biochemistry

1. Hormones
UNIT XI
MISS HADISA
BIOCHEMISTRY
QADRI COLLEGE OF HEALTH SCIENCES

2. Hormones
organic substances, produced in small "amounts
by specific tissues (endocrine glands),
secreted into the blood stream, control the
metabolic and biological activities in the target
cells"

3. Chemical Messenger
Hormones may be regarded as the chemical
messengers involved in the transfer of
information form one tissue to another and
from cell to cell.

4. Hormones Help In The
Regulation Of
Metabolism
Contraction Of Cardiac & Smooth Muscle
Glandular Secretion
Some Immune Functions
Growth & Development
Reproduction
Extracellular Fluid

5. Hormones Receptors
Hormone receptors are protein molecules found
on the surface or inside cells that act as
"receiving stations" for hormones. When a
hormone binds to its specific receptor, it
initiates a series of biochemical reactions that
regulate various cellular processes and
functions.

6. Endocrine System
The endocrine system is a collection of glands
that produce and release hormones into the
bloodstream to regulate various bodily
functions and maintain homeostasis.

7. Local Hormones Circulating Hormones
Produced and act locally within a specific
tissue or organ.
Produced by specialized glands and
released into the bloodstream.
Generally have a short-range or
paracrine effect on nearby cells.
Have a systemic effect, affecting distant
cells throughout the body.
Examples include prostaglandins,
cytokines, and growth factors.
Examples include insulin, cortisol,
estrogen, and testosterone.
Released in response to local stimuli or
specific physiological conditions.
Released in response to signals from the
hypothalamus or other regulatory
systems.
Diffuse across the extracellular fluid to
reach nearby target cells.
Circulate through the bloodstream to
reach target cells throughout the body.
Action is usually rapid and short-lived.
Action can be both rapid and short-lived
or slow and long-lasting, depending on
the hormone.

11. Lipid-soluble Hormones
• Steroid Hormones:
testosterone, estrogen, and progesterone.
• Thyroid Hormones:
triiodothyronine (T3) and thyroxine (T4).
• Vitamin D Hormone:
calcitriol.
These hormones are lipid-soluble, meaning they can
easily cross cell membranes and bind to intracellular
receptors to initiate their physiological effects.

12. Water-soluble Hormones
1. amines
epinephrine
norepinephrine
melatonin
seratonin
2. peptides, proteins, and glycoproteins
insulin
growth hormone
ADH

13. 3. Eicosanoids
prostaglandins
leukotrienes

14. Action of Lipid Soluble Hormones
Lipid-soluble hormones bind to and activate
receptors within cells
The activated receptors then alter gene
expression which results in the formation of
new proteins.
The new proteins alter the cells activity and
result in the physiological responses of those
hormones.

16. Action of Water Soluble Hormones
Water-soluble hormones alter cell functions by
activating plasma membrane receptors, which
set off a cascade of events inside the cell
First messenger - the water soluble hormone
that binds to the cell membrane receptor
Second messenger - a chemical activated
inside the target cell -Cyclic AMP - a typical
second messenger

18. Pineal Gland
The pineal gland is a small endocrine gland in the brain
that produces and secretes the hormone

19. Pineal Gland
• Pineal gland regulates sleep-wake cycles through
melatonin secretion.
• It plays a role in maintaining the body's circadian
rhythm.
• Pineal gland may influence reproductive
hormone production.
• It is associated with the production of serotonin,
a neurotransmitter.
• Pineal gland has connections to spiritual and
mystical experiences.

20. Pancreas
• Endocrine and exocrine organ that regulates
blood sugar (glucose) levels.
• Produces insulin and glucagon to control
glucose metabolism.
• Located in the abdomen, behind the stomach.
• Helps in digestion by secreting digestive
enzymes.
• Plays a vital role in the development of
diabetes mellitus.

21. Pancreas
The pancreas is a glandular organ that produces
digestive enzymes and insulin.

22. Names Of Pancreatic Hormones
insulin,
glucagon,
somatostatin,
pancreatic polypeptide.

23. Hormone Target Area Function
Insulin
Liver, Muscles,
Adipose Tissue
Stimulates glucose uptake and
storage, lowers blood glucose
levels, promotes glycogen
synthesis, and inhibits
gluconeogenesis.
Glucagon Liver
Increases blood glucose levels
by stimulating glycogen
breakdown (glycogenolysis)
and promoting
gluconeogenesis.
Somatostatin
Pancreas,
Gastrointestinal
Tract
Inhibits the secretion of
various hormones, including
insulin and glucagon, and
regulates the digestive
processes.
Pancreatic
Polypeptide
Pancreas,
Gastrointestinal
Tract
Regulates pancreatic exocrine
function, inhibits gallbladder
contraction, and influences
gut motility and secretion.

24. Diabetes Mellitus
Since insulin play the crucial role in regulating
the metabolism of carbohydrates, fats and
protein, so any problem in the insulin either
insufficient production or insufficient
utilization, cause a serious chronic metabolic
problem known as diabetes mellitus

25. Hypothalamus Gland
The hypothalamus is a small region in the brain
that plays a crucial role in controlling various
bodily functions and maintaining homeostasis

26. Hormones Of Hypothalamus Gland
1-Thyrotropin-releasing hormone (TRH)
2-Corticotropin-releasing hormone (CRH)
3-Gonadotropin-releasing Hormone( GnRH)
4- Prolactin release-inhibiting hormone (PRIH)
5-Growth hormone-releasing hormone (GRH)
6-Growth hormone release-inhibiting hormone
(GRIH)

27. Hormone Target Area Function
Thyrotropin-releasing
hormone (TRH)
Anterior pituitary
gland
Stimulates the release of
thyroid-stimulating
hormone (TSH) from the
anterior pituitary gland,
which regulates the
thyroid gland's activity.
Corticotropin-
releasing hormone
(CRH)
Anterior pituitary
gland
Stimulates the release of
adrenocorticotropic
hormone (ACTH) from the
anterior pituitary gland,
which regulates the
adrenal glands and the
production of cortisol.
Gonadotropin-
releasing hormone
(GnRH)
Anterior pituitary
gland
Stimulates the release of
luteinizing hormone (LH)
and follicle-stimulating
hormone (FSH) from the
anterior pituitary gland,
which regulates the
reproductive system.

28. Hormone Target Area Function
Prolactin release-
inhibiting hormone
(PRIH)
Anterior pituitary
gland
Inhibits the release of
prolactin from the anterior
pituitary gland, helping to
regulate lactation (milk
production) in females.
Growth hormone-
releasing hormone
(GRH)
Anterior pituitary
gland
Stimulates the release of
growth hormone (GH)
from the anterior pituitary
gland, which plays a role in
growth, metabolism, and
other physiological
processes.
Growth hormone
release-inhibiting
hormone (GRIH)
Anterior pituitary
gland
Inhibits the release of
growth hormone from the
anterior pituitary gland,
helping to regulate its
secretion and maintain
growth hormone levels.

29. Pituitary Galnd
The pituitary gland is a small endocrine gland located at
the base of the brain that produces and releases
hormones that regulate various bodily functions

30. Hormones Of The Anterior
Pituitary
I. Human growth hormone (hGH)
II. Thyroid-stimulating hormone (TSH)
III. Follicle-stimulating hormone (FSH)
IV. Luteinizing hormone (LH)
V. Prolactin (PRL)
VI. Adrenocorticotrophic hormone (ACTH)
VII. Melanocyte-stimulating hormone (MSH)

31. Hormone Target Area Function
Human Growth
Hormone (hGH)
Various tissues
Promotes growth, cell
reproduction, and
regeneration
Thyroid-
Stimulating
Hormone (TSH)
Thyroid gland
Stimulates the thyroid
gland to produce
thyroid hormones
Follicle-Stimulating
Hormone (FSH)
Ovaries
(females) /
Testes (males)
Stimulates follicle
development and
estrogen production
(females) / stimulates
sperm production
(males)

32. Hormone Target Area Function
Luteinizing
Hormone (LH)
Ovaries (females)
/ Testes (males)
Triggers ovulation and
progesterone production
(females) / stimulates
testosterone production
(males)
Prolactin (PRL) Mammary glands
Stimulates milk
production in females and
has various other
functions
Adrenocorticotrop
hic Hormone
(ACTH)
Adrenal glands
Stimulates the adrenal
glands to produce cortisol
and other stress-related
hormones
Melanocyte-
Stimulating
Hormone (MSH)
Skin, hair follicles
Regulates skin
pigmentation and
melanin production

33. Thyroid gland
The thyroid gland is a small, butterfly-shaped organ in
the neck that produces hormones regulating
metabolism and controlling various bodily functions.

34. Thyroid Hormones
Thyroid hormones are synthesized from iodine
and tyrosine within a large glycoprotein
molecule called thyroglobulin (TGB)
Thyroxine (T4)
Triiodothyronine (T3)
Calcitonin (CT)

35. Hormone Target Area Function
Thyroxine (T4)
Throughout the
body
Acts as a precursor
hormone, converted to
T3, which regulates
metabolism and energy
production. It influences
growth, development,
and various physiological
processes.
Triiodothyronine
(T3)
Throughout the
body
The biologically active
form of thyroid hormone.
It regulates metabolism,
energy production, and
plays a crucial role in
growth, development,
and maintaining overall
physiological balance. It
influences cellular
metabolism and affects
multiple organ systems.

36. Hormone Target Area Function
Calcitonin (CT)
Bone and
Kidneys
Regulates calcium
metabolism by
inhibiting bone
breakdown
(resorption) and
enhancing calcium
excretion by the
kidneys. It helps
maintain calcium
homeostasis by
reducing blood
calcium levels and
promoting bone
health. It also has a
minor role in
regulating blood
calcium levels.

37. T3 & T4 functions
• Increase basal metabolic rate
• Stimulate synthesis of Na+/K+ ATPase
• Increase body temperature (calorigenic effect)
• Stimulate protein synthesis
• Increase the use of glucose and fatty acids for
ATP production

38. T3 & T4
• Stimulate lipolysis
• Enhance some actions of catecholamines
• Regulate development and growth of nervous
tissue and bones

39. Calcitonin Functions
It is responsible for building of bone &
stops resorption of bone (lowers
blood levels of Calcium)

41. Parathyroid Glands
The parathyroid glands are embedded on the posterior
surfaces of the lateral lobes of the thyroid

42. Hormones Of Parathyroid Gland
• parathyroid hormone (PTH)

43. Function Description
Calcium Regulation
PTH plays a crucial role in maintaining
calcium homeostasis in the body. It
increases blood calcium levels by
stimulating the release of calcium from
bones (bone resorption) and enhancing
the reabsorption of calcium in the
kidneys, reducing calcium excretion. It
also promotes the activation of vitamin
D, which aids in the absorption of calcium
from the intestines.
Phosphate Regulation
PTH decreases phosphate levels in the
blood by promoting its excretion through
the kidneys, thus helping to maintain
phosphate balance. This is achieved by
inhibiting phosphate reabsorption in the
kidneys and reducing the production of
active vitamin D, which decreases
phosphate absorption from the
intestines.

44. Function Description
Activation of Vitamin D
PTH stimulates the
activation of vitamin D in
the kidneys. The active
form of vitamin D, called
calcitriol, plays a vital role
in calcium absorption from
the intestines, which
contributes to the
maintenance of calcium
homeostasis.

45. Function Description
Bone Remodeling and
Calcium Mobilization
PTH acts on the bones
to stimulate
osteoclasts, cells
responsible for
breaking down bone
tissue, leading to bone
resorption. This process
releases calcium into
the bloodstream,
raising blood calcium
levels when needed.

46. Function Description
Regulation of
Parathyroid Gland
Function (Feedback)
PTH helps regulate its own
production through a negative
feedback loop. When blood
calcium levels are too high, PTH
secretion decreases, reducing
the release of calcium from
bone and enhancing calcium
excretion. Conversely, when
blood calcium levels are low,
PTH secretion increases,
promoting the release of
calcium from bone and calcium
reabsorption in the kidneys.

47. Parathyroid hormone (PTH) regulates the
homeostasis of calcium and phosphate
• increase blood calcium level
• decrease blood phosphate level

49. Adrenal Glands
• The adrenal glands are located superior to the
kidneys • Consists of an outer cortex and an
inner medulla

51. Adrenal Gland Cross Sections

52. Adrenal Gland
• Cortex produces 3 different types of
hormones from 3 zones of cortex
• Medulla produces epinephrine &
norepinephrine

53. The Zona Glomerulosa
(Outer Zone)
• secretes mineralocorticoids (aldosterone)
• increase reabsorption of Na+ with Cl- ,
bicarbonate and H2O • It promotes excretion
of K+ and H+

54. The zona fasciculata
(middle zone)
• secretes Glucocorticoids (cortisol)
• increase rate of protein catabolism & lipolysis
• conversion of amino acids to glucose
• provide resistance to stress by making nutrients
available for ATP production
• raise blood pressure by vasoconstriction
• anti-inflammatory Adrenal Glands The zona
reticularis (inner zone)
• secretes Androgens
• insignificant in males
• in females is converted to estrogen in
postmenopausal Adren

55. The zona reticularis
(inner zone)
• secretes Androgens
• insignificant in males
• in females is converted to estrogen in
postmenopausal