We are basically doing medicine business.

1. ENDOCRINOLOGY

2. ENDOCRINOLOGY
Endocrinology is the study of chemical
communication systems that provide the
means to control a huge number of physiologic
processes. Like other communication
networks, endocrine systems contain
transmitters, signals and receivers that are
called, respectively hormone producing cells,
hormones and receptors.

3. Endocrine System
• Endocrine System is the collection of glands
located throughout the body that produces the
hormones and releases them into the blood
stream, where they can produce some specific
action at their target cells or tissues.

4. Overview of the Endocrine System

5. Functions of Endocrine System
• The endocrine system broadcasts its hormonal
messages to essentially all cells by secretion into
blood and extracellular fluid. Like a radio
broadcast, it requires a receiver to get the
message - in the case of endocrine messages,
cells must bear a receptor for the hormone being
broadcast in order to respond.

6. Each Endocrine gland produces one or more
hormones, each of which is governs a particular
body function such as:
• Growth
• Repair of tissues
• Sexual Development
• Reproductive function &
• Body’s response to the Stress

7. • Many endocrine glands release hormones in
response to triggering hormone produced by the
pituitary gland.
• The activity of the pituitary gland is partly
controlled by the brain through the
hypothalamus, which produces releasing
hormone that stimulates the release of that
particular hormone from an appropriate
endocrine gland required.
• A feed back system usually regulates the blood
hormone level
(a): If the level of a particular hormone rises too
high in the blood, the pituitary gland releases
another hormone that inhibits the activity of that
specific hormone.

8. Target Cells/Tissues: Those cells or tissues that
bear special receptors for the hormones, to be
get affected by the hormonal activity are called as
target cells or tissues.

10. • Endocrine action: the hormone is distributed in
blood and binds to distant target cells.
• Paracrine action: the hormone acts locally by
diffusing from its source to target cells in the
neighborhood.
• Autocrine action: the hormone acts on the
same cell that produced it.

12. CELL A
CELL B
TRANSPORT VIA BLOODSTREAM TO DISTANT TARGET TISSUES
HORMONE
SECRETION
HORMONE
SIGNALLING
BETWEEN
“NEIGHBORING”
IDENTICAL
CELLS OF SAME
TYPE
ENDOCRINE
NEUROCRINE
AUTOCRINE
CELL A
NEURON
HORMONE
TRANSPORT VIA BLOODSTREAM TO
DISTANT PARTS OF THE BODY
CELL B
CELL
TYPE X
RESPONSE
CELL
TYPE X
CELL
TYPE X
STIMULUS1
2
4
SIGNALLING BETWEEN
“NEIGHBORING” BUT
DIFFERENT
CELLS VIA ECF
CELL
TYPE A
CELL
TYPE B
PARACRINE3

13. The Pituitary Gland
• aka hypophysis = “growing below”
• Located in sella turcica
• Connected to the hypothalamus by the
infundibulum
• Master gland of the endocrine system
• 2 parts
• Posterior pituitary = Neurohypophysis
• “Nervous part”
• Anterior pituitary = adenohypophysis
• Hypophyseal portal veins supply the
anterior pituitary from the hypothalamus

14. The Pituitary Gland

16. Posterior Pituitary Hormones
• Neurohypophysis is nervous tissue
• Cell bodies are in the hypothalamus
• Make hormones
• Axons run down the infundibulum
• Carry hormones to axon terminals
• Axon terminals are in the posterior pituitary
• Store hormones
• Produces 2 hormones
• Antidiuretic hormone (ADH)
• Target – kidneys
• Effect – reabsorption of water
• Oxytocin
• Targets – reproductive organs
• Effects – contractions of smooth muscles (labor contractions,
milk ejection; ducts deferens, prostate gland – ejaculations)

17. Anterior Pituitary Hormones
• Gonadotropins stimulate growth & development of
gonads
• Follicle stimulating hormone (FSH) stimulates
gametes
• Targets – follicle cells (females), testes
(males)
• Effects – follicle development & estrogen
secretion (females), sperm maturation (males)
• Luteinizing hormone (LH)
• Targets – follicle cells (females), interstitial
cells of testes (males)
• Effects – ovulation, formation of corpus
luteum, secretion of progesterone (females),
testosterone secretion (males)

18. Anterior Pituitary Hormones
• Thyroid stimulating hormone (TSH)
• Target – thyroid gland
• Effect – triggers the release of thyroid
hormones
• Adrenocorticotropic hormone (ACTH)
• Target – adrenal cortex
• Effect – cells that produce steroid
hormones called glucocorticoids

19. Anterior Pituitary Hormones
• Prolactin
• Target - breast
• Effect - stimulates milk production
• Growth hormone
• Target – all cells
• Effect - stimulates growth in general and the
skeletal system in particular
• Melanocyte stimulating hormone (MSH)
• Target - melanocytes
• Effect – increases melanin production and
distribution

