Dn. Tietjen et al., MICROPENIS IN HYPOGONADOTROPIC HYPOGONADISM - RESPONSE OF THE PENILE ANDROGEN RECEPTOR TO TESTOSTERONE TREATMENT, The Journal of urology, 160(3), 1998, pp. 1054-1057
Purpose: We determine whether testosterone therapy alters penile andro
gen receptor expression within the hypogonadotropic hypogonadal (HPG)
micropenis. Materials and Methods: In protocol 1 a strain of mice with
micropenis due to congenital HPG and wild type litter mates were divi
ded into testosterone treated and untreated groups. Treatment was init
iated on day 15 of life. On day 90 of life (day 75 of treatment) the m
ice were sacrificed, and the penises were removed and weighed. In prot
ocol 2 microphallic mice treated with testosterone were sacrificed on
days 0, 6, 30, 60 and 75 after the initiation of treatment. Untreated
HPG and wild type litter mates served as controls. At autopsy the peni
s was removed and weighed, and androgen receptor content was determine
d by Western immunoblotting. Results: Testosterone treatment resulted
in 6-fold up regulation in HPG penile androgen receptor, approximately
1.4-fold higher than in the normal wild type pubescent penis. Testost
erone induced and wild type pubescent penile androgen receptor up regu
lation was maintained for approximately 75 and 60 days, respectively.
Despite improved HPG penile androgen receptor expression penile growth
did not become normal. Average total penile weight plus or minus stan
dard deviation was 7.2 +/- 3.5 mg. in untreated HPG mice. Testosterone
significantly improved average HPG penile weight to 23.5 +/- 1.8 mg.
(p <0.001). However, the testosterone treated micropenis failed to rea
ch average normal penile size (38.6 +/-: 2.6 mg., p <0.001). Conclusio
ns: Testosterone increases the concentration and duration of penile an
drogen receptor expression within the HPG micropenis. Despite this imp
rovement microphallic HPG penile growth does not become normal.