1. In the name of GOD Iran Kashan university of medical sciences
Faculty of medicine
department of Physiology and pharmacology
Mahdi noureddini
Assistant professor of physiology
Dr. Noureddini

2. Endocrinology and Reproduction
Kashan university of medical sciences
Faculty of medicine
department of Physiology and pharmacology
Mahdi noureddini
Assistant professor
Dr. Mahdi Noureddini

3. Introduction to Endocrinology
Pituitary Hormones and Their Control by the Hypothalamus
Thyroid Metabolic Hormones
Adrenocortical Hormones
Insulin, Glucagon, and Diabetes Mellitus
Parathyroid Hormone, Calcitonin, Calcium and Phosphate Metabolism, Vitamin D, Bone, and Teeth
Reproductive and Hormonal Functions of the Male
Female Physiology Before Pregnancy and the Female Hormones
Pregnancy and Lactation
Fetal and Neonatal Physiology
Dr. Mahdi Noureddini

4. Introduction to Endocrinology
Coordination of Body Functions by Chemical Messengers
1. Neurotransmitters
2. Endocrine hormones
3. Neuroendocrine hormones
4. Paracrine
5. Autocrines
6. Cytokines are peptides secreted by cells into the extracellular fluid and can
function as autocrines, paracrines, or endocrine hormones. Examples of
cytokines include the interleukins and other lymphokines that are secreted
by helper cells and act on other cells of the immune system . Cytokine hormones (e.g., leptin) produced by adipocytes are sometimes called adipokines.
Dr. Mahdi Noureddini

5. MODES OF HORMONE DELIVERY I:
AUTOCRINE:
Hormone released feeds-back on the cell of origin, again without entering blood circulation.
PARACRINE:
Hormone released diffuses to its target cells through immediate extracellular space.
Blood is not directly involved in the delivery.
Dr. Mahdi Noureddini

6. MODES OF HORMONE DELIVERY II:
ENDOCRINE:
Most common (classical) mode, hormones delivered to target cells by blood.
NEUROENDOCRINE:
Hormone is produced and released by a neuron, delivered to target cells by blood.
Dr. Mahdi Noureddini

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10. Chemical Structure and Synthesis of Hormones
1. Proteins and polypeptides: 2. Steroids : 3. There are no known polysaccharides or nucleic acid hormones.
Dr. Mahdi Noureddini

11. CHEMISTRY OF HORMONES
Peptide hormones: largest, most complex, and most common hormones.
Anterior(prolactin,FSH, LH,TSH) and posterior pituitary gland, the pancreas (insulin and glucagon), the parathyroid gland (parathyroid hormone), and many others(TRH-3,GH-200)
Steroid hormones: lipid soluble molecules synthesized from cholesterol. adrenocortical steroids (e.g. cortisol and aldosterone). the ovaries (estrogen and progesterone), the testes (testosterone), and the placenta (estrogen and progesterone).
Amines: small molecules derived from individual amino acids.
Derivatives of the amino acid tyrosine: thyroid (thyroxine and triiodothyronine) and the adrenal medullae (catecholamines: epinephrine and norepinephrine).
Eicosanoids: small molecules synthesized from fatty acid substrates (e.g. arachidonic acid) located within cell membranes
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18. Amine Hormone Structures and Functions
Made of 1-2 amino acids
Receptors
Surface
Intracellular
Small size, OH group
Benzine ring
Examples
Thyroxin (Tyrosine)
Epinephrine (Tyrosine)
MELATONIN(Tryptophan)
Dr. Mahdi Noureddini

19. Amine Hormone Structures and Functions
Dr. Mahdi Noureddini
Figure 7-8: Tyrosine-derived amine hormones

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21. Protein and Polypeptide Hormones: Synthesis and Release
Dr. Mahdi Noureddini
Figure 7-3: Peptide hormone synthesis, packaging, and release

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24. Lipid Hormone
Steroid Hormones
Eicosanoids
Dr. Mahdi Noureddini

25. Steroid Hormones: Structure and Action
From cholesterol, lipophilic, enter target cell,
Cytoplasmic or nuclear receptors (mostly)
Activate DNA for protein synthesis
Slower acting, longer half-life
Examples: cortisol, estrogen & testosterone
Dr. Mahdi Noureddini

26. Steroid Hormones: Structure and Action
Figure 7-6: Steroid hormones are derived from cholesterol
Dr. Mahdi Noureddini

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28. Eicosanoids
small molecules synthesized from fatty acid substrates (e.g. arachidonic acid) located within cell membranes
Dr. Mahdi Noureddini

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30. A Structural Classification of Hormones
Dr. Mahdi Noureddini
Figure 18.2

31. Hormone Secretion, Transport, and Clearance from the Blood
Onset of Hormone Secretion After a Stimulus, and Duration of Action of Different Hormones
Concentrations of Hormones in the Circulating Blood, and Hormonal Secretion Rates
Dr. Mahdi Noureddini

32. Blood levels of the hormone
STEROIDS( m/l) Epinephrine and norepinephrine(10-10m/l) peptide(10-12m/l)
Dr. Mahdi Noureddini

33. Feedback Control of Hormone Secretion
Negative Feedback Prevents Overactivity of Hormone Systems.
Surges of Hormones Can Occur with Positive Feedback.
Cyclical Variations Occur in Hormone Release.
Dr. Mahdi Noureddini

