SHBG | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Identifiers | |||||||||||||||||||||||||||||||||||||||||||||||||||
Aliases | SHBG , ABP, SBP, TEBG, sex hormone binding globulin, Sex hormone-binding globulin | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 182205; MGI: 98295; HomoloGene: 813; GeneCards: SHBG; OMA:SHBG - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Androgen-binding protein, Sex hormone-binding globulin | |||||||
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Identifiers | |||||||
Symbol | SHBG | ||||||
Alt. symbols | ABP | ||||||
NCBI gene | 6462 | ||||||
HGNC | 10839 | ||||||
OMIM | 182205 | ||||||
RefSeq | NM_001040 | ||||||
UniProt | P04278 | ||||||
Other data | |||||||
Locus | Chr. 17 p13-p12 | ||||||
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Sex hormone-binding globulin (SHBG) or sex steroid-binding globulin (SSBG) is a glycoprotein that binds to androgens and estrogens. When produced by the Sertoli cells in the seminiferous tubules of the testis, it is called androgen-binding protein (ABP). [5] [6]
Other steroid hormones such as progesterone, cortisol, and other corticosteroids are bound by transcortin. SHBG is found in all vertebrates apart from birds. [7]
Testosterone and estradiol circulate in the bloodstream, loosely bound mostly to serum albumin (~54%), and to a lesser extent bound tightly to SHBG (~44%). Only a very small fraction of about 1 to 2% is unbound, or "free," and thus biologically active and able to enter a cell and activate its receptor. SHBG inhibits the function of these hormones. Thus, the local bioavailability of sex hormones is influenced by the level of SHBG. Because SHBG binds to testosterone (T) and dihydrotestosterone (DHT), these hormones are made less lipophilic and become concentrated within the luminal fluid of the seminiferous tubules. The higher levels of these hormones enable spermatogenesis in the seminiferous tubules and sperm maturation in the epididymis. SHBG’s production is regulated under the influence of FSH [6] on Sertoli cells, enhanced by insulin, retinol, and testosterone.
The relative binding affinity of various sex steroids for SHBG is dihydrotestosterone (DHT) > testosterone > androstenediol > estradiol > estrone. [8] DHT binds to SHBG with about 5 times the affinity of testosterone and about 20 times the affinity of estradiol. [9] Dehydroepiandrosterone (DHEA) is weakly bound to SHBG, but dehydroepiandrosterone sulfate is not bound to SHBG. [8] Androstenedione is not bound to SHBG either, and is instead bound solely to albumin. [10] Estrone sulfate and estriol are also poorly bound by SHBG. [11] Less than 1% of progesterone is bound to SHBG. [12]
SHBG levels are usually about twice as high in women as in men. [9] In women, SHBG serves to limit exposure to both androgens and estrogens. [9] Low SHBG levels in women have been associated with hyperandrogenism and endometrial cancer due to heightened exposure to androgens and estrogens, respectively. [9] During pregnancy, due to activation of SHBG production in the liver by high estrogen levels, SHBG levels increase by five-fold to ten-fold. [9] The high SHBG levels during pregnancy may serve to protect the mother from exposure to fetal androgens that escape metabolism by the placenta. [9] A case report of severe hyperandrogenism in a pregnant woman due to a rare instance of genetic SHBG deficiency illustrates this. [9] [13]
SHBG is produced mostly by the liver and is released into the bloodstream. Other sites that produce SHBG include the brain, uterus, testes, and placenta. [14] Testes-produced SHBG is called androgen-binding protein.
