Effects of anabolic-androgenic steroid use or gonadal testosterone suppression on serum leptin concentration in men.
OBJECTIVE
Serum leptin concentration shows a sexual dimorphism that is not accounted for by gender differences in adiposity. A strong inverse association exists between serum leptin and testosterone concentrations in men, pointing to a likely influence of gonadal sex steroids on serum leptin concentration. The aim of this study was to investigate whether manipulation of sex steroid hormones in men would alter serum leptin concentration independently of changes in fat mass.


METHODS
The effects of sex steroid suppression on serum leptin concentration were investigated in nine healthy men in whom testosterone had been reversibly suppressed for 5 weeks after treatment with intramuscular triptorelin. The effects of sex steroid supplementation were investigated in nine male bodybuilders who self-administered anabolic--androgenic steroids (AAS) for a mean period of 6.5 weeks. A control group received no hormonal treatment.


RESULTS
Testosterone concentration was significantly reduced by triptorelin administration (7.32+/- 1.92ng/ml at baseline compared with 1.15+/-0.57ng/ml at 5 weeks, P=0.002). High-dose AAS use was confirmed by urine analysis. Body fat percentage was unaffected by the AAS or triptorelin intervention (P>0.19). Leptin concentration was significantly reduced after one cycle of AAS use (2.40+/-0. 98ng/ml off cycle compared with 1.63+/-0.37ng/ml on cycle, P=0.012), and was significantly increased by triptorelin administration (2. 96+/-1.50ng/ml at baseline compared with 6.63+/-4.67ng/ml at five weeks, P=0.004). No significant change occurred in the control group.


CONCLUSIONS
Androgenic sex hormone supplementation decreases serum leptin concentration, whereas suppression increases serum leptin concentration, independently of changes in body fat mass in healthy men. The sexual dimorphism evident in serum leptin concentration is likely to be due to a suppressive effect of testosterone on serum leptin concentration in males.
Lipid Laboratory, Department of Internal Medicine, University of Cape Town Medical School, Anzio Road, Observatory, 7925, South Africa.
M S
MS
Hislop
B D
BD
Ratanjee
S G
SG
Soule
A D
AD
Marais
D000273:Adipose Tissue; D000328:Adult; D045930:Anabolic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D000728:Androgens / Q000008:administration & dosage / Q000494:pharmacology*; D001823:Body Composition; D006801:Humans; D007328:Insulin / Q000097:blood; D020738:Leptin; D008074:Lipoproteins / Q000097:blood; D008297:Male; D008875:Middle Aged; D011506:Proteins / Q000378:metabolism*; D013739:Testosterone / Q000037:antagonists & inhibitors* / Q000097:blood; D017329:Triptorelin Pamoate / Q000494:pharmacology; D014891:Weight Lifting
D045930:Anabolic Agents; D000728:Androgens; D007328:Insulin; D020738:Leptin; D008074:Lipoproteins; D011506:Proteins; D017329:Triptorelin Pamoate; D013739:Testosterone