Portal de Periódicos da CAPES

Progesterone and pregnenolone 17α-hydroxylase: substrate specificity and selective inhibition by 17α-hydroxylated products

1976; Pergamon Press; Volume: 7; Issue: 8 Linguagem: Inglês

10.1016/0022-4731(76)90079-0

1878-2353

P. Kremers,

Hormonal and reproductive studies

In vitro biochemical properties of steroid-17α-hydroxylase have been studied using rat testes and beef adrenal microsomes as enzyme sources. Steroid-17α-hydroxylase has a greater affinity for pregnenolone than for progesterone. Furthermore, pregnenolone competitively inhibits the hydroxylation of progesterone and vice-versa. The first products of the reaction, 17α-hydroxypregnenolone and 17α-hydroxyprogesterone inhibit competitively the hydroxylation of both pregnenolone and progesterone with a similar efficiency. This paper indicates that cortisol and androgens are principally synthesized through the so called Δ5 pathway.