HPA axis and Glucocorticoids Flashcards
(32 cards)
What are the symptoms of Morbus Cushing ?
- Adiposity
- Diabetes-like metabolism
- Arterial hypertony
- Immune suppression
- Osteoporosis
- Muscle fatigue
What are the symptoms of Morbus Addison ?
- Anorexia
- Spontaneous hypoglycaemia
- Hypotonia
- Osteoporosis
- Feaver
- Autoimmune diseases
- Muscle pain
Name the three parts of the adrenal.
- Capsule
- Cortex
- Medulla
Where in the adrenal are steroids and catecholamines produced ?
- Steroids in the cortex
- Catecholamines in the medulla
Name the rate-limiting step in the biosynthesis of cortisol.
- Conversion of cholesterin into pregnenolon by steroid acute regulator (StaR)
Name the two cell organells in which the cortisol biosynthesis takes place.
- Mitochondrien
- Endoplasmatic reticulum
Cholesterol is converted into cortisol in five steps. Name the intermediates in the correct order.
- Cholesterol
- Pregnenolon
- 17-OH-Pregnenolon
- 17-OH-Progesteron
- 11-Desoxycortisol
- Cortisol
What is CRH and where is it produced ?
- Corticotropin releasing hormone
- Produced in the paraventricular nucleus (PVN) of the hypothalamus
What is ACTH and where is it produced ?
- Adrenocorticotropic hormone
- Produced by cleaving of POMC in the pituitary
Describe shortly the regulation of cortisol biosynthesis in the HPA axis.
- CRH is produced in the hypothalamus and transported into the pituitary
- In the pituitary CRH stimulates the secretion of ACTH
- ACTH is transported into the adrenals where it stimulates the production of cortisol
- The secretion of cortisol inhibits the secretion of CRH and ACTH
Name the difference in speed of feedback regulation between CRH and ACTH on one hand and cortisol on the other hand. What is the reason for this difference ?
- CRH and ACTH are feedback regulated in minutes; their level rises and falls completely a few times a day
- The cortisol level is much more stable and the complete rise or fall takes much longer
- The reason is the difference in half-life
To which molecule is cortisol binding in the blood ?
Transcortin
Describe shortly how an glucocorticoid nuclear receptor (GCNR) is working ?
- GCNR is bound to a heat-shock protein (HSP) in the cytoplasm
- After the binding of a steroid hormone to the GCNR the HSP dissociates
- The bound receptor translocates into the nucleus and bind to a glucocorticoid response element
- Transcription is activated
Name two catabolic effects of cortisol taking place in the muscles.
- Increased proteolysis
- Decreased glucose uptake
Name two catabolic effects of cortisol taking place in adipose tissue.
- Increased Lipolysis
- Decreased glucose uptake
Name three anabolic effects of cortisol taking place in the liver.
- Increased gluconeogenesis
- Increased glycogenolysis
- Decreased glucose uptake
What is the effect of glucocorticoids on the immune system ?
They are acting immunosuppressive
- Down regulation of innate immune responses
- Down regulation of adaptive immune responses
Name four short-term stress responses.
- Increased heart rate
- Increased blood pressure
- Liver converts glycogen to glucose and releases glucose to blood
- Increased metabolic rate
Name two long-term stress responses initated by the secretion of mineralocorticoids by the adrenal cortex.
- Retention of sodium and water by kidneys
- Increased blood volume and blood pressure
Name three long-term stress responses initated by the secretion of glucocorticoids by the adrenal cortex.
- Proteins and fats converted to glucose or broken down for energy
- Increased blood glucose
- Suppression of immune system
Stress physiology is a central action. What are thereby the Fight-or-flight-responses ?
- Increased mental activity
- Dilated pupils
- Increased respiratory rate
- Increased heart rate
- Increased blood pressure
- Increased blood glucose
- Increased blood flow to skeletal muscles
Name the main cause for Morbus Cushing.
GCR defect caused by a tumor
Name five symptoms of Morbus Cushing.
- “Moon face”, central obesity
- Osteoporosis
- Immunosuppression
- Muscle weakness
- Depression
Name the main cause for Morbus Addison.
- GCR defect caused by an autoimmune disease
- Can in rare cases be caused geneticly
