The antidiuretic hormone (ADH), also known as vasopressin, is produced in the hypothalamus and secreted by the neurohypophysis. It acts on the kidneys to increase water reabsorption in the collecting ducts. Specifically, ADH binds to vasopressin receptors on principal cells in the collecting duct, activating a G protein that stimulates adenylate cyclase to produce cAMP. cAMP activates protein kinase A, which causes aquaporin-2 water channels to insert into the cell membrane. This allows water to move from the collecting duct into the blood, increasing blood volume and pressure while decreasing plasma osmolality. ADH secretion is stimulated by low blood

1. A N T I D I U R ET I C
H O R M O N E
B Y ; O M E R A S L A N K A N

2. ANTIDIURETIC
HORMONE
• The antidiuretic hormone (ADH), also
known as Vasopressin
• Is produced in the Supraoptic nucleus
(SON) in the hypothalamus
• Is secreted by the neurohypophysis
• Is decrease blood volume, decrease
blood pressure
• Is increase plasma osmolality

3. EFFECT ON THE
KIDNEYS
• The nephron consists of
• Renal corpuscles (Glomerulus and Bowman’s capsule)
• Kidney tubules (Proximal convoluted tubule (PCT), and Distal
convoluted tubule (DCT) are located in the cortex
• The loop of Henle is located in the medulla.
• Many nephrons empty their filtrate into one collecting duct.
• The collecting duct is made of principal cells which are the
target of ADH
• On the cell membrane there are vasopressin type 2 receptors.
receptors.

4. IT ACTIVATES A G
STIMULATORY PROTEIN
• That goes to an effector enzyme on the
cell membrane –Adenylate cyclase
• >The effector enzyme has a specific
point of attachment for the Gs protein.
• >The effector enzyme becomes very
active

5. ADENYLATE
CYCLASE
• Has a specific enzyme – GTPase
• GTPase cuts the GTP and turns it into
GDP (removes a phosphate)
• >G protein is turned off
• Energy is produced and used to convert
ATP to cAMP
• >cAMP activates protein kinase A (pkA)

6. THE ACTIVATED
PKA
• Goes to the cell nucleus and stimulates specific
genes
• > They undergo transcription and translation and
produce specific proteins
• > They go to the endoplasmic reticulum, then to
the Golgi apparatus and are packed into vesicles
• > The specific proteins are called aquaporin type
2
• Aquaporin type 3 and 4 are located on the cell
membrane and are always open.

7. AQUAPORIN 2
• is phosphorylated by pkA
• > Vesicle merge with the cell membrane
• > Water located in the collective duct goes into the principal cell and
into the blood.
• When the water goes to the blood, the plasma volume rises
• > increase plasma volume → increase blood pressure
• > increase water in circulation → Decrease plasma osmolality
drops
• > Plasma becomes isotonic (about 300 milliosmoles per liter)

8. • (1) Low blood volume → low blood pressure
• > Decrease blood pressure causes the hormone Angiotensin II
to be secreted
• > Angiotensin II binds to certain receptors
• > They signal the hypothalamus to release the ADH
• (2) High plasma osmolality
• > Osmolality refers to the concentration solutes and water
inside the plasma
• > High plasma osmolality - decrease water, increase solutes
(hypertonic plasma)
• > Low plasma osmolality - increase water, decrease solutes
(hypotonic plasma)

9. REFERENCES
• Human physiology 12th edition
• Dr. Matt & Dr. Mike
• Wikipedia
• Dr. Ninja Nerd

10. THANK YOU