Views: 1 Author: Site Editor Publish Time: 2021-11-01 Origin: Site
The best raw steroid powders supplier said synthesis and mechanism of raw steroid powders
Raw steroid powders include sex hormones and adrenocortical hormones. They are cholesterol derivatives, which are fat soluble, so they can regulate gene expression through the plasma membrane and bind to intracellular receptors (also known as nuclear receptors, NR).
Raw steroid powders is usually carried out in the adrenal cortex, gonads (testis and ovary), brain, placenta and adipose tissue. Two kinds of enzymes are mainly involved in the synthesis process: cytochrome P450 enzyme (CYP) and hydroxysteroid dehydrogenase (HSD).
The first step in raw steroid powders is to remove six carbons from the side chain of cholesterol to produce pregnenolone.
This is the rate limiting step of this pathway, including three-step reaction. In the human body, cholesterol side chain lyase (cholesterol-20,22-desmolase, also known as CYP11a or p450ssc) catalyzes.
The enzyme binds to the inner membrane of mitochondria in all steroidogenic tissues, so it is necessary to transport cholesterol to mitochondria first.
The transport process is mediated by the raw steroid powders regulatory protein (star) on the outer membrane, which is the rate limiting link of this step.
Adrenocorticotropic hormone (ACTH) can increase camp, activate pKa, activate cholesterol ester hydrolase and star phosphorylation, so as to promote corticosteroid synthesis.
Pregnenolone in 3 β Progesterone, also known as progesterone, is a common precursor of many hormones.
In general, progesterone hydroxylated at position 21 will enter the mineralocorticoid series and eventually produce aldosterone. If hydroxylated at position 17, it will enter the glucocorticoid series.
The cleavage of glucocorticoid side chain can produce androgen, and the aromatization of androgen a ring can form estrogen.
However, hormones have complex transformation networks, and there will be many changes in different tissues and conditions.
Adrenal cortex can synthesize a variety of steroid hormones, including androgens and a small amount of estrogen in addition to glucocorticoids and mineralocorticoids.
The sex hormone produced by adrenal gland is mainly dehydroepiandrosterone (DHEA), which has weak androgen effect and can be transformed into more effective androgen or estrogen in gonad as other hormone precursors.
In congenital adrenal hyperplasia and other diseases, DHEA will increase, leading to masculinization such as female hirsutism.
The most important glucocorticoid is cortisol, which can raise blood glucose.
The mechanisms include antagonizing insulin, reducing glucose utilization, promoting gluconeogenesis, and increasing the decomposition of skeletal muscle protein and fat triglycerides.
In order to save energy for gluconeogenesis, corticosteroids also have anti-inflammatory effects by inhibiting phospholipase A2 to reduce prostaglandin synthesis, but long-term use can easily lead to diabetes, hypertension and other diseases.
In the absence of hormones, steroid receptors (SR) are usually basal phosphorylated and form complexes with heat shock proteins (HSPs).
After binding with hormone, the receptor dissociates and dimerizes from heat shock protein, transports to nucleus, binds to target gene specific sites containing hormone response element (HRE), and recruits a series of auxiliary activation complexes to regulate target gene transcription.
Glucocorticoid receptor (GR or GCCR) is a typical nuclear hormone receptor, which is encoded by NR3C1 (member 1 of group C of nuclear receptor subfamily 3).
The corresponding HRE, also known as GRE, has the ggaacannntgttct sequence. GR also has coactivators, such as SRC (steroid receptor coactivator) protein.
In the liver, the two main target genes of cortisol are gluconeogenesis gene, PCK1 (cytoplasmic phosphoenolpyruvate carboxylation kinase) and g6pc (glucose-6-phosphatase).
The maximum expression of PCK1 and g6pc genes requires other factors, including nuclear receptor PPAR α。 So code PPAR α PPARa gene is also a target of cortisol activation.
In adipose tissue, GR promotes lipolysis and preadipocyte differentiation and maturation by activating HSL expression.
In skeletal muscle, glucocorticoids promote glycogen and protein hydrolysis, and the carbon frame of amino acids can be used as a raw material for liver gluconeogenesis.
Mineralocorticoid is mainly aldosterone, whose main function is to retain sodium and expel potassium, accompanied by the absorption of chlorine and water, so it has the effect of raising hypertension.
The mechanism is to induce the expression of sodium pump (sodium potassium ATPase), epithelial sodium channel (ENaC) and Na + - Cl co transporter (NCC) through mineralocorticoid receptor (MR).
Raw steroid powders are mainly synthesized in gonads, and many reactions are the same as those of corticosteroids.
Testes and ovaries contain an additional enzyme, 17 β- Hydroxysteroid dehydrogenase (hsd17b) can convert androgen into testosterone. Steroids 5 α- Reductase (srd5a) reduces testosterone to dihydrotestosterone (DHT), and its activity is 10 times that of the former.
There is aromatase (CYP19A1) in ovary and placenta, also known as estrogen synthase, which can catalyze the aromatization of a ring. It is the rate limiting enzyme for the synthesis of estrogen (estrone, estradiol, etc.).
In fact, testis and adipose tissue also contain aromatase, so men also have a small amount of estrogen to maintain a certain balance with androgen.
Under some pathological conditions, too high aromatase activity will lead to excessive estrogen, infertility and feminization.