Endocrine Pharmacology Flashcards
Adrenal steroids are manufactured by enzymes located in the:
Mitochondria and SER
Three primary pathways (adrenal cortex)
MGA
- Mineralocorticoid
- Glucocorticoid
- Androgen/estrogen
Precursor for steroid biosynthesis
Cholesterol
Synthesis and secretion is controlled by CRH from the hypothalamus and ACTH from the pituitary
Cortisol / hydrocortisone
Steroid binding proteins
- Corticotropin binding globulin (CBG) aka transcortin
- Albumin
MOA: Glucocorticoids
● Steroids exert their effects by altering protein synthesis through a direct effect
on the cell’s nucleus
● glucocorticoids first enter the cell and bind to a receptor in the cytosol
● ”hormone-receptor“ complex (transcription factor)
● this complex travels (translocates) to the nucleus
● binds to specific DNA gene segments that control inflammation and other
processes
● transcription factor:
○ modulates the transcription of DNA mRNA units
○ inhibits other transcirption factors (nuclear factor-kappa B, activator
protei-1) that normally activate inflammatory genes
■ thus, turning off proinflammatory genes and suppressing the
production of inflammatory products
● Changes in mRNA transcription ultimately lead to a change of protein
synthesis in the cell
MOA: Glucocorticoids
Rapid effect mediated by
Surface receptors
MOA: Glucocorticoids
Delayed effect
more prolonged; mediated by intracellular receptor; affects
transcription at the genomic level
MOA: Glucocorticoids
Genomic effects
takes SEVERAL HOURS OR DAYS TO OCCUR because of the time required to alter protein synthesis and create new proteins that reach meaningful concentrations in the cell
Physiological Effects: Glucocorticoids
AEI
● Anti-inflammatory
● immunosuppresion
● Effects on Glucose, Protein, and Lipid Metabolism
Glucocorticoid Effect on Glucose, Protein, and Lipid Metabolism
● increase blood glucose
● increase liver glycogen
● inhibits the uptake of glucose into muscle and fat
● muscle breakdown to amino acids
● lipid breakdown to free fatty acids
Effects:
● maintain blood glucose levels and liver glycogen
levels
● enables a supply of energy substrate readily
available for increased activity
Anti-inflammatory Effects: Glucocorticoids
Attenuate the heat, swelling, and tenderness regardless of the cause
glucocorticoids act on macrophages, lymphocytes, and endothelial cells to
inhibit inflammatory proteins (cytokines):
○ IL-1, IL-6, TNF alpha, IFN gamma,
■ Primary chemical signal for activating other inflammatory cells (T lymphocytes, fibroblasts, NK cells)
Anti-inflammatory effects: Glucocorticoids
reduce the number of circulating lymphocytes, eosinophils, and other cells
Anti-inflammatory effects: Glucocorticoids
inhibit the transcription and expression of adhesion molecules:
endothelial leukocyte adhesion molecule 1, intracellular adhesion
molecule 1
responsible for attracting leukocytes in the bloodstream to
endothelial cells at the site of inflammation
endothelial leukocyte adhesion molecule 1, intracellular adhesion
molecule 1
Anti-inflammatory Effects: Glucocorticoids
Inhibit the production of proinflammatory substances:
prostaglandins and
leukotrienes
Anti-inflammatory Effects: Glucocorticoids
activate genes to synthesize annexins / lipocortins
inhibits phospholipase A2 enzyme