The conversion of one hormone to another is catalyzed by a certain enzyme. As depicted in the rectangular boxes in the following steroid conversion chart.
The level of an enzyme presence in a particular body tissue determines the extent to which the hormone conversion will take place. The amount of a certain hormone in particular areas is a critical factor affecting hormonally related health concerns.
Steroid conversion chart
(conversion enzymes are shown in rectangular boxes)
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At a Glance Chart Enzymes affecting Steroid Production/Activity and Conversion Pathways |
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Enzyme |
Converts |
Prod'n /Activity / Conversion Pathway ▲ increased by |
Prod'n /Activity /Conversion Pathway ▼ decreased by |
Comments |
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Cholesterol side-chain cleavage enzyme; |
Cholesterol ➔ PREGNENOLONE (in mitochondria); |
LH |
Estrogens;
Lead; Vitamin A deficiency; Certain drugs |
Series of reactions occur at the inner membrane; |
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(17α-hydroxylase) |
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LH |
TESTOSTERONE (affects cAMP pathway)
Ethanol; Nicotine; Certain drugs |
Catalyzes hydroxylation and cleavage (converts steroids from a 21-carbon to a 19-carbon molecule in Δ4 and Δ5- hydroxysteroid pathways); |
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(17ß-Hydroxysteroid Dehydrogenase) |
DHEA ➔ ANDROSTENEDIOL
ANDROSTENEDIONE ⇔ TESTOSTERONE
ESTRONE (E1) ➔ ESTRADIOL (E2) |
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Drugs: Cotinine, Danazol, Cyclosporin A, Lithium chloride. Lignans (E.g. in flaxseed) |
Lignans - Enterolactones (lignan precursors) found in E.g.flaxseed inhibit
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(3ß-Hydroxysteroid Dehydrogenase) |
PREGNENOLONE ➔ PROGESTERONE
DHEA ➔ ANDROSTENEDIONE |
LH
FSH via LH
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TESTOSTERONE
Lead; Daidzein /genistein /biochanin A (isoflavones), Aflatoxin |
In the male, FSH, stimulates release of a Sertoli cell factor that increasesLH effect on 3ß-HSD activity; |
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TESTOSTERONE➔ DIHYDRO-TESTOSTERONE (DHT) |
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In testes, liver, brain, prostate, external genitalia, skin, hair follicles and sebaceous glands; DHT more potent than TESTOSTERONE; DHT involved in BPH,prostate cancer, hirsutism |
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TESTOSTERONE ➔ ESTRADIOL
ANDROSTENEDIONE ➔ ESTRONE (in females)
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Gonadotropins (E.g. FSH, LH, hCG); Age; Obesity; Insulin; Alcohol.
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PROLACTIN Smoking; Anti-mullerian hormone Certain Drugs Finasteride; PROGESTERONE Nettle root
Flavonoids |
In females, FSH increases aromatase activity, enhancing this conversion; |
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Hydrogen Peroxide (H2O2). Blocks conversion of:
PREGNENOLONE ➔ PROGESTERONE ;
Dioxins (in fatty meats, dairy) ➔ low TESTOSTERONE, and limited prostate growth;
Aminoglutethimide ➔ low TESTOSTERONE;
Lead, cadmium ➔ low TESTOSTERONE;
Cyclic-AMP Second Messenger System. C-AMP pathway directly affected by:
• Biphenol-A (BPA);
• Nicotine;
• Nitrate/NO;
• Glucocorticoids;
• Drugs - Lindane; Indmethacin. Chloroquine. EDS. DBA, Cotinine, Tylosin, Gossypol;
Nitrous oxide (NO). Blocks steroid production;?????
