Cholesterol
®!
HO
Pregnenolone
®!
o
Progesterone
11 - Deoxy - corticosterone
Corticosterone
Aldosterone
H2COH
I
C=O
17a- Hydroxy - pregnenolone
17a- Hydroxy-progesterone
®
C=O
j
H210H
11 - Deoxy - cortisol
CD)
HO
Cortisol
Cortisone
Fig.16.10. The most important steroid hormones of the
vertebrates and their biosynthesis from cholesterol [39].
The reactions of the L\4 and L\s pathways (p. 639) are indicated by the corresponding symbols. 1, Oxidative cleavage
of the side-chain on C-20; 2, oxidation at C-3 and L\S/L\4
16.3 Steroid Hormones of the Vertebrates
637
o
II
!J.5
--=®:........~-HO
Dehydroepi-androsterone
®!
Androstendione
~
HO
® H O
Oestrone
OH
/'; 5 _ Androstendiol
Testosterone
Oestradiol
isomerization; 3, hydroxylation at C-17; 4, oxidative cleavage of the side-chain at C-17; 5, reduction at C-17; 6,
hydroxylation at C-21; 7, hydroxylation at C-ll; 8, oxidation at C-18; 9, oxidation at C-ll ; 10, aromatization of ring
A and cleavage of C-19; 11, oxidation/reduction at C-17