Steroid Hormones13.10-13.12Katlyn 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 groupso Mineralocorticoid

o Regulate concentrations of ions (Na and K)

o Glucocorticoidso 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 is a supplement to surgical

abortions

The 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