1. ADRENOCORTICOTROPIC
HORMONES
DR. RUPALI A. PATIL
ASSOCIATE PROFESSOR, PHARMACOLOGY DEPARTMENT
GES’S SIR DR. M. S. GOSAVI COLLEGE OF PHARMACEUTICAL
EDUCATION & RESEARCH, NASHIK
2. ADRENAL GLANDS
▪ It is located at the top or above the kidney
▪ Adrenalin, the hormone it produces.
▪ TWO PARTS
▪ Inner part :“medulla”
▪ Medulla is the source of epinephrine(adrenalin) and Non-
epinephrine. Epinephrine raises blood sugar levels, cause
nervousness and perspirations on acute emergencies.
▪ Sympathetic neurons innervate
▪ Outer part “cortex”
▪ Cortex releases cortisone which is essential for adapting to
stress and maintaining blood sugar level and aldosterone that
regulates thesalt and water balance of the body. 1
4. ADRENAL HORMONES
– Mineralcorticoids
• Mostly aldosterone (retain Na+,
secrete K+)
– Glucocorticoids
• Secreted in response to ACTH
• Cortisol (hydrocortisone) is
most important
– Stimulate gluconeogenesis (fat
and protein catabolism)
– Also glycolysis
– Stress response
– Suppresses immune system
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5. Hormones of the Adrenal Medulla
• Hormones synthesized in adrenal medulla are:
• dopamine
• adrenaline/ noradrenaline (epinephrine/norepinephrine)
• 80% of released catecholamine is epinephrine
• Hormones are secreted & stored in the adrenal medulla & released in
response to appropriate stimuli
4
6. Tyrosine
(1) Tyrosine hydroxylase
Dopa
PLP
CO2
(2) Dopa decarboxylase
Dopamine
(3) Dopamine hydroxylaseCu++
Vit C
Norepinephrine
SAM (4) N-METHYL TRANSFERASE
SAH
Epinephrine
SAM (5) Catechol-O-methyl transferase
SAH
Metanephrine
(6) Mono amino oxidase
VMA (Vanillyl mandalic acid)
(+)O2
5
Synthesis of
catecholamines
7. Mechanism of Action
• receptor mediated – adrenergic receptors
• peripheral effects are dependent upon the type &
ratio of receptors in target tissues
Receptor
Norepinephrine ++++ ++
Epinephrine
++++ ++++
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9. DIFFERENCES BETWEEN EPINEPHRINE & NOREPINEPHRINE
Epinephrine >> norepinephrine – in terms of cardiac stimulation leading to greater
cardiac output ( stimulation).
Epinephrine < norepinephrine – in terms of constriction of blood vessels – leading
to increased peripheral resistance – increased arterial pressure.
Epinephrine >> norepinephrine –in terms of increasing metabolism
Epi = 5-10 x Norepinephrine
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10. Effects of Epinephrine
Metabolism:
- glycogenolysis in liver and skeletal muscle
• can lead to hyperglycemia
- mobilization of free fatty acids
- increased metabolic rate
• O2 consumption increases
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13. PHEOCHROMOCYTOMA
•a catecholamine-secreting tumour of chromaffin cells of the adrenal medulla
adrenal pheochromocytoma (90%)
• paraganglioma – a catecholamine secreting tumour of the sympathetic
paraganglia
extra-adrenal pheochromocytoma
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15. Diagnosis and Treatment
• Diagnosed by high plasma catecholamines & increased metabolites in urine
• No test for adrenal or extra-adrenal
• Treatment is surgical resection
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18. GLUCOCORTICOIDS - CORTISOL
• a steroid hormone
- plasma bound to corticosteroid binding globulin (CBG or transcortin)
• essential for life (long term) 2hr
• the net effects of cortisol are catabolic
- prevents against hypoglycemia
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21. REGULATION OF CORTISOL RELEASE
• Cortisol release is regulated by ACTH
• Release follows a daily pattern - circadian
• Negative feedback by cortisol inhibits the secretion of ACTH & CRH
• Release increase by:
• physical trauma
• infection
• extreme heat and cold
• exercise to the point of exhaustion
• extreme mental anxiety
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24. PHARMACOKINETICS
• Well absorbed & effective by oral route, except DOCA.
