HORMONE–RELEASING HORMONE(GHRH), andTHYROID-
RELEASING HORMONE(TRH), initiating the hormonal
cascades that generate tremendous growth spurts
as well as the development of the secondary sex
characteristics. The PITUITARY GLANDresponds with
accelerated secretion of FOLLICLE-STIMULATING HOR-
MONE(FSH), GROWTH HORMONE(GH), LUTEINIZING HOR-
MONE, AND THYROID-STIMULATING HORMONE (TSH)
which in turn stimulate the gonads (OVARIESin
females and TESTESin males) and affect METABOLISM
in cells throughout the body. Surges in the sex
hormones—ESTROGENS, PROGESTERONE, andTESTOS-
TERONE—complete the metamorphosis.
The hormonal changes that take place during
PREGNANCY are among the most profound the
human body experiences. The PLACENTA, the devel-
oping fetus’s lifeline, produces dozens of hor-
mones otherwise not found in the body. These
hormones, coupled with hormonal changes in the
woman’s body, sustain the woman’s body as a
supportive environment for the unborn child and
prepare it for further support (lactation) after
birth. The hormones of pregnancy allow the mus-
cles and ligaments of the abdomen to soften
stretch to accommodate the enlarging UTERUS,
increase the woman’s BLOODsupply and metabo-
lism (including thyroid hormones and INSULINpro-
duction), and increase vital functions such as
BLOOD PRESSUREand HEART RATE.
Over the subsequent four or so decades the
reproductive hormonal cascades slow. By midlife
women end FERTILITYand enter MENOPAUSE, the ces-
sation of MENSTRUATIONand OVULATION. Rapid drops
in estrogen and progesterone elicit major changes
in a woman’s body. The changes in men are less
dramatic though nonetheless apparent. Testos-
terone levels peak around age 22 and steadily
decline, tapering by age 60 to about 50 percent of
peak levels. Men notice redistribution of body fat,
decreased MUSCLEmass, and thinning scalp HAIR.
Also with advancing age levels of the hormones
of the adrenal cortex, particularly cortisol, begin to
decline. This affects body functions ranging from
blood pressure and heart rate to immune response
and GLUCOSE metabolism. These changes are
among the changes some researchers believe hold
the key to slowing, halting, or even reversing
some of the events and consequences of aging.
Accompanying these and other endocrine changes
that occur with advancing age are increased risks
for numerous health conditions such as CARDIOVAS-
CULAR DISEASE(CVD), DIABETES, LIVER disease, and
kidney disease. Nearly all hormonal production
and endocrine processes diminish by age 80, and
the body itself slows.
See alsoANTI-AGING APPROACHES; LIFE EXPECTANCY;
LIFESTYLE AND HEALTH.aldosterone A steroid HORMONEthe adrenal cor-
tex of the ADRENAL GLANDSproduces that plays a
key role in regulating BLOOD PRESSURE. Aldosterone
is vital for life; the body can sustain its functions
for only a few days without it. Chemically aldo-
sterone is a mineralocorticosteroid, a type of
steroid (cholesterol-based structure) that influ-
ences the body’s balance of minerals such as
sodium and potassium. Aldosterone targets cells in
the KIDNEYS that regulate the amounts of these
minerals which remain in the bloodstream. The
adrenal cortex releases aldosterone when the
amount of potassium in the BLOODincreases or
when the kidneys release the hormone RENINin
response to decreased blood volume flowing
through the kidneys. Renin initiates a series of
enzyme conversions that result in the production
of angiotensin II, which then stimulates aldos-
terone production in the adrenal cortex.LICORICE AND ALDOSTERONE
Long-term, excessive consumption of natural
licorice (Glycyrrhiza glabra extract or gly-
cyrrhizic acid) interferes with aldosterone bind-
ing and allows aldosterone levels in the BLOODto
rise, establishing symptoms similar to those
HYPERALDOSTERONISM. Doctors call the resulting
condition pseudo-hyperaldosteronism. Most
licorice-flavored candies and other products in
the United States do not contain natural licorice.
However, natural licorice is an ingredient in
many products in other countries, notably in
Europe.The release of aldosterone increases sodium
retention in the blood and potassium excretion
into the URINE, raising levels of sodium and drop-
ping the levels of potassium in the blood. The
higher sodium level correspondingly draws more
water into the blood, increasing the blood volume.aldosterone 111