Flashcards in LMP301 Lecture 7: Endocrine Disease Deck (78)
List the principle endocrine glands
3. Thyroid gland
4. Parathyroid gland
5. Adrenal gland
What types of hormones does the hypothalamus release?
- Releasing hormones
- Inhibiting hormones
What are the releasing hormones released by the hypothalamus?
- GHRH (growth hormone)
- TRH (thyrotrophin)
- CRH (corticotrophin)
- GnRH (gonadotrophin)
What are the inhibiting hormones released by the hypothalamus?
Hypothalamus usually sends signals to...
Pituitary gland is divided into...
- Anterior Pituitary
- Posterior pituitary
What hormones are released by the a. pituitary?
- GH (growth)
- TSH (thyroid-stimulating)
- ACTH (adrenocorticotrophic)
- LH (luteinizing)
- FSH (Follicle-stimulating)
- PRL (Prolactin.)
What hormones are released by the p. pituitary?
- Antidiuretic hormone (ADH/vasopressin)
Hormones secreted by thyroid gland
Hormones secreted by adrenal cortex
- Mineralocorticoids (aldosterone)
- Glucocorticoids (cortisol)
- Adrenal androgens
Thyroid gland controls...
Hormones secreted by parathyroid gland
PTH (parathyroid hormone)
Parathyroid gland controls...
Ca++ levels in the body
The adrenal gland is divided into
- Adrenal cortex
- Adrenal medulla
Hormones secreted by adrenal medulla
Catecholamines: E and NE
Hormones secreted by ovaries
Hormones secreted by the testes
Hormones secreted by pancreas
- Glucagon (alpha cells)
- Insulin (Beta cells)
- Somatostatin (delta cells)
how are hormones classified?
- Neuroendocrine, NT
What are endocrine hormones?
- sent through blood and carried to target cells
What are paracrine hormones?
- act on nearby cells
Example of paracrine hormone?
Glucagon act on B-cells of the pancreas
Example of endocrine hormone?
ACTH from pituitary act on adrenal cortex
What are autocrine hormones?
- hormone act on cell that secreted it
Example of autocrine hormone
1,25(OH)2vitD from prostate & pancreas
What are NT/NE hormones?
Hormones secreted from neural axon terminals
Examples of NT/NE hormones
Ways in which the endocrine system is controlled:
1. Feedback (positive and negative)
___ interaction between hormone and their receptor
2 types of receptors
1. Cell surface receptors
2. Intracellular receptors
Cell surface receptors
Used by large, liquid insoluble hormones
- Rapid response
- intracellular signalling pathway
Used by smaller, liquid soluble hormones
- Gene regulation
- in cytosol or nucleus
- activates TF
- slow response
Relationship between hypothalamus and p. pituitary
Hormones produced by hypothalamus can be stored in the p. pituitary until signal for release
Relationship between hypothalamus and a. pituitary
Hypothalamus sends signal (releasing hormones), and the corresponding hormones are produced at the a. pituitary
Effect of GnRH on a. pituitary
stimulate LH/FSH production
Effect of CRH on a. pituitary
stimulate ACTH production
Effect of GHRH on a. pituitary
stimulate GH production
Effect of somatostatin on a. pituitary
Inhibit GH and TSH production
Effect of TRH on a. pituitary
Stimulate TSH and prolactin production
Effect of domapine on a. pituitary
inhibit prolactin production
What is prolactin mostly affected by?
If dopamine inhibiting signal is there. TRH does not have a major effect (unless abundance of TRH)
Target organ of LH/FSH
Target organ of ACTH
Target organ of GH
liver, other tissues
Target organ of TSH
Target organ of prolactin
breasts, other tissues
LH/FSH stimulates production of...
ACTH stimulates production of...
GH stimulates production of...
TSH stimulates production of...
Hormone concentration in blood ____ due to normal reasons, such as...
- episodic secretion patterns
- circadian rhythm
How do we investigate endocrine diseases?
use dynamic tests (provocative tests)
Test hormone response and feedback following a stimulating / inhibiting signal
What dynamic test is used for Cushing's syndrome?
Dexamethasone suppression tests
What dynamic test is used for Addison's disease?
Synacthen test (using synthetic ACTH)
What dynamic test is used for diabetes & acromegaly?
Oral glucose tolerance test
"Spade-like" hands is a symptom of...
increased GH in adults
Most likely cause of acromegaly?
pituitary adenoma (tumour)
Clinical features of acromegaly?
- rough facial features
- soft tissue thickens
- spade-like hands
- protruding jaw (prognathism)
- impaired glucose tolerance / diabetes
Why do people with acromegaly tend to have impaired glucose tolerance?
- GH opposes effects of insulin
- IGF-1 initially acts like insulin and lowers glucose, but overtime, the insulin receptors become insensitive due to continual large outputs of IGF
Major effects of GH (somatotrophin)
- Reduce glucose metabolism (less insulin receptors)
- Increase lypolysis (use FA for energy)
- Increase AA transport into muscles, liver, adipose cells
- Increase proteins synthesis (transcription & translation in the liver)
- Increase IGF
Factors that enhance effects of GH
- Low glucos
Factors that supresse effects of GH
- High glucose
GH can be directly measured by...
2 dynamic tests given to diagnose problems with GH
- Use insulin to induce hypoglycemia -> will GH be secreted in response to low glucose? (GH deficiency)
- Glucose tolerance test -> will high glucose stop GH secretion? (acromegaly)
How to measure IGF-1 (somatomedin C)?
IGF-1 is an indicator of...
Why is it so good?
Very stable in the blood stream; easy to detect because very concentrated in the blood
IGF-1 is what type of hormone?
Endocrine, autocrine, paracrine
The body has more insulin or IGF-1?
_____ in response to a GTT is the diagnostic test for acromegaly
Lack of GH suppression
glucose tolerance test
Treatment of acromegaly
What kind of drugs can treat acromegaly?
- GH agonists
- GHRH angonists (not as effective)