C HAPTER 13 – L IPIDS – By: Mackenzie Stuck & Carlie Strawser

13.10 W HAT ARE SOME OF THE PHYSIOLOGICAL ROLES OF STEROID HORMONES ? Cholesterol: Starting material for the synthesis of steroid hormones Aliphatic side chain on the D ring is shortened Removal of the six – carbon unit Secondary alcohol group Oxidized to a ketone Progesterone: resulting molecule

A DRENOCORTICOID H ORMONES Product of Adrenal Glands “Adjacent to the renal” Two groups Mineralocorticoids Regulates concentration of ions Glucocorticoids Control carbohydrate metabolism “Corticoid” Indicates the secretion is the cortex of the gland

E X : M INERALOCORTICOIDS Aldosterone Enhances re-absorption of Na ions in the kidneys Increases the loss of Potassium Controls tissue swelling

E X : G LUCOCORTICOIDS Cortisol Increases glucose and glycogen concentrations Expense of other nutrients Cortisone (ketone derivative) Used to treat: Inflammatory diseases Rheumatoid arthritis Bronchial asthma

S EX H ORMONES Testosterone (male) Promotes normal growth of the male genital organs Increased testosterone Deep voice Facial and body hair

Estradiol Synthesized from testosterone Aromatization of the A ring Regulates cyclic changes in the uterus and ovaries Menstrual cycle Increases the level of Estradiol Luteinizing Hormone (LH) causes Ovulation Prepare uterine lining for fertilization No fertilization = decrease

13.11 W HAT ARE BILE SALTS ? Bile Salts Oxidized products of cholesterol 1 st : cholesterol is oxidized to the trihydroxy derivative 2 nd : end of aliphatic chain is oxidized to the carboxylic acid 3 rd : forms an amide bond with an amino acid Taurine Sports drinks

P HYSICAL PROPERTIES OF BILE SALTS Powerful detergents 1 end Strongly hydrophilic Rest of the molecule Largely hydrophobic Can disperse dietary lipids facilitates digestion Similar to the action of soap on dirt Remove bile salts in 2 ways Break down products of cholesterol Solubilize cholesterol

13.12 W HAT ARE PROSTAGLANDINS, T HROMBOXANES, AND L EUKOTRIENS ? Prostaglandins A group of fatty-acid-like substances Discovered in the 1930’s by Kurzrok Leib Ulf Von Euler Named it thinking it came from prostate gland Small amount in both sexes

C YCLOOXYGENASE (COX) Catalyzing enzyme in the presence of arachidonic acid synthesized in the body creating prostaglandins Two types COX – 1 PGE2 (Prostaglandin E group) Carbonyl group at the 9 th carbon Lowers blood pressure Used as a decongestant Induces labor

COX – 2 Responsible for making prostaglandins Occurs when inflammatory cells interact with resident cells because the tissue is injured

T HROMBOXANES A class of arachidonic acid Drived from PGH2 Has a cyclic acetal ring induces platelet aggregation thromboxanes A2 causes blood to clot more NSAI in COX enzymes can cause excessive bleeding

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