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| References
- Heart,
circulation, and the effects of testosterone. |
5.
Winkler UH. Effects of androgens on haemostasis.
Maturitas 1996;24:147-155.
Abstract: Androgen deficiency is associated with an increased
incidence of cardiovascular disease. There is evidence that
thromboembolic disease as well as myocardial ifarction in hypogonadic
males are mediated by low baseline fibrinolytic activity. Hypogonadism
in males is associated with an enhancement of fibrinolytic inhibition
via increased synthesis of the plasminogen activator inhibitor
PAI 1. On the other hand, stanozolol and danazol reduce PAI
1 and are associated with increased fibrinolytic activity. However,
in male abusers of anabolic steroids the net effect on the haemostatic
system may change from anti- to prothrombotic; there appears
to be an individual threshold dose above which thrombogenic
effects on platelets and vasomotion may overcome the profibrinolytic
effects on PAI 1. There are numerous reports on weight-lifters
dying of atherothrombotic ischemic heart disease while abusing
anabolic steroids. Androgens are known to have profound effects
on carbohydrate and lipid metabolism. In fact, much of the individual
inconsistency of the effects of androgens on fibrinolytic and
haemostatic activity appears to be based on the close interrelationship
of these metabolic systems. Androgens may have unfavourable
effects on the HDL/LDL cholesterol ratio, on triglyceride levels
and on the insulin/insulin-like growth factor 1 (IGF 1) system.
Hypertriglyceridemia as well as insulin resistance are both
associated with low fibrinolytic activity and increased PAI
1 levels. On the other hand, lipoprotein(a), a recently acknowledged
independent risk factor of CVD was shown to respond favourable
to androgen treatment, in men as well as in women. In women,
agonistic as well as antagonistic effects of estrogens and progestins
need to be taken into account. In fact, estradiol may modulate
testosterone effects on haemostasis. Androgen medication in
premenopausal women, such as danazol, was found to reduce PAI
1 suggesting an improvement of the fibrinolytic activity. Also,
in hormone replacement therapy (HRT) androgenic progestins or
complex compounds with androgenic effects are associated with
a marked reduction of PAI 1 and an improvement of fibrinolytic
activity. Further improvement of fibrinolytic activity may be
associated with the marked decrease of lipoprotein (a) (Lp(a))
in women on androgenic HRT. However, little is known on the
interrelationship of estrogens, 19-nortestosterone or progesterone
derivatives and testosterone. an interrelationship that may
have substantial impact on the metabolic and particularly haemostatic
net effects of a preparation. In summary, information on the
effects of androgens on haemostasis is limited and may be particularly
incomplete due to the fact that interaction with other sex steroids
appears to be an important confounder. In any case, there are
numerous effects of synthetic androgens on the synthesis and
release of haemostatic factors, namely an increase of the inhibitors
of coagulation and a decrease of the inhibitor of the fibrinolytic
system. However, the use of androgens in patients with congenital
deficiencies of these coagulation factors or previous events
of cardiovascular disease has yielded disappointing results.
On the other hand, particularly the reduction of fibrinolytic
inhibition (PAI 1) and Lp(a) were considered favourable effects
of androgens with regard to the risk of cardiovascular disease.
Differences between preparations with pronounced androgenic
versus antiandrogenic effects and the effect of combined preparations
need to be studied in much more detail. The profibrinolytic
effects of androgens may be of particular interest with regard
to favourable effects of HRT on cardiovascular disease.
Notes: The profibrinolytic effects of androgens may be of
particular interest with regard to favourable effects of HRT
on cardiovascular disease.However, in male abusers of anabolic
steroids the net effect on the haemostatic system may change
from being anti- to prothrombotic.
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