Steroid hormone

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Phone:617-632-7753

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.

Overview

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.

Synthesis

Steroids made from Cholesterol

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, some much stronger, than the natural steroids whose receptors they activate.

Some examples of synthetic steroid hormones:

• Glucocorticoids: prednisone, dexamethasone, triamcinolone
• Mineralocorticoid: fludrocortisone
• Vitamin D: dihydrotachysterol
• Androgens: oxandrolone, decadurabolin (also known as anabolic steroids)
• Estrogens: diethylstilbestrol (DES)
• Progestins: norethindrone, medroxyprogesterone acetate

Steroid abuse

Steroid hormone abuse must be differentiated from other causes of irregular menses and hirsutism.

Disease	Differentiating Features
Pregnancy	Pregnancy always should be excluded in a patient with a history of amenorrhea Features include amenorrhea or oligomenorrhea, abnormal uterine bleeding, nausea/vomiting, cravings, weight gain (although not in the early stages and not if vomiting), polyuria, abdominal cramps and constipation, fatigue, dizziness/lightheadedness, and increased pigmentation (moles, nipples) Uterine enlargement is detectable on abdominal examination at approximately 14 weeks of gestation Ectopic pregnancy may cause oligomenorrhea, amenorrhea, or abnormal uterine bleeding with abdominal pain and sometimes subtle or absent physical symptoms and signs of pregnancy
Hypothalamic amenorrhea	Diagnosis of exclusion Seen in athletes, people on crash diets, patients with significant systemic illness, and those experiencing undue stress or anxiety Predisposing features are as follows weight loss, particularly if features of anorexia nervosa are present or the BMI is <19 kg/m2 Recent administration of depot medroxyprogesterone, which may suppress ovarian activity for 6 months to a year Use of dopamine agonists (eg, antidepressants) and major tranquilizers Hyperthyroidism In patients with weight loss related to anorexia nervosa, fine hair growth (lanugo) may occur all over the body, but it differs from hirsutism in its fineness and wide distribution
Primary amenorrhea	Causes include reproductive system abnormalities, chromosomal abnormalities, or delayed puberty If secondary sexual characteristics are present, an anatomic abnormality (eg, imperforate hymen, which is rare) should be considered If secondary sexual characteristics are absent, a chromosomal abnormality (eg, Turner syndrome ) or delayed puberty should be considered
Cushing syndrome	Cushing syndrome is due to excessive glucocorticoid secretion from the adrenal glands, either primarily or secondary to stimulation from pituitary or ectopic hormones; can also be caused by exogenous steroid use Features include hypertension, weight gain (central distribution), acne, and abdominal striae Patients have low plasma sodium levels and elevated plasma cortisol levels on dexamethasone suppression testing
Hyperprolactinemia	Mild hyperprolactinemia may occur as part of PCOS-related hormonal dysfunction Other causes include stress, lactation, and use of dopamine antagonists A prolactinoma of the pituitary gland is an uncommon cause and should be suspected if prolactin levels are very high (>200 ng/mL) Physical examination findings are usually normal As in patients with PCOS, hyperprolactinemia may be associated with mild galactorrhea and oligomenorrhea or amenorrhea; however, galactorrhea also can occur with nipple stimulation and/or stress when prolactin levels are within normal ranges A large prolactinoma may cause headaches and visual field disturbance due to pressure on the optic chiasm, classically a gradually increasing bi-temporal hemianopsia
Ovarian or adrenal tumor	Benign ovarian tumors and ovarian cancer are rare causes of excessive androgen secretion; adrenocortical tumors also can increase the production of sex hormones Abdominal swelling or mass, abdominal pain due to fluid leakage or torsion, dyspareunia, abdominal ascites, and features of metastatic disease may be present Features of androgenization include hirsutism, weight gain, oligomenorrhea or amenorrhea, acne, clitoral hypertrophy, deepening of the voice, and high serum androgen (eg, testosterone, other androgens) levels In patients with an androgen-secreting tumor, serum testosterone is not suppressed by dexamethasone
Congenital adrenal hyperplasia	Congenital adrenal hyperplasia is a rare genetic condition resulting from 21-hydroxylase deficiency The late-onset form presents at or around menarche Patients have features of androgenization and subfertility Affects approximately 1% of hirsute patients More common in Ashkenazi Jews (19%), inhabitants of the former Yugoslavia (12%), and Italians (6%) Associated with high levels of 17-hydroxyprogesterone A short adrenocorticotropic hormone stimulation test with measurement of serum17-hydroxyprogesterone confirms the diagnosis Assays of a variety of androgenic hormones help define other rare adrenal enzyme deficiencies, which present similarly to 21-hydroxylase deficiency
Anabolic steroid abuse	Anabolic steroids are synthetic hormones that imitate the actions of testosterone by increasing muscle bulk and strength Should be considered if the patient is a serious sportswoman or bodybuilder Features include virilization (including acne and hirsutism), often increased muscle bulk in male pattern, oligomenorrhea or amenorrhea, clitoromegaly, gastritis, hepatic enlargement, alopecia, and aggression Altered liver function test results are seen
Hirsutism	Hirsutism is excessive facial and body hair, usually coarse and in a male pattern of distribution Approximately 10% of women report unwanted facial hair There is often a family history and typically some Mediterranean or Middle Eastern ancestry May also result from use of certain medications, both androgens, and others including danazol, glucocorticoids, cyclosporine, and phenytoin Menstrual history is normal When the cause is genetic, the excessive hair, especially on the face (upper lip), is present throughout adulthood, and there is no virilization When secondary to medications, the excessive hair is of new onset, and other features of virilization, such as acne and deepened voice, may be present

External links

• Template:McGrawHillAnimation

• Steroidogenic enzymes: Review on structure, function, and role in regulation of steroid hormone biosynthesis