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Response of human skeletal
muscle to the anabolic steroid
stanozolol
Janice L Hosegood, Antony J Franks
As part of a larger trial assessing the value of stanozolol
in preventing postoperative deep vein thrombosis' we
studied whether stanozolol increased the size of human
skeletal muscle fibres.
Patients, methods, and results
We studied 16 patients undergoing elective
abdominal surgery, eight of whom received 10 mg
stanozolol orally each day for 14-21 days before
operation as part of the larger trial.' Patients were
matched in pairs for age, sex, and body build (percentage
overweight for height was calculated from tables
giving expected weight for height). None of the
patients had a history of abdominal operations, recent
weight loss, endocrine disorder, or treatment with
corticosteroids, and none had a malignant condition.
Consent was obtained from the patients and the trial
was approved by the hospital ethical committee.
A biopsy specimen of rectus abdominis at least 1 cm
long was taken at operation (avoiding tendinous
insertions) before diathermy or retractors were used.
These were processed according to a routine protocol,
and serial cryostat sections were stained with haematoxylin
and eosin, reduced nicotinamide-adenine
dinucleotide diaphorase, Gomori's trichrome, and
adenosine triphosphatase preincubated at pH 9-4,
4-63, and 4.35.2 An image based analysis system (IBAS
1, Konitron Bildanalyse System) was used to measure
the smallest diameter of the myofibres (the greatest
distance across the lesser aspect of the fibres in the
section stained with adenosine triphosphatase and
preincubated at pH 9-4).2 At least 200 type I fibres and
200 type II fibres were measured in each sample except
one, in which only 151 type I fibres were present. All
of the fibres within fascicles chosen at random were
measured. The variability in measurements between
operators was found to be less than 3%. A paired
Wilcoxon rank test was performed on the mean
diameters of the fibres in the two groups.
The diameters of type I fibres were significantly
larger (002<p<0005) in the patients treated with
stanozolol compared with the controls (table). There
was no significant difference (p>005) between the
type II (a and b) fibres in the treated and control
groups. Type Ilc fibres were present in varying and
small numbers in the samples (0-4% of the total), but
no statistical analysis was performed on these.
Comment
These results show an increase in the bulk of type I
(oxidative) fibres in response to the anabolic steroid
stanozolol. Changes in the size of muscle fibres are
most common in type II fibres, which atrophy with
disuse, malnutrition, and excess glucocorticoids and
show hypertrophy after "strength building" exercise.
Arduous long term physical exercise leads to an
increase in the bulk of type I fibres, both by hypertrophy
of fibres and by transformation of fibre type3;
and the oxidative capacity of the muscle increases
concurrently.4 The bulk of fibres may also increase
in certain diseases such as Duchenne muscular
dystrophy, in which the composition of the hypertrophied
muscle is abnormal.
The muscle we examined is not usually used in
exercise. If, however, an increased bulk of type I fibres
in other skeletal muscle increased its aerobic potential
it might fatigue less readily. Any resulting increase in
exercise might lead to secondary hypertrophy of type II
fibres, improving performance and, incidentally,
masking a predominant direct effect on type I fibres in
Department of Pathology,
University of Leeds, Leeds
LS2 9JT
Janice L Hosegood, MB,
senior house officer
Antony J Franks, MRCPATH,
senior lecturer
Correspondence and
requests for reprints to: Dr A
J Franks, Bradford Health
Authority, Bradford, West
Yorkshire BD9 6RL.
Mean diameters oftype Ifibres
([rn) in pairs ofpatients and
controls matched for age, sex,
and body build
Patients treated
Pair no with stanozolol Controls
1 44 33
2 46 47
3 56 44
4 40 39
5 62* 57
6 51 43
7 57 43
8 41 40
*Only 151 fibres were available for
measurement in this sample.
1028 BMJ VOLUME 297 22 OCTOBER
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Response of human skeletal muscle to the anabolic ...[BMJ. 1988] - PubMed Result