Sonicated specimens of freshly ejaculated sperm from two groups of husbands (n = 6, age 32-38 years; n = 7, age 27-38 years) of infertile couples in the range of sperm concentration between 237.5 and 568.5; 131.1 and 256.7 millions per ejaculate were separately incubated with [7n-3H]pregnenolone and [1,2,6,7- 3H]dehydroepiandrosterone. Using the reverse-isotope dilution technique [3H]dehydro-epiandrosterone and [ 3H]testosterone formed from the respective substrates were isolated and characterized, yielding 1.2 × 10-2 to 4.6 × 10 -2% and 7.1 × 10-2 to 2.5 × 10-1%. Such metabolites were not evident in the controls. These results provide evidence for metabolic transformation of pregnenolone to testosterone via the Δ5-3β-hydroxy route.
- 17β-hydroxysteroid oxidoreductase
- 3β-hydroxysteroid dehydrogenase-5,4-ene isomerase
- human spermatozoa
- male infertility
- testosterone synthesis