endocrinology

2. ENDOCRINOLOGY

3.  Introduction
 Hormones
-chemistry of hormones
-hormone receptors
-mechanism of action
 Pituitary gland
 Thyroid gland
 Endocrine functions of Pancreas
 Adrenal cortex
 Adrenal medulla
 Endocrine functions of other organs
 Local hormones
CONTENTS

4. The various physiological activities in our body are controlled by
some chemical substances called chemical messengers or
Chemical mediators.
Chemical messengers
Secreted by Endocrine glands, nerve endings, cells of other
tissues carry the message (signal) from the controlling cells
(signaling cells) to the target cells.
Introduction

5. Chemical messengers
Classical hormones local hormones
Recent classification of these messengers
-Endocrine messengers
-Neurocrine messengers
-Paracrine messengers
-Autocrine messengers

6. Endocrine glands

7.  Is a chemical substance that is secreted into internal body
fluids by one cell or a group of cells and has a physiological
control effect on other cells of the body.
Chemistry of hormones
- Hormones are classified depending on the chemical nature
Steroid hormones
Protein hormones
Derivatives of the amino acid- tyrosine
Hormones

8. Hormone receptors
 The receptors of the hormones are
large proteins present in the target
cells.
 Each receptor is highly specific for
one single hormone
Situation of hormone receptors
-Cell membrane
-Cytoplasm
-Nucleus

9. Regulation of hormone receptors
-Up regulation
-Down regulation
Mechanism of hormonal action
1. By altering the permeability of cell membrane
2. By altering the intracellular enzyme
3. By activating the gene

10. The neurotrasmitter substances in a synapse or neuromuscular
junction act by changing the permeability of postsynaptic
membrane.
example: NMJ
1. By altering the permeability of cell membrane

11.  Protein hormones and catecholamines
 The hormone, which acts on the target cell, is called first
messenger
 HR-complex activates the enzymes of the cell and causes the
formation of another substance called second messenger or
intracellular hormonal mediator.
- Cyclic AMP
- Calcium Ions and Calmoduline
- Inositol triphosphate (IP3)
- Diacylglycerol (DAG)
- Cyclic Guanosine Monophosphate (cGMP)
2. By Activating the Intracellular enzymes

13.  Thyroid and steroid hormones
3. By Activating on genes

14.  Also known as HYPOPHYSIS
PITUITARY GLAND

16. Regulation of secretion

17. HYPOTHALAMOHYPOPHYSEALPORTALSYSTEM

18. Releasing and Inhibitory hormones

19. Growth hormone
 Secreted by the acidophils, known as somtotropes
 Is a protein, having a single chain polypeptide with
191 amino acids, 21,500mol wt
 Responsible for general growth of the body
Anterior pituitary hormones

21. Effects of GH
Effects of GH on protein metabolism
 Increases the amino acid transport through the cell
membrane
 Increases the RNA translation
 Increases transcription of DNA to RNA
 Decreases catabolism of protein

22. Effects of GH on fat metabolism
Excess GH
Fat mobilization from adipose tissues
Large quantities of acetoacetic acid formed by liver and released
into body fluids
(Ketosis)
Resulting in fatty liver

23. Effects of GH on carbohydrate metabolism
GH causes conservation of glucose, by following mechanisms
-Decrease in the peripheral utilization of glucose for the
production of energy
-Increase in the deposition of glycogen in the cells
- Diabetogenic effect of GH

24. Effect of GH on bones
 GH increases the growth of the skeleton
 Increase in the protein deposits by chondriocytes and
osteogenic cells
 And it causes conversion of chondriocytes into osteogenic
cells

25. Mode of action GH on Bones and Metabolism

26. Thyroid Stimulating Hormone (TSH)
 Necessary for the growth and secretory actions of thyroid
gland
Adrenocorticotropic Hormone (ACTH)
 Necessary for the structural integrity and the secretory activity
of adrenal cortex

27. Follicle Stimulating Hormone
 In males it accelerates spermeogenesis in combination with
testosterone
 In females it is responsible for development of graafian follicle
from primordial follicle
 Secretion of estrogen

