A young couple has had regular, unprotected sexual intercourse for 4 years, without a pregnancy
They are seeking help at an assisted reproduction/in vitro fertilization clinic for infertility. The husband is very serious about weight training and physical fitness. Semen analysis reveals a sperm count of 10 million/ml (i.e., very low). His blood analysis reveals an elevated testosterone level. The psychiatrist at the clinic suspects that the husband injects (i.e., abuses) testosterone (T), which turns out to be true.
The husband has read online that T stimulates spermatogenesis, and so is confused as to why he has a low sperm count. This is explained based on:
A. injected T must first be converted to DHT in the testis
B. high levels of injected T are toxic to sperm
C. injected T increases levels of sex hormone–binding globulin (SHBG), thereby reducing the "free" T level
D. injected T inhibits intratesticular production of T
E. injected T increases circulating estrogen, which inhibits spermatogenesis
ANS: D
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