Steroid Hormones Cholesterol Starting material

Steroid Sex Hormones Androgens: male sex hormones synthesized in the testes responsible for the development of male secondary sex characteristics

Steroid Hormones Among the synthetic anabolic steroids are: Prohormones, see p.515 Chemical Connections 20G Why are these hormones of interest? Do steroids really work? i.e. improve muscle mass and performance? . . .

A resounding Yes . . .

Steroid Sex Hormones Estrogens: female sex hormones synthesized in the ovaries from progesterone  testosterone . . . (aromatization) estradiol responsible for the development of female secondary sex characteristics and control of the menstrual cycle

Steroid Sex Hormones A woman's monthly cycle w/o the pill (Blue and Red solid lines) A woman's monthly cycle on the pill (Blue and Red dashed lines) Progesterone-like analogs are used in oral contraceptives: they Make the body think it is Pregnant at all times. . .  preventing folicle stimulation and ovulation. . .

Steady stream of Progesterone required for implantation and development of oocyte Other pills block Progesterone all together. . .e.g. RU- 486 Progesterone Prevents egg from staying implanted . . Gets released. . .

Steroid Hormones Adrenocorticoid hormones synthesized in the adrenal cortex. regulate metabolism of carbohydrates. decrease inflammation. involved in the reaction to stress.

Bile Salts Bile salts, the oxidation products of cholesterol. synthesized in the liver, stored in the gallbladder, and secreted into the intestine where they emulsify dietary fats and aid in their absorption and digestion

Other Classes Lipids: - Prostaglandins - Thromboxanes - Leukotrienes Prostaglandins: a family of compounds that have the 20-carbon skeleton of prostanoic acid.

Prostaglandins Not stored in tissues - synthesized from membrane-bound 20-carbon polyunsaturated fatty acids in response to specific physiological triggers. One such polyunsaturated fatty acid is arachidonic acid.

Prostaglandins

COX Enzymes The COX (cyclooxygenase) enzyme occurs in two forms: 1. COX-1 catalyzes the normal physiological production of prostaglandins. 2. COX-2 is responsible for the production of prostaglandins in inflammation. Tissue is injured or damaged, special inflammatory cells invade the injured tissue and interact with resident cells, e.g. smooth muscle cells or skin. This interaction activates COX-2 and prostaglandins are synthesized. Aspirin helps relieve this anti-inflammatory response By inhibiting the production of prostaglandins . . .

Thromboxanes Thromboxanes are also derived from arachidonic acid. Thromboxane A2 induces platelet aggregation and vasoconstriction. Aspirin and other NSAIDs inhibit the synthesis of thromboxanes by inhibiting the COX enzyme.

Challenge Questions How Does Aspirin prevent strokes caused by blood clots in the brain? NOTE: Doctors recommend 81mg/ day for people at risk for Heart Attack or stroke. . .

Leukotrienes Leukotrienes are also synthesized from arachidonic acid. They occur mainly in leukocytes. They produce muscle contractions, especially in the lungs and thereby can cause asthma-like attacks. In this regard, they are 100 times more potent than histamine. Several recently-developed anti-asthma drugs inhibit the synthesis of leukotrienes.