28. Luteinizing Hormone
 In males it is known as ICSH
 In females along with FSH it causes maturation of vesicular
follicle
 Ovulation
 Formation and secretory functions of corpus luteum

29. Prolactin
 Secretion of milk
β-Lipotropin
 Mobilizes fat from adipose tissue and promotes lipolysis

30. Anti Diuretic Hormone (vasopressin)
 Secreted by supra optic nucleus, and paraventricular nucleus
 Is a polypeptide with 9 amino acids
Actions
 Reabsorption of water from DCT and Collecting duct
 In large amounts, it causes constriction of arteries
Posterior pituitary hormones

31. Oxytocin
 Secreted by paraventricular nucleus and in small quantity by
supraoptic nucleus
 Is a ploypeptide with 9 aminoacids
Actions
 Causes contraction of myoepithelial cells- ejection of milk
 On pregnant uterus causes contraction and helps in the
expulsion of fetus
 Causes contraction in non pregnant uterus and facilitate the
transport of sperms in female genital tract

32. Anterior pituitary Posterior pituitary
DISORDERS OF PITUITARY GLAND
Hypersecretion
Gigantism
Acromegaly
Acromegalic
gigantism
Cushing’s disease
Hyposecretion
dwarfism
Acromicria
Simmond’s disease
or
Pituitary cachexia
Hypersecretion
Syndrome of
inappropriate
hypersecretion of
ADH (SIADH)
Hyposecretion
Diabetes insipidus

33. Pre-puberty: Gigantism
 An overproduction of growth hormone before epiphyseal
closure.
 These children grow to be over 7 ft (213 cm) in height and
have disproportionately long limbs
bone growth, > 7 ft. tall

35. Post-puberty: Acromegaly
Some tissues still grow even after puberty :
cartilage in nose, hands, feet, ridges of eyebrow,
chin, tongue
Metabolic effects:
 constant increase in blood sugar
 increased insulin  type 2 diabetes.
 Increase muscle in tunica media  narrowing of arteries,
heart attack

36. Excess growth hormone produced after puberty has little effect on
the growth of the skeleton, but it results in a disease affecting
terminal skeletal structures known as acromegaly

38. Dwarfism
 Deficiency of GH in immature
individual. A deficiency of growth hormone secretion before
puberty results in pituitary dwarfism.
 Pituitary dwarfs, who can be as little as 3 to 4 ft (91–122 cm) tall,
are generally well proportioned except for the head, which may be
relatively large when compared to the body.

39.  Unlike cretins, whose dwarfism is caused by a deficiency of
thyroxine, pituitary dwarfs are not mentally retarded;
 They are often sexually immature.
 They can be treated by injections of synthetic growth hormone,
somatropin, which are produced by genetically engineered
bacteria.

40.  Eruption timing and the shedding is delayed
 Clinical crowns appear smaller than normal
 The dental arch is smaller than normal so crowding
 There is no shortening in length of anatomic crown as expected
though the roots may be smaller
 Dwarfism due to deficiency of somatomedin C known as
Lorain dwarfism

41.  Recombinant human GH (RnGH)
 First used to treat GHD
 Supply of RnGH has made it possible to supply GH for
general shortness
 Metabolic side effects:
- Acceleration of puberty
- Pancreatitis
- Intracranial hypertension
- May ↑ risk of leukemia and stroke

42. Acromicria
 Deficiency of GH in adults
 Due to atrophy of acidophilic cells, tumor of chromophobes
and panhypopituitarism
 Atrophy or thinning of extremities
 Persons become lethargic and obese
 Loss of sexual functions

43. Simmond’s disease (pituitary cachexia)
 Occurs mostly in panhypopituitarism
 Due to atrophy or degeneration of anterior pituitary
 Rapidly developing senile decay
 Loss of hair and tooth
 Skin of face becomes dry and wrinkled

44. Syndrome of inappropriate Hypersecretion of ADH
(SIADH)
 Excessive secretion of ADH
 The cells during cerebral tumors, lung tumors and lung cancers
secrete ADH
 Sodium concentration in ECF reduced to 110 mEq/L.
(Normal-142mEq/L)
 When it falls below, patient may die because of convulsions
and coma

