Hormonal
receptors
Adie Kooffreh
0323
objectives
what is a hormone receptors?
 Types of hormone receptors
 Types of hormones and their different
receptors
 intracellular and extracellular hormones
Hormone receptors: this is a molecule
that can bind to a specific hormones.
Receptors for peptide hormones are
usually found on the plasma membrane
of cells.
Lipid-soluble hormones are usually
found within the cytoplasm. Upon
hormone binding, the receptor can
initiate multiple signaling pathways
which ultimately lead to changes in the
behavior of target cells
Water soluble hormone receptors:
– Water-soluble hormones include glycoprotein,
catecholamine's and peptide hormones composed
of polypeptides, e.g. thyroid-stimulating
hormone, follicle-stimulating hormone , leutinizing
hormone and insulin. These molecules are not lipidsoluble and therefore cannot diffuse through cell
membranes. Consequently, receptors for peptide
hormones are located on the plasma membrane.
– The main two types of transmembrane hormone
receptor are the G-protein-coupled receptor and the
enzyme-coupled receptor. These receptors generally
function via intracellular second messengers,
including cyclic AMP (cAMP), cyclic GMP (cGMP), inositol
1,4,5-trisphosphate (IP3) and the calcium (Ca2+)calmodulin system
Lipid soluble hormone receptors :
– Steroid hormone receptors and related receptors
are generally soluble proteins that function
through gene activation. Their response elements
are DNA sequences (promoters) that are bound
by the complex of the steroid bound to its
receptor. The receptors themselves are zincfinger proteins.These receptors include those
for glucocorticoids,estrogens, androgens, thyroid
hormone (T3), calcitriol (the active form
of vitamin D), and the retinoids (vitamin A)
Steroid hormone receptors:
– steroid hormone receptors are found on
the plasma membrane, in the cytosol and also in
the nucleus of target cells. They are
generally intracellular receptors (typically
cytoplasmic) and initiate signal
transduction for steroid hormones which lead to
changes in gene expression over a time period of
hours to days
– Steroid receptors of the nuclear receptor family are all transcription
factors. Depending upon the type of receptor, they are either
located in the cytosol and move to the cell nucleus upon activation,
or remain in the nucleus waiting for the steroid hormone to enter
and activate them. This uptake into the nucleus is facilitated
by nuclear localization signal (NLS) found in the hinge region of the
receptor. This region of the receptor is covered up by heat shock
proteins (HSPs) which bind the receptor until the hormone is
present. Upon binding by the hormone the receptor undergoes a
conformational change releasing the HSP, and the receptor
together with the bound hormone enter the nucleus to act upon
transcription.
Intracellular receptors
– Intracellular receptors are receptors located
inside the cell rather than on its cell
membrane. Classic hormones that use
intracellular receptors include thyroid and
steroid hormones.
Laron syndrome
– Autosomal recessive disorder characterized by
insensitivity to growth hormone. Caused by
mutation to the gene encoding for the growth
hormone receptors (GHR)
Spontaneous ovarian
hyperstimulation syndrome (OHSS)
– This is caused a mutation in the FSH receptor.
 McCune Albright syndrome, a hereditary
disorder characterised by autonomous
hyperfunctioning of multiple endocrine tissues
(including the thyroid), bony lesions (fibrous
dysplasia), and irregulary shaped hyperpigemted skin
lesions due to the gsp oncogene
– https://www.youtube.com/watch?v=Nm9u4lNCP
yM
– https://www.youtube.com/watch?v=qLL8_z9N5c
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