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Encyclopedia > Adrenarche

Adrenarche refers to a stage of maturation of the cortex of the human adrenal glands. It typically occurs between ages 6 and 10 years and involves both structural and functional changes. Adrenarche is a process related to puberty but distinct from hypothalamic-pituitary-gonadal maturation and function. In mammals, the adrenal glands are the triangle-shaped endocrine glands that sit atop the kidneys. ... Puberty refers to the process of physical changes by which a childs body becomes an adult body capable of reproduction. ... In the anatomy of mammals, the hypothalamus is a region of the brain located below the thalamus, forming the major portion of the ventral region of the diencephalon and functioning to regulate certain metabolic processes and other autonomic activities. ... Located at the base of the skull, the pituitary gland is protected by a bony structure called the sella turcica. ... A sex organ, or primary sexual characteristic, narrowly defined, is any of those parts of the body (which are not always bodily organs according to the strict definition) which are involved in sexual reproduction and constitute the reproductive system in an complex organism; namely: Male: penis (notably the glans penis...

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Structural and functional changes of adrenarche

Structural changes of adrenarche include increased size and mass of the adrenal cortex, and completion of differentiation into the three zones: zona glomerulosa, zona fasciculata, and zona reticularis. The zona reticularis (inner region of the adrenal cortex) secretes and synthesize small amounts of weak androgens, steroids that have masculinizing effects. ...


One of the primary functional changes is further differentiation of sex steroid synthesis among the three zones, so that as in adults, the zona glomerlulosa primarily produces mineralocorticoids such as aldosterone, the zona fasciculata primarily produces glucocorticoids such as cortisol, and the zona reticularis primarily produces androgens such as dehydroepiandrosterone, dehydroepiandrosterone sulfate, and androstenedione. A sex steroid is a steroid hormone which interacts with vertebrate androgen or estrogen receptors. ... Mineralocorticoids is a class of steroids characterised by their similarity to aldosterone and their influence on salt and water metabolism. ... Aldosterone is a steroid synthesized in the mid-section of the adrenal cortex of the adrenal gland. ... Glucocorticoids are a class of steroid hormones characterised by an ability to bind with the cortisol receptor and trigger similar effects. ... Cortisol (hydrocortisone, C21H30O 5 ), is a corticosteroid hormone synthesized in the zona fasciculata of the cortex of the adrenal glands. ... Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates. ... Dehydroepiandrosterone (DHEA) is a natural steroid hormone produced from cholesterol by the adrenal glands. ... Categories: Stub | Androgens ...


The second important functional change is a steady increase over several years in the daily production of adrenal androgens. A characteristic aspect of early adrenarche is an inhibition of 3β-hydroxysteroid dehydrogenase, the enzyme which mediates the hydroxylation of 17-hydroxypregnenolone to 17-hydroxyprogesterone, and DHEA to androstenedione. Blood levels of DHEA, androstenedione, and especially DHEAS can be measured by physicians as markers of adrenal maturation. Hydroxylation is any chemical process that introduces one or more hydroxyl groups (-OH) into a compound (or radical) thereby oxidising it. ... Dehydroepiandrosterone (DHEA) is a natural steroid hormone produced from cholesterol by the adrenal glands. ... Categories: Stub | Androgens ...


Role of adrenarche as part of puberty

An initiator of adrenarche has not yet been identified. Researchers have unsuccessfully tried to identify a new pituitary peptide, to be called "adrenal androgen stimulating hormone". Others have proposed that adrenarchal maturation is a gradual process intrinsic to the adrenal glands that has no distinct trigger. A third avenue of research is pursuing a possible relationship with either fetal or childhood body mass and related signals such as insulin and leptin. Many children born small for gestational age (SGA) because of intrauterine growth retardation (IUGR) have an earlier onset of adrenarche, which raises the possibility that timing of adrenarche may be affected by physiological programming in infancy. Adrenarche also occurs prematurely in many children who are overweight, suggesting a possible relationship with body mass or adiposity signals. The structure of insulin Red: carbon; green: oxygen; blue: nitrogen; pink: sulfur. ... Leptin is a protein hormone produced by adipose tissue. ... Intrauterine growth retardation or Intrauterine growth restriction (IUGR) refers to the condition during pregnancy where a fetus is considered to be too small for its gestational age (generally in the 10th percentile). ... Obesity is an excess storage of fat and can affect any mammal, such as the mouse on the left. ...