45.  Thyroid is an endocrine gland situated at the root of the neck
on either side of trachea.
THYROID GLAND

46.  Composed of large number of follicles
 Follicular cavity is filled with a colloidal substance known as
thyroglobulin from which secretes T3 and T4
 Between the follicles, the parafollicular cells are present,
which secretes calcitonin
Histology

47. Thyroid hormones
 T4- tetraiodothyronine
(thyroxine)
 T3- triiodothyronine is more potent
 Calcitonin

48. Regulation of
secretion

49. Effect on basal metabolic rate
-It increases the metabolic rate as much as 60%-100% above
normal in all tissues except brain, retina, spleen, testes and lungs
-T3 stimulates increase in Oxygen uptake by all tissues
( metabolism of all tissues is increased)
Functions of thyroid hormones

50. Effect on protein metabolism
The protein synthesis is accelerated by the following ways:
-increasing the Translation of RNA
-increasing the Transcription of DNA to RNA
-increasing the activity of Mitochondria
-increasing the activity of cellular enzymes

51. Effect on carbohydrate metabolism
 absorption of glucose from GIT
 uptake through cell membrane
 glycogenolysis, gluconeogenesis
Effect on fat metabolism
 Mobilization of fat from adipose tissues and fat depots.
 Increases deposition of fat in liver, decreases plasma
cholesterol level

52.  Decrease in vitamin levels due to their utilization during
formation of enzymes
 Increase in body temperature due to increased metabolic
processes and BMR
 Is important hormone to promote growth and development of
brain during fetal and few years of postnatal life
 Effects on CVS- HR
Force of contraction
BP

53. Effect on respiration
 Increases rate and force of respiration
Effect on GIT
 Increases appetite and food intake
 Increases secretions and movements
Effect on skeletal muscle
 With slight increase, muscle work with more vigor
Excessive secretion causes thyrotoxic myopathy

54. Effect on sleep
 Hypo secretion causes excessive sleep (somnolence)
Effect on sexual function
 Hyposecretion causes complete loss of libido
 Hypersecretion causes impotence

55. Disorders of thyroid hormones
1. Hyperthyroidism
Causes:- Grave’s Disease (commonest cause)
- Multinodular Goiter
- Thyroiditis and Others

57. Dental considerations
 Patients with untreated hyperthyroidism can be difficult to
deal with a result of heightened anxiety and irritability.
 The sympathetic overactivity may lead to fainting.
 Local anesthesia is the main means of pain control.
 Conscious sedation is frequently desirable to control
excessive anxiety. Benzodiazepens may potentiate
antithyroid drugs, and therefore nitrous oxide, which is
more rapidly controllable is probably safer.
 Povidone iodine and similar compounds are avoided

58.  Carbimazole occasionally causes agranulocytosis, which may
cause oral or oropharyngeal ulcerations.
 Otherwise treated thyrotoxic patient presents no special
problems in dental treatment.
 After treatment of hyperthyroidism the patients are at risk for
developing hypothyroidism, which may pass unrecognized.

59. 2. Hypothyroidism
I. Primary Hypothyroidism
Secondary Hypothyroidism
II Cretinism
Myxedema.
Cretinism
 Signs like sluggish movement and croaking sound while
crying.
 Retarded mental, physical and sexual growth
 Because of large tongue, guttural breathing may present which
sometimes choke the baby

60. Myxedema
-Swelling of the face
-Bagginess under the eyes
-Non pitting type of edema due to accumulation of proteins with
hyaluronic acid and chondroitin sulfate
-Other symptoms of hypothyroidism-

62. Dental considerations :
 The main danger is of precipitating myxoedema coma
by use of sedatives (including diazepam or midazolam), opioid
analgesics or tranquilizers.
Therefore these should be avoided or given in low dose.
 Local anesthesia is satisfactory for pain control.
 Conscious sedation can be carried out with nitrous oxide and oxygen.

63.  General anesthesia may be complicated because of possible
ischemic heart disease and the danger of coma.
 GA must be delayed until thyroxine has been started.