20. Pituitary Hormones

21. The Thyroid Gland
• Location – inferior to thyroid cartilage
• Thyroid follicles
• Follicle cells make thyroglobulin (contains tyrosine) &
absorb iodine from the interstitial fluid
• Tyrosine + iodine makes thyroxine (T4) or triiodothyronine
(T3)
• Target cells – most cells
• Effect of thyroid hormones – increase energy utilization,
oxygen consumption, growth, development
• Thyroid hormone release is controlled by TSH from the
anterior pituitary
• Structure also includes C cells
• Produce calcitonin (CT)
• Targets – bone, kidneys
• Effect of calcitonin – lowers blood calcium levels

22. The Thyroid Gland

23. Control of Thyroid Hormones

24. The Parathyroid Glands
• Location – posterior surfaces of the thyroid
gland
• Principal cells (chief cells) produce
parathyroid hormone (PTH)
• Target cells – bone, kidneys, intestines
• Effect of PTH – increases blood calcium
levels

25. The Parathyroid Glands

26. The Thymus
• Location – posterior to the sternum
• Produces thymosins which enhance
lymphycyte production
• Development
• Childhood – large
• Puberty – largest
• Adulthood – decreases in size

27. The Thymus Gland

28. The Adrenal Gland
• Location – on top of the kidney
• Structure – outer cortex and inner medulla
• Medulla
• Secretes epinephrine & norepinephrine
• Target – most cells
• Effect
• Epinephrine – increase cardiac activity, blood
pressure, blood glucose; constricts blood
vessels in skin, dilates blood vessels in
skeletal & cardiac muscle
• Norepinephrine – increases cardiac activity,
constricts most blood vessels

29. The Adrenal Glands
• The adrenal cortex is composed of 3 layers
• Zona glomerulosa secretes mineralocorticoids, mostly
aldosterone
• Target – kidneys
• Effect – increases blood sodium levels, decreases
blood potassium levels
• Zona fasciculata – secretes glucocorticoids (cortisol,
corticosterone)
• Target – most cells
• Effect – conserve blood glucose, anti-inflammatory
effects
• Controlled by ACTH
• Zona reticulares – secretes androgens
• Effects are uncertain

30. The Adrenal Glands

31. • Hormones: Hormones are organic chemical
messengers synthesized in glands secreted into
blood or extracellular fluid by one cell that affect
the functioning of other cells.
• hormones usually affects only a limited number
of cells, which are called target cells. A target cell
responds to a hormone because it bears
receptors for the hormone.

32. • Two important terms are used to refer to
molecules that bind to the hormone-binding sites
of receptors:
• Agonists are molecules that bind the receptor
and induce all the post-receptor events that lead
to a biologic effect. e.g. natural hormones.
• Antagonists are molecules that bind the receptor
and block binding of the agonist, but fail to trigger
intracellular signaling events. e.g. drugs etc.

33. TYPES OF HORMONES
1. Steroid hormones: Steroid hormones are
lipids and, more specifically, derivatives of
cholesterol. e.g. Testosterone, Estrogens,
Aldosterone.
2. Peptide Hormones: Hormones that have
peptide chain and by nature they are
proteins are called as peptide or protein
Hormones. e.g. Thyroid stimulating Hormone
(TSH), Growth hormone, Insulin & Glucagon
etc.

34. 3. Amino Acid Derivatives: Hormones that are
derived from amino acids are called as amino
acid derivatives. e.g. Thyroxin and
Catecholamines.
4. Fatty Acid Derivatives: Hormones that are
derived from fatty acids are called as fatty acid
derivatives. The principal groups of hormones
of this class are Prostaglandins, Prostacyclins,
Leukotrienes and Thromboxanes.

35. CORTICOSTEROIDS
• Corticosteroids are a family of drugs that include
cortisol (hydrocortisone)—an adrenal hormone
found naturally in the body—as well as synthetic
drugs.
• Corticosteroid drugs are usually refered to the
term Steroids, because they are having steroidal
ring in their nucleus.

36. • Corticosteroid drugs are either derived from
natural source or synthetic variants of naturally
occurring corticosteroids.
• Naturally corticosteroids are produced by the
adrenal gland situated at the top of the kidneys.
• Corticosteroid Hormones are of two types:
• Glucocorticoids
• Mineralocorticoids

37. CORTICOSTEROIDS
H y d r o c o r tis o n e ( C o r tis o l)
C o r tic o s te r o n e
G lu c o c o r tic o id s
A ld o s te r o n e
M in e r a lo c o r tic o id s
C o r tic o s te r o id s
D e h y d r o e p ia n d r o s te r o n e
A n d r o s te n e d io n e
T e s to s te r o n e
A n d r o g e n s
A d r e n a l C o r te x A d r e n a l M e d u lla
A d r e n a l G la n d

38. • Glucocorticoids A group of corticosteroid
hormones that affect carbohydrate metabolism
(gluconeogenesis, liver glucagon deposition,
elevation of blood sugar levels ), inhibit
corticotrophin secretion, and posses pronounced
anti-inflammatory activity.
• Mineralocorticoids: A group of corticosteroid
hormones that regulate the balance of water and
electrolytes (ions such as sodium and potassium)
in the body.
• In addition to this Corticosteroids also reduces
the inflammation & suppresses the allergic
reactions & immune system activity.

