Adrenal hormone

In mammals, the adrenal glands (also known as suprarenal glands) are endocrine glands that sit at the top of the kidneys. They are chiefly responsible for releasing hormones in response to stress through the synthesis of corticosteroids such as cortisol and catecholamines such as adrenaline (epinephrine) and noradrenaline. They also produce androgens in their innermost cortical layer. The adrenal glands affect kidney function through the secretion of aldosterone, and recent data (1998) suggest that adrenocortical cells under pathological as well as under physiological conditions show neuroendocrine properties; within normal adrenal glands, this neuroendocrine differentiation seems to be restricted to cells of the zona glomerulosa and might be important for an autocrine regulation of adrenocortical function.

1. Suprarenal Glands
•Divided into two
parts; each with
separate functions
•Suprarenal Cortex
•Suprarenal Medulla
ADRENAL GLAND HORMONES
The Adrenal Gland
The adrenal system
vitally important for
the survival of stress
Preparation for
flight or fight

2. The Adrenal Glands
•Adrenal medulla
•Adrenal cortex
Three specific zones and
each produces a
specific class of
steroid hormone
Zonaglomerulosa–
mineralocorticoids
(Aldosterone)
Zonafasciculata–
glucocorticoids
( Cortisole)
Zonareticularis-
androgens

3. Steroid biosynthesis: 3 main pathways
“corticoid”= ..from the cortex
“minerals”= Na
+
, K
+
,..
“gluco..” = increases sugar“andros” = male
“gen..”=generate
Mineralocorticoid
Pathway
Glucocorticoid
Pathway
Androgen Pathway
Steroid biosynthesis:
The 3 main pathways.

4. Biosynthetic pathway
of Adrenal cortex
hormones:

5. Mineralocorticoids
•Aldosterone exerts the 90% of the mineralocorticoid activity. Cortisol also have mineralocorticoid activity, but
only 1/400
th
that of aldosterone.
•Aldosterone increases renal tubular (principal cells) reabsorption of sodium & secretion of potassium
•Aldosterone stimulates sodium & potassium transport in sweat glands, salivary glands, & intestinal epithelial cells
Action
s of
aldost
erone
Regulation of
aldosterone secretion

6. Renin-Angiotension-Aldosterone System Mode of Action of Aldosterone
Associated Clinical Conditions
Hyperaldosteronism:
The overproduction of aldosterone by the adrenal glands
Leads to arterial hypertension(high blood pressure) associated with hypokalemia, usually a
diagnostic clue.
Conn’s syndrome is primary hyperaldosteronism caused by an aldosterone-producing adenoma.
Hypoaldosteronism:
This condition may result in hyperkalemia.
It can also cause urinary sodium wasting, leading to volume depletion and hypotension.

7. Hormones of the Adrenal Cortex
(Glucocorticoids)
Glucocorticoids (including cortisone and cortisol)
Produced in the middle layer of the adrenal cortex
Promote normal cell metabolism
Help resist long-term stressors
Released in response to increased blood levels of ACTH
Effect of cortisol on protein metabolism
•Reduction of protein storage in all cells
except those of liver –↑ protein
catabolism & ↓ protein synthesis
•Cortisol increases liver & plasma proteins
•Mobilizes aminoacidsfrom non hepatic
cells, thus increase blood amino acid
level.
•↑ amino acid transport to liver cells & ↓
transport of amino acids into other cells
Functions of glucocorticoids REGULATION OF CORTISOL SECRETION

8. Hormones of the Adrenal Cortex
Sex hormones
Produced in the inner layer of the adrenal cortex
Androgens (male) and some estrogen (female)
stimulates or controls the development and maintenance of male characteristics invertebrates
by binding to androgen receptors.
Androgens
Different class of Androgens
 Dihydroepiandrosterone
(DHEA)
 Androstenediol
 Androstenedione
 Dyhydrotestosterone
Functions of Androgen Hormones
Testes formation
Androgens regulates certain Y chromosome genes, particularly
SRY, control development of the male phenotype, including
conversion of the early bipotentialgonad into testes.
Androgen effects:
Acts as paracrine hormone required by the Sertolicells in order to
support sperm production
During puberty, they stimulate the germ cells to differentiate into
sperm.
Spermatogenesis
Inhibition of fat deposition
Increase muscle mass