64.  Endocrine function of pancreas is performed by the islets of
Langerhans
 4 types of cells of islets of langerhans
- A (alpha) GLUCAGON
- B (beta) INSULIN
- D (delta) SOMATOSTATIN
- F (PP) PANCREATIC POLYPEPTIDE
PANCREAS

65.  Insulin is secreted by β- cells of islets of langerhans
 Is a polypeptide with mol wt 5808, has two amino acid chains
linked by disulfide bridges, alpha chain contains 21 and beta
chain contains 30 amino acids.
Insulin

66. Effect on carbohydrate metabolism
High carbohydrate diet
Insulin secretion
Increased permeability of cell membrane
Transport of glucose from blood into cell
 Promotes conversion of glucose to glycogen and stored in
muscle and liver
 Inhibits glycogenolysis, gluconeogenesis
Actions

67. Effect on protein metabolism
 Insulin accelerates synthesis and storage of proteins
Effect on fat metabolism
 Insulin activates the enzymes which converts glucose into fatty
acid and triglycerides
 Promotes the storage of fat in adipose tissue
Effect on growth
 Anabolism of protein -> promotes growth

68.  Secreted by α-ells of islets of langerhans
 It is a polypeptide contains 29 amino acids, mol wt 3485.
Actions of glucagon
 Increases glycogenolysis, gluconeogenesis
 Shows lipolytic and ketogenic actions
 Secretion of bile Secretion of gastric juice
Glucagon

69.  Secreted by Hypothalamus, δ-cells of islets of langerhans, δ-
cells in stomach, small intestine
 Is a polypeptide, 14(pancreas) and 28(intestine) amino acids
 Inhibits- glucagon, insulin, GH
 Decreases the motility of stomach, duodenum, gallbladder
 Increased secretion seen with increase in glucose, amino acids,
cholecystokinin
Somatostatin

70.  Secreted by Fcells or PPcells
 Polypeptide with 36 amino acids
 Increase secretion of glucagon
 Increase secretion stimulated by presence of chyme containing
more proteins
Pancreatic polypeptide

71. Type-1 (IDDM)
 Due to deficiency of insulin
 Not associated with obesity but associated with acidosis or
ketosis
 Occurs before 40 years- juvenile diabetes
 Causes degeneration, destruction by viral infection, congenital
disorder, auto immune disease of beta cells
Diabetes mellitus

72. Type-2 (NIDDM)
 Occurs after 40 years- maturity onset diabetes
 Associated with obesity
 Causes- absence or reduced number of insulin receptors
 Endocrine disorders like gigantism, acromegaly and cushing’s
syndrome- secondary diabetes

73.  Loss of glucose in urine
 Osmotic diuresis
 Polyuria, polydipsia, polyphagia
 Asthenia(loss of strength)
 Acidosis, circulatory shock, coma
 Chronic diabetes- diabetic retinopathy- diabetic nephropathy-
diabetic neuropathy
Signs and symptoms

74.  Excessive secretion of insulin
 Occurs due to tumor of beta cells
 Signs and symptoms- hypoglycemia, neuroglycopenic
symptoms like clonic convulsions and unconsciousness, coma
Hyperinsulinism

75. Good
morning

76.  There are two endocrine organs
in the adrenal gland, one
surrounding the other
 Situated on the upper pole of
each kidney (Suprarenal glands)
 Each gland weighs about 4 gms
Adrenal glands

77. Histology
Is formed by three layers
of structures

78.  Hormones
- Mineralocorticoids (Life Saving Hormone)
- Glucocorticoids (Life Protecting Hormone)
- Sex hormones
 Are steroid in nature and synthesized mainly from cholesterol
 Mineralocorticoids binds to plasma protein- globulins,
glucocorticoids combine with plasma protein glucocorticoid-
binding globulin or transcortin
Adrenal cortex

79. Mineralocorticoids
- Aldosterone
- 11-Deoxycorticosterone
 These are C21 steroids
 90% of mineralocorticoid activity is provided by aldosterone

80. Functions of Mineralocorticoids
Mineralocorticoids
K+ in ECF
Na+ and Cl-
ECF volume & Blood volume
Cardiac Dysfunction Shock Death

