The document provides information about the endocrine system. It discusses hormones, their classifications, target cell responses, and hormone receptors. It also describes the pineal gland and its hormone melatonin. The hypothalamus and pituitary gland are examined, including the hormones they regulate such as ADH, oxytocin, gonadotropins, growth hormone, and thyroid stimulating hormone. The thyroid gland and thyroid hormones are also summarized.

1. ENDOCRINE SYSTEM
By
H.Khorrami Ph.D.
http://scribd.com/khorrami4
khorrami4@yahoo.com

3. Common Definitions
 Hormones
 Definition
 Synthesis
 Storage
 Control
 Negative Feedback
 Positive feedback
 Feedforward
 Bloodstream transportation
 Signal transduction

4. Hormone classifications
 Water soluble
 Water insoluble
 Peptide &
polypeptide
 Glycoprotein
 Amines
 Steroids

5. Target Cell Responses to
Hormones
 Hormones bind with receptors to initiate the
cellular response to a chemical signal
 Target cells convert the signal into a
biochemical change inside the cell
 Via second messenger systems
 Via direct gene activation

6. Different ways of cell’s response
 Cause contraction of muscle tissue
 Secretion of cellular products
 Effecting ion exchange through channels
 Cause synthesis of new peptides and proteins
 Cause breakdown of storage molecules

7. Hormone receptors
 Receptors are complex proteins that only respond to
specific hormones
 Receptors for water-soluble hormones are found on the
plasma membrane
 Receptors for lipid-soluble hormones are found in the
cytoplasm or the nucleus
 Receptors will down-regulate and decrease sensitivity
when there is prolonged exposure to high levels of a
hormone
 Receptors have the ability to up-regulate and increase
sensitivity in response to sustained low levels of a
hormone
 Not all cells have receptors for all hormones and some
cell respond differently to different concentrations of

11. Steroid hormone on target cell

12. G-protein

15. DAG & IP3

16. Caffein & Cholera
 Caffein as PDE inhibitor : thus increase cAMP
 Cholera toxin hydrolyse Gsα subunit thus
destroy GTPase activity of the subunit so locked
into the active state

19. The synthesis, release, and degradation of
hormones are regulated

20. Steroid hormones

21. Nitric oxide as a transmitter

22. Hormone secretion controlled
by:
 Neural
 Hormonal
 Humoral
 Combination
 Negative feedback
 Positive feedback
 Feed forward

24. Epiphysis(pineal gland)

25. Pineal gland
 Pinealocytes: produce and secret melatonin
 Peptidergic neuron-like cells
 Interstitial cells
 Perivascular phagocytes
 Pineal neurons

26. melatonin
 Melatonin was discovered in 1958
 By American physician Aaron B. Lerner
 Derivative of tryptophan

27. Melatonin secretion

28. Melanopsin
 Discovered in 1998 by Ignacio Provencio
 Provencio(2000):mammals, including humans,
also produce melanopsin
 Melanopsin ganglion cells *(1-2%): light
detection

29. Light signal transmition
 Retina
 SCN of HT
 PVN
 Intermediolateral cell column
 Superior cervical ganglia
 Pineal gland

35. Melatonin receptores
 Most abundant in SCN & anterior pituitary(
pars tuberalis)
 Mel1A & Mel1B
 Block out the blue rays of light(480nm) to
avoid postpartum depression

36. Melatonin actions
 Decrease gonadotropin secretion
 Decrease motor activity
 Lower body temperature
 Induce fatigue
 Free radical scavenger
 Anti-inflammatory
 Antioxidant

39. Adenohypophysis and
Neurohypophysis

42. Hypothalamus & its nucleuses

46. ADH(Arginine-vasopressin)
 9 AA
 Gene on ch.20
 Secreted with neurophysin II
 5/6 by nucleus supraoptic
 1/6 by paraventricular nucleus
 If ECF > 290 mosmol/lit
 Half life: 15-20 min

48. ADH receptors
 V1A
 Vasoconstriction of mesangial cells
 V1B
 Stimulate ACTH secretion
 V2
 Phosphorylation of aquaporin
 Water reabsorption in kidney

49. ADH actions
 Water reabsorption
 Vasoconstriction… increase blood pressure
 Long-term memory
 Temperature regulation
 Circadian rhythm
 Aggression
 Sexual behavior

50. ADH secretion
 Ach
 Adrenalin(β)
 CCK
 Ang II
 Norepinephrin(α)
 Ethanol
Stimulators Inhibitors

54. beta

56. Oxytocin & vasopressin

57. Oxytocin
 9 AA
 Secreted with neurophysin I
 5/6 by paraventricular nucleus
 1/6 by nucleus supraoptic

58. OT secretion
 Ach
 Adrenalin(β)
 5-HT
 Estradiol
 Angiotensin II
 Hugging
 Norepinephrin(α)
 Opioids
 GABA
 DA
Stimulators Inhibitors

62. Gonadotropins

63. LH surge during sleep

64. Joke, massage,..
 Increase serotonin,
dopamine
 Decrease cortisol

66. Noradrenergic neurons (lucus
ceruleus)
 Increase GHRH secretion
 Increase GnRH secretion
 Increase TRH secretion
 Decrease OT secretion (alpha)
 Increase ADH secretion (beta)
 Increase OT secretion (beta)
 Increase CRH secretion
 Decrease GHRH secretion (beta)
 Decrease ADH secretion (alpha)