The gene for SHBG is called Shbg, located on chromosome 17 [14] on the short arm between the bands 17p12→p13. [15] Overlapping on the complementary DNA strand is the gene for spermidine/spermine N1-acetyltransferase family member 2 (SAT2). Nearby are the genes for p53 and ATP1B2, and fragile X mental retardation, autosomal homolog 2 (FXR2) on the complementary strand. [16] There are eight exons, of which exon 1 has three variations called 1L, 1T and 1N which are triggered by three promoters: PL, PT and PN respectively. SHBG comes with the 1L, 2, 3, 4, 5, 6, 7, and 8 exons connected together. A variation includes SHBG-T which is missing exon 7 but with exon 1T promoted by promoter PT on the opposite strand, which shared with that for SAT2. [17]
There are variations in the genetic material for this protein that have different effects. In humans common polymorphisms include the following:
Rs6259, also called Asp327Asn location 7633209 on chromosome 17, results in there being an extra N-glycosylation site, and so an extra sugar can be attached. This results in a longer circulation half-life for the protein, and raised levels. Health effects include a lowered risk of endometrial cancer and an increased risk of systemic lupus erythematosus. [18]
Rs6258 also called Ser156Pro is at position 7631360 on chromosome 17.
Rs727428 position 7634474 is in several percent of humans. [19]
(TAAAA)(n) is five base pairs that repeats a variable number of times on the opposite DNA strand. [20]
The mechanism of activating the promoter for SHBG in the liver involves hepatocyte nuclear factor 4 alpha (HNF4A) binding to a DR1-like cis-element which then stimulates production. Competing with HNF4A at a third site on the promoter is PPARG-2 which reduces copying the gene to RNA. If the HNF4A level is low, then COUP-TF binds to the first site and turns off production of SHBG. [7]
Sex hormone-binding globulin is homodimeric, meaning it has two identical peptide chains making up its structure. The amino acid sequence is the same as for androgen-binding protein produced in testes, but with different oligosaccharides attached. [14]
SHBG has two laminin G-like domains which form pockets that bind hydrophobic molecules. The steroids are bound by the LG domain at the amino end of the protein. [7] Inside the pocket of the domain is a serine residue that attracts the two different types of steroids at different points, thus changing their orientation. Androgens bind at the C3 functional groups on the A ring, and estrogens bind via a hydroxyl attached to C17 on the D ring. The two different orientations change a loop over the entrance to the pocket and the position of trp84 (in humans). Thus the whole protein signals what hormone it carries on its own surface. [7] The steroid binding LG domain is coded by exons 2 to 5. [7] A linker region joins the two LG domains together. [7]
When first produced, the SHBG precursor has a leading signal peptide attached with 29 amino acids. The remaining peptide has 373 amino acids. [21] There are two sulfur bridges.
The sugars are attached at two different N-glycosylation points on asparagine (351 and 367) and one O-glycosylation point (7) on threonine. [21]
A calcium ion is needed to link the two elements of the dimer together. Also a zinc ion is used to orient an otherwise disorganised part of the peptide chain. [7]
SHBG has both enhancing and inhibiting hormonal influences and thus can be viewed as a hepatokine. It decreases with high levels of insulin, growth hormone, insulin-like growth factor 1 (IGF-1), androgens, prolactin and transcortin. High estrogen and thyroxine levels cause it to increase.