39. Biosynthesis of Corticosteroids
A c e t a t e E x o g e n o u s S o u r c e ( 6 0 - 8 0 % )
M ix e d F u n c t io n O x id a s e s
N A D P H
O 2
C o r tic o s te r o id s
C h o le s te r o l

40. PHYSIOLOGICAL FUNCTIONS OF
CORTICOSTEROIDS
• Carbohydrate metabolism
• Protein metabolism
• Lipid metabolism
• Electrolyte and water balance
• Cardiovascular system
• Central nervous system
• Kidneys
• Skeletal muscles

41. CORTICOSTEROID DRUGS
• Corticosteroid Drugs are commonly known as
“STEROIDS.”
• Corticosteroids are either derived from the
natural source or may be the synthetic analogs of
the naturally occurring Corticosteroid Hormones.
• Corticosteroid drugs are primarily used for their
effect in dumping down the inflammation.

42. Commonly Used CORTICOSTEROID DRUGS
include:
• Hydrocortisone (Hy-Cortisone)
• Betamethasone
• Dexamethasone
• Cortisone
• Prednisolone
• Methyleprednisolone
• Triamcinolone
• Mometasone
• Fluocinolone
• Beclomethasone

43. MODE OF ACTION OF
CORTICOSTEROID DRUGS
• Corticosteroid drugs reduces inflammation by
blocking the action of chemical mediators like
prostaglandins produced in the body, that are
responsible for triggering inflammatory response.
• Corticosteroid drugs also depresses the immune
system response temporarily by reducing the
activity of certain types of white blood corpuscles
(WBC’s) i.e.; reducing the release of histamine
from basophils.
• Corticosteroid drugs often produces dramatic
improvement response by producing sense of
euphoria & sense of well being.

44. USES OF CORTICOSTEROID DRUGS
Corticosteroid drugs are used :
• To replace the deficient natural hormones when
adrenal gland is malfunctioning, e.g. Addison’s
disease.
• As a part of therapy in many inflammatory disorders
due to the excessive or inappropriate activity of
immune system like Rheumatoid Arthritis,
Glomerulonephritis, Inflammatory bowl disease etc.
• To treat & relieve asthma.
• In the treatment of some blood cancers like leukemia &
lymphatic system like lymphomas
• To prevent & treat rejection of organ transplants in
conjunction of immunosuppressive agents.

45. CORTICOSTEROIDS
ANTIINFLAMMATORY ACTION
• Prevent or suppress the development of the
manifestations of inflammation.
• Inhibit inflammatory response due to radiant,
mechanical, chemical, infectious, or immunological
origin.
• Life saving in above conditions.
• Treatment of disease that result from undesirable
immune reactions e.g. urticaria, rejection of
transplanted organs.

46. What is inflammation?
• Inflammation -
• protective response intended to eliminate the
initial cause of cell injury and the necrotic cells
and tissues arising from the injury.
• Inflammation is intimately associated with the
repair process which includes parenchymal cell
regeneration and scarring.

47. Five classic local signs of Acute
Inflammation
These were known
• Heat
• Redness
• Swelling
• Pain
• Loss of function
by the Romans
• Calor
• Rubor
• Tumor
• Dolor
• Functio laesa

48. • The major components responsible for these
local signs are
• Heat - vasodilatation
• Redness - vasodilatation
• Swelling - vascular permeability
• Pain - mediator release
• Loss of function - mediator release
Five classic local signs of Acute
Inflammation

50. Fig 2.1 Graphic of
Acute Inflammation

51. Vascular permeability
• Vasodilation, increased blood flow
• Increased intravascular hydrostatic pressure
• Transudate - ultra filtrate blood plasma (contains
little protein)
• Again, this is very transient and just gets the
process started. Think Acute Inflammation,
think EXUDATE
• Increased vascular permeability

52. Vascular permeability
• Exudate - (protein-rich with pmn’s)
• Exudate is the characteristic fluid of acute
inflammation
• Intravascular osmotic pressure decreases
• Osmotic pressure of interstitial fluid increases
• Outflow of water and ions - edema

53. Fig 2.2 Graphic
of Vascular
Changes

54. Fig
2.4

55. IMMUNOSUPPRESSIVE ACTION OF
CORTICOSTEROIDS
• Intercellular communication among leukocytes through
interference with the production or function of lymphokines
• Function of macrophages by:
• Inhibition of Macrophage Migration-Inhibition Factor
(MIF)
• Interference with the facilitating action of gamma
interferon
• Inhibition of synthesis and release of Interleukin-1 (IL-1)
Suppression of T-cells
• Interference with the activation of cytotoxic lymphocytes
by Interleukin-2 (IL-2)
• Inhibition of formation of natural killer lymphocytes
(NKL)

56. IMMUNOSUPPRESSIVE ACTION OF
CORTICOSTEROIDS
• Large doses of steroids reduce antibody production,
but unaffected by moderate doses
• Inhibition of the production and effects of interleukin-2
and blockade of the effects of MIF impair delayed
hypersensitivity reactions
• Reduce the antigen release from the grafted tissue
• Interfere with the sensitization of antibody forming cells