Objectives: To elucidate the metabolic effects of topical testosterone for
the treatment of microphallus in children.
Methods. We administered 5% testosterone ointment to 50 prepubertal boys fu
r the treatment of microphallus, allowing us to observe its metabolic effec
t on plasma concentrations of testosterone as a marker of transdermally abs
orbed testosterone, insulin-like growth factor (IGF)-I as a marker of growt
h hormone secretion status, and osteocalcin as a marker of bone metabolic t
urnover.
Results: Transdermal application of testosterone for 30 days at a dose that
affects penile growth increased mean (a SD) plasma testosterone concentrat
ions from 7.5 +/- 5.1 to 31.0 +/- 8.2 ng/dL (pre- vs post-treatment, respec
tively; P< 0.01). This was associated with a slight but statistically signi
ficant elevation of IGF-I concentrations (117.2 +/- 76.9 vs 154.4 +/- 81.5
ng/mL; P < 0.05). No significant change in osteocalcin levels was found.
Conclusions: When using testosterone ointment as a treatment fur microphall
us, it should be borne in mind that this application has systemic effects.