ACTH Flashcards
What is the prohormone of ACTH and the target organ for it?
Prohormone: pro-opiomelanocortin (POMC)
Target organ: the adrenal cortex
What is the function of ACTH?
Controls the production and secretion of cortisol and other glucocorticoids
List 4 functions of glucocorticoids
Protein breakdown - increase the rate of protein breakdown in the muscles to release amino acids.
Glucose formation - liver converts amino acids to glucose
Lipolysis - stimulate the breakdown of triglycerides to release fatty acids
Resistance to stress. Anti-inflammatory effects.
What are some symptoms of cushing syndrome?
Unexplained central obesity, stretch marks, osteoporosis, weakness, hypertension, moon faces and a buffalo hump.
What are some tests that can determine Cushing syndrome?
Plasma ACTH, Metyrapone stimulation test, Inferior petrosal sinus sampling.
What can be done to treat cushing syndrome?
Normalise cortisol levels, monitor and treat cortisol-dependent comorbidities. Vaccinate against influenza, herpes zoster. Surgical resection of primary adrenal ectopic focus underlying CS.
What is the mainstay of treatment?
Removal of the tumour. Using agents like metyrapone and ketoconazole, an adrenal enzyme blocker. Also inhibits gonadal steroidogenesis
What is the function of pasireotide in cushing disease?
Its a long somatastatin analogue and it suppresses ACTH secretion which may lead to reduction of cortisol secretion.
What causes adrenocortical insufficiency?
May be caused by deficient adrenal production of gluco and mineralcorticoids.
Dysfunction may be due to addison disease or secondary adrenocortical insufficiency.
What are some symptoms of addisons disease?
Fatigue, weakness, anorexia, N&V
What are some differences between addison disease and secondary adrenal insufficiency?
Addison’s disease: Hyperpigmentation, abnormal response to short corticotropin stimulation test. ACTH levels are elevated.
Secondary adrenal insufficiency:
Hypopigmentation, a normal corticotropin stimulation test. Low ACTH levels.
What is the treatment for Addison Disease?
Hydrocortisone and cortisone acetate. Mimic endogenous cortisol production. Administer 67% of the dose in the morning and the remainder is given 6-8 later.
What are some adverse effects of glucorticosteroids?
Growth inhibition in children, muscle wasting, osteoporosis, salt retention, depression, psychosis.