68. Dopaminergic neurons (substantia
nigra)
 Increase GHRH
 Increase GnRH secretion
 Increase OT secretion
 Decrease prolactin

70. Serotonergic neurons
 Increase GHRH secretion
 Increase CRH secretion
 Decrease TRH secretion

72. Growth hormone
 191 AA , 188+ 3
 1.5-3 ng/ml after puberty
 6 ng/ml in childhood
 Half life: 20 min/ IGF-1 hl: 20hrs
 Ca is necessary for release

73. Insulin like growth factors
s IGF-I IGF-II
Stimulated
by
Insulin PRL, hPL
Receptor Tyrosin kinase No tyrosin kinase
Secretion
by
Liver Liver
Secreted in Adult Fetus
Defect Laron dwarfism

74. Growth hormone effects
 Entrance of AA
 Beta cells
 Anabolism of proteins
 Inhibits catabolism of proteins
 Lipolysis, ketogenesis
 Hyperglycemia
 Decrease glucose demands
 Glycogenesis
 Glycogenolysis

75. Growth hormone on bone
 Proliferation
 Deposit of protein by osteocytes &
chondrocytes
 Conversion of chondrocytes to osteoblasts

76. Growth hormone functions

77. Growth hormone
 Highest level at puberty
 Decline by 14% per decade after 30
 500mg/day at 20
 25mg/day at 80
 SST may increases with age

78. Ghrelin
 Ghrelin, the most potent GH stimalant
 Ghrelin circulates in the bloodstream, secreted
primarily from the stomach, but is also
produced by neurons in the hypothalamic
arcuate nucleus Although the anterior pituitary
somatotrophs contain receptors for ghrelin,
suggesting a direct action, it is more likely that
ghrelin exerts its main effects in the
hypothalamus by triggering GHRH secretion
 Ghrelin levels fall in response to rising levels
of GH, providing evidence for a gastro-
hypophysial feedback loop

79. Growth hormone
 GHRH
 Ghrelin
 Catecholamine (β)
 Serotonin
 Dopamine
 L-arginine
 Hypoglycemia
 Stress
 ADH
 Glucagon
 Deep sleep (SWS)
 Physical training
 Fever
 Injury or trauma
 Alpha adrenergic
 Hyperglycemia
 Somatostatin
 excessive exercise
 Growth hormone
 Melatonin
stimulators inhibitors

80. GH insulin  IGF1

82. Anatomy & histology of thyroid

84. Anatomy & histology of thyroid

86. Thyroid hormones act on
metabolism
 BMR: 35- 40 Kcal/m2/hr ( women: 6-10% less)
 Hypothyroid: 25 Kcal/m2/hr
 Hyperthyroid: 60- 65 Kcal/m2/hr

87. Thyroid gland
 Colloid in 3th month
 Thyroglobulin synthesis in 29th day
 TSH, T4, TBG in 11th week(3mth)
 T3 in24th week(6 mth)

88. Thyroid hormone biosynthesis
 Iodide trapping ; Na-K ATPase dependent
 Oxidation; Iodide to Iodine
 Organification
 Coupling
 Storage as thyroglobulin
 Pinocytosis
 Proteolysis
 Deiodination
 Release

89. Effectors
 Proliferation
 Growth of gland
 Vasculature
 Iodide traping
 Hormone synthesis
 Hormone release
 Thiocyanate,
perchloric
 Thiouracil,
carbimazol
 Iodide exess( Wolf
Chaikoff effect)
 PTU
TSH inhibitors

90. Tyrosine and derivatives

94. Thyroid hormone storage
 T4 35%
 T3 5%
 MIT 25%
 DIT 24-42%

95. Thyroid hormone synthesis

96. Thyroid hormone secretions
 T4 4-11 mcg/dl
 T3 80-200 ng/dl
 MIT
 DIT
 rT3

97. Thyroid hormone carrier
proteins
 TBG(α2macroglobulin)> PA > Albumin
 80% 10-15% 5-10%
 T4 99.97% 0.03% free
 T3 99.7% 0.3% free

98. Thyroid hormone
 Plasma T4> 20 times of T3
 Activity of T3> 4 times of T4

99. Iodine
 Total body 50mg
 In thyroid 15mg
 Minimal daily requirement 70-150µg/day
 Maximum power of the pump: 120µg/day

101. Metabolism
BMR
 Normally 35-40 Kcal/m2/hr
 10% less in women
 In hyperthyroids 60-65 Kcal/m2/hr
 In hypothyroids 25 Kcal/m2/hr

103. Thyroid hormone actions
 Na-K ATPase activity
 Increase cAMP → lipolysis
 Increase size of mitochondria and enzymatic activity
 Catecholamine activity
 Increase absorption of oxygen
 Thermogenesis
 Oxydation of fats →increase FFA→ decrease cholesterol
 Increase hepatic LDL receptors
 Glycogenolysis
 Intestinal absorption of glucose
 Increase HR
 Increase PP
 Hematopoesis
 Increase turnover of hormones and drugs
 Increase need to insulin, PTH & glucocorticosteroids

104. TSH
 28 KD
 Proteolysis of Tg
 Iodide pump
 Iodination
 Coupling
 Secretion
 Proliferation of thyrocytes

105. Signs of hypo & hyperthyroidism