In an effort to explain obesity-related reductions in SHBG, recent evidence suggests sugar or monosaccharide-induced hepatic lipogenesis, hepatic lipids in general, and cytokines like TNF-alpha and interleukins reduce SHBG, whereas insulin does not. For example, anti-psoriatic drugs that inhibit TNF-alpha cause an increase in SHBG. The common downstream mechanism for all of these, including the effect of thyroid hormones, [22] was downregulation of hepatocyte nuclear factor 4 (HNF4). [23] [24] [25] [26]
Reference ranges for blood tests for SHBG have been developed: [27] [28]
Population | Range |
---|---|
Adult female, premenopausal | 40–120 nmol/L |
Adult female, postmenopausal | 28–112 nmol/L |
Adult male | 20–60 nmol/L |
Infant (1–23 months) | 60–252 nmol/L |
Prepubertal (2–8 years) | 72–220 nmol/L |
Pubertal female | 36–125 nmol/L |
Pubertal male | 16–100 nmol/L |
SHBG levels are decreased by androgens, administration of anabolic steroids, [32] polycystic ovary syndrome (PCOS), hypothyroidism, obesity, Cushing's syndrome, and acromegaly. Low SHBG levels increase the probability of type 2 diabetes. [33] SHBG levels increase with estrogenic states (oral contraceptives), pregnancy, hyperthyroidism, cirrhosis, anorexia nervosa, and certain drugs. Long-term calorie restriction increases SHBG in rodents and men, while lowering free and total testosterone and estradiol and having no effect on DHEA-S, which lacks affinity for SHBG. [34] PCOS is associated with insulin resistance and excess insulin lowers SHBG, which increases free testosterone levels. [35]
In utero, the human fetus has a low level of SHBG, allowing increased activity of sex hormones. After birth, the SHBG level rises and remains at a high level throughout childhood. At puberty the SHBG level halves in girls and goes down to a quarter in boys. [7] The change at puberty is triggered by growth hormone, and its pulsatility differs in boys and girls.[ clarification needed ] In the third trimester of pregnancy, the SHBG level of the parent escalates to five to ten times the usual level for a woman. [7] [9] A hypothesis is that this protects against the effect of hormone produced by the fetus. [7]
Obese girls are more likely to have an early menarche due to lower levels of SHBG. [7] Anorexia or a lean physique in women leads to higher SHBG levels, which in turn can lead to amenorrhea. [7]
Reduced levels of SHBG and also certain polymorphisms of the SHBG gene are implicated in the development of insulin resistance and type 2 diabetes. [36] Such effects apparently involve direct action at the cellular level where it became apparent that cell membranes of certain tissues contain specific high-affinity SHBG receptors. [37]
SHBG is a useful correlate and indirect marker of estrogen-induced procoagulation and by extension thrombosis, for instance with birth control pills. [38] [39] [40]
Oral contraceptives containing ethinylestradiol can increase SHBG levels 2- to 4-fold and decrease free testosterone concentrations by 40 to 80% in women. [41] They can be used to treat symptoms of hyperandrogenism like acne and hirsutism. [41] [9] Some oral contraceptives, namely those containing high doses of ethinylestradiol (which have been discontinued and are no longer marketed), can increase SHBG levels as much as 5- to 10-fold. [9]
Some medications, such as certain anabolic steroids like mesterolone and danazol and certain progestins like levonorgestrel and norethisterone, have high affinity for SHBG and can bind to it and displace endogenous steroids from it, thereby increasing free concentrations of these endogenous steroids. [42] [43] [44] It has been estimated that therapeutic levels of danazol, methyltestosterone, fluoxymesterone, levonorgestrel, and norethisterone would respectively occupy or displace from testosterone 83–97%, 48–69%, 42–64%, 16–47%, and 4–39% of SHBG binding sites, while others with low affinity for SHBG such as ethinylestradiol, cyproterone acetate, and medroxyprogesterone acetate would occupy or displace from testosterone 1% or fewer SHBG binding sites. [42] [45]