9. Hormones of the Adrenal Medulla
Produces two similar hormones
(catecholamines)
Epinephrine
Norepinephrine
These hormones prepare the body to
deal with short-term stress
Biosynthesis of catecholamines
A catecholamine(CA) is has a
catechol (benzene with two hydroxyl
side groups) and a side-chain amine.
Theyhaveahalf-lifeofafewminuteswhen
circulatingintheblood.Theycanbedegraded
eitherbymethylationbycatechol-O-
methyltransferases(COMT)orbydeaminationby
monoamineoxidases(MAO).
Features of Catecholamines
Twocatecholamines,norepinephrineand
dopamine,actasneuromodulatorintheCNSand
ashormonesinthebloodcirculation.
Highcatecholaminelevelsinbloodareassociated
withstress,whichcanbeinducedfrom
psychologicalreactionsorenvironmental
stressorssuchaselevatedsoundlevels,
intenselight,orlowbloodsugarlevel.

10. Effects of Catecholamine
Catecholaminescause general physiological changes that prepare the body for physical activity
(fight-or-flight).
Some typical effects are increases in heart rate, blood pressure, blood glucose levels, and a
general reaction of the sympathetic nervous system.
Action of Epinephrine on a Liver Cell
1. Epinephrine is lipophobicand needs to bind to
specific receptor proteins on cell surface.
2. Acting through intermediary G proteins the hormone
bound receptor activates the enzyme adenenylylcyclase
which converts ATP to cAMP
3. Cyclic AMP performs as a 2ndary messenger and
activates protein kinase-A an enzyme that was previously
inactive
4. Protein kinase–A phosphorylates and activates the
enzyme phosphorylasewhich catalysesthe hydrolysis of
glycogen into glucose.

11. IP
3/CA
++
Second-Messenger System
1. The hormone epinephrine binds to specific receptor proteins
on the cell surface.
2. Acting through G-proteins, the hormone-bound receptor
activates the enzyme phospholipase C, which converts
membrane phospholipids into inositol triphosphate (IP
3)
3. IP
3 diffuses through the cytoplasm and binds to receptors on
the endoplasmic reticulum
4. The binding of IP
3to the receptor stimulates the endoplasmic
reticulum to release Ca++ into the cytoplasm
5. Some of the released Ca++ binds to the receptor protein
called calmodulin
6. The Ca++/Calmodulincomplex activates other intracellular
proteins –producing the horomoneeffects
Disorders of the Adrenal Gland
1. Hypoaldosteronism
loss of water/Na+
Addison’s disease –low aldosterone & cortisol
2. Hyperaldosteronism
3. Cushing’s syndrome
Hyper secretion of cortisol, androgens, aldosterone

12. Cushing’s syndrome
Cushing'ssyndromeassociatedwithprolonged
exposuretoinappropriatelyhighlevelsofthe
hormonecortisol.Thiscanbecausedbytaking
glucocorticoiddrugs,ordiseasesthatresultin
excesscortisol,ACTH,orCRHlevels.
Cause:
MostcommoncauseofCushing'ssyndromeis
exogenousadministrationofglucocorticoids
prescribedbyahealthcarepractitionertotreat
otherdiseases.
Effectofsteroidtreatmentofavarietyof
disorderssuchasasthmaandrheumatoid
arthritis,orinimmunosuppressionafteranorgan
transplant.
Signs and symptoms
Rapid weight gain, particularly of the trunk and
face with sparing of the limbs(central obesity).
Growth of fat pads along the collar bone and on
the back of the neck (buffalo hump) and a round
face often referred to as a “moon face.”
Thinning of the skin (which causes easy
bruising and dryness, particularly the hands)
Hyperhydrosis(excess sweating),
Telangiectasia(dilation of capillaries),