L9: Adrenocortical Hormones Flashcards
What are the 3 types of corticosteroids that adrenal cortex secretes?
- Mineralocorticoids (electrolyte balance)
- Glucocorticoids (glucose balance, protein, and fat metabolism)
- Androgens
two main steroids released from adrenal cortex
aldosterone and cortisol
What are all human steroid hormones synthesized from?
cholesterol
How are steroid hormones synthesized from?
- they are synthesized from cholesterol.
- 80% of cholesterol is provided by low-density lipoproteins (LDL) which are circulating the plasma
- LDL then moves from the blood and into IF to bind to receptors on adrenocortical cell membranes, which are then internalized by endocytosis
- LDL is then delivered to mitochondria where it can be cleaved into various steroid hormones produced by adrenal cortex
What is the rate limiting step in the process of steroid hormones synthesis?
cleavage
Which of the two main steroid hormones synthesized by adrenal cortex have a longer half-life in blood?
cortisol
What does high concentrations of aldosterone in the plasma lead to?
it increases renal tubular reabsorption of Na and secretion of K
One of the main roles of aldosterone in the body
retain Na within the body
Does aldosterone cause a rise or a drop in arterial pressure?
it causes a rise in arterial pressure
Pressure naturesis
an increase in kidney excretion of salt due to the rise in arterial pressure which is due to aldosterone
Pressure diuresis
an increase in kidney excretion of water due to the rise in arterial pressure which is due to aldosterone
What part of the adrenal cortex is responsible for the secretion of aldosterone, cortisol and androgens?
aldosterone -> cells in the zona glomerulosa
cortisol -> cells in the zona fasciculata
androgens -> cells in the zona reticularas
Does the regulation of aldosterone secretion act independently or dependently of the regulation of cortisol and androgens?
it acts independently
4 main factors that play a role in regulation of aldosterone secretion
- Increase in K+ in extracellular fluid.
- Increase in angiotensin II in extracellular fluid
- Increase in Na+ in extracellular fluid
- ACTH from anterior pituitary is necessary, but does not control rate of secretion.
Which two of the four factors work together to cause a great increase in aldosterone secretion?
increase in potassium and angiotensin II in extra cellular fluid (1 +2)
Renin-Angiotensin-Aldosterone System (RAAS)
- hormone system within the body which is essential for regulation of blood pressure and fluid balance
- comprised of renin, angiotensin II, and aldosterone
- primarily regulated by rate of renal blood flow
Two ways in which cortisol effects carbohydrate metabolism
- Stimulation of gluconeogenesis ( this is done in two ways - cortisol increases the enzyme required to convert amino acids into glucose in the liver cells, and cortisol mobilized amino acids from muscle)
- Adrenal diabetes
adrenal diabetes
- presence of cortisol leads to increase in gluconeogenesis and decrease of glucose utilization by tissues causing plasma concentration of glucose to increase
- this leads to pancreas secreting insulin, however tissues are not as sensitive to insulin
- tissues aren’t as sensitive to insulin so injection of insulin is not going to have the same effect as for pancreatic diabetes
Two ways in which cortisol effects protein metabolism
- Reduction of cellular proteins in all cells bu liver (two ways in which this can occur - decreased protein synthesis and increased catabolism of proteins)
- Increased protein production in liver
Two ways in which cortisol effects fat metabolism
- Promotes mobilization of fatty acids from adipose tissue
- Enhanced oxidation of fatty acids in the cells
- these two traits together shift the metabolic systems of the cells from glucose for energy to fatty acids
main stress hormone
cortisol
What is an anti-inflammatory hormone?
Cortisol is also an anti-inflammatory hormone which means it prevents the widespread tissue and nerve damage associated with inflammation
Is cortisol expressed in the same amounts during day and night?
no, cortisol is expressed in higher amounts throughout the day than at night