• Absorption into systemic circulation occurs from topical sites of application as well, but the
extent varies depending on the compound, site, area of application & use of occlusive
dressing.
• Water soluble esters, e.g. Hydrocortisone hemisuccinate, Dexamethasone sod. phosphate
• i.v. / i.m., act rapidly & achieve high concentrations in tissue fluids.
• Insoluble esters, e.g. Hydrocortisone acetate, Triamcinolone acetonide
• cannot be injected i.v., slowly absorbed from i.m. site & produce more prolonged effects.
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25. Metabolism
The corticosteroids are metabolized primarily by hepatic microsomal enzymes. Pathways are—
(i) Reduction of 4, 5 double bond & hydroxylation of 3-keto group.
(ii) Reduction of 20-keto to 20-hydroxy form.
(iii) Oxidative cleavage of 20C side chain (only in case of compounds having a 17-hydroxyl group) to yield 17-
ketosteroids.
These metabolites are further conjugated with glucuronic acid or sulfate and are excreted in urine.
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• Hydrocortisone : high first pass metabolism, has low oral: parenteral activity ratio.
• Oral bioavailability of synthetic corticoids is high.
• 90% bound to plasma protein - cortisol-binding globulin (cbg; transcortin) as well as to albumin.
• Transcortin : increases during pregnancy & by oral contraceptives—corticoid levels in blood are increased
but hypercorticism does not occur, because free cortisol levels are normal.
27. 26
• Plasma t½ of hydrocortisone : 1.5 hours.
• Biological t½ is longer because of action through intracellular receptors & regulation of protein
synthesis—effects that persist long after the steroid is removed from plasma.
• Synthetic derivatives are more resistant to metabolism & are longer acting.
• Phenobarbitone & phenytoin induce metabolism of hydrocortisone, prednisolone &
dexamethasone, etc. to decrease their therapeutic effect.
28. Actions of cortisol depends on its plasma level:
1. Permissive Actions
Its presence even at small amounts permits certain processes to occur
Glycogenolysis: Glucagon & catecholamines
2. Physiological Actions
Effects of the normally present hormone levels in plasma
3. Pharmacological Actions
Effects of the high levels of hormone in plasma
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30. I. Effect on metabolism
II. Effect on CNS
Required for normal EEG pattern
III. Weak mineralocorticoid effect
IV. Anti-stress effect
V.C.catecholamines
Permissive action
Blood glucose
Plasma a.a.
Plasma FFA
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31. Physiological Actions of Cortisol
• promotes gluconeogenesis
• promotes breakdown of skeletal muscle protein
• enhances fat breakdown (lipolysis)
• suppresses immune system
• breakdown of bone matrix (high doses)
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40. EFFECT ON BLOOD CELLS AND IMMUNITY
• Decrease production of eoisinophils and lymphocytes
• Suppresses lymphoid tissue systemically therefore decrease in T cell & antibody
production there by decreasing immunity
• Decrease immunity could be fatal in diseases such as tuberculosis
• Decrease immunity effect of cortisol is useful during transplant operations in
reducing organ rejection.
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46. 45
II. Pharmacotherapy (for nonendocrine diseases)
Use in nonendocrine diseases is empirical and palliative, but may be life saving.
Guidelines for use of corticosteroids
• A single dose (even excessive) is not harmful
• Short courses (even high dose) are not likely to be harmful in the absence of contraindications
• Long-term use is potentially hazardous
• Initial dose depends on severity of the disease
• No abrupt withdrawal after a corticoid has been given for > 2 to 3 weeks: may precipitate adrenal
insufficiency.
