Steroid Hormones(13.10-13.12)

Jack Snyder James Sanders

Chapter 13 Section 10

What are some of the Physiological Roles of Steroid Hormones?o Cholesterol is the starting material for the synthesis of steroid hormoneso Progesterone serves as the starting compound for both sex hormones and the

adrenocorticoid hormones

A. Adrenocorticoid Hormoneso The adrenocorticoid hormones are products of the adrenal glands

o Classified into two groups according to function: Mineralocorticoids and Gluccocorticoids.

o Mineralocorticoids regulate the concentrations of ions (mainly Na+ and K+)

o Gluccocorticoids control carbohydrate metabolism

Chapter 13 Section 10 cont.

o An oxidation product of cholesterol is progesterone, which is a sex hormone. It also gives rise to the synthesis of other sex hormones, such as testosterone and estradiol .

o Progesterone is also a precursor of the adrenocorticoid hormones. Within this group cortisol and cortisone are best known for their anti-inflammatory action.

Chapter 13 Section 10 cont.

Anabolic Steroids Made from testosterone to increase muscular development

• Disadvantages Affects secondary sexual characteristics and too much can result

in undesirable side effects Not very effective when taken orally, must be injected to achieve

the best results.

Chapter 13 Section 10 cont.

Hormonal Cycle› Levels of the sex hormones during the blood stream of

the phases of one menstrual cycle in which pregnancy does not occur.

› Development of an ovarian follicle during the cycle.› Phases of development of the endometrium, the lining

of the uterus. › The endometrium thickens during the proliferative

phase. The secondary phase which follows the ovulation, the endometrium continues to thicken and the glands secrete a glycogen-rich nutritive material in preparation to receive an embryo.

Chapter 13 Section 10 cont.

Oral Contraception› Prevents ovulation during pregnancy› In the pill a synthetic progesterone-like

compound is supplied together with an estradiol-like compound

› Triple bond derivatives of testosterone are used most often in birth control pills Norethindone Norethynodrel Ethynodiol Diacetate

Chapter 13 Section 11

Bile salts are oxidation products of cholesterol› They emulsify all kinds of lipids, including

cholesterol and are essential in the digestion of fats

Chapter 13 Section 11 cont.

Bile salts can disperse dietary lipids in the small intestine into fine emulsions, there by facilitating digestion.

Remove excess cholesterol:› They are themselves breakdown products

of cholesterol, so cholesterol is eliminated via bile salts.

› They solubilize deposited cholesterol in the form of bile salt

Chapter 13 Section 12

Prostaglandins › Group of fatty acid like substances were

discovered by Kurzrok and Leib in the 1930s when they demonstrated that seminal fluid cause a hysterectomized uterus to contract

› Isolated these compounds from human semen and, thinking it came from the prostate gland, named them prostaglandins

› It is synthesized from Arachidonic acid (ring closure)

Chapter 13 Section 12 cont.

Thromboxanes › Derivative of arachidonic acid (ring

closure) › Is known to induce platelet aggression › Causes other platelets to clump, there by

increasing the size of the blood clot › Do not use aspirin and anti-inflammatory

agents a week before planned surgery because aspirin and other NSAIDS may cause excessive bleeding.

Thromboxane + Leukotrienes

Chapter 13 Section 12 cont.

Leukotrienes› Group of substances that act to mediate

hormonal responses› Derived from Arachidonic acid by an

oxidative mechanism› No ring closure › Occur mainly to white blood cells but are

also found in other tissues in the body. › Produce long lasting muscle contractions,

especially the lungs

Chapter 13 Section 12 cont.

Both Prostaglandins and the Leukotrienes cause inflammation and fever, so the inhibition of their production of the body is a major pharmacological concern