Hormones - General Features

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Hormones General Features
R.C. Gupta Professor and Head Department of
Biochemistry National Institute of Medical
Sciences Jaipur, India
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E M B - R C G
EMB-RCG
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E M B - R C G
EMB-RCG
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E M B - R C G
EMB-RCG
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EMB-RCG
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E M B - R C G
EMB-RCG
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Definition
E M B - R C G
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E M B - R C G
EMB-RCG
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E M B - R C G
EMB-RCG
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• Hormone receptors

E M B - R C G
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E M B - R C G
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s

• Nucleic acids include deoxyribonucleic acid
  (DNA) and ribonucleic acid (RNA)
• Both are information molecules
• DNA stores genetic information
• The entire genetic material present in the DNA
  of an organism is known as its genome

Nucleus
Cell membrane
E M B - R C G
1, 2, 3, 4, 5 and 6 are hormone receptors
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E M B - R C G
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Classification of hormones
E M B - R C G
EMB-RCG
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E M B - R C G
EMB-RCG
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E M B - R C G
EMB-RCG
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E M B - R C G
EMB-RCG
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Group I hormones
E M B - R C G
EMB-RCG
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E M B - R C G
EMB-RCG
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Mechanism of action of Group I hormones
E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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• Nucleic acids include deoxyribonucleic acid
  (DNA) and ribonucleic acid (RNA)
• Both are information molecules
• DNA stores genetic information
• The entire genetic material present in the DNA
  of an organism is known as its genome

E M B - R C G
EMB-RCG
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Group II hormones
E M B - R C G
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The hormone binds to its receptor on the cell
surface, and does not enter the cell
A second messenger is required to carry the
message inside the cell
E M B - R C G
The second messenger is produced by an effector
EMB-RCG
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Mechanism of action of Group II hormones
E M B - R C G
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E M B - R C G
EMB-RCG
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cAMP
E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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Receptor
G-Protein
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E M B - R C G
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Hormone
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The GTP-bearing a-subunit dissociates from the b-
and g-subunits
The a-subunit goes and binds to adenylate
cyclase
E M B - R C G
Adenylate cyclase is activated
Active adenylate cyclase produces cAMP
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a
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E M B - R C G
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E M B - R C G
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cGMP
E M B - R C G
cGMP is formed from GTP by guanylate cyclase
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E M B - R C G
EMB-RCG
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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• Nucleic acids include deoxyribonucleic acid
  (DNA) and ribonucleic acid (RNA)
• Both are information molecules
• DNA stores genetic information
• The entire genetic material present in the DNA
  of an organism is known as its genome

E M B - R C G
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E M B - R C G
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E M B - R C G
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Ca and/or phosphoinositides
E M B - R C G
Binding of these hormones to their receptors
activates phosphoinositidase
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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Tyrosine kinase
E M B - R C G
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E M B - R C G
EMB-RCG
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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Insulin receptor
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E M B - R C G
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Autophosphorylated insulin receptor
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E M B - R C G
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Regulation of hormone secretion
E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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Assay of hormone concentrations
E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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Radio-immuno-assay (RIA)
E M B - R C G
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E M B - R C G
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E M B - R C G
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Briefly, the steps are
A series of tubes, marked S1, S2, S3, S4 etc
(standards) and U (unknown), is set up
E M B - R C G
A fixed, and relatively small, amount of antibody
(Ab) is added to each tube
A fixed amount of labeled hormone (Ag) is
added to each tube
EMB-RCG
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Unlabeled hormone (Ag) is added to tubes
marked S1, S2, S3 , S4 etc in increasing
amounts (C1, C2, C3 , C4 etc)
E M B - R C G
Patients serum having an unknown amount of
unlabeled hormone (CU) is added to the tube
marked U
EMB-RCG
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The tubes are incubated for a fixed period
Ag and Ag compete with each other to
bind to the limited amount of Ab
E M B - R C G
Some Ab combines with Ag and some with Ag
EMB-RCG
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The tubes are centrifuged
E M B - R C G
Ag-Ab and Ag-Ab complexes settle at the
bottom
EMB-RCG
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E M B - R C G
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E M B - R C G
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E M B - R C G
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E M B - R C G
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Calibration curve
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Enzyme-immuno-assay (EIA)
E M B - R C G
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E M B - R C G
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E M B - R C G
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An ELISA plate with wells molded in it
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E M B - R C G
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The steps are
Standard hormone solutions in increasing
concentrations (C1, C2, C3 etc) are added to the
wells marked S1, S2, S3 etc
E M B - R C G
Patients serum having an unknown hormone
concentration (CU) is added to the well
U
Hormone molecules bind to the fixed
antibody molecules
EMB-RCG
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A second antibody recognizing a different
epitope of the antigen (hormone) is tagged with
an enzyme
E M B - R C G
It is added to each well in a relatively large
amount
The enzyme-linked antibody also binds to the
hormone
EMB-RCG
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The unbound enzyme-linked antibody molecules are
washed off
E M B - R C G
Each well now contains complexes of the fixed
antibody, the antigen and the
enzyme-linked antibody
EMB-RCG
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A fixed amount of substrate of the enzyme is
added to each well
The enzyme converts the substrate into a coloured
product
E M B - R C G
EMB-RCG
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After a fixed incubation period, intensity of
colour (absorbance) is measured in each well
E M B - R C G
The absorbance is proportional to the enzyme
concentration
The enzyme concentration is proportional to the
hormone concentration
EMB-RCG
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A calibration curve is plotted between the
known concentrations of hormone (C1, C2,
C3 etc) and the absorbance
E M B - R C G
The hormone concentration in the patients
serum (CU) can be read off from the
calibration curve
EMB-RCG
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Calibration curve
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Chemiluminescence-immuno-assay (CLIA)
E M B - R C G
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E M B - R C G
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E M B - R C G
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Chemiluminescence is measured by a luminometer
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E M B - R C G