Metabolism in vivo of [7α-3H]pregnenolone by the dog ovary

In order to determine if the ovarian metabolism of pregnenolone differed between estrus and pregnancy, [7α-³H]pregnenolone was infused by the ovarian artery in anesthetized dogs and steroids containing tritium isolated in ovarian vein blood.

• 1.

  1. Within 5 min the canine ovary metabolized pregnenolone to 17α-hydroxy-pregnenolone, progesterone, 17α-hydroxyprogesterone, dehydroepiandrosterone, androsterone, testosterone and probably estradiol.

• 2.

  2. Induction of mating in the female dog by treatment with human chorionic gonadotropin was associated with a high capacity of the ovary to convert pregnenolone to testosterone and androstenedione.

• 3.

  3. Dogs in the early part of pregnancy metabolized a considerable amount of the infused pregnenolone to progesterone.