Levonorgestrel implants enhanced the suppression of spermatogenesis by testosterone implants: comparison between Chinese and non-Chinese men.
BACKGROUND
Previous male contraceptive studies showed that progestins enhance spermatogenesis suppression by androgens in men.


OBJECTIVE
We compared the efficacy of spermatogenesis suppression by the combination of levonorgestrel (LNG) with testosterone (T) implants to that by T implants alone in two different ethnic groups.


METHODS
This was a randomized trial performed in two centers with two treatment groups.


METHODS
The study was performed at the Academic Medical Center in the United States and the Research Institute in China.


METHODS
Forty non-Chinese and 40 Chinese healthy male volunteers were studied.


METHODS
Subjects were randomized to receive four LNG implants together with four T implants (inserted on d 1 and wk 15-18) vs. T implants alone for 30 wk.


METHODS
The primary end point compared the efficiency of suppression to severe oligozoospermia (1 x 10(6)/ml) by LNG plus T implants vs. that by T implants alone. The secondary end point examined differences in spermatogenesis suppression between Chinese and non-Chinese subjects.


RESULTS
LNG plus T implants caused more suppression of spermatogenesis to severe oligozoospermia during the treatment period than T implants alone at both sites (P < 0.02). In Chinese men, severe oligozoospermia was achieved in more than 90% of the men in both treatment groups. Suppression to severe oligozoospermia was less in the non-Chinese men (59%) after T alone (P < 0.020); this difference disappeared with combined treatment (89%). T implant extrusion occurred in six men. Acne and increased hemoglobin were the most common adverse events.


CONCLUSIONS
T implants resulted in more pronounced spermatogenesis suppression in Chinese men. Addition of LNG implants to T implants enhanced the suppression of spermatogenesis in the treatment period in both Chinese and non-Chinese men.
Wang
Christina
C
General Clinical Research Center, Harbor-UCLA Medical Center, 1000 W. Carson Street, Torrance, CA 90509, USA. wang@labiomed.org
Wang
Xin Hai
XH
Nelson
Anita L
AL
Lee
Ka Kui
KK
Cui
Yu Gui
YG
Tong
Jian Sun
JS
Berman
Nancy
N
Lumbreras
Leslie
L
Leung
Andrew
A
Hull
Laura
L
Desai
Sagar
S
Swerdloff
Ronald S
RS
D000328:Adult; D002681:China / Q000208:ethnology; D003267:Contraception / Q000379:methods*; D004343:Drug Implants / Q000008:administration & dosage / Q000494:pharmacology; D004357:Drug Synergism; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D016912:Levonorgestrel / Q000008:administration & dosage / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D009845:Oligospermia / Q000139:chemically induced; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013076:Sperm Count; D013091:Spermatogenesis / Q000187:drug effects*; D013739:Testosterone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D014481:United States
D004343:Drug Implants; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D016912:Levonorgestrel; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone