HORMON

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HORMON
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What is hormon?

• Many organs in the body secreted biologically
  active compound called endocrine hormones, which
  are transported via blood stream to other tissues
  or organs where they exert a biological effect
• As classically defined, is a substance that is
  synthesized in one organ and transported by the
  circulatory system to act on another tissue
• Hormones can act on adjacent cells (paracrine)
• Hormones can act on the cell in which they were
  synthesized without entering the sistemic
  circulation (autocrine)

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Long-Distance Regulators

• Animal hormones are chemical signals that are
  secreted into the circulatory system and
  communicate regulatory messages within the body
• Hormones reach all parts of the body, but only
  target cells are equipped to respond
• Hormones convey information via the bloodstream
  to target cells throughout the body

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What is the importance of hormones?

• Several hormones may control one, process or one
  hormon may control several process
• Provide communication beetween cells, tissues and
  organs
• This comunication is responsible for the
  regulation of wide range of functions including
  growth, reproduction, development, homeostasis,
  and response to external stimuli. Failure in this
  comunication channels are common and lead to many
  diseases of the endocrine system

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How do hormones act?

• In order to act , hormones must interact with
  other loci on or in the target cell
• These sites are termed receptors
• A receptor is a locus to which the hormone binds
  in order to elicit its action

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RECEPTOR

• A receptor has two function
• First, it must be able to distinguish the
  hormone from all the other chemicals present in
  the circulation and bind it.
• The hormone binding sites on receptors have
  evolved to have unique configurations that are
  complementary to the hormones they bind.
• Generally, hormone-receptor interactions are
  noncovalent in nature and are reversible.

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RECEPTOR

• - Second, the receptor must able to transmit the
  information gained from the binding to trigger a
  cellular response.
• Thus, subtances that bind hormones, even
  tightly, but do not trigger subsequent responses
  are not receptors.

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Types of Hormones

• Hormon can be clasisified in several ways,
  according
• 1-Chemical composition
• Cholesterol derivates this include
  glucorticoid, mineralocorticoid, esterogen,
  progestin
• Amino acid -tyrosine
• Polypeptyde-ACTH,TRH
• Glycoprotein-TSH, FSH, LH
• 2-Solubility properties-lipophilic dan
  hidrophilic
• 3-Location of reseptor
• 4-Nature of signaling used to mediate hormonal
  action within the cell

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Clasification of hormones by mechanism of action

• Group I hormones
• Hormon that bind to intracellular receptors
• Androgens
• calcitriol
• esterogens
• glucocorticoids
• mineralocorticoids
• progestins
• retinoic acid

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Group II Hormones Hormones that bind to cell
surface receptors

• A.The second messenger is cAMP
• Calcitonin, glucagon, LH, Somatosatin,
• B.The second mesenger is cGMP
• Nitric oxide, atrial natriuretic factor
• C.The second messenger is calcium or phosphatidyl
  inositols (or both)
• Gastrin, oxitocyn, cholecistokinin, TRH,
  Acetilcholin
• D.The second messenger is a kinase or phosphatase
  cascade
• Adponectin, insulin , leptin, GH, Prolactin,
  IGF-I , IGF-II, EGF

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General features of hormon classes
Group I Group II
Types Steroid, iodothyronines,calcitriol, retinoids Polypeptides, protein, glycoproteins, cathecolamines
Solubility Lipophilic Hydrophilic
Transport protein Yes No
Plasma halflife Long ( hours to days) Short (minutes)
Receptor Intracellular Plasma membran
Mediator Receptor-hormone complex cAMP.cGMP, Ca2,metabolites complex phosphoinositols, kinase cascade
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WHERE HORMONES ARE SYNTHESIZED?

• Hormones are synthesized in discrete organs
  designed solely for spesific purpose
• Pituitary TSH, FSH, LH, GH, Prolactin, ACTH
• Some organs are disigned to perform two distinct
  but closely related function
• Ovaries produce mature oocyte and reproductive
  hormones estradiol and progesteron
• The testes produce mature spermatozoa and
  testesterone
• Hormones are also produced in specialized cells
  within other organs
• Small intestine glucagon like peptide
• Thyroid calcitonin
• Kydney angiotensin II
• The synthesis of some hormones requires the
  parenchimal cells of more than one organ
• Skin, liver, kidney calcitriol.

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Hormon are synthesized and modified for full
activity in a variety of ways

• Some hormones are synthesized in final form and
  secreted immediattely , included in this class
  are the hormon derived from cholesterol
• Others are synthesized in final form and stored
  in producing cells, example catecholamine
• The others hormone synthesized and from precursor
  molecules in the producing cell, then are
  processed and secreted upon a physiologic cue,
  examples insulin
• Converted to active forms from precurssor
  molecules in the periphery, examples T3, DHT

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Control Pathways and Feedback Loops

• The endocrine system secretes hormones that
  coordinate slower but longer-acting responses
  including reproduction, development, energy
  metabolism, growth, and behavior
• A common feature is a feedback loop connecting
  the response to the initial stimulus
• Negative feedback regulates many hormonal
  pathways involved in homeostasis

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• Signaling by any of these hormones involves three
  key events
• Reception
• Signal transduction
• Response

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SECRETORY CELL
SECRETORY CELL
Hormone molecule
Hormone molecule
VIA BLOOD
VIA BLOOD
Signal receptor
TARGET CELL
TARGET CELL
Signal transduction pathway
Signal receptor
OR
Cytoplasmic response
DNA
Signal transduction and response
mRNA
DNA
NUCLEUS
Nuclear response
Synthesis of specific proteins
NUCLEUS
Receptor in plasma membrane
Receptor in cell nucleus
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• Binding of a hormone to its receptor initiates a
  signal transduction pathway leading to responses
  in the cytoplasm or a change in gene expression
• The same hormone may have different effects on
  target cells that have
• Different receptors for the hormone
• Different signal transduction pathways
• Different proteins for carrying out the response

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Different receptors
different cell responses
Epinephrine
Epinephrine
Epinephrine
? receptor
? receptor
a receptor
Glycogen deposits
Vessel dilates
Glycogen breaks down and glucose is released from
cell
Vessel constricts
Intestinal blood vessel
Skeletal muscle blood vessel
Liver cell
Different intracellular proteins
different cell responses
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Paracrine Signaling by Local Regulators

• In paracrine signaling, nonhormonal chemical
  signals called local regulators elicit responses
  in nearby target cells
• Types of local regulators
• Neurotransmitters
• Cytokines and growth factors
• Prostaglandins help regulate aggregation of
  platelets, an early step in formation of blood
  clots

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The hypothalamus and pituitary integrate many
functions of the vertebrate endocrine system

• The hypothalamus and the pituitary gland control
  much of the endocrine system
• Tropic hormones, hormones that regulate endocrine
  organs
• Tropic hormones are secreted into the blood and
  transported to the anterior pituitary

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Hypothalamus
Neurosecretory cells of the hypothalamus
Axon
Posterior pituitary
Anterior pituitary
Oxytocin
HORMONE
ADH
Mammary glands, uterine muscles
Kidney tubules
TARGET
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Tropic Effects Only FSH, follicle-stimulating
hormone LH, luteinizing hormone TSH,
thyroid-stimulating hormone ACTH,
adrenocorticotropic hormone
Neurosecretory cells of the hypothalamus
Nontropic Effects Only Prolactin MSH,
melanocyte-stimulating hormone Endorphin
Portal vessels
Nontropic and Tropic Effects Growth hormone
Hypothalamic releasing hormones (red dots)
Endocrine cells of the anterior pituitary
Pituitary hormones (blue dots)
Endorphin
Growth hormone
MSH
Prolactin
ACTH
TSH
FSH and LH
HORMONE
Pain receptors in the brain
Bones
Liver
Melanocytes
Mammary glands
Adrenal cortex
Thyroid
Testes or ovaries
TARGET
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Posterior Pituitary Hormones

• The two hormones released from the posterior
  pituitary act directly on nonendocrine tissues
• Oxytocin induces uterine contractions and milk
  ejection
• Antidiuretic hormone (ADH) enhances water
  reabsorption in the kidneys

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Anterior Pituitary Hormones

• The anterior pituitary produces both tropic and
  nontropic hormones

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Tropic Hormones

• The four strictly tropic hormones are
• Follicle-stimulating hormone (FSH)
• Luteinizing hormone (LH)
• Thyroid-stimulating hormone (TSH)
• Adrenocorticotropic hormone (ACTH)
• Each tropic hormone acts on its target endocrine
  tissue to stimulate release of hormone(s) with
  direct metabolic or developmental effects

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Nontropic Hormones

• Nontropic hormones produced by the anterior
  pituitary
• Prolactin stimulates lactation in mammals but has
  diverse effects in different vertebrates
• MSH influences skin pigmentation in some
  vertebrates and fat metabolism in mammals
• Endorphins inhibit pain

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Growth Hormone

• Growth hormone (GH) has tropic and nontropic
  actions
• It promotes growth directly and has diverse
  metabolic effects
• It stimulates production of growth factors

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• The thyroid gland produces calcitonin, which
  functions in calcium homeostasis

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Parathyroid Hormone and Calcitonin Control of
Blood Calcium

• Two antagonistic hormones, parathyroid hormone
  (PTH) and calcitonin, play the major role in
  calcium (Ca2) homeostasis in mammals. Calcitonin
  stimulates Ca2 deposition in bones and secretion
  by kidneys, lowering blood Ca2 levels

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• Two Glands of Hormon Thyroid and parathyroid
  Located
• Produce hormone (PTH)

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Calcitonin
Thyroid gland releases calcitonin.
Reduces Ca2 uptake in kidneys
Stimulates Ca2 deposition in bones
STIMULUS Rising blood Ca2 level
Blood Ca2 level declines to set point
Homoeostasis Blood Ca2 level (about 10 mg/100
mL)
STIMULUS Falling blood Ca2 level
Blood Ca2 level rises to set point
Parathyroid gland
Stimulates Ca2 release from bones
PTH
Increases Ca2 uptake in intestines
Stimulates Ca2 uptake in kidneys
Active vitamin D
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Insulin and Glucagon Control of Blood Glucose

• The pancreas secretes insulin and glucagon,
  antagonistic hormones that help maintain glucose
  homeostasis
• Glucagon is produced by alpha cells
• Insulin is produced by beta cells

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Body cells take up more glucose.
Insulin
Beta cells of pancreas release insulin into the
blood.
Liver takes up glucose and stores it as glycogen.
STIMULUS Rising blood glucose level (for
instance, after eating a carbohydrate- rich meal)
Blood glucose level declines to set
point stimulus for insulin release diminishes.
Homeostasis Blood glucose level (about 90 mg/100
mL)
STIMULUS Dropping blood glucose level (for
instance, after skipping a meal)
Blood glucose level rises to set point stimulus
for glucagon release diminishes.
Alpha cells of pancreas release glucagon into
the blood.
Liver breaks down glycogen and releases glucose
into the blood.
Glucagon
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Target Tissues for Insulin and Glucagon

• Insulin reduces blood glucose levels by
• Promoting the cellular uptake of glucose
• Slowing glycogen breakdown in the liver
• Promoting fat storage

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• Glucagon increases blood glucose levels by
• Stimulating conversion of glycogen to glucose in
  the liver
• Stimulating breakdown of fat and protein into
  glucose

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Diabetes Mellitus

• Diabetes mellitus is perhaps the best-known
  endocrine disorder
• It is caused by a deficiency of insulin or a
  decreased response to insulin in target tissues
• It is marked by elevated blood glucose levels

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Adrenal Hormones Response to Stress

• The adrenal glands are adjacent to the kidneys
• The adrenal medulla secretes epinephrine
  (adrenaline) and norepinephrine (noradrenaline)
• They are secreted in response to stress-activated
  impulses from the nervous system
• They mediate various fight-or-flight responses

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Melatonin and Biorhythms

• The pineal gland, located in the brain, secretes
  melatonin
• Light/dark cycles control release of melatonin
• Primary functions of melatonin appear to relate
  to biological rhythms associated with
  reproduction

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Invertebrate regulatory systems also involve
endocrine and nervous system interactions

• Diverse hormones regulate homeostasis in
  invertebrates
• In insects, molting and development are
  controlled by three main hormones
• Brain hormone stimulates release of ecdysone from
  the prothoracic glands
• Ecdysone promotes molting and development of
  adult characteristics
• Juvenile hormone promotes retention of larval
  characteristics

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Hormones Released from the Anterior Pituitary or
Adenohypophysis

• Somatotrophs
• Human Growth Hormone (hGH)
• Hypothalamic control
• hGH releasing hormone
• hGH inhibiting hormone
• Target Tissues
• General body cells, particularly bone, muscle,
  cartilage, and the liver.

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Hormones Released from the Anterior Pituitary or
Adenohypophysis

• Hormone affects
• promotes the synthesis of insulin-like growth
  factors
• Controls normal growth patterns by increasing
  protein synthesis, lipolysis, ATP production, and
  carbohydrate metabolism
• In adults, it help maintain muscle and bone mass
  and promote healing and tissue repair

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Hormones Released from the Anterior Pituitary or
Adenohypophysis

• Hypo-secretion
• During childhood causes Dwarfism
• Hyper-secretion
• During childhood causes
• Gigantism (up to 8 9 ft.)
• During Adulthood causes
• Acromegaly
• Enlargement of the small bones of the hand and
  feet
• Enlargement of the cranium, nose, and lower jaw
• Tongue, liver, and kidneys become enlarged

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Hormones Released from the Anterior Pituitary or
Adenohypophysis

• Thyrotrophs
• Thyroid Stimulating Hormone (TSH)
• Hypothalamic Control
• Thyrotropin Releasing Hormone (TRH)
• Target Tissue
• Follicular cells of the Thyroid gland
• Hormone affects
• controls the production of T3 and T4

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Endocrine activity of the Thyroid Gland

• Follicular cells
• T3 and T4
• Target Tissue
• Almost all body tissues
• Hormone effects
• Increases body metabolism
• Increases gluconeogenesis
• Increases glycolysis
• Increases lipolysis
• Increased basal metabolic rate (BMR)
• Increases heart rate and force of contraction

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Endocrine activity of the Thyroid Gland

• Hypothyroidism
• endemic goiter (due to I2 deficiency)
• Myxedema bagginess under the eyes and swelling
  of the face.
• Arteriosclerosis due to increase in blood
  cholesterol
• Cretinism extreme hypothyroidism during infancy
  and childhood

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Endocrine activity of the Thyroid Gland

• Hypothyroidism
• Cretinism Physical and mental growth and
  development is greatly retarded
• Hyperthyroidism
• Toxic goiter
• Graves Disease with exophthalmos

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Hormones Released from the Anterior Pituitary or
Adenohypophysis

• Corticotrophs
• Adrenocorticotropic hormone (ACTH)
• Hypothalamic Control
• Corticotropic releasing hormone (CRH)
• Target Tissue
• Adrenal cortex, Zona Fasciculata
• Hormone affects
• control production of glucocorticoids such as
  cortisol

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Endocrine activity of the Adrenal Cortex

• Zona glomerulosa
• Mineralocorticoids such as Aldosterone
• Hormonal control
• renin-angiotensin pathway
• permissive effect of ACTH
• Target tissue
• Principle cells of the DCT and collecting duct
• Hormone affects
• increases reabsorption of Na and water

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Endocrine activity of the Adrenal Cortex

• Hyper-secretion
• Aldosteronism
• Hypokalemia, increase in extracellular fluid and
  blood volume,and hypertension, may also have
  period of muscular paralysis
• Hypo-secretion
• Addisons disease
• Mineralocorticoids deficiency, death occurs in
  four days to two weeks if untreated

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Endocrine activity of the Adrenal Cortex

• Zona Fasciculata
• Glucocorticoids such as cortisol and cortisone
• Hormone control
• ACTH
• Target tissue
• Liver and general body cells
• Hormone affects
• Stimulates gluconeogenesis by the liver
• Decreased glucose utilization by cells

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Endocrine activity of the Adrenal Cortex

• Hormone affects
• Elevated blood glucose levels
• Reduction of protein stores in all body cells
  except the liver
• increased plasma protein levels
• promote lipolysis and beta oxidation of fat
• Helps body recover from stress
• Prevention of inflammation

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Endocrine activity of the Adrenal Cortex

• Hypo-secretion
• Addisons disease - glucocorticoid deficiency
• person becomes highly susceptible to disease and
  deteriorating effects of stress
• Hyper-secretion
• Cushings Syndrome
• mobilization of fat from lower body to the
  thoracic and upper abdominal regions giving raise
  to Buffalo Torso

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Interactions of hormones in response to stress
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Endocrine activity of the Adrenal Cortex

• Zona reticularis
• Produces small amounts of androgens, mostly
  dehydroepiandosterone (DHEA), DHEA may be
  converted into estrogens
• Hormone Control
• Believed to be ACTH
• Target tissue
• General body cells

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Endocrine activity of the Adrenal Cortex

• Hyper-secretion
• Adrenogenital Syndrome
• in females causes beard growth, deeper voice,
  masculine distribution of body hair, and growth
  of the clitoris to resemble a penis.
• Picture In pre-pubertal males it causes the
  rapid develop of secondary sexual conditions

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Endocrine Activity of the Adrenal Cortex

• Hyper-secretion
• Adrenogenital Syndrome
• in females causes beard growth, deeper voice,
  masculine distribution of body hair, and growth
  of the clitoris to resemble a penis.
• Picture Virilizing adrenal hyperplasia in a
  newborn female baby, DHEA was converted to
  testosterone

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Endocrine Activity of the Adrenal Cortex

• Hyper-secretion
• Picture micropenis in a newborn baby boy.
• micropenis is a result of hypopituitarism and
  lack of production of LH and therefore
  testosterone by the cells of Leydig

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Other Thyroid Hormones

• Parafollicular cells
• Calcitonin

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Parathyroid Hormones

• Principle Cells
• PTH

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PTH and Calcitonin Interaction
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Both Pancreatic Hormones interaction