Selective androgen receptor modulators (SARMs) also reduce SHBG. [46]
Compound | Structure | SHBG RBA (%) | SHBG K (106 M−1) | CBG RBA (%) | CBG K (106 M−1) |
---|---|---|---|---|---|
Aminoglutethimide | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Androstanolone | Steroidal | 220 | 5500 | 1.3 | 0.83 |
Betamethasone | Steroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Cholecalciferol | Steroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Cimetidine | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Clomifene | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Cortisol (hydrocortisone) | Steroidal | 0.13 | 1.6 | 100 | 76 |
Cortisone acetate | Steroidal | 0.10 | 1.2 | <0.1 | <0.1 |
Cyproterone acetate | Steroidal | 0.10 | 1.2 | <0.1 | <0.1 |
Danazol | Steroidal | 18 | 240 | 10 | 6.5 |
Dexamethasone | Steroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Diazoxide | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Diethylstilbestrol | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Digitoxin | Steroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Digoxin | Steroidal | <0.01 | <0.2 | <0.1 | <0.1 |
DL-DOPA | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Dopamine | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Enclomiphene | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Epinephrine | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Estradiol | Steroidal | 49 | 680 | <0.1 | <0.1 |
Estradiol benzoate | Steroidal | 0.70 | 8.6 | <0.1 | <0.1 |
Ethinylestradiol | Steroidal | 0.80 | 9.9 | <0.1 | <0.1 |
Ethisterone | Steroidal | 55 | 780 | 0.33 | 0.21 |
Fludrocortisone | Steroidal | <0.01 | <0.2 | 0.74 | 0.47 |
Fluoxymesterone | Steroidal | 4.8 | 60 | <0.1 | <0.1 |
Flutamide | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Homovanillic acid | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Hydrocortisone hemisuccinate | Steroidal | <0.01 | <0.2 | 8.7 | 5.6 |
Indometacin | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Levonorgestrel | Steroidal | 31 | 420 | <0.1 | <0.1 |
Medroxyprogesterone | Steroidal | 0.15 | 1.9 | 13 | 8.1 |
Medroxyprogesterone acetate | Steroidal | 0.08 | 1.0 | 6.5 | 4.2 |
Melatonin | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Mesterolone | Steroidal | 180 | 3600 | <0.1 | <0.1 |
Mestranol | Steroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Methoxytryptophol | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Methyldopa | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Methylserotonin | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Methyltestosterone | Steroidal | 39 | 530 | <0.1 | <0.1 |
Metiamide | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Metribolone | Steroidal | 1.7 | 21 | 0.36 | 0.23 |
Metyrapone | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Mexrenone | Steroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Nafoxidine | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Nandrolone | Steroidal | 5.8 | 72 | 0.10 | 0.63 |
Norepinephrine | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Norethisterone | Steroidal | 11 | 140 | 0.28 | 0.18 |
Noretynodrel | Steroidal | 1.3 | 16 | 0.16 | 0.10 |
Normetanephrine | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Phenytoin | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Potassium canrenoate | Steroidal | 0.18 | 2.2 | 0.83 | 0.53 |
Prednisolone | Steroidal | 0.04 | 0.49 | 59 | 41 |
Prednisone | Steroidal | 0.17 | 2.1 | 5.0 | 3.2 |
Progesterone | Steroidal | 0.71 | 8.8 | 36 | 24 |
Promegestone | Steroidal | 0.007 | 0.09 | 0.40 | 0.25 |
Prorenone | Steroidal | 8.2 | 100 | <0.1 | <0.1 |
Reserpine | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Rifampin | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Serotonin | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Spironolactone | Steroidal | 0.03 | 0.37 | <0.1 | <0.1 |
Tamoxifen | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Testolactone | Steroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Testosterone | Steroidal | 100 | 1600 | 8.3 | 5.3 |
Testosterone enanthate | Steroidal | 0.007 | 0.086 | <0.1 | <0.1 |
