Steroid Hormone Animation

Steroid hormones are steroids which act as hormones. Mammalian steroid hormones can be grouped into five groups by the receptors to which they bind: glucocorticoids, mineralocorticoids, androgens, estrogens, and progestagens. Vitamin D derivatives are a sixth closely related hormone system with homologous receptors, though technically sterols rather than steroids.

The natural steroid hormones are generally synthesized from cholesterol in the gonads and adrenal glands. 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 proteins such as sex hormone binding globulin or corticosteroid binding globulin. Further conversions and catabolism occurs in the liver, other "peripheral" tissues, and in the target tissues.

Because steroids and sterols are lipid soluble, they can diffuse fairly freely from the blood through the cell membrane and into the cytoplasm of target cells. In the cytoplasm the steroid may or may not undergo an enzyme-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: two receptor subunits join together to form one functional DNA-binding unit that can enter the cell nucleus. In some of the hormone systems known, the receptor is associated with a heat shock protein which is released on the binding of the ligand, the hormone. Once in the nucleus, the steroid-receptor ligand complex binds to specific DNA sequences and induces transcription of its target genes.

The Estrogen Receptor Hormonal Mechanisms

Estrogen receptor refers to a group of receptors which are activated by the hormone 17β-estradiol (estrogen). Two types of estrogen receptor exist: ER which is a member of the nuclear hormone family of intracellular receptors and the estrogen G protein coupled receptor GPR30 (GPER), which is a G-protein coupled receptor. This article refers to the nuclear hormone receptor ER.

The main function of the estrogen receptor is as a DNA binding transcription factor which regulates gene expression. However the estrogen receptor also has additional functions independent of DNA binding.

Estrogen receptor Molecular and cellular mechanism,Steroid hormones are chemical substances secreted by glands in the abdomen with involved in the regulation of variety of the functions including sodium balace,metabolism and reproductive functions.For example

Vitamin D receptor molecular surface

Calcitriol receptor, also known as the Vitamin D receptor (VDR) and also known as NR1I1 (nuclear receptor subfamily 1, group I, member 1), is a member of the steroid hormone receptor family of nuclear receptors. Upon activation by vitamin D, the VDR forms a heterodimer with the retinoid-X receptor and binds to hormone response elements on DNA resulting in expression or transrepression of specific geneproducts.

Glucocorticoids are known to decrease expression of VDR which is expressed in most tissues of the body. Its most well known function is the regulation of intestinal transport of calcium.

This gene encodes the nuclear hormone receptor for vitamin D3. This receptor also functions as a receptor for the secondary bile acid lithocholic acid. The receptor belongs to the family of trans-acting transcriptional regulatory factors and shows sequence similarity to the steroid and thyroid hormone receptors. Downstream targets of this nuclear hormone receptor are principally involved in mineral metabolism though the receptor regulates a variety of other metabolic pathways, such as those involved in the immune response and cancer. Mutations in this gene are associated with type II vitamin D-resistant rickets. A single nucleotide polymorphism in the initiation codon results in an alternate translation start site three codons downstream. Alternative splicing results in multiple transcript variants encoding the same protein

Glucocorticoid Hormone

Glucocorticoid hormone predominately affects the metabolism of carbohydrates and to a lesser extent, fats and proteins, Glucocorticoid are made in the outside portion of the adrenal glands and it’s chemically classed as steroids.

Action of Glucocortocoid hormone

Glucocorticoid hormones are steroid hormones that influence nutrient metabolism, These hormones activate genes for proteins involved in process such as the synthesis of glucose, the breakdown of proteins, and the mobilization of fats.

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Glucocorticoid hormone predominately affects the metabolism of carbohydrates and to a lesser extent, fats and proteins, Glucocorticoid are made in the outside portion of the adrenal glands and it’s chemically classed as steroids.

Action of Glucocortocoid hormone

Glucocorticoid hormones are steroid hormones that influence nutrient metabolism, These hormones activate genes for proteins involved in process such as the synthesis of glucose, the breakdown of proteins, and the mobilization of fats.

Glucocorticoid hormones are secreted by endocrine glands into the blood stream. They enter cells through transporters in the plasma membrane, once inside the cytosol the hormone molecules can bind to glucocortocid receptors, which function as transcription factors that activate genes. The binding of the hormone causes proteins that were bound to the receptor such as the heat shock protein hsp90 to be released.

Release of HSP90allows two receptors to bind and form a dimer as well as exposing a nuclear localization signal on the receptor.The receptor dimer is then allowed to enter into the nucleus through a nuclear pore.

The receptor dimer is able to bind to a specific DNA sequence regions called glucocortocid response elements, or GREs,that are near target genes.The GREs function as enhancers, so that binding of a receptor dimer to a GRE activates transcription of the nearby target gene.