Encyclopedia of Health and Medicine

antidiuretic hormone (ADH) 113
the presence of abnormal proteins, and biopsy of
representative amyloid deposits.
Treatment Options and Outlook
There is no curative treatment for amyloidosis.
When amyloidosis is secondary, treatment for the
underlying condition often mitigates the symptoms
and progression of the amyloidosis. Treatment
for primary amyloidosis targets symptom
relief. In some people, a regimen of CHEMOTHERAPY
halts the amyloidosis progression for up to several
years. Kidney, heart, or liver transplantations are
sometimes viable options when amyloid deposits
accumulate in these organs. STEM CELL transplantation
shows promise for long-term relief, though
existing amyloid deposits remain in the tissues.
Many people are able to control their symptoms
for long periods of time through carefully selected
therapeutic measures.
Risk Factors and Preventive Measures
There are no known risk factors or preventive
measures for primary amyloidosis. Multiple
myeloma and chronic inflammatory disorders and
infections are significant risk factors for secondary
amyloidosis. Amyloidosis is more likely to develop
when these conditions are long-term and poorly
controlled. Though it is not possible to prevent
secondary amyloidosis, prompt and appropriate
treatment for the underlying condition may mitigate
its manifestation.
See also CHRONIC FATIGUE SYNDROME; FAMILIAL
MEDITERRANEAN FEVER; INFLAMMATION; ORGAN TRANS-
PLANTATION; SARCOIDOSIS.
androgens A collective term for the “male” sex
hormones, prohormones (chemical precursors the
body converts to hormones), and metabolites
(byproducts of HORMONE METABOLISM). Androgens
are steroid hormones the body synthesizes from
cholesterol; they are variably anabolic (they build
MUSCLE mass, some more actively than others).
Androgens are also the precursors (starting point)
for the ESTROGENS (“female” sex hormones). The
most abundant and familiar androgen is TESTOS-
TERONE. In addition to establishing male secondary
sex characteristics and FERTILITY, androgens have
multiple functions in men and women both with
regard to muscle mass and STRENGTH, BONE DENSITY,
LIBIDO (sex drive), and metabolism.
Men and women alike have androgens (just as
both sexes also have estrogens). The gonads, or
sex glands (OVARIES in women and TESTES in men),
synthesize (produce) most of the androgens in the
BLOOD circulation. The adrenal cortex of the ADRE-
NAL GLANDS and adipose (fat) cells also synthesize
androgens. The HYPOTHALAMUS’s secretion of
GONADOTROPIN-RELEASING HORMONE (GNRH) regulates
the hormonal cascade for endogenous (within the
body) androgen production and release. Some
androgens are available as exogenous supplements
used to treat disorders of androgen deficiency as
well as taken illicitly to enhance athletic performance.
ENDOGENOUS ANDROGENS
androstane
androstanediol
androstenedione androstenolone
androsterone
DEHYDROEPIANDROSTERONE (DHEA)
dihydrotestosterone TESTOSTERONE
See also ANABOLIC STEROIDS AND STEROID PRECUR-
SORS; HIRSUTISM; HORMONE THERAPY; HYPOGONADISM;
INFERTILITY; INSULIN RESISTANCE; POLYGLANDULAR DEFI-
CIENCY SYNDROME; PROSTATE CANCER; SPERMATO-
GENESIS.
antidiuretic hormone (ADH) A peptide HOR-
MONE, also called vasopressin, the HYPOTHALAMUS
synthesizes (produces) and the posterior lobe of
the PITUITARY GLAND stores and releases. ADH regulates
the amount of water the KIDNEYS withhold in
the bloodstream. The hypothalamus signals the
pituitary gland to release ADH when the body
needs additional fluid, such as during excessive
sweating with heat or intense exercise. Increased
ADH in the BLOOD causes the kidneys to withhold
more water from the circulating blood, raising
blood volume and decreasing URINE production. In
high concentrations, ADH acts to constrict peripheral
arterioles (the smallest arteries deep in the tissues).
In combination, these effects are among the
body’s mechanisms for regulating BLOOD PRESSURE.
Dysfunction of the pituitary gland, and less commonly
the hypothalamus, can result in inadequate
levels of ADH in the bloodstream, causing the rare