81. On sodium ions
 Acts on DCT and collecting duct and increase the reabsorption
of sodium
On extra cellular fluid volume
 Along with sodium water also reabsorbed- increase in ECF
volume
On blood pressure
 Increase in ECF causes increase in BP

82. Aldosterone escape or Escape phenomenon
Aldosterone
Reabsorption of Na+ and Water
ECF, Blood Pressure
ANP (Atrial Natriuretic Peptide)
Na+ & Water excretion through urine

83.  70.3
Regulation Of Secretion

84. Glucocorticoids
- Cortisol
- Corticosterone
- Cortisone
 Secreted mainly by zona fasciculata, small quantity by zona
reticularis
 C21 Steroids having 21 carbon atoms
 Life protecting hormone as it helps to withstand the stress and
trauma in life

85. Functions of glucocorticoids
On carbohydrate metabolism
 Increases blood sugar level (Adrenal Diabetes)
- By promoting gluconeogenesis
- By inhibiting glucose uptake & utilization by peripheral cells
On protein metabolism
 Promotes catabolism of proteins
 Except for liver cells, it causes decrease protein synthesis by
inhibiting amino acid transport into cells & by inhibiting RNA
formation

86. On fat metabolism
 Causes mobilization and redistribution of fats
 Increases ketone bodies in blood- ketogenic effect
On mineral metabolism
 Retains sodium, excretes potassium
 Inhibits calcium absorption from intestine – excretion of
calcium through urine

87.  It accelerates excretion of water- in adrenal insufficiency
causes water retention and water intoxication after water
load
On CNS
 Insufficiency of these causes personality changes like
irritability and lack of concentration

88. Permissive action of glucocorticoids
 The actions of some hormones are executed only in the
presence of these hormones
- Calorigenic effect of glucagon
- Lipolytic, brochodilation & pressor action of catecholamines
- On Resistance to stress
 It is assumed that they enhances the resistance
- Immediate release & transport of amino acids from tissues to
liver for synthesis of new proteins which are essential to
withstand the stress
- Release of fatty acids produces more energy during stress
- Enhancement of vascular reactivity of catecholamines

89. Anti- inflammatory effects
 Prevent the inflammatory changes in the cells caused by injury
or infection by acting at all stages of inflammation
Anti-allergic actions
 Prevent the various reactions in allergic conditions
Immunosuppressive effects
 Suppress the immune system by decreasing the number of
circulating T lymphocytes, also prevent release of inerleukin-2
by T cells

90. Regulation Of
Secretion

91. Most of the hormones secreted are male sex hormones
(Androgens) and in small amounts of estrogens and
progesterone also secreted
 The androgens are- Dehydroepiandrosterone
- Androstenedione
- Testosterone
 Androgens in general are responsible for masculine feature of
the body
Adrenal sex hormones

92. Hyperactivity Hypoactivity
Disorders of Adrenal cortex

93. Any condition that produces an elevation in glucocorticoid levels.
Etiology
 Primary hypothalamic – pituitary diseases associated with
hypersecretion of ACTH (Cushing Diseases).
 Microadenomas
 Corticotroph cell hyperplasia.
Cushing’s syndrome (Hypercortisolism)

94.  Primary adrenal neoplasms (ACTH independent)
 Adrenal adenoma
 Adrenal Carcinoma
 Primary pigmented nodular adrenal hyperplasia
 Carney Complex
 McCune Albright Syndrome
 Ectopic ACTH by a non endocrine neoplasm

95. Clinical Features
 Obesity – centripetal, buffalo lump,
moon like facies
 Reproductive dysfunction – Menstrual irregularity, loss of libido,
hirsuitism, acne
 Psychiatric abnormalities – agitated depression & lethargy,
psychosis, memory and cognition affected, Insomnia.
 Bone – Children – poor linear growth and weight gain.
Osteoporosis – Vertebral collapse
 Pathologic fractures – rib and vertebral compression fracture

96.  Skin – Skin thinning, separation
and exposure of the
subcutaneous vascular tissue.
 Liddles Sign – dorsum of land
 Plethoric appearance
 Red – Purple livid striae
 Increase skin pigmentation

