Steroid hormone

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Steroid hormone

Steroid hormones are steroid

Steroid

A steroid is a terpenoid lipid characterized by a carbon skeleton with four fused rings, generally arranged in a 6-6-6-5 fashion.Steroids vary by the functional groups attached to these rings and the oxidation state of the rings....
s that act as hormone

Hormone

Hormones are chemicals released by cells that affect cells in other parts of the body. Only a small amount of hormone is required to alter cell metabolism....
s. Steroid hormones can be grouped into five groups by the receptor

Receptor (biochemistry)

In biochemistry, a receptor is a protein molecule, embedded in either the plasma membrane or cytoplasm of a cell, to which a mobile signaling molecule may attach....
s to which they bind: glucocorticoid

Glucocorticoid

Glucocorticoids are a class of steroid hormones which bind to the glucocorticoid receptor , which is present in almost every animal cell.GCs are part of the feedback mechanism in the immune system which turns immune activity down....
s, mineralocorticoid

Mineralocorticoid

Mineralocorticoids are a class of steroid hormones characterised by their similarity to aldosterone and their influence on salt balance and water balance ....
s, androgen

Androgen

Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors....
s, estrogen

Estrogen

Estrogens are a group of steroid compounds, named for their importance in the estrous cycle, and functioning as the primary female sex hormone....
s, and progestagen

Progestagen

Progestagens are a group of hormones including progesterone.The progestagens are one of the five major classes of steroid hormones, in addition to the estrogens, androgens, mineralocorticoids, and glucocorticoids....
s. Vitamin D

Vitamin D

Vitamin D is a group of fat-soluble prohormones, the two major forms of which are vitamin D2 and vitamin D3 . The term vitamin D also refers to metabolites and other analogues of these substances....
derivatives are a sixth closely-related hormone system with homologous receptors, though technically sterol

Sterol

Sterols are an important class of organic molecules. They occur naturally in plants, animals and fungi, with the most familiar type of animal sterol being cholesterol, which has been shown to contribute to high blood pressure and heart disease....
s rather than steroids.

natural steroid hormones are generally synthesized from cholesterol

Cholesterol

Cholesterol is a lipidic, waxy alcohol found in the cell membranes and transported in the blood plasma of all animals. It is an essential component of mammalian cell membranes where it is required to establish proper membrane permeability and membrane fluidity....
in the gonad

Gonad

The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells....
s and adrenal gland

Adrenal gland

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Synthesis

The natural steroid hormones are generally synthesized from cholesterol

Cholesterol

Gonad

The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells....
s and adrenal gland

Adrenal gland

In mammals, the adrenal glands are the star-shaped endocrine glands that sit on top of the kidneys; their name indicates that position . They are chiefly responsible for regulating the stress response through the biosynthesis of corticosteroids and catecholamines, including cortisol and adrenaline, respectively....
s. These forms of hormones are lipids. They can enter the cell membrane quite easily and enter right into the nuclei. Steroid hormones are generally carried in the blood bound to specific carrier protein

Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
s such as sex hormone-binding globulin or corticosteroid-binding globulin. Further conversions and catabolism occurs in the liver, in other "peripheral" tissues, and in the target tissues.

Synthetic steroids and sterols

A variety of synthetic steroids and sterols have also been contrived. Most are steroids, but some non-steroidal molecules can interact with the steroid receptors because of a similarity of shape. Some synthetic steroids are weaker, and some much stronger, than the natural steroids whose receptors they activate.

Some examples of synthetic steroid hormones:

Glucocorticoids: prednisone
Prednisone

Prednisone is a synthetic corticosteroid drug that is usually taken orally but can be delivered by intramuscular injection and can be used for a number of different conditions....
, dexamethasone
Dexamethasone

Dexamethasone is a potent synthetic member of the glucocorticoid class of steroid hormones. It acts as an anti-inflammatory and immunosuppressive drug....
, triamcinolone
Triamcinolone

Triamcinolone is a chemical synthesis corticosteroid given orally, by Injection , inhalation, or as a topical ointment or cream....
Mineralocorticoid: fludrocortisone
Fludrocortisone

Fludrocortisone is a synthetic corticosteroid with moderate glucocorticoid potency and much greater mineralocorticoid potency.The brand name in the U.S....
Vitamin D: dihydrotachysterol
Dihydrotachysterol

