Download Steroid Hormones

Steroid
Hormones
13.10-13.12
Katlyn Raker and Amanda
Carl
Physiological roles
 Cholesterol
is the starting material for the
synthesis of steroid hormones
 Progesterone

Compound for


Sex hormones
Adrenocorticoid hormones
Adrenocoticoid hormones
 Products
of adrenal glands

Adjacent to the renal (kidney)
o
Classified into 2 groups
o
Mineralocorticoid
o
o
Regulate concentrations of ions (Na and K)
Glucocorticoids
o
Control carbohydrate metabolism
Corticoid

Indicates the site of the secretion is the cortex (outer
part of gland)
 Aldosterone


Most important mineralocorticoids
Increased secretion of aldosterone enhances the
reabsorption of Na and Cl ions in the kidney tubules
and increases the loss of K
 Controls
tissue swelling
 Cortisol



Major glucocorticoid
Increase glucose and glycogen concentration in the
body
Fatty acids from fat storage cells and amino acids
from body proteins

Transported to liver and under the influence of cortisol it
manufactures glucose and glycogen
 Cortisol

and cortisone (Ketone derivative)
Anti-flammatory effects
Sex hormones
 Male

Testosterone
Promotes growth of genital organs
Synthesized in testes from cholesterol
 Female
Estradiol
Synthesized from corresponding male hormone by
aromatization of the A ring

Along with progesterone it regulates the cyclic
changes in the uterus and ovaries (Period)

Level of estradiol rises uterus thickens
Luteinizing hormone (LH)
 Triggers
ovulation
 Estradiol
and progesterone

Promote further preparation of the uterine lining to
receive the fertilized ovum

No fertilization means the progesterone production
stops and estradiol production decreases
 Progesterone
is essential for the implantation of the
fertilized ovum

Blocking its action leads to a miscarriage

The levels of sex hormones in the blood stream during
a period (menstration) prevent pregnancy

Development of an ovarian follicle
 Proliferative
phase- The endometrium (lining of the
uterus) thickens
 Secretory
phase- the lining continues to thicken and
the glands secrete a glycogen rich nutritive material
in preparation to receive an embryo

If there is no embryo the new outer layers disintegrate
which causes blood flow
Mifepristone (RU486)
 Blocks
action of progesterone by binding
to the same receptor sites

Ovum is aborted since the progesterone
cannot reach the receptor molecule

If pregnancy is established Mifepristone can be
taken no less than 72 hours after intercourse for
49 days of gestation
Facts
 Mifepristone
abortions
 The

is a supplement to surgical
morning after pill is not an abortion pill
Since estradiol and progesterone
regulate the growth of breasts,
Mifepristone has been noted to be
effective against breast cancer
Bile salts
 Oxidation
products of cholesterol
 Powerful detergents



One end is negatively charged so its strongly
hydrophilic
The rest is largely hydrophobic
Disperse dietary lipids in the small intestine into fine
emulsions which facilitates digestion

Similar to soap and dirt
Prostaglandis
 Group

of fatty acid like substances
Discovered by Kurzruk and Leib in the 1930’s
 Name
came from Ulf von Euler of Sweden who
isolated the two compounds from semen, thinking
they came from the prostate gland
 Mature male= secretes .1mg per day
 Both
sexes= a little is present throughout the body
 Synthesized
in the body from arachidonic acid by a
ring closure at carbons 8 and 12


Catalyst= COX (cyclooxygenase)
Aspirin inhibits this enzyme
Thromboxanes


Includes a ring closure
Another class of a arachidonic acid
derivative

Induces platelet aggregation

Increases size of blood clot

Aspirin impairs the clotting from thromboxane
Leukotrienes (LTR’s)
 Causes
inflammation and fever
 Acts to mediate hormonal responses



No ring closure
Mostly occur in white blood cells
Produce long lasting muscle contractions
especially in the lungs


Can cause asthma like attacks
You would take zafirlukast (Accolate) to help
chronic asthma because it acts against the
inflammation