97.  Muscle – Proximal myopathy
- Bruising
 Cardiovascular–Hypertension – 75%
 Infections – more common Fungal infections – tinea
versicolor, candidiasis.
 Poor wound healing
Treatment
Surgical removal of adrenal tumors & pituitary tumors. Benign
tumors causing ectopic ACTH syndrome.
Medical Treatment
Metapyrone, Aminoglutethimide, Ketaconazole, Mitotane

98. Increased secretion of aldosterone
 Based on cause
Primary hyperaldosteronism
-Tumors in zona glomerulosa
Secondary hyperaldosteronism
- CCF
- Nephrosis
- Toxemia of pregnancy
- Cirrhosis of liver
Hyperaldosteronism

99. Signs & Symptoms
 Increase in ECF & Blood volume
 Hypertension
 Prolonged depletion of K+ causes renal damage leads to
polyuria, polydipsia
 Muscular weakness due to K+ depletion
 Due to excretion of large amount of H+ ions causes metabolic
alkalosis, which in turn reduces blood calcium- tetany

100. Abnormal quantities of adrenal androgen secretion develops
andrenogenital syndrome
Cause
Tumor of zona reticularis
Symptoms in females (Adrenal virilism)
-Increased muscular growth
-Deepening of voice
-Amenorrhea
-Enlargement of clitoris
-Male type hair growth
Andrenogenital syndrome

101. Symptoms in males
-Feminization
-Gynacomastia
-Atropy of testis

102.  Due to failure of adrenal cortex to secrete all corticosteroids
 Classified into
Primary – Due to adrenal cause
Secondary – Due to failure of ant pituitary to secrete ACTH
Tertiary – Due to failure of hypothalamus to secrete CRF
Addison’s disease or Chronic Adrenal
Insufficiency

103. Signs and symptoms
 Pigmentation of skin and mucus membrane
 Muscular weakness
 Dehydration with loss of sodium
 Hypotension & Hypoglycemia
 Decreased cardiac output leading to decreased size of heart
 Nausea, vomiting and diarrhea
 Susceptibility to any type of infection
 Inability to withstand any stress

104.  Characterized by sudden collapse associated with an increase
in need for large quantities of Glucocorticoids
Causes
-Exposure to even mild stress
-Hypoglycemia due to fasting
-Trauma
-Surgical operation
-Sudden withdrawal of glucocorticoid treatment
Sudden collapse occurs, the condition becomes fatal if not treated
in time
Addisonian Crisis or Adrenal Crisis or Acute
Adrenal Insufficiency

105.  Medulla is the inner part of the adrenal gland
 Made up of interlacing cords of cells known as Chromaffin
cells, Pheochrom cells or chromophil cells
Hormones of Adrenal medulla
-Adrenaline or Epinephrine
-Noradrenaline or Norepinephrine
-Dopamine
Adrenal medulla

106. Synthesis of
catecholamines

107.  Mode of action of these hormones are executed by binding
with receptors called Adrenergic receptors
- Alpha adrenergic receptors (α-1 α-2 )
receptors mediate more of noradrenaline action than the
adrenaline action
- Beta adrenergic receptors (β1 β2 )
β1- equal actions of both adrenaline, noradrenaline
β2- more adrenaline action than noradrenaline

108. On metabolism (via alpha and beta receptors )
General metabolism: Adr increases oxygen consumption, CO2
removal, BMR – calorigenic hormone
Carbohydrate metabolism: Increases glycogenolysis
Fat metabolism: Mobilization of free fatty acids from adipose
tissues
On blood (via beta receptors )
Adr decreases coagulation time, increases RBC count
Actions

109. On Heart (via beta receptors )
 Adr has stronger effect on heart
 It increases Heart rate (Chronotropic effect )
Force of contraction (Ionotropic effect)
Excitability of heart muscle (Bathmotropic effect)
On Blood vessels (via alpha and beta 2 receptors)
 Noradr- Constriction (alpha) – Increase peripheral resistance
 Adr - Dilatation in skeletal muscle, liver and heart (beta 2)-
Decrease peripheral resistance