• Infection, severe trauma, surgery or any stress during corticoid therapy—increase the dose.
• Use local therapy (cutaneous, inhaled, intranasal, etc) wherever possible.
48. 47
• Infective diseases
• Eye diseases
• Skin diseases
• Intestinal diseases
• Cerebral edema
• Malignancies
• Organ transplantation and skin allograft
• Septic shock
• Thyroid storm
• To test pituitary-adrenal axis function
49. 48
ADVERSE EFFECTS
1. Cushing’s habitus
2. Fragile skin, purple striae—typically on thighs & lower abdomen, easy bruising, telangiectasis, hirsutism.
Cutaneous atrophy localized to the site occurs with topical application as well.
3. Hyperglycaemia: may be glycosuria, precipitation of diabetes.
4. Muscular weakness: proximal (shoulder, arm, pelvis, thigh) muscles are primarily affected. Myopathy occurs
5. Susceptibility to infection: nonspecific for all types of pathogenic organisms.
6. Delayed healing: of wounds and surgical incisions.
7. Peptic ulceration: risk is doubled; bleeding and silent perforation of ulcers may occur
8. Osteoporosis: vertebrae & other flat spongy bones.
Calcium supplements + vit D,
Estrogen/raloxifene or androgen replacement therapy in females & males respectively.
However, bisphosphonates are the most effective drugs in this regard.
Avascular necrosis of head of femur, humerous, or knee joint
50. 49
9. Posterior subcapsular cataract: may develop after several years of use, especially in children.
10.Glaucoma: may develop in susceptible individuals after prolonged topical therapy.
11.Growth retardation: Recombinant GH given concurrently
12. Foetal abnormalities: Intrauterine growth retardation can occur after prolonged therapy, and neurological/
behavioural disturbances in the offspring are feared. Prednisolone : safer than dexa/ beta methasone, as it is
metabolized by placenta, reducing foetal exposure.
13.Psychiatric disturbances: High dose: Mild euphoria ---- manic psychosis.
Nervousness, decreased sleep & mood changes.
Depressive : after long-term use.
14. Suppression of hypothalamo-pituitary-adrenal (HPA) axis: malaise, fever, anorexia, nausea, postural
hypotension, electrolyte imbalance, weakness, pain in muscles & joints
53. Adrenal Cortex Dysfunctions
HYPOADRENALISM – Addison’s Disease
• Adrenal cortex produces inadequate amounts of hormones
• Caused by autoimmunity against cortices 80%
• Also caused by tuberculosis, drugs, cancer
•Plasma sodium decreases & may lead to circulatory collapse
• Melanin Pigmentation: uneven distribution of melanin deposition in thin skin
•eg. Mucous membranes, lips, thin skin of the nipples.
• Treatment:
• Total destruction, if untreated, could lead to death within a few days.
• Treatment – small quantities of mineralocorticoids & glucocorticoids daily 52
54. HYPERADRENALISM – Cushing’s Syndrome
• Caused by exogenous glucocorticoids & by tumours (adrenal or pituitary)
• Zona glomerulosa tumour increases aldosterone
-increased sodium, blood pressure
-80% suffer from hypertension
• Zona reticularis tumour increases cortisol
- excess protein catabolism, redistribution of fat
• Features : Buffalo torso
• Redistribution of fat from lower parts of the body to the thoracic & upper abdominal areas
• Moon Face
• Oedematous appearance of face
• Acne & hirsutism (excess growth of facial hair)
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55. WHAT WOULD THE FEEDBACK LOOP LOOK LIKE FOR
CUSHING’S SYNDROME?