7α-Thioprogesterone | Steroidal | 0.06 | 0.74 | 36 | 24 |
7α-Thiospironolactone | Steroidal | 0.59 | 7.3 | <0.1 | <0.1 |
Thyroxine | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Triiodothyronine | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Trimethyltrienolone | Steroidal | 0.90 | 11 | 0.11 | 0.07 |
Vanillylmandelic acid | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
Zuclomifene | Nonsteroidal | <0.01 | <0.2 | <0.1 | <0.1 |
The reference ligands (100%) for the RBA (%) values were testosterone for SHBG and cortisol for CBG . |
Progestogen | SHBG (%) | CBG (%) |
---|---|---|
17α-Allyl-19-nortestosterone | <1 | ? |
Allylestrenol | <1 | ? |
Chlormadinone acetate | <1 | <1 |
Cyproterone acetate | <1 | <1 |
Desogestrel | <1 | <1 |
Dienogest | <1 | <1 |
Drospirenone | <1 | <1 |
Etonogestrel | 15 | <1 |
Gestodene | 40 | <1 |
Levonorgestrel | 50 | <1 |
Medroxyprogesterone acetate | <1 | <1 |
Megestrol acetate | <1 | <1 |
Nomegestrol acetate | <1 | <1 |
Norelgestromin | <1 | ? |
Norethisterone | 16 | <1 |
Noretynodrel | <1 | <1 |
Norgestimate | <1 | <1 |
Progesterone | <1 | 36 |
Promegestone | <1 | <1 |
Segesterone acetate | <1 | ? |
Δ4-Tibolone | 1 | <1 |
Values are RBAs (%). The reference ligand (100%) for SHBG was dihydrotestosterone and for CBG was cortisol. |
Compound | SHBG (%) |
---|---|
5α-Androstane-3β,17β-diol | 17 |
5β-Androstane-3α,17β-diol | 5 |
Dihydrotestosterone | 100 |
Ethylestrenol | <1 |
Fluoxymesterone | <1 |
Mesterolone | 440 |
Metandienone | 2 |
Metenolone | 3 |
Methyltestosterone | 5 |
Metribolone | <1 |
Nandrolone | 1 |
Oxymetholone | <1 |
Stanozolol | 1 |
Testosterone | 19 |
Values are RBAs (%). The reference ligand (100%) for SHBG was dihydrotestosterone. |
Compound | SHBG (%) |
---|---|
3β-Androstanediol | 100 |
Androstenediol | 77 |
Bolandiol | 24 |
Dihydroethisterone | 100 |
Dihydroethyltestosterone | 18–21 |
Dihydromethylandrostenediol | 77 |
Dihydronandrolone | 44 |
Dihydrotestosterone | 100 |
Dihydrotrestolone | 47 |
4,17α-Dimethyltestosterone | 97 |
Drostanolone | 39 |
Ethisterone | 92 |
Fluoxymesterone | 3 |
11-Ketodihydrotestosterone | 0 |
Medroxyprogesterone acetate | 16 |
Megestrol acetate | 0 |
Mestanolone | 84 |
Methasterone | 58 |
Methyl-1-testosterone | 69 |
Methylandrostenediol | 40 |
Methyltestosterone | 64 |
Mibolerone | 6 |
Nandrolone | 16 |
Nandrolone decanoate | 0 |
Nandrolone phenylpropionate | 0 |
Norethandrolone | 3 |
Norethisterone | 21 |
Normethandrone | 7 |
Oxandrolone | 0 |
Oxymetholone | 3 |
Progesterone | 13 |
Stanozolol | 36 |
1-Testosterone | 98 |
Testosterone | 82 |
Testosterone benzoate | 8 |
Testosterone cypionate | 6 |
Testosterone enanthate | 9 |
Δ4-Tibolone | 8 |
Trestolone | 12 |
Trestolone enanthate | 12 |
Vinyltestosterone | 36 |
Values are RBAs (%). The reference ligand (100%) for SHBG was dihydrotestosterone. |
Compound | SHBG (%) | CBG (%) | ||||||
---|---|---|---|---|---|---|---|---|
Aldosterone | <0.2 | 6.0 | ||||||
Corticosterone | <0.2 | 107 | ||||||
Cortisol | <0.2 | 100 | ||||||
Dexamethasone | <0.2 | <0.1 | ||||||
Dihydrotestosterone | 100 | 0.8 | ||||||
Estradiol | 8.7 | <0.1 | ||||||
Metribolone | 0.2 | <0.1 | ||||||
Moxestrol | <0.2 | <0.1 | ||||||
Progesterone | <0.2 | 25 | ||||||
Promegestone | <0.2 | 0.9 | ||||||
Testosterone | 26 | 3 | ||||||
Values are RBAs (%). The reference ligand (100%) for SHBG was dihydrotestosterone and for CBG was cortisol. |
Compound | RBA to SHBG (%) | Bound to SHBG (%) | Bound to albumin (%) |
---|---|---|---|
17β-Estradiol | 50 | 37 | 61 |
Estrone | 12 | 16 | 80 |
Estriol | 0.3 | 1 | 91 |
Estrone sulfate | 0 | 0 | 99 |
17β-Dihydroequilin | 30 | ? | ? |
Equilin | 8 | 26 | 13 |
17β-Dihydroequilin sulfate | 0 | ? | ? |
Equilin sulfate | 0 | ? | ? |
Δ8-Estrone | ? | ? | ? |
The reference ligand (100%) for the SHBG RBA (%) values was testosterone. |
When checking serum estradiol or testosterone, a total level that includes free and bound fractions can be assayed, or the free portion may be measured alone. Sex hormone-binding globulin can be measured separately from the total fraction of testosterone.
