steroid hormones cholesterol starting material. steroid sex hormones androgens: androgens: male sex...
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Steroid HormonesSteroid Hormones
HO
Cholesterol Starting material
Steroid Sex HormonesSteroid Sex Hormones• Androgens:Androgens: male sex hormones
• synthesized in the testes• responsible for the development of male secondary sex characteristics
AndrosteroneTestosteroneO
OH
H3C
H3C H3C
H3C
O
HO
Steroid HormonesSteroid Hormones• Among the synthetic anabolic steroids are:
O
H3C
H3C
MethandienoneO
CH3
H3CH3C
OHOH
CH3
MethenoloneO
H3C
H3CO
4-Androstene-3,17-dione
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 . . .
AndrosteroneTestosteroneO
OH
H3C
H3C H3C
H3C
O
HO
Steroid Sex HormonesSteroid Sex Hormones• Estrogens: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 HormonesSteroid Sex Hormones
• Progesterone-like analogs are used in oral contraceptives: they Make the body think it is Pregnant at all times. . .
preventing folicle stimulation and ovulation. . .
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)
Prevents egg from staying implanted . . Gets released. . .
•Steady stream of Progesterone required for implantation and development of oocyte
Other pills block Progesterone
all together. . .e.g. RU- 486
Progesterone
Steroid HormonesSteroid Hormones• Adrenocorticoid hormonesAdrenocorticoid hormones
• synthesized in the adrenal cortex.• regulate metabolism of carbohydrates.• decrease inflammation.• involved in the reaction to stress.
Bile SaltsBile Salts• Bile saltsBile 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
HO
H3C
CH3
H3C
OH
HO NH
O
HO
H3C
CH3
H3C
OH
HO NH
O
SO32-
Glycocholate(from glycine)
Taurocholate(from taurine)
COO-
Other Classes Lipids: Other Classes Lipids: - - ProstaglandinsProstaglandins- - ThromboxanesThromboxanes - Leukotrienes - Leukotrienes
• Prostaglandins:Prostaglandins: a family of compounds that have the 20-carbon skeleton of prostanoic acid. COOH
2
3
4
5
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89
2011
1213
1415
1617
1819
1
10
ProstaglandinsProstaglandins• 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.
COOH
Arachidonic acid1514
89
11 12
6 5
ProstaglandinsProstaglandins
15
9 9
11 11
Arachidonic acid
PGF2PGE2
PGG2
Aspirin and other NSAIDs inhibit this enzyme
15
9
11
9
11
15
OOH
COOHO
O
OH
COOH
O
HO
COOH
OH
COOH
2O2
15
cyclooxygenase (COX)
HO
HO
COX EnzymesCOX 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 responseBy inhibiting the production of prostaglandins . . .
ThromboxanesThromboxanes• 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.
O
OOH
COOH
Thromboxane A2
189
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10
Challenge QuestionsChallenge 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. . .
LeukotrienesLeukotrienes• 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.OH OH
COOH
Leukotriene B4
1512
20