Androgens


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androgens

Male sex hormones. Androgens are STEROIDS and include testosterone and androsterone. As drugs, they are used to stimulate the development of sexual characteristics in boys when there is inadequate output from the testicles and to stimulate red cell formation in APLASTIC ANAEMIA. See also ANABOLIC STEROIDS. The term androgen derives from the Greek andros , a man and gennao , to make.

Androgens

Male sex hormones produced by the adrenal glands and testes, the male sex glands.

androgens

steroid hormones secreted by the adrenal cortex in both sexes and by the testis, responsible for male characteristics and male reproductive function; involved also in the synthesis of oestrogens in the ovary. (Applies also to synthetic hormones with similar action). See also anabolic steroids, hormones; Table 1.
Table 1: Hormones
Site of productionName of hormoneMain targetsInvolved in regulating:Secretion controlled by:
HypothalamusReleasing and inhibiting hormonesAnterior pituitary (via local blood vessels)Secretion of anterior pituitary hormonesOther brain regions; feedback re regulated hormones and their actions
Neurohormones released from posterior pituitary:
OxytocinUterus, breastsLabour and lactationAfferent information from target organs
Antidiuretic hormone (ADH, vasopressin)KidneysWater loss: ECF volume and osmolalityHypothalamic osmoreceptors
Anterior pituitary(Human) growth hormone (H)GHMost cellsGrowth and metabolismHypothalamic releasing and inhibiting hormones via local blood vessels
ProlactinBreastsMilk production
Trophic hormones:
Thyroid-stimulating (TSH)Thyroid glandThyroid secretions
GonadotrophinsOvary or testisGerm cell maturation and hormone secretions
Adrenocorticotrophic (ACTH)Adrenal cortexCortisol secretion
Pineal bodyMelatoninWidespread, including brain, thymus, etc.
  • Sleep/wake cycle
  • Antioxidant
  • Immune system
Hypothalamus; varying light input from retina
Thyroid
  • Thyroxine
  • Triiodothyronine
  • Calcitonin
  • Most cells
  • Bone, kidneys, gut
  • Cellular oxidative metabolism
  • Decreases ECF [Ca2+]
  • TSH from anterior pituitary. Negative feedback from blood hormone concentration
  • ECF [Ca2+]
ParathyroidsParathormoneBone, kidneys, gut
  • Calcium and phosphorus absorption, secretion and turnover in bone.
  • Increases ECF [Ca2+]
ECF [Ca2+]
Adrenal: Cortex
  • Cortisol
  • Aldosterone
  • Androgens
  • Most cells
  • Kidneys
  • Gonads & other tissues
  • Metabolism
  • Response to stress
  • Na and K balance
  • Sex characteristics and reproductive function
  • ACTH from anterior pituitary
  • ECF [Na+] [K+]
  • Renin-angiotensin
  • ACTH
Medulla
  • Adrenaline
  • Noradrenaline
Heart, smooth muscle, glandsCardiovascular and metabolic adjustments to activity and stressSympathetic nervous system
Atrial wallAtrial natriuretic hormoneKidneysBlood volume; increases sodium (therefore also water) loss in urineStretch of atrial wall by venous pressure
Gonads: TestisAndrogens (mainly testosterone)Genitalia and other tissuesReproductive function and sex characteristicsAnterior pituitary gonadotrophins
Ovary
  • Oestrogens
  • Progesterone
Uterus, breasts and other tissuesMenstrual cycle, pregnancy, lactation
Pancreas
  • Insulin, glucagon
  • Somatostatin
  • Most cells
  • Other secretory cells in the pancreas
Blood levels, storage and cellular uptake of nutrients, notably glucose, but also proteins and fatsBlood levels of nutrients; autonomic nervous system; other gastrointesinal hormones
Alimentary tract
StomachGastrinGastric acid-secreting cellsGastrointestinal functions: motility, digestive juices and other secretionsLocal chemical and mechanical factors in the alimentary tract
Small intestine
  • Secretin
  • Cholecystokinin- pancreozymin (CCK-PZ)
  • Somatostatin, motilin
  • Other peptide hormones including vasoactive intestinal peptide (VIP)
  • Widespread on
  • GI tract
Several GI functions including bile flow, pancreatic enzyme and exocrine secretionsIngestion of food, distension of GI tract

androgens (anˑ·dr·jenz),

n.pl hormones produced in the adrenal cortex that maintain secondary male characteristics.
References in periodicals archive ?
Piton says that the list of genes that were altered by androgens in the study might be useful to identify new genes that might be involved in ASD or in other diseases that occur more often in males.
In prostate cancer, the androgen receptor (lock) is activated by the androgen (key) resulting in a signal that causes prostate cancer proliferation.
When the team administered small doses of androgens to mice that were taking the equivalent of medications given to women undergoing IVF therapy, they developed more mature, egg-containing follicles than mice that didn't receive androgens.
Evaluation of androgen, estrogen (ER alpha and ER beta), and progester-one receptor expression in human prostate cancer by real-time quantitative reverse transcription-polymerase chain reaction assays.
In a woman's body, one of the main purposes of androgens is to be converted into the female hormones called estrogens.
The ligand-binding domain, where androgens bind, results in a conformational change in the AR, where it dissociates from heat shock proteins in the cytoplasm, and localizes to the nucleus (13).
There is not a consensus case definition for androgen deficiency; there are few data on the performance of screening criteria; and the long-term implications of replacement are unclear in the most commonly affected populations: older men and men with chronic illness.
It appears that insulin resistance creates a vicious cycle that shifts into androgen excess and the androgen excess then promotes insulin resistance.
61) The increased production of steroid biosynthetic enzymes in resistant tumors suggests that one mechanism by which these carcinomas overcome androgen deprivation is by compensatory synthesis of androgens, with consequently increased AR activity.
Excessive and deficient androgen levels have been linked to:
Thus, peri- and postmenopausal women have approximately half the level of circulating androgens of women in their 20s (FIGURE 1, TABLE 1, page 75).