Sexual function does not change when serum testosterone levels are pharmacologically varied within the normal male range.
OBJECTIVE
To examine the relationship between serum T levels and sexual function when T levels are varied in the normal male range by pharmacological means. Two groups of healthy men were treated with a depot form of GnRH agonist leuprolide acetate (Lupron depot; TAP Pharmaceuticals, Chicago, IL) on days 1 and 31 to suppress endogenous T production and either 4 (n = 6) or 8 (n = 5) mg/d T replacement by a sustained release, long-acting T microcapsule formulation on day 1.


METHODS
Sexual function was evaluated by daily logs of sexual activity and electroencephalogram-coupled nocturnal penile tumescence recording before and after 9 weeks of treatment.


RESULTS
Serum T levels in 4 and 8 mg/d groups were at low and high ends of the normal male range, respectively (10.5 +/- 1.7 versus 26.5 +/- 3.4 nmol/L). The number and duration of rapid eye movement (REM) periods, latency to REM sleep, erections/REM period, magnitude, and duration of tumescence were not significantly different between the 4 and 8 mg groups. Sexual logs also did not show significant differences in overall scores or in subcategories of intensity of sexual feelings (libido) and sexual activity between the two doses.


CONCLUSIONS
These data indicate that erectile function and sexual activity and feelings are restored by relatively low T levels. These data may help explain why some partially hypogonadal men continue to have normal sexual function and the absence of good correlation between serum T levels in the normal range and sexual function.
Buena
F
F
Department of Medicine, Harbor-University of California, Los Angeles Medical Center, Torrance 90502.
Swerdloff
R S
RS
Steiner
B S
BS
Lutchmansingh
P
P
Peterson
M A
MA
Pandian
M R
MR
Galmarini
M
M
Bhasin
S
S
D000328:Adult; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000187:drug effects; D006801:Humans; D016729:Leuprolide / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D010410:Penile Erection / Q000187:drug effects* / Q000502:physiology; D012016:Reference Values; D012725:Sexual Behavior / Q000187:drug effects* / Q000502:physiology; D012895:Sleep, REM / Q000187:drug effects; D013739:Testosterone / Q000097:blood*
D003692:Delayed-Action Preparations; D013739:Testosterone; D016729:Leuprolide