MK - Endocrine Pharmacology II Flashcards
What are the main functions of thyroid hormone? (4)
Key role in metabolism and development
Increases:
- Lipid, carbohydrate and protein metabolism
- Oxygen consumption
- Heat production
- Basal metabolic rate
How is the thyroid hormone synthesised?
Thyroid hormone is synthesised from tyrosine
What are 3 features of thyroid gland production?
1) Thyroid glands produce:
- Thyroxine (T4= prohormone)
- Triiodothyronine (T3)
Both are tyrosine-based hormones
2) Production requires IODINE
3) Target cells contain thyroid hormone nuclear receptor (TR).
What is childhood iodine deficinecy called?
cretinism
What are examples of hypothroidism (2) and what are some symptoms?
- Myxoedema
- Hashimoto’s disease/ Hashimoto’s thyroiditis most common =autoimmune disease
Symptoms: fatigue/depression/weight gain/cold intolerance
Low T3/T4, High TSH
What is an example of hyperthroidism (2) and what are some symptoms?
- Graves’ disease (diffuse toxic goitre) –often autoimmune
Symptoms:
anxiety/ hyperactivity/Weight loss/goitre/bulging eyes/ tachycardia/sweating
High levels of thyroxine will inhibit TSH so :
- High T3/T4
- Low TSH
What are 2 pharmacological interventions of hyperthroidism?
1) Thioureylenes inhibit thyroid gland
- Inhibit iodination of tyrosine
- Inhibit thyroperoxidase and prevent the formation of thyroxine
2) Protirelin are synthetic TRH, used to test functionality of anterior pituitary
Disorders of the hypothalamic POSTERIOR pituitary axis- and treatment
Antidiuretic horomone / vasopressin
- Aid in renal fluid reabsorption of water
Hormone analogue of ADH (Desmopressin)
What are the 3 hormones present in the adrenal glands?
Adrenal cortex:
- Aldosterone
- Androgens
- Cortisol
What is aldosterone and what does it cause?
It is the body’s major MINERALOCORTICOID hormone
- Acts on kidney nephrons (distal tubule & collecting duct)
Causes:
- Increased Na+ retention
- Increased K+ excretion
Regulates water and electrolyte balance
Regulation of Aldosterone Secretion (5)
- ↓ extracellular fluid
- Activates kidney release of renin
- Renin convert Angiotensin to Ang I then
- ACE converts to AngII
- Ang II acts on the adrenal cortex to stimulate aldosterone production
Aldosterone Action (4)
Aldosterone release
- More Na+ retention
- ECF volume increases
- Increased cardiac output
- Increased blood pressure
What are the functions of cortisol (metabolic, on tissues and organs(3) and on anti-inflammatory and immune responses(2))?
Metabolic
- Actions oppose those of insulin
Actions on tissue and organs
- Muscle contractility
- Decreases bone formation
- Modulates perception
Anti-inflammatory and Immune responses
- Inhibits body response to tissue injury
- Decreases prostaglandins
What are all steroid hormones made from?
Cholesterol
How are both aldosterone and cortisol formed? (3)
1) Cholesterol → Pregnenolone first step in STEROIDOGENESIS
- ACTH and Angiotensin II increase Pregnenolone production
2) From Pregnenolone both Aldesterone and Cortisol (and the Sex Steroids) are made
- 17a-hydroxylase converts aldosterone precursors → cortisol precursors
3) Corticosterone → Aldosterone stimulated by Angiotensin II
- 11-b-hydoxylase is final enzyme in synthesis of Cortisol