Dihydrotachysterol is a synthetic vitamin D analog activated in the liver that does not require renal hydroxylation like vitamin D2 and vitamin D3 ....
Androgens: oxandrolone
Oxandrolone

Oxandrolone is an anabolic steroid created by Searle Laboratories, now Pfizer under the trademark Anavar, and introduced into the US in 1964....
, nandrolone
Nandrolone

Nandrolone is an anabolic steroid that may be present naturally in the human anatomy, albeit in minute quantities of less than 0.4 ng/ml. Nandrolone is most commonly sold commercially as its decanoate ester and less commonly as a phenylpropionate ester ....
(also known as anabolic steroid
Anabolic steroid

Anabolic steroids, or anabolic-androgenic steroids , are a class of steroid hormones related to the hormone testosterone. They increase Protein biosynthesis within cells, which results in the buildup of Cell tissue , especially in muscles....
s)
Estrogens: diethylstilbestrol
Diethylstilbestrol

Diethylstilbestrol is a Pharmacology, an orally active synthetic nonsteroidal estrogen that was first synthesized in 1938. In 1971 it was found to be a teratogen when given to pregnant women....
(DES)
Progestins: norethindrone, medroxyprogesterone acetate

Effects

Steroids exert a wide variety of effects mediated by slow genomic as well as by rapid nongenomic mechanisms. They bind to nuclear receptor

Nuclear receptor

In the field of molecular biology, nuclear receptors are a class of proteins found within the interior of cells that are responsible for sensing the presence of hormone and certain other molecules....
in the cell nucleus

Cell nucleus

In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
for genomic actions. Membrane-associated steroid receptors activate intracellular signaling cascades involved in nongenomic actions.

Because steroids and sterols are lipid

Lipid

Lipids are broadly defined as any fat-soluble , naturally-occurring molecule, such as fats, oils, waxes, cholesterol, sterols, fat-soluble vitamins , monoglycerides, diglycerides, phospholipids, and others....
-soluble, they can diffuse

Diffusion

Molecular diffusion, often called simply diffusion, is a net transport of molecules from a region of higher concentration to one of lower concentration by random molecular motion....
fairly freely from the blood through the cell membrane

Cell membrane

The cell membrane is the interface between the cellular machinery inside the cell and the fluid outside.It is a semipermeable lipid bilayer found in all cell ....
and into the cytoplasm

Cytoplasm

The cytoplasm is the part of a Cell that is enclosed within the plasma membrane. In eukaryote cells the cytoplasm contains organelles, such as mitochondrion, that are filled with liquid kept separate from the rest of the cytoplasm by biological membranes....
of target cells. In the cytoplasm, the steroid may or may not undergo an enzyme

Enzyme

Enzymes are biomolecules that catalysis chemical reactions. Almost all enzymes are proteins. In enzymatic reactions, the molecules at the beginning of the process are called Substrate , and the enzyme converts them into different molecules, the products....
-mediated alteration such as reduction, hydroxylation, or aromatization. In the cytoplasm, the steroid binds to the specific receptor, a large metalloprotein. Upon steroid binding, many kinds of steroid receptor dimerize

Dimer

File:Carboxylic acid dimers.pngA dimer is a chemical or biological entity consisting of two identical subunits called monomers, which are held together by either intramolecular forces or weaker intermolecular forces....
: Two receptor subunits join together to form one functional DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
-binding unit that can enter the cell nucleus. In some of the hormone systems known, the receptor is associated with a heat shock protein

Heat shock protein

Heat shock proteins are a class of functionally related proteins whose expression is increased when cell are exposed to elevated temperatures or other stress....
, which is released on the binding of the ligand

Ligand

In chemistry, a ligand is either an atom, ion, or molecule that bonds to a central metal, generally involving formal donation of one or more of its electrons....
, the hormone. Once in the nucleus, the steroid-receptor ligand complex binds to specific DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
sequences and induces transcription of its target gene

Gene

A gene is the basic unit of heredity in a living organism. All living things depend on genes. Genes hold the information to build and maintain their cell and pass genetic trait to offspring....
s.

External links

Steroidogenic enzymes: