Endocrine system - Pituitary hormones & insulin III Flashcards
What are the hormones of Adrenal Gland?
- Mineralocorticoids (Mineral Balance)
Aldosterone - Glucocorticoids (Glucose Metabolism)
Cortisol - Androgens (Masculinisation)
Dehydroepiandrosterone - Catecholamines (Sympathetic activation)
Adrenaline/Noradrenaline
Aldosterone (mineralocorticoid)(Recollect BP regulation RAAS)
Secretion – Stimulated by increased plasma [K+]
and RAAS system; largely independent of Hypothalamus-pituitary axis (ACTH)
Sodium secretion happens in the…
kidney
sodium reabsorption ^^^^ =
Sodium reabsorption^
water reabsorption^
Potassium excretion in urine^
Hypoaldosteronism =
Deficiency in the enzyme required for synthesis of aldosterone
e.g. Hyperkalaemia, Hyponatremia, Hypovolemia, Hypotension and others
Primary hyperaldosteronism (Conn’s syndrome) =
Excess aldosterone level
e.g. Hypokalaemia, Hypernatremia, Hypervolemia, Hypertension and others
Androgens
Dehydroepiandrosterone (DHEA) and its derivatives are steroid hormone that regulates the development and maintenance of MALE characteristics (masculinisation)
Androgens secretion?
Regulated by the level of ACTH (but no feedback axis to ACTH/CRH)
Hypoandrosteronism and symptoms/effects= Deficiency in the enzyme required for synthesis of DHEA
Loss of energy, erectile dysfunction, libido, loss of muscle and bone mass and others
Hypoandrosteronism and symptoms/effects= Deficiency in the enzyme required for synthesis of DHEA
Loss of energy, erectile dysfunction, libido, loss of muscle and bone mass and others
Predominately in women =
Excess DHEA level
Excess hair (pubic and auxiliary hair growth), masculinisation
What is the cortisol?
It’s your body’s main stress hormone
[ Cortisol and its derivatives are steroid hormones that regulates the glucose metabolism ]
Cortisol secretion;
Regulated by the level of ACTH/CRH(HPA axis)
Gluconeogenesis^, protein breakdown^
Decrease- glucose iuptake/ protein synthesis
Lipolysis^
Decrease - Glucose uptake, lipogeneis
High Physiological levels: Anti-inflammatory/immunosuppressive effects
Permissive role for other endocrine hormones
Several Biological functions
Where does glugonegenesis take place?
Liver
Protein breakdown
Glucose uptake/ protein synthesis HAPPENS in the
muscle
Glucose uptake, lipogeneis HAPPENS in the
adipose
What is cushing’s syndrome?
ACTH-secreting pituitary tumour
excess glucocorticoids
Symptoms of cushing’s syndrome?
- upper body obesity with thin arms and legs
- Buffalo hump
- Red, round face
- High blood pressure
- Vertigo
- Blurry vision
- acne
- Female balding
- water retention
- Menstrual irregularities
- thin skin and bruising
- purple striae
- poor wound healing
- Hirsutism
- severe depression
- cognitive difficulties
- emotional instability
sleep disorders
-fatigue
Cortisol – Addison’s disease
Adrenal insufficiency
Autoimmune disease or by HIV or TB
not producing sufficient, cortisol, aldosterone and androgens
Symptoms of Addison’s disease
Hair Loss
Blurred vision
Abdominal pain
Decreased appetite
Darkening of the skin
Weight Loss
Hypoglycaemia
Postural Hypotension
Because of Addison’s disease
ACTH production increased, as is MSH (share same POMC-precursor as ACTH)
→ increase melanin content in skin
Posterior Pituitary Hormones
Paraventricular (PVN) and supraoptic (SON) nuclei, and the neurons carrying oxytocin and ADH (vasopressin) to the posterior pituitary, where they are stored/ released
What stimulates antidiuretic hormone (ADH) / Arginine Vasopressin (AVP)
Stimulated by Hypovolemia, Hyperosmolality and Hypotension
ADH/AVP function
1) Increase permeability and hence re-absorption of water.
2) Stimulate ACTH release
3) Blood vessels – vasoconstriction (at higher [ADH])
DCT & CD:
distal convoluted tubules and collecting ducts
What decreases because of ADH
diabetes insipidus (DI): polyuria and polydipsia
Pituitary DI:
Inadequate release of ADH
Nephrogenic DI:
Dysfunction of receptors in collecting ducts
What increase because of ADH
Syndrome of inappropriate ADH secretion (SIADH)
CNS pathologies, malignancy, CNS drugs
Rétention of water in the body, highly concentrated urine
Hyponaterimia (dilution effect not sodium loss)
Oxytocin - positive feedback?
Stimulate “milk let-down”, expression of breast milk
Uterine smooth muscle - contraction
Maternal behaviour / sexual behaviour
Hormones of Pancreas;
Insulin
Acid amino chains in insulin
Initially as proinsulin (human, 86aa)
mw ~ 5800
A-Chain: 21 aa
B-Chain: 30 aa
Disulphide Bridges: 3
Half-life of 5-9 minutes
Insulin - enzymes;
Involves 3 enzymes:
proconvertase 1 (PC1)
proconvertase 2 (PC2)
carboxypeptidase H (CPH)
What is the ratio of zinc and insulin crystalloid core?
2 Zn 2+ : 6 insulin crystalloid core
(in secretory granules)
Insulin»_space;> Function (anabolic hormone)
Chronic metabolic disorder characterised by hyperglycaemia
Insulin deficiency (Type 1)
Impaired b-cell function and/ or loss of insulin sensitivity (insulin resistance) (Type 2)
