C1- Steriods and Hormones Flashcards
define hormone
Hormones → a class of signalling molecules which regulate physiology and behaviour in organisms
steriod hormone
a signalling molecule with a steroid structure
define steroids
a class of compounds defines structure of 17 carbon atoms in four rings. steroids vary by the nature and position of attached groups. These small modifications have huge effects on biological activities.
the 4 basic types of hormones
endocrine → signal carried in the bloodstream
autocrine →affected the cell that secreted it
paracrine→ intercellular
Intracrine →intracellular
basic hormone life cycle
synthesis → storage → secretion →transport → recognition → relay → degration
define agonist
Activates a receptor to produce a response
define antagonist
Blocks action of an agonist.
Inverse agonist
Induces an opposite response to agonist.
what is a Selective Receptor Modulator
Different effect in different tissues (mimics a hormone)
what is a sterol
steroid with a hydroxy group
cholesterol
-Forms 30% of the cell membrane and modulates fluidity.
what is cholesterol a precursor for (building block)
Biosynthetic precursor for:
Steroid hormones
Vitamin D
Bile acids
what are glucorticoid receptors
Glucocorticoid receptors are proteins inside cells that act as transcription factors. Transcription factors are like “switches” that turn certain genes on or off in the DNA to control the cell’s activities. the glucocorticoid hormone turns of these receptors
Corticosteriods (two types)
- A class of steroid hormones that are produced in the adrenal gland.
Glucocorticoids
Affect metabolism of carbohydrates, fats and proteins.
Mineralocorticoids
Regulate electrolytes in the body by acting on ion transport in kidneys
what is signal transduction
-When a signal is transmitted through a cell.
what is the membrane permeability of period hormones
Steroid hormones are generally membrane-permeable due to their lipophilicity
peptide hormones membrane permeability
Peptide hormones cannot enter the cell because they are too hydrophilic. so we need an adapter that spans the membrane. It binds to a receptor on the outside of the cell membrane and this causes changes on the inside of the cell instead.
define lipophilicity
Lipophilicity refers to the ability of a molecule to dissolve in lipids.
In medicinal chemistry the two adjectives to describe the scale are lipophilic and polar.
log P
LogP is a number that tells you how lipophilic (fat-loving) or hydrophilic (water-loving) a substance is.
If LogP is high, the substance is more lipophilic (fat-loving), meaning it prefers fat over water.
If LogP is low or negative, the substance is more hydrophilic (water-loving), meaning it prefers water over fat.
issues with the scales of Lipophilicity
If a drug is too polar, it cannot passively diffuse across the lipophilic cell membrane.
If a drug is too lipophilic, it is more susceptible to metabolism (and other disadvantages).
