3 +/- 12.8, P = 0.012) and serum sex hormone binding globulin (SHBG; nmol/L; 53.3 +/- 13.3 versus 11.2 +/- 1.9, P < 0.01). The decline of SHBG indicates a good tissue sensitivity to the androgen. There were no significant differences between hormonal parameters before and after placebo treatment. In conclusion, the immunosuppressive effect of the androgen, stanazolol, was confirmed in the investigated postmenopausal osteoporotic women.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of probenecid on the excretion kinetics of stanozolol, an anabolic steroid, in rats

The pharmacokinetic behaviour and the mechanism of renal excretion of stanozolol (STZ), as affected by co-treatment with probenecid, were studied in male Sprague-Dawley rats. Pharmacokinetic parameters following intravenous (i.v.) administration of STZ (20 mg kg-1 body wt.) were measured in both STZ-treated (control) and STZ plus probenecid-treated (treatment) groups. In order to assess the renal clearance of STZ, bolus doses of STZ and inulin (40 mg kg-1 body wt.) were injected i.v. either in the presence or absence of probenecid (40 mg kg-1 body wt.). The blood and urine concentrations of STZ were determined by capillary gas chromatography-mass spectrometry (GC-MS). In the probenecid treatment group, the area under the plasma disappearance and urinary excretion curves (AUC) of STZ were significantly decreased (P < 0.01) and the volume of distribution (Vd) and total clearance (CLt) were significantly increased statistically (P < 0.05 and P < 0.01, respectively). No remarkable differences in the urine flow rate, urine pH values, glomerular filtration rate (GFR) or renal clearance were observed in the treatment group. However, the clearance ratio in the treatment group was significantly increased from 11.72 to 17.27. From these results, it is suggested that the significant decrease of AUC, i.e. increase of disappearance of STZ in plasma by co-administration with probenecid, is due to the increase of the clearance ratio.