110. On Blood Pressure
Adr increases systolic BP, decreases diastolic BP
Noradr increases both systolic & diastolic BP
On respiration
Adr increases force and rate of respiration
 Adrenaline secretion increases Fight or Flight reactions of brain
 Causes contraction of smooth muscle
 Increases secretion of many glands

111. Dopamine
 Secreted by medulla and by dopaminergic neurons in some
areas of brain particularly, basal ganglia
 It acts as neurotransmitter
 Deficiency of dopamine, basal ganglia produces nervous
disorder called Parkinsonism

112. Is a condition characterized by Hypersecretion of catecholamines
Cause
 Tumor of chromophil cells in adrenal medulla
 Tumor of sympathetic ganglia (extra adrenal
pheochromocytoma)
Pheochromocytoma

113. Signs and symptoms
Hypertension- characteristic feature
Others- Anxiety
Chest pain
Fever, Headache
Hyperglycemia
Palpitation
Sweating and Flushing
Tachycardia
Weight loss

114. Pineal gland :
- secretes melatonin (inhibits onset of puberty)
Thymus :
- Endocrine glands ( secretion of Thymosin and Thymin )
Endocrine function of Kidney:
- Secretion of Erythropoietin, Thrombopoietin,Prostaglandins,
Renin, 1,25 – Dihydroxy cholecalciferol
Endocrine function of heart:
- Secretion of Atrial Natriuretic Peptide
Endocrine functions of other organs

115.  Local hormones are the substances which act on the same area
of their secretion or in immediate neighborhood
Classified into two types
Hormones synthesized in tissues-Prostaglandins and related
substances, others like Acetylcholine, Serotonin, Histamine,
Substance P, Heparin, Leptin, GI hormones
Hormones synthesized in Blood- Serotonin, Angiotensinogen,
Kinins
Local hormones

116. Prostaglandins
 Are unsaturated fatty acids with a cyclopentane ring & 20
carbon atoms
 Synthesized from Arachidonic acid
 Types- PGD2, PGE2, PGF2
 Actions
-Vasodilatation
-Gastric secretion
-Inhibit release of free fatty acids from adipose tissue
-Increase the velocity of sperm transport in female genital tract
-Induce abortion if injected intra-amniotically
-Stimulate jaxtaglomerular apparatus to secrete Renin

117. Thromboxanes (A2 & B2)
 Important in hemostasis by accelerating aggregation of
platelets
Prostacyclin
 Causes vasodilation and inhibits plate aggregation
Leukotrienes
 These are the mediators of allergic responses, and promote
inflammatory reactions
Lipoxins (A & B)
 Lipoxin A causes dilation of minute blood vessels, both inhibit
the cytotoxic effects of killer T cells

118. Acetylcholine
 It is the neurotransmitter substance at the NMJ
 Inhibits cardiac function & causes vasodilation
Serotonin (5-hydroxytryptamine)
 Inhibits impulses of pain sensation in posterior gray horn of
spinal chord, causes mood depression and sleep,
vasoconstriction
Histamine
 During allergic condition, inflammation or damage of tissues-
vasodilation- entry of fluid and proteins from blood into
affected tissue

119. Substance P
 Is a neurotransmitter substance, increases the mixing and
propulsive movements of small intestine
Heparin
 Produced by mast cells and basophils, is a natural
anticoagulant
Leptin
 Secreted by adipocytes in adipose tissue
 Inhibits feeding center resulting in stoppage of food intake
 Stimulates the metabolic reactions involved in utilization of fat
stored in adipose tissue

120. Kinins
 Kinins are biologically active protein hormones which are
circulating in blood
 Two kinins in humans are- Bradykinin
- Kallidin
 Actions of bradykinin
-Dilates blood vessels decreases BP
-Increases permeability of capillaries edema
 Kallidin is a vasodilator hormone
 Plasma Kallikrein activates factor XII during blood
coagulation, and are potent vasodilators

121.  Textbook of physiology, 3rd edition Ganong
 Textbook of medical physiology,7th edition Guyton
 Textbook of human Physiology, Sembulingam
 Davidson. TextBook of Medicine 20th ed., Elsevier
Publishers
 www.endocrinology.org
References

122. Thank
You