Steroid Hormones
Hormones acting through Nuclear Receptors

Author: Gianpiero Pescarmona
Date: 04/04/2007


Steroid Hormones Structure

IUPAC recommended ring lettering (left) and atom numbering (right) of the steroid skeleton. The four rings A-D form a sterane core (more on structure and nomenclature).



Adrenal synthesis

Control Analysis of Adrenal Steroidogenesis 2003

Cholesterol as a source for steroid hormones synthesis

Steroids are derived from cholesterol.

Synthesis takes place a part in the cytoplasm and a part in mitochondria.

DHEAS (dehydroepiandrosterone sulfate) plays a central role in steroid hormones metabolism, linking peripheral tissues to adrenals

KEGG PATHWAYS: Steroid hormones Pathway (Free on the Web)

Steroid sulfatase locally releases free DHEA from serum DHEAS.


Steroids Hormones Synthesis step by step

Cholesterol import to mitochondria

Cholesterol import is mediated by

  1. TSPO translocator protein 18kDa. Present mainly in the mitochondrial compartment of peripheral tissues, the protein encoded by this gene interacts with some benzodiazepines and has different affinities than its endogenous counterpart. The protein is a key factor in the flow of cholesterol into mitochondria to permit the initiation of steroid hormone synthesis. Alternate transcriptional splice variants, encoding different isoforms, have been characterized.
  2. "StAR":

The Molecular Biology, Biochemistry, and Physiology of Human Steroidogenesis and Its Disorders 2011

Enzymes involved in steroid hormones synthesis

KEGG PATHWAYS: Steroid hormones Pathway (Free on the Web)

Adrenals disorders

Enzymes involved in steroid hormones synthesis display different activity in different individuals according to

  • polymorphisms
  • SNP (Single Nucleotide Polymorphism)
  • SPM (Single Point Mutation)

Additional figure on enzymes involved in steroids synthesis

Open Questions

The following list links to the available information on this topic:







Pregnenolone central role

Tissue and cellular localization of steroids synthesis


Regulation depends on a feedback loop that involves:

  • hypothalamus
  • anterior pituitary
  • adrenals
  • peripheral tissues

Steroids synthesis is strongly affected by aging and local conditions.

a deeper insight

Hormones synthesis takes place in different cell compartments

Sex hormones synthesis

Oxygen availability as a regulatory factor of androgen synthesis by adrenocortical cells. 1993


C21-Steroid hormone metabolism

Steroid Metabolism Enzymes with Links

Androgen and estrogen metabolism

Inhibition of 11ss-hydroxysteroid dehydrogenase type 1 as a promising therapeutic target. 2007

Delayed Treatment with Dehydroepiandrosterone Sulfate Enhances Gene Expression Related to Neuroplasticity 2003

Steroid hormones and Type II Diabetes

Regulation of Steroid Hormones Synthesis


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