34. CONTROL OF HORMONE RELEASE: ( feedback )
The synthesis and secretion of most hormones are usually regulated by negative feedback systems.
As hormone levels rise, they stimulate target organ responses. These in turn, inhibit further hormone release.
The stimuli that induce endocrine glands to synthesize and release hormones belong to one of the following major types:
Humoral
Neural
Hormonal
Dr. Mahdi Noureddini

35. ENDOCRINE SYSTEM
Dr. Mahdi Noureddini

36. Blood levels of the hormone
Hormones ARE CONSTANTLY BE
-SYNTHESIZED
- BROKEN DOWN
The actual concentration of a circulating hormone in blood at any time reflects:
Its rate of release.
The speed of its inactivation and removal from the body.
Dr. Mahdi Noureddini

37. Clearance of Hormones from the Blood
Feedback regulation of hormones can occur at all Two factors can increase or decrease the concentration of a hormone in the blood.
the rate of hormone secretion into the blood
The second is the rate of removal of the hormone from the blood,
Metabolic clearance rate = Rate of disappearance of hormone from the plasma/Concentration of hormone in each milliliter of plasma
Dr. Mahdi Noureddini

38. Clearance of Hormones from the Blood
(1) metabolic destruction by the tissues,
(2) binding with the tissues,
(3) excretion by the liver into the bile,
(4) excretion by the kidneys into the urine.
Dr. Mahdi Noureddini

39. Transport of Hormones in the Blood
Water-soluble hormones
Steroid and thyroid hormones,
Dr. Mahdi Noureddini

40. Mechanisms of Action of Hormones
Hormone Receptors and Their Activation
Intracellular Signaling After Hormone Receptor Activation
Second Messenger Mechanisms for Mediating Intracellular Hormonal Functions
Hormones That Act Mainly on the Genetic Machinery of the Cell
Dr. Mahdi Noureddini

41. Hormone Receptors and Their Activation
1. In or on the surface of the cell membrane.
The membrane receptors are specific mostly for the protein, peptide, and catecholamine hormones.
2. In the cell cytoplasm.
The primary receptors for the different steroid hormones are found mainly in the cytoplasm.
3. In the cell nucleus.
The receptors for the thyroid hormones are found in the nucleus and are believed to be located in direct association with one or more of the chromosomes.
Dr. Mahdi Noureddini

42. The Number and Sensitivity of Hormone Receptors Are Regulated
The Number and Sensitivity of Hormone Receptors Are Regulated. (down and up -regulation )
This down-regulation of the receptors :decreases the target tissue’s responsiveness to the hormone
can occur as a result of
(1) inactivation of some of the receptor molecules,
(2) inactivation of some of the intracellular protein signaling molecules
(3) temporary sequestration of the receptor to the inside of the cell, away from the site of action of hormones that interact with cell membrane receptors
4) destruction of the receptors by lysosomes after they are internalized,
(5) decreased production of the receptors.
up-regulation of receptors and intracellular signaling proteins.
When this occurs, the target tissue becomes progressively more sensitive to the stimulating effects of the hormone.
Dr. Mahdi Noureddini

43. Intracellular Signaling After Hormone Receptor Activation
Ion Channel–Linked Receptors.
G Protein–Linked Hormone Receptors.
Enzyme-Linked Hormone Receptors.
leptin receptor
Intracellular Hormone Receptors and Activation of Genes.
( adrenal and gonadal steroid hormones, thyroid hormones, retinoid hormones,and vitamin D)
Dr. Mahdi Noureddini

44. Protein &Polypeptide and Amine Hormone Receptors
Surface receptor
Hormone binds
Transduction
Enzyme activation
Open channels
Second messenger systems
Synthesis
Dr. Mahdi Noureddini
Figure 7-5: Membrane receptors for peptide hormones

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47. Types of receptors
Dr. Mahdi Noureddini

48. Adenylyl Cyclase–cAMP The Cell Membrane Phospholipid
Second Messenger Mechanisms for Mediating Intracellular Hormonal Functions
Adenylyl Cyclase–cAMP
The Cell Membrane Phospholipid
Calcium-Calmodulin
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53. Signal transduction mechanisms of hormones
Activation of adenylate cyclase
Inhibition of adenylate cyclase
Increased phospho-inositide turnover
Tyrosine kinase activation
b-adrenergic
a2-adrenergic
a1-adgrenergic
Insulin
LH, FSH, TSH, hCG
Opioid
Angiotensin II
Growth factors (PDGF, EGF, FGF, IGF-1
Glucagon
Muscarinic cholinergic – M2
Muscarinic cholinergic – M3
Growth hormone
Vasopressin- V2
Vasopressin –V1
Prolactin
ACTH
Dr. Mahdi Noureddini

54. Hormones That Act Mainly on the Genetic Machinery of the Cell
Steroid Hormones Increase Protein Synthesis
Thyroid Hormones Increase Gene Transcription in the Cell Nucleus
Dr. Mahdi Noureddini

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56. Steroid Hormones: Structure and Action
Figure 7-7: Steroid hormone action
Dr. Mahdi Noureddini

57. Measurement of Hormone Concentrations in the Blood
Radioimmunoassay
Enzyme-Linked Immunosorbent Assay (ELISA)
Dr. Mahdi Noureddini

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