A free androgen index expresses the ratio of testosterone to SHBG and can be used to summarize the activity of free testosterone.
Steroid | SHBG affinity | Plasma protein binding in men | Plasma protein binding in women (follicular phase) | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
RBA (%) | K (106 M−1) | Total (nM) | Unbound (%) | SHBG (%) | CBG (%) | Albumin (%) | Total (nM) | Unbound (%) | SHBG (%) | CBG (%) | Albumin (%) | |
Aldosterone | 0.017 | 0.21 | 0.35 | 37.1 | 0.10 | 21.2 | 41.6 | 0.24 | 36.8 | 0.23 | 21.9 | 41.2 |
3α-Androstanediol | 82 | 1300 | 0.41 | 0.85 | 13.7 | <0.1 | 85.5 | 0.068 | 0.71 | 27.9 | <0.1 | 71.4 |
Androstenediol | 97 | 1500 | 4.3 | 3.24 | 60.4 | <0.1 | 36.3 | 2.4 | 1.73 | 78.8 | <0.1 | 19.4 |
Androstenedione | 2.3 | 29 | 4.1 | 7.85 | 2.82 | 1.37 | 88.0 | 5.4 | 7.54 | 6.63 | 1.37 | 84.5 |
Androsterone | 1.1 | 14 | 2.0 | 4.22 | 0.73 | 0.52 | 94.5 | 1.5 | 4.18 | 1.77 | 0.54 | 93.5 |
Corticosterone | 0.18 | 2.2 | 12 | 3.39 | 0.09 | 77.5 | 19.0 | 7.0 | 3.28 | 0.22 | 78.1 | 18.4 |
Cortisol | 0.13 | 1.6 | 400 | 3.91 | 0.08 | 89.5 | 6.57 | 400 | 3.77 | 0.18 | 89.7 | 6.33 |
Cortisone | 0.22 | 2.7 | 72 | 16.2 | 0.54 | 38.0 | 45.3 | 54 | 15.8 | 1.30 | 38.6 | 44.3 |
Dehydroepiandrosterone | 5.3 | 66 | 24 | 4.13 | 3.38 | <0.1 | 92.4 | 17 | 3.93 | 7.88 | <0.1 | 88.1 |
11-Deoxycorticosterone | 1.9 | 24 | 0.20 | 2.69 | 0.80 | 36.4 | 60.1 | 0.12 | 2.62 | 1.91 | 36.9 | 58.6 |
11-Deoxycortisol | 1.3 | 16 | 1.4 | 3.37 | 0.67 | 77.1 | 18.9 | 0.60 | 3.24 | 1.57 | 77.1 | 18.1 |
Dihydrotestosterone | 220 | 5500 | 1.7 | 0.88 | 59.7 | 0.22 | 39.2 | 0.65 | 0.47 | 78.4 | 0.12 | 21.0 |
Estradiol | 49 | 680 | 0.084 | 2.32 | 19.6 | <0.1 | 78.0 | 0.29 | 1.81 | 37.3 | <0.1 | 60.8 |
Estriol | 0.35 | 4.3 | 0.037 | 8.15 | 0.44 | <0.2 | 91.3 | 0.10 | 8.10 | 1.06 | <0.2 | 90.7 |
Estrone | 12 | 150 | 0.081 | 3.96 | 7.37 | <0.1 | 88.6 | 0.23 | 3.58 | 16.3 | <0.1 | 80.1 |
Etiocholanolone | 0.11 | 1.4 | 1.3 | 8.15 | 0.14 | 0.44 | 91.3 | 1.2 | 8.13 | 0.35 | 0.46 | 91.1 |
Pregnenolone | 1.1 | 14 | 2.4 | 2.87 | 0.50 | 0.16 | 96.5 | 2.2 | 2.85 | 1.21 | 0.16 | 95.8 |
17α-Hydroxypregnenolone | 0.19 | 2.3 | 5.4 | 4.27 | 0.12 | <0.1 | 95.5 | 3.5 | 4.26 | 0.30 | <0.1 | 95.4 |
Progesterone | 0.71 | 8.8 | 0.57 | 2.39 | 0.26 | 17.2 | 80.1 | 0.65 | 2.36 | 0.63 | 17.7 | 79.3 |
17α-Hydroxyprogesterone | 0.8 | 9.9 | 5.4 | 2.50 | 0.31 | 41.3 | 55.9 | 1.8 | 2.44 | 0.73 | 42.1 | 54.7 |
Testosterone | 100 | 1600 | 23 | 2.23 | 44.3 | 3.56 | 49.9 | 1.3 | 1.36 | 66.0 | 2.26 | 30.4 |
In men, the concentrations of SHBG, CBG, and albumin were 28 nM, 0.7 μM, and 0.56 mM, respectively. In women, the concentrations of SHBG, CBG, and albumin were 37 nM, 0.7 μM, and 0.56 mM, respectively. |
SHBG has been known under a variety of different names including: [52] [53] [54]
