Download MBBS (Bachelor of Medicine and Bachelor of Surgery) Latest Hormone 1 Lecture PPT
HORMONES
o Term hormone was introduced by Starling and
Bayliss in 1905.
o Hormones are the chemical messengers produced by
endocrine gland and transported by blood to other
tissue or organ where these stimulate a change in
some metabolic activity.
o They are produced from by one type of cell and have
regulatory effect on the activities of other type of cell
or on itself.
o The tissue or organ stimulated by a specific hormone
are called Target Tissue/ Target organ
o .
Hormones act on specific cells and organs called
target cell or target organ.
o Target cell or organ is that cell which has specific
receptors for the hormone which bind to them
with or without any demonstratable biochemical
or physiological response
o Concentration of hormone is very low in blood
but..
o Presence of receptors on target tissue
Specific binding between hormone and receptor
Very high local concentration
o Makes the target tissue highly specific to
hormones
CLASSIFICATION OF HORMONES BY
MECHANISM OF ACTION
I. Hormones that bind to intracellular receptors
1. Androgens
2. Calcitriol (1,25[OH]2-D3)
3. Estrogens
4. Glucocorticoids
5. Mineralocorticoids
6. Progestins
7. Retinoic acid
8. Thyroid hormones (T3 and T4)
II. HORMONES THAT BIND TO CELL SURFACE
RECEPTOR
A. The second messenger is cAMP
? 2-Adrenergic catecholamines
? -Adrenergic catecholamines
? Adrenocorticotropic hormone (ACTH)
? Antidiuretic hormone (vasopressin)
? Calcitonin
? Human Chorionic gonadotropin, (HCG)
? Corticotropin-releasing hormone
? Follicle-stimulating hormone (FSH)
? Glucagon
? Luteinizing hormone (LH)
? Melanocyte-stimulating hormone (MSH)
? Parathyroid hormone (PTH)
? Somatostatin
? Thyroid-stimulating hormone (TSH
B. The second messenger is cGMP
? Atrial natriuretic factor
? Nitric oxide
C. The second messenger is calcium or
phosphatidylinositols (or both)
? Acetylcholine (muscarinic)
? 1-Adrenergic catecholamines
? Angiotensin II
? Antidiuretic hormone (vasopressin)
? Cholecystokinin
? Gastrin
? Gonadotropin-releasing hormone
? Oxytocin
? Thyrotropin-releasing hormone (TRH
D. The second messenger is a kinase or phosphatase
cascade
? Adiponectin
? Chorionic somatomammotropin
? Epidermal growth factor (EGF)
? Erythropoietin (EPO)
? Fibroblast growth factor (FGF)
? Growth hormone (GH)
? Insulin
? Insulin-like growth factors I and II
? Leptin
? Nerve growth factor (NGF)
? Platelet-derived growth factor
? Prolactin
HORMONES
STIMULUS
PROPERTY
GROUP I
GROUPII
1.HORMONES
Adrenal steroids, thyroid Hypothalamic
hormones,
hormones, sex hormones, pituitary
hormones,
calcitriol ,retinoids
pancreatic
hormones,
Adrenal hormones
2.Chemical nature
Steroids,
iodothyronines, Peptides & polypeptides,
retinoids
proteins,
glycoproteins,
Catecholamines
3.Solubility
Hydrophobic,
Water Hydrophilic Water soluble
insoluble
4.Transport Protein
Required
Not required
5.Receptors location
Cytoplasm and nucleus
Cell membrane
6.Mediators of action
Hormone
-Receptors cAMP
Complex
cGMP
Ca ++
Phosphoinositides,
kinase Cascade etc.
SUBCLASSIFICATION OF GROUP II.A HORMONES
Hormones That Stimulate Hormones
That
Inhibit
Adenylyl Cyclase (HS)
Adenylyl Cyclase (HI)
ACTH
Acetylcholine
ADH
2-Adrenergics
-Adrenergics
Angiotensin II
Calcitonin
Somatostatin
CRH
Glucagon
TSH
This post was last modified on 30 November 2021