CHAPTER 13 – LIPIDS13.10 – 13.12By: Mackenzie Stuck & Carlie Strawser

13.10 WHAT ARE SOME OF THE PHYSIOLOGICAL ROLES OF STEROID HORMONES?

  Cholesterol: Starting material for the synthesis

of steroid hormonesAliphatic side chain on the D ring is shortened

Removal of the six – carbon unit Secondary alcohol group

Oxidized to a ketoneProgesterone: resulting molecule

ADRENOCORTICOID HORMONES

Product of Adrenal Glands“Adjacent to the renal”

Two groupsMineralocorticoids

Regulates concentration of ionsGlucocorticoids

Control carbohydrate metabolism “Corticoid”

Indicates the secretion is the cortex of the gland

EX: MINERALOCORTICOIDS

AldosteroneEnhances re-absorption of Na ions in

the kidneysIncreases the loss of Potassium Controls tissue swelling

EX: GLUCOCORTICOIDS

CortisolIncreases glucose and glycogen

concentrations Expense of other nutrientsCortisone (ketone derivative) Used to treat:

Inflammatory diseasesRheumatoid arthritisBronchial asthma

SEX HORMONES

Testosterone (male) Promotes normal growth of the male

genital organsIncreased testosterone

Deep voiceFacial and body hair

Estradiol Synthesized from testosterone

Aromatization of the A ringRegulates cyclic changes in the uterus and

ovariesMenstrual cycleIncreases the level of Estradiol Luteinizing Hormone (LH) causes Ovulation

Prepare uterine lining for fertilizationNo fertilization = decrease

13.11 WHAT ARE BILE SALTS?

Bile SaltsOxidized products of cholesterol

1st: cholesterol is oxidized to the trihydroxy derivative

2nd: end of aliphatic chain is oxidized to the carboxylic acid

3rd: forms an amide bond with an amino acid

Taurine Sports drinks

PHYSICAL PROPERTIES OF BILE SALTS

Powerful detergents1 end

Strongly hydrophilicRest of the molecule

Largely hydrophobic Can disperse dietary lipidsfacilitates digestionSimilar to the action of soap on dirt

Remove bile salts in 2 waysBreak down products of cholesterol

Solubilize cholesterol

13.12 WHAT ARE PROSTAGLANDINS, THROMBOXANES, AND LEUKOTRIENS?

  Prostaglandins

A group of fatty-acid-like substancesDiscovered in the 1930’s by

KurzrokLeib

Ulf Von EulerNamed it thinking it came from

prostate glandSmall amount in both sexes

CYCLOOXYGENASE (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 9th carbon Lowers blood pressure Used as a decongestant Induces labor

COX – 2 Responsible for making

prostaglandinsOccurs when inflammatory cells

interact with resident cells because the tissue is injured

THROMBOXANES

A class of arachidonic acidDrived from PGH2Has a cyclic acetal ringinduces platelet aggregation

thromboxanes A2 causes blood to clot more

NSAI in COX enzymes can cause excessive bleeding

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