Dehydroepiandrosterone (DHEA), also known as androstenolone, is an endogenous steroid hormone precursor. It is one of the most abundant circulating steroids in humans. DHEA is produced in the adrenal glands, the gonads, and the brain. It functions as a metabolic intermediate in the biosynthesis of the androgen and estrogen sex steroids both in the gonads and in various other tissues. However, DHEA also has a variety of potential biological effects in its own right, binding to an array of nuclear and cell surface receptors, and acting as a neurosteroid and modulator of neurotrophic factor receptors.
Estrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal activity: estrone (E1), estradiol (E2), and estriol (E3). Estradiol, an estrane, is the most potent and prevalent. Another estrogen called estetrol (E4) is produced only during pregnancy.
Testosterone is the primary male sex hormone and androgen in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testicles and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. It is associated with increased aggression, sex drive, dominance, courtship display, and a wide range of behavioral characteristics. In addition, testosterone in both sexes is involved in health and well-being, where it has a significant effect on overall mood, cognition, social and sexual behavior, metabolism and energy output, the cardiovascular system, and in the prevention of osteoporosis. Insufficient levels of testosterone in men may lead to abnormalities including frailty, accumulation of adipose fat tissue within the body, anxiety and depression, sexual performance issues, and bone loss.
An androgen is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes the embryological development of the primary male sex organs, and the development of male secondary sex characteristics at puberty. Androgens are synthesized in the testes, the ovaries, and the adrenal glands.
A steroid hormone is a steroid that acts as a hormone. Steroid hormones can be grouped into two classes: corticosteroids and sex steroids. Within those two classes are five types according to the receptors to which they bind: glucocorticoids and mineralocorticoids and androgens, estrogens, and progestogens. Vitamin D derivatives are a sixth closely related hormone system with homologous receptors. They have some of the characteristics of true steroids as receptor ligands.
Transcortin, also known as corticosteroid-binding globulin (CBG) or serpin A6, is a protein produced in the liver in animals. In humans it is encoded by the SERPINA6 gene. It is an alpha-globulin.
Dihydrotestosterone is an endogenous androgen sex steroid and hormone primarily involved in the growth and repair of the prostate and the penis, as well as the production of sebum and body hair composition.
Steroid hormone receptors are found in the nucleus, cytosol, and also on the plasma membrane of target cells. They are generally intracellular receptors and initiate signal transduction for steroid hormones which lead to changes in gene expression over a time period of hours to days. The best studied steroid hormone receptors are members of the nuclear receptor subfamily 3 (NR3) that include receptors for estrogen and 3-ketosteroids. In addition to nuclear receptors, several G protein-coupled receptors and ion channels act as cell surface receptors for certain steroid hormones.
