Transcript Hypothalamic/Pituitary Axis

Hormones – An Introduction
FSH – A peptide hormone
Method of Action – Steroid Hormones
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Steroids transport via carrier
proteins – why?
Movement through plasma
membrane into cytoplasm of target
Interaction with specific receptors
Binding to response elements in
target genes
Influence on transcription
Steroid receptor structure
AF1
Transact
Ligand Binding
DNA binding/Dimerisation
DBD
NL
Transact
DNA Sequence – Differs, depending on receptor complex
eg., GGTCAnnnTGACCC for estrogen receptor bound to ligand
Method of Action – Peptide Hormones
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Interact with ligand bound receptor
on plasma membrane – why?
Consequence of interaction with
receptor is signal transduction –
eg., activation of GTP, influence on
adenylate cyclase/cAMP/protein
kinase
Gene activation indirect, but signal
amplification can be more rapid
G-Protein Coupled Receptor Function
Richardson, 2001
Hypothalamic-Pituitary Axis:
An Historical Perspective
Michelangelo’s
“Creation of Adam”
Outline of Brain
FUNCTIONAL ANATOMY OF
THE HYPOTHALAMUS AND
PITUITARY
Chapter 3b - Ronald M.
Lechan, M.D., Ph.D., and
Roberto Toni, M.D.
Adenohypophysis = Anterior Pituitary
“Glandular”
Neurohypophysis=
Posterior Pituitary
(neurons that extend
here have cell bodies
in hypothalamus
Hypothalamic/Pituitary Axis –
Vasculature and Gross Morphology
Adapted from http://www.uwyo.edu/wjm/Repro
Pituitary Histology
GH, PRL secreting
FSH, LH etc
Note the differences in morphology and staining patterns
(acidophilic vs basophilic) reflecting differences in secretions
b/w cell types. Tissue is also highly vascularized