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56. CARBOHYDRATE METABOLISM
“Adrenal diabetes”
• Hypersecretion of cortisol results in increase blood glucose levels, up to 2 x normal (200mg/dl)
• Prolonged over-secretion of insulin “burns out” the beta cells of the pancreas resulting in life
long diabetes mellitus
PROTEIN METABOLISM
• Decrease protein content in most parts of the body resulting in muscle weakness
• In lymphoid tissue – decrease protein synthesis results in suppression of immune system
• Lack of protein deposition in bones can result in osteoporosis
• Collagen fibers in subcutaneous tissue tear forming striae
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57. 56
• Combination of any other drug with corticosteroids in fixed dose formulation for internal use is banned.
• Metyrapone Inhibits 11-β hydroxylase in adrenal cortex and prevents synthesis of hydrocortisone so that
its blood level falls → increased ACTH release → increased synthesis, release and excretion of 11-
desoxycortisol in urine. Thus, it is used to test the responsiveness of pituitary and its ACTH producing
capacity.
• Aminoglutethimide, trilostane & high doses of the antifungal drug Ketoconazole: Inhibit steroidogenic
enzymes. Ketoconazole reduces gonadal steroid synthesis as well.
Use: Cushing’s disease when surgery / other measures are not an option.
• Glucocorticoid antagonist / Antiprogestin: Mifepristone : In Cushing’s syndrome --- suppress the
manifestations of corticosteroid excess, but blockade of feedback ACTH inhibition leads to over-
secretion of ACTH → more hydrocortisone is produced, which tends to annul the GR blocking action of
mifepristone.
Use: Only in an inoperable cases of adrenal carcinoma & in patients with ectopic ACTH secretion.
SOME IMPORTANT POINTS
59. • Produced in the Zonaglomerulosa
• Primary mineralocorticoid :Aldosterone
• Aldosterone is secreted in response to
• high extracellular potassium levels
• low extracellular sodium levels
• low fluid levels & blood volume. 58
60. ALDOSTERONE
• Steroid hormone
• Essential for life (acute)
• Responsible for regulating Na+ reabsorption in the distal tubule and the
cortical collecting duct
• Target cells are called “principal (P) cell”
- Stimulates synthesis of more Na/K-ATPase pumps
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62. REGULATION OF ALDOSTERONE RELEASE
• Direct stimulators of release
- increased extracellular K+
- decreased osmolarity
- ACTH
• Indirect stimulators of release
- decreased blood pressure
- decreased macula densa blood flow
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63. EFFECTS OF ALDOSTERONE
• Renal & circulatory effects (ECF volume regulation, sodium & potassium ECF
concentrations)
• Promotes reabsorption of sodium from the ducts of sweat & salivary glands
during excessive sweat/saliva loss.
• Enhances absorption of sodium from the intestine especially colon: absence
leads to diarrhea.
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64. ALDOSTERONE EFFECT ON METABOLISM IN 3 WAYS:
1) Increases urinary excretion of
potassium ions
2) Increases interstitial levels of
sodium ions
3) Increases water retention &
blood volume
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66. Renin-angiotensin system (RAS) or the renin-angiotensin-aldosterone system
(RAAS) : a hormone system regulating blood pressure & water (fluid) balance.
Low blood volume----- renin secretion by juxtaglomerular cells in the kidneys
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Renin stimulates production of Angiotensin I
Angiotensin I Angiotensin II constriction of blood vessels
Aldosterone secretion increased blood pressure
Reabsorption of sodium & water into the blood
67. MINERALOCORTICOID DEFICIENCY
Symptoms
• Water loss : decreased ECF volume
• Hyperkalemia
• Hyponatremia
• Mild acidosis
• Increase RBC concentration
• Low blood pressure: increased cardiac output
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Kalium is the Latin word for Potassium
Hypokalemia : low potassium levels in the blood & hyperkalemia : high potassium levels.
Natrium is the Latin word for Sodium
Hyponatremia : low levels of sodium & hypernatremia : high levels of sodium
Causes
• Hypo-aldosternism
• Angiotensin inhibitors
• Heparin therapy
• Primary adrenal insufficiency
• NSAIDs