Clinical Chem Endocrinology

to maintain physiological & biochemical homeostasis

to respond to changes in physiological status, e.g., pregnancy, puberty & trauma

Function of endocrine system

Obesity

________ caused by physical injury or inborn damage to the hypothalamus.

secretion of ACTH

Normally dexamethasone suppresses the ________ (cortisol level

Chemical messengers

Hormones are ________ that are formed in endocrine glands and released into bloodstream to regulate the distant target cells and organs.

Endocrine glands

tissues/organs that produce and secrete/release chemical substances (hormones) directly into the blood circulation or intercellular space

synthesises, releases

endocrine gland receives chemical signals which ______ and ______ hormone

internal, external

Hormones can also be synthesised and secreted in response to i____ or e____ stress

protein/polypeptide hormone
steroid hormone
amine hormone

3 different types of hormones

insulin and growth hormone

give 2 examples of protein/peptide hormones

protein/polypeptide hormone

What hormone is mostly synthesised by anterior pituitary, placenta, pancreas, & parathyroid glands?

water, receptors

protein/polypeptide hormones are ____-soluble; attach to cell membrane ______

oestrogens, testosterone

give 2 examples of steroid hormones

steroid hormone

What hormone is synthesised by gonads, placenta & adrenal glands

lipid, carrier proteins

steroid hormone is ____-soluble; require c____ p_____

epinephrine, thyroid hormones

give two examples of amine hormone

amine hormone

What hormone is synthesised by thyroid gland & adrenal medulla

Hypothalamus obesity

obesity caused by physical injury or inborn damage to the hypothalamus

it is the complete loss of pituitary function

What is panhypopituitarism?

stillbirth or death soon after birth

What happens if panhypopituitarism is congenital/neonatal onset?

growth hormone deficiency, gonadotropins (LH & FSH) deficiency, TSH deficiency, ACTH deficiency

Symptoms of panhypopituitarism

growth retardation (children)

decreased muscle bulk & strength, increased body fat, fatigue, social withdrawal, loss of motivation (adults)

growth hormone deficiency results in:

decreased body hair & libido, irregular or no menstruation, infertility (women)

erectile dysfunction, infertility, decreased facial & body hair

gonadotropins (LH & FSH) deficiency results in:

inability to tolerate cold temperature, mild myxedema, dry skin, fatigue, weight gain, constipation

TSH deficiency result in (symptoms may take 4-8 weeks to appear) :

nausea, vomiting, low blood pressure, hypoglycaemia, decreased glycogen reserves, fatigue

ACTH deficiency is rare, but can be life threatening
It can result in:

laboratory evaluation
measurement of pituitary hormones & hormones from the target endocrine glands by using immunoassays

CT scan or MRI

diagnosis of panhypopituitarism:

hormone replacement therapy, surgery, radiation therapy

treatment of panhypopituitarism:

excess glucocorticoids (cortisol) or very high cortisol levels in the body

Cushing's syndrome is characterised by:

cortisol, ACTH, tumours, corticosteroids, autoimmune

Causes of Cushing's syndrome:
c_____-secreting adrenal adenoma or carcinoma (~10% each)

A_____-secreting pituitary adenoma (~70%) or non-pituitary _____ that secrete excess plasma A____ (10%)

prolonged consumption of synthetic c_______ (e.g., prednisone, dexamethasone) in a______ and inflammatory diseases

24-hour urine free cortisol measurement
serum ACTH level
overnight dexamethasone suppression test
differential diagnosis via 48-hour dexamethasone suppression test
Other tests: saliva test, imaging test

Laboratory testing of Cushing's Syndrome via immunoassays

40-260, >300,

Serum ACTH level
pituitary-dependent Cushing’s syndrome: ______ pg/ml

ectopic ACTH production by non-pituitary tumour: _____ pg/ml

adrenal tumour: ____ pg/ml

overnight dexamethasone suppression test
exclude cushing’s syndrome: cortisol level ___- nmol/L

failure to suppress: further investigation is required

low dose, 50, no

differential diagnosis via 48-hour dexamethasone suppression test
_____ test: confirm the presence of Cushing’s syndrome

Cushing’s syndrome: ___% suppression of plasma cortisol

Cushing’s syndrome due to adrenal tumour or ectopic ACTH secretion: ___ suppression

serum ACTH

differential diagnosis via 48-hour dexamethasone suppression test
need to combine with ______ measurement

surgery
radiation therapy
medications
reduce the dosage of corticosteroid medications

Treatment for Cushing's syndrome: