Dr Mohand Hassan Moalla 1 Adrenal gland Dr

Dr. Mohand Hassan Moalla 1

Adrenal gland Dr. Mohand Hassan Moalla 2

Adrenal gland (Suprarenal gland) Dr. Mohand Hassan Moalla 3

sympathetic nervous system adrenal medulla norepinephrine 20% adrenal cortex Dr. Mohand Hassan Moalla 4

Anatomical consideration of adrenal gland n n • • adrenal glands (right & left) are located at the superior poles of the two kidneys (suprarenal gland) adrenal gland is composed of two distinct parts the adrenal medulla the adrenal cortex Dr. Mohand Hassan Moalla 5

adrenal cortex Dr. Mohand Hassan Moalla 6

Introduction Adrenocortical Hormones (Corticosteroids) Mineralocorticoids aldosterone Androgens hormone Glucocorticoids androstenedione cortisol Dr. Mohand Hassan Moalla 7

Introduction n 1. 2. 3. The adrenal cortex secretes an entirely different group of hormones, called corticosteroids (Adrenocortical Hormones) corticosteroids are all synthesized from the steroid cholesterol Corticosteroids (Adrenocortical Hormones) : Mineralocorticoids have gained this name because they especially affect the electrolytes of the FCF Glucocorticoids have gained their name because they exhibit important effects that increase blood glucose concentration also addition effects on the metabolism of fat and protein Androgens hormone which exhibit about the same effects in the body as the male sex hormone testosterone Dr. Mohand Hassan Moalla 8

Introduction zona glomerulosa (15 %) aldosterone cortisol zona fasciculata ( 75%) medulla zona reticularis (10%) Dr. Mohand Hassan Moalla Androgen 9

Introduction The hormones of the adrenal cortex are derivatives of cholesterol aldosterone cortisol Dr. Mohand Hassan Moalla Androgen hormone 10

Cortisol hormone Dr. Mohand Hassan Moalla 11

Cortisol hormone n Chemistry of Cortisol n Control of Cortisol secretion n Mechanism of Cortisol action n Action of Cortisol n Abnormalities (excess & deficiency) Dr. Mohand Hassan Moalla 12

Chemistry of Cortisol n Cortisol (C 21) is major glucocorticoid hormone n Cortisol is synthesized from cholesterol Dr. Mohand Hassan Moalla 13

Control of cortisol secretion Dr. Mohand Hassan Moalla 14

Dr. Mohand Hassan Moalla 15

Control of cortisol secretion n n The secretion of cortisol by the zona fasciculata is regulated exclusively by the hypothalamic-pituitary axis CRH is secreted by the hypothalamus and acts on the corticotrophs of the anterior pituitary to cause secretion of ACTH acts on the cells of the adrenal cortex to stimulate the synthesis and secretion of cortisol diurnal secretory pattern. Negative feedback is exerted by cortisol in the hypothalamic-pituitary axis. Hassan Moalla Dr. Mohand 16

Mechanism of cortisol action Dr. Mohand Hassan Moalla 17

Cytoplasmic receptor cortisol transcription protein Dr. Mohand Hassan Moalla 18

Action of cortisol Dr. Mohand Hassan Moalla 19

Action of cortisol n. CHO n Hyperglycemic hormone Ø Gluconeogenesis (direct effect) Ø Premssive effect Ø facilitated effect of glucagon and catecholamine Ø anti-insulin effect Dr. Mohand Hassan Moalla 20

Action of cortisol n. Protein n Proteins catabolism Ø Muscle wasting Ø Loss of connective tissue in the bone Ø Skin (thin) q Proteins Anabolism (liver) Fat Ø Mobilization of fat from adipose tissue q Dr. Mohand Hassan Moalla 21

NE E response cortisol Blood Vessel Dr. Mohand Hassan Moalla 22

Action of cortisol n CVS Ø vascular smooth muscle becomes responsive to norepinephrine and epinephrine n Immunity system Ø Anti-inflammatory effects Ø Suppression of immune response q Renal system Ø Increases in glomerular filtration rate (GFR). q RBCS → Erythropieosis Dr. Mohand Hassan Moalla 23

Action of cortisol n Fetus Ø Surfactant (7 th intrauterine life) n Minor mineralocorticoid Dr. Mohand Hassan Moalla 24

Cortisol Minor mineralocorticoid CVS Immunity system Sensitivity Blood vessel metabolism Fetus CHO n Protein n Lipolysis surfactant n suppression Dr. Mohand Hassan Moalla Renal system ↑GFR 25 RBCs Erythropieosis

Abnormalities (excess & deficiency) Cushing's Syndrome (excess) Addison's Disease (deficiency) Dr. Mohand Hassan Moalla 26

aldosterone hormone Dr. Mohand Hassan Moalla 27

aldosteone hormone n Chemistry of aldosteone n Control of aldosteone secretion n Mechanism of aldosteone action n Action of aldosteone Dr. Mohand Hassan Moalla 28

Chemistry of aldosteone n Strong mineralocorticoid n double-bond oxygen at C 18 (keto group) n aldosterone is synthesized from cholesterol Dr. Mohand Hassan Moalla 29

Control of aldosterone secretion Dr. Mohand Hassan Moalla 30

Control of aldosterone secretion Serum K+. ACTH Dr. Mohand Hassan Moalla angiotensin II 31

Control of aldosterone secretion n The regulation of aldosterone secretion by the zona glomerulosa : 1. ACTH stimulates cholesterol desmolase, the first step in the biosynthetic pathway 2. renin- angiotensin II-aldosterone system 3. changes in serum potassium (K+) levels. Dr. Mohand Hassan Moalla 32

Ca+2 depolarization K+ K+ Second messenger K+ ↑ Activity enzymes of Aldosterone synthesis Dr. Mohand Hassan Moalla K+ channels K+ K+↑ 33

Mechanism of aldosterone action Dr. Mohand Hassan Moalla 34

Cytoplasmic receptor aldosterone transcription protein • Na reabsorption • K excretion Dr. Mohand Hassan Moalla 35

Action of aldosterone Dr. Mohand Hassan Moalla 36

Action of aldosterone n aldosterone has three actions on the late distal tubule and collecting ducts of the kidney: 1. It increases Na+ reabsorption (P cell) 2. it increases K+ secretion (P cell) 3. it increases H+ secretion. (I Cell) n P cell= principal cells (C. T) n I cell = intercalated cells (D. T) Dr. Mohand Hassan Moalla 37

Adrenal androgens Dr. Mohand Hassan Moalla 38

androgenic hormone n Chemistry of androgenic hormone n Control of androgenic hormone secretion n Mechanism of androgen hormone action n Action of androgenic hormone n Abnormalities (excess) Dr. Mohand Hassan Moalla 39

Chemistry of androgenic hormone n • • n n The androgens (C 19), represented in the adrenal cortex by dehydroepiandrosterone (DHEA) androstenedione, The androgens have a double-bond oxygen at C 17 androgens is synthesized from cholesterol (zona reticularis) cholesterol androstenedione Dr. Mohand Hassan Moalla 40

Control of androgenic hormone secretion ACTH controls adrenal androgens (DHEA) secretion 1. ACTH stimulates cholesterol desmolase, the first step in the biosynthetic pathway n Dr. Mohand Hassan Moalla 41

Mechanism of androgenic hormone action Dr. Mohand Hassan Moalla 42

Cytoplasmic receptor DHEA transcription protein Dr. Mohand Hassan Moalla 43

Action of androgenic hormone n Androgens are the hormones that exert: n masculinizing effects (minor) n Hair grows (Pubic /axilla) Dr. Mohand Hassan Moalla 44

Abnormalities (excess) ADRENAL ANDROGEN HYPERSECRETION hirsutism adult females female pseudohermaphroditism newborn females Dr. Mohand Hassan Moalla precocious pseudopuberty prepubertal males 45

adrenal medulla Dr. Mohand Hassan Moalla 46

ganglia Post-ganglionic neuron Preganglionic neuron Dr. Mohand Hassan Moalla Effector organ 47

1 : 4 norepinephrine Chromaffin cells Dr. Mohand Hassan Moalla 48

adrenal medulla n Both epinephrine and norepinephrine n which are derived from the amino acid tyrosine Cortisol norepinephrine phenylethanolamine-N-methyltransferase (PNMT) epinephrine Dr. Mohand Hassan Moalla 49

Dr. Mohand Hassan Moalla 50