The principal physical consequences of adrenarche are androgen effects, especially pubic hair and the change of sweat composition that produces adult body odor. Increased oiliness of the skin and hair and mild acne may occur. In most boys, these changes are indistinguishable from early testicular testosterone effects occurring at the beginning of gonadal puberty. In girls, the adrenal androgens of adrenarche produce most of the early androgenic changes of puberty: pubic hair, body odor, skin oiliness, and acne. In most girls the early androgen effects coincide with, or are a few months behind, the earliest estrogenic effects of gonadal puberty (breast development and growth acceleration). As female puberty progresses, the ovaries and peripheral tissues become more important sources of androgens. Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates. ... Pubic hair is hair in the frontal genital area and in the crotch, and sometimes at the top of the inside of the legs; these areas form the pubic region. ... Sweating (also called perspiration or sometimes transpiration) is the loss of a watery fluid, consisting mainly of sodium chloride and urea in solution, that is secreted by the sweat glands in the skin of mammals. ... Body odor is the smell of sweat and whatever bacteria are growing on the body. ... Acne is an inflammatory disease of the skin, caused by changes in the pilosebaseous units (skin structures consisting of a hair follicle and its associated sebaceous gland). ... Human male anatomy The testicles, known medically as testes (singular testis), are the male generative glands in animals. ... Testosterone is a steroid hormone from the androgen group. ... Estrogens (or oestrogens) are a group of steroid compounds that function as the primary female sex hormone. ... Human female internal reproductive anatomy Ovaries are a part of a female organism that produces eggs. ...


Parents and many physicians often infer (incorrectly) the onset of puberty from the first appearance of pubic hair (termed pubarche). However, the independence of adrenarche and gonadal puberty is apparent in children with atypical or abnormal development, when one process may occur without the other. For instance, adrenarche does not occur in many girls with Addison's disease, who will continue to have minimal pubic hair as puberty progresses. Conversely, girls with Turner syndrome will have normal adrenarche and normal pubic hair development, but true gonadal puberty never occurs because their ovaries are defective. Pubic hair is hair in the frontal genital area and in the crotch, and sometimes at the top of the inside of the legs; these areas form the pubic region. ... Pubarche refers to the first appearance of pubic hair in a child. ... Addisons disease (also known as chronic adrenal insufficiency, or hypocortisolism) is a rare endocrine disorder. ... Turner syndrome is a human genetic abnormality, caused by a nondisjunction in the sex chromosomes that occur to females (1 out of every 2,500 births). ...


Premature adrenarche

Premature adrenarche is the most common cause of the early appearance of pubic hair (premature pubarche) in childhood. As described above, adrenarche should be distinguished from true central precocious puberty, from congenital adrenal hyperplasia, and from androgen-producing tumors of the adrenals or gonads. Pediatric endocrinologists do this by demonstrating advanced levels of DHEAS and other adrenal androgens, with prepubertal levels of gonadotropins and gonadal sex steroids. As mentioned above, premature adrenarche occurs more often in children with intrauterine growth retardation and in overweight children. Simple premature adrenarche causes no problems for a child and need not be treated but occasionally may precede the condition of excessive androgens in adolescence referred to as polycystic ovary syndrome. Pubarche refers to the first appearance of pubic hair in a child. ... Precocious puberty means early puberty. ... Congenital adrenal hyperplasia (CAH) refers to any of several autosomal recessive diseases resulting from defects in steps of the synthesis of cortisol from cholesterol by the adrenal glands. ... Pediatric endocrinology is a medical subspecialty dealing with variations of physical growth and sexual development in childhood, as well as diabetes and other disorders of the endocrine glands. ... Gonadotropins are protein hormones secreted by gonadotrope cells of the pituitary gland of vertebrates. ... A sex steroid is a steroid hormone which interacts with vertebrate androgen or estrogen receptors. ... Polycystic ovary syndrome (PCOS, also known clinically as Stein-Leventhal syndrome), is an endocrine disorder that affects 5–10% of women. ...


See also

adrenal cortex, androgens, puberty, precocious puberty. In mammals, the adrenal glands are the triangle-shaped endocrine glands that sit atop the kidneys. ... Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates. ... Puberty refers to the process of physical changes by which a childs body becomes an adult body capable of reproduction. ... Precocious puberty means early puberty. ...


  Results from FactBites:
 
Adrenarche - Wikipedia, the free encyclopedia (679 words)
Adrenarche refers to a stage of maturation of the cortex of the human adrenal glands.
A characteristic aspect of early adrenarche is an inhibition of 3β-hydroxysteroid dehydrogenase, the enzyme which mediates the hydroxylation of 17-hydroxypregnenolone to 17-hydroxyprogesterone, and DHEA to androstenedione.
Adrenarche also occurs prematurely in many children who are overweight, suggesting a possible relationship with body mass or adiposity signals.
  More results at FactBites »

 
 

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