Equilin is a naturally occurring estrogen sex hormone found in horses as well as a medication. It is one of the estrogens present in the estrogen combination drug preparations known as conjugated estrogens and esterified estrogens. CEEs is the most commonly used form of estrogen medications in hormone replacement therapy (HRT) for menopausal symptoms in the United States. Estrone sulfate is the major estrogen in CEEs while equilin sulfate is the second major estrogen in the formulation, present as about 25% of the total.
2-Methoxyestradiol is a natural metabolite of estradiol and 2-hydroxyestradiol (2-OHE2). It is specifically the 2-methyl ether of 2-hydroxyestradiol. 2-Methoxyestradiol prevents the formation of new blood vessels that tumors need in order to grow (angiogenesis), hence it is an angiogenesis inhibitor. It also acts as a vasodilator and induces apoptosis in some cancer cell lines. 2-Methoxyestradiol is derived from estradiol, although it interacts poorly with the estrogen receptors. However, it retains activity as a high-affinity agonist of the G protein-coupled estrogen receptor (GPER).
Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological disorders, and certain hormone-sensitive cancers. It is usually taken by mouth but is also used as a patch and vaginal ring.
Norgestimate, sold under the brand name Ortho Tri-Cyclen among others, is a progestin medication which is used in birth control pills for women and in menopausal hormone therapy. The medication is available in combination with an estrogen and is not available alone. It is taken by mouth.
Danazol, sold as Danocrine and other brand names, is a medication used in the treatment of endometriosis, fibrocystic breast disease, hereditary angioedema and other conditions. It is taken by mouth.
Mesterolone, sold under the brand name Proviron among others, is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of low testosterone levels. It has also been used to treat male infertility, although this use is controversial. It is taken by mouth.
Estrogen insensitivity syndrome (EIS), or estrogen resistance, is a form of congenital estrogen deficiency or hypoestrogenism which is caused by a defective estrogen receptor (ER) – specifically, the estrogen receptor alpha (ERα) – that results in an inability of estrogen to mediate its biological effects in the body. Congenital estrogen deficiency can alternatively be caused by a defect in aromatase, the enzyme responsible for the biosynthesis of estrogens, a condition which is referred to as aromatase deficiency and is similar in symptomatology to EIS.
3α-Androstanediol also known as 5α-androstane-3α,17β-diol and sometimes shortened in the literature to 3α-diol, is an endogenous steroid hormone and neurosteroid and a metabolite of androgens like dihydrotestosterone (DHT).
Estetrol (E4), or oestetrol, is one of the four natural estrogenic steroid hormones found in humans, along with estrone (E1), estradiol (E2), and estriol (E3). Estetrol is a major estrogen in the body. In contrast to estrone and estradiol, estetrol is a native estrogen of fetal life. Estetrol is produced exclusively by the fetal liver and is found in detectable levels only during pregnancy, with relatively high levels in the fetus and lower levels in the maternal circulation.
3β-Androstanediol, also known as 5α-androstane-3β,17β-diol, and sometimes shortened in the literature to 3β-diol, is an endogenous steroid hormone and a metabolite of androgens like dehydroepiandrosterone (DHEA) and dihydrotestosterone (DHT).
5α-Dihydroethisterone is an active metabolite of the formerly clinically used but now-discontinued progestin ethisterone and the experimental and never-marketed hormonal antineoplastic agent ethynylandrostanediol (HE-3235). Its formation from its parent drugs is catalyzed by 5α-reductase in tissues that express the enzyme in high amounts like the liver, skin, hair follicles, and prostate gland. 5α-DHET has significant affinity for steroid hormone receptors and may contribute importantly to the activities of its parent drugs.
The pharmacology of estradiol, an estrogen medication and naturally occurring steroid hormone, concerns its pharmacodynamics, pharmacokinetics, and various routes of administration.