Long-term transdermal dihydrotestosterone therapy: effects on pituitary gonadal axis and plasma lipoproteins.

In order to investigate whether dihydrotestosterone (DHT) alone has an inhibiting effect on pituitary luteinizing hormone (LH) secretion, and whether this natural androgen has any effect on plasma lipids when administered transdermally, dihydrotestosterone was applied for 3 mth in a daily dose of 125 or 250 mg in gel form for transdermal absorption (Andractim) to elderly males with relatively low plasma testosterone levels. The results clearly show that DHT inhibits LH secretion, as plasma LH levels were decreased, although testosterone, free testosterone, estradiol and free estradiol levels were decreased. Regarding plasma lipid levels, DHT administration for 3 mth resulted in a moderate decrease in plasma cholesterol and low-density lipoprotein (LDL) levels, and a slight decrease in high-density lipoprotein (HDL)-cholesterol levels, the HDL/TLC ratio remaining constant. This suggests that percutaneous DHT administration is a relatively safe modality of androgen replacement therapy as far as atherogenicity is concerned.