Lecture 11 Flashcards
Steroid hormones
derived from the (cholesterol framework)
Move across membranes and bind inside the cell
Thyroid hormones is an example
Protein/peptide hormones and Catecholamines
Too large/polar to cross membranes
Act on protein receptors at the cell surface which triggers signals to the cell
Prohormones
are inactive forms of hormones
Converted to active form by enzymes
Detection of Hormones
Hormones are found at much lower concentrations than other clinical analytes
Radioimmunoassay developed in the 1960s are the reference method though being replaced by ELISA Assays
Epinephrine (Adrenalin) and Norepinephrine
Both “Fight or flight” hormones
Stimulate lipolysis/glycogenesis, increase heart rate -> making more energy available
both Catecholamine hormones
secreted by Adrenal Medulla
Between Epinephrine and Norepinephrine, which is more potent?
Epinephrine it is also more abundant
Pituitary Hormones: Types
Growth Hormone (GH), Follicle Stimulating Hormone (FSH), and Luteinizing Hormone (LH)
- What type of hormone are pituitary hormones?
Peptide Hormones
What do Pituitary hormones regulate?
Growth and fertility -especially during puberty
What does LH trigger
Ovulation
What does GH stimulate?
stimulates glycogenesis/lipolysis making more energy available
Thyroid hormones
T3 and T4 (aka thyroxine) are thyroid hormones
affects metabolism, growth and activity of other hormones
What is T4 considered?
A prohormone
converted to T3 by Thyroglobulin
- What are Thyroid hormones similar too?
Steroid hormones
Able to cross cell membrane due to them being non polar
TSH
Thyroid stimulating hormone
elevated when T3/T4 is low and needs to produce more
Hyperthyroidism
Grave’s disease
Hypothyroidism
Hashimoto’s thyroiditis
Glucocorticoids
steroid hormones that affect glucose metabolism
Cortisol
major glucocorticoid
Stimulates glycogenesis/lipolysis and reduces inflammation
What is cortisol considered?
the stress hormone b/c stress = elevated levels
Mineralocorticoids
Steroid hormones that affect mineral (electrolyte) absorption are called Mineralocorticoids
What is a major mineralocorticoids?
Aldosterone
Cortisol and Aldosterone both released by what?
Adrenal Cortex
Dehydroepiandrosterone (DHEA)
the precursor for both M and F hormones
the most abundant, though not the most potent, steroid hormone
Androstenedione
metabolic precursor (prohormone) of testosterone
Testosterone
most masculinizing steroid hormone released/formed in the testes
Androsterone
metabolic product of testosterone – weaker response to masculinizing
Estrogens
Steroid hormones responsible for female characteristics are released/formed in the ovaries
Xenobiotic metabolism
Most polar substances -> kidneys
Non-polar substances made more polar in 2 phases
Xenobiotic Metabolism Phases
Phase 1: Enzymes called Mixed Function Oxidases (MFO) or Cytochrome P450s (CYP) perform a variety of reactions -> more polar
Phase 2: Called Conjugation – involves reactions that attach polar groups such as glucuronide or sulfate
Acute toxicity
refers to dangers of short-term exposure
If you survive you are not at continued risk
Example carbon monoxide (CO) or cyanide (CN-) poisoning
Long-term toxicity
mostly involves danger from accumulated DNA damage
ED 50
effective dose to 50% of those exposed
TD 50
toxic dose to 50% of those exposed
toxic means some undesirable side effects are seen
LD 50
lethal dose to 50% of those exposed
Therapeutic Index (TI)
The ratio of TD50/ED 50
Ames test
measures how effective a compound is at mutating the DNA of bacteria
Bacteria that require the AA histidine are used
Ames test result
More toxic compounds = more mutations and more bacterial colonies
Pharmoacokinetics
preferred route of drug delivery is ingestion
Absorption in the intestine requires that a molecule have?
a moderate polarity
a molar mass <500 g/mol
Hepatotoxicity
Liver is the body’s detoxing organ
at the greatest risk of being damaged by foreign substances
Liver enzymes are widely used indicators of what?
exposure to a toxin
Chromatography
Technique to separate mixtures containing many compounds
Based on a sort of “filtering” of the mixture through a material called the stationary phase
Different types of chromatography
Liquid chromatography: Liquid is the mobile phase, solid is the stationary phase
Gas Chromatography: Gas is the mobile phase and liquid in contact with solid is the stationary phase. Aids in the detection of drug/alcohol, or their metabolites
