Map Key
Generic Enzyme
Generic kinase
Protein kinase
Lipid kinase
Generic phosphatase
Protein phosphatase
Lipid phosphatase
Generic phospholipase
Generic protease
Metalloprotease
G-alpha
RAS - superfamily
G beta/gamma
Regulators (GDI, GAP, GEF)
Generic channel
Ligand-gated channel
Voltage-gated channel
Transporter
Normal process
Pathological process
Positive effect
Negative effect
Unspecified effect
Technical link
Disrupts in disease
Emerges in disease
Enhances in disease
Weakens in disease
Organsim specific interaction

Generic binding protein
Receptor ligand
Cell membrane glycoprotein
Transcription factor
DNA
RNA
Compound
Inorganic ion
Predicted metabolite or user's structure
Reaction
Generic receptor
GPCR
Receptors with enzyme activity
Mitochondria
EPR
Golgi
Nucleus
Lysosome
Peroxisome
Cytoplasm
Extracellular

Normal process
Pathological process
Binding
Cleavage
Covalent modifications
Phosphorylation
Dephosphorylation
Transformation
Transport
Catalysis
Transcription regulation
MicroRNA binding
Competition
Influence on expression
Unspecified interactions
Pharmacological effect
Toxic effect
Group relation
Complex subunit
Similarity reaction
A complex or a group
Organism specific object

Androstenedione and testosterone biosynthesis and metabolism p.1


Log In to Post A Comment

Androstenedione and testosterone biosynthesis and metabolism p.1

Androstenedione and testosterone biosynthesis and metabolism part 1

Androstenedione is a 19-carbon steroid hormone produced as an intermediate stepin the biochemical pathway that produces the androgen Testosterone and theestrogens Estrone and Estradiol.

Androstenedione originates either from the conversion ofDehydroepiandrosterone or from 17-alpha-Hydroxyprogesterone. These twometabolites have the common precursor - 17-alpha-Hydroxypregnenolone and they areproduced as results of different transformations. The first one - formation ofDehydroepiandrosterone catalyzed by Cytochrome P450, family 17, subfamily A,polypeptide 1 ( CYP17 ) [1], [2], [3]. Andthe second reaction is mediated by Hydroxy-delta-5-steroid dehydrogenase, 3 beta- andsteroid delta-isomerase 1 ( HSD3B1 ) [4], [5], andhydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 2 (HSD3B2 ) [6], [7], [8], [9]with 17-alpha-Hydroxyprogesterone as a product.17-alpha-Hydroxypregnenolone is a product of oxidative metabolism ofCholesterol.

Dehydroepiandrosterone comes into subsequent oxidative transformation withproduction of 16Alpha-hydroxydehydroepiandrosterone. This oxidation is catalyzedby Cytochrome P450, family 3, subfamily A, polypeptide 7 ( CYP3A7) [10], [11], [12] and Cytochrome P450, family 3, subfamily A,polypeptide 4 ( CYP3A4) [13], [10], [11].Oxidative metabolite of this reaction as well as Dehydroepiandrosterone can befurther sulfated by steroid sulfatase (microsomal), isozyme S ( STS ) [14], [15], [16], [15], [14].Dehydroepiandrosterone and Dehydroepiandrosterone sulfate can betransformed into other compounds with hormonal activity, Androstendiol andAndrostendiol sulfate, respectively. These two reactions are catalyzed byHydroxysteroid (17-beta) dehydrogenase 1 ( HSD17B1) [17], [18], [17], [18], Hydroxysteroid (17-beta) dehydrogenase 2 (HSD17B2) [19], [20], [20], [21],and Hydroxysteroid (17-beta) dehydrogenase 7 ( HSD17B7 ) [22], [23], [23], [24].

Androstendiol and Androstenedione are further converted toTestosterone. Formation of Testosterone from Androstendiol iscatalyzed by HSD3B1 [25], [26] and HSD3B2 [27], [28], [26], whereas Hydroxysteroid (17-beta)dehydrogenase 3 ( HSD17B3 ), HSD17B7, HSD17B2 and HSD17B1catalyze formation of testosterone from Androstenedione [29], [30], [31], [32], [22], [33], [23], [34], [30], [21], [20].