Neuroendocrinology
Key Points
-Neurosecretory cells and neuroendocrine integration
-Embryology, anatomy and blood supply of the hypothalamo-pituitary axis
-Hormones of the posterior pituitary
-Hormones of the anterior pituitary
-Negative feedback, primary and secondary endocrinopathies
-Control of growth hormone and prolactin secretion
-Micro and macro-adeneomas
Different signaling mechanisms are shown below, with hormones a hormone
secreting gland cell releases a hormone into the blood which travels along and binds
to its target cell.
Comparing to neurotransmission, in both cases there is packaging of peptides into
vesicles, the peptides are released and then the peptides interact with their
receptors.
With regards to neurotransmission the release point of the peptides is very close to
where the receptors are, resulting from neurosecretion of a neurotransmitter.
The receptor doesn’t know whether the agonist has come from a few nm away from
an axon terminal or from many micrometres away via the circulation. The receptor
binding is the same.
Nerve cells mainly synapse with other neurones, but many do synapse with effector
cells e.g. gland cells.
Finally there is neuroendocrine transmission, this is a combination of both neural
and endocrine signaling.
Here, we can see a conventional nerve cell, that receives excitation and generates APs
which travel down the axon and when they reach the axon terminal they cause
, release of a signaling molecule. But here instead we have release of a hormone into
the blood. So it is a neurohormone.
Then in the blood it circulates around acting like a normal hormone. In this process
there has been transduction of an electrical signal to a chemical one.
Below can be seen other related signaling mechanisms
When we release something from a cell that just diffuses locally and affects
neighbouring cells, this is paracrine transmission.
Autocrine is when cells release things and what it has released affects its own
growth.
Intracrine is something that happens entirely within the cell.
Neuroendocrine cells are neurosecretory cells that release signal molecules
(hormones) from their synaptic terminal into the blood. This is controlled via
synaptic transmission from presynaptic neurones – neuroendocrine integration.
Hypothalamo-Pituitary Axis
The pituitary we always consider part of the hypothalamus, the hypothalamo-
pituitary axis.
The hypothalamus contains two main types of neurosecretory cells, the
magnocellular (meaning large cells) and parvocellular (meaning small cells).
The pituitary gland itself is bi-lobed consisting of an anterior and posterior lobe. The
anterior is larger and posterior smaller.
Key Points
-Neurosecretory cells and neuroendocrine integration
-Embryology, anatomy and blood supply of the hypothalamo-pituitary axis
-Hormones of the posterior pituitary
-Hormones of the anterior pituitary
-Negative feedback, primary and secondary endocrinopathies
-Control of growth hormone and prolactin secretion
-Micro and macro-adeneomas
Different signaling mechanisms are shown below, with hormones a hormone
secreting gland cell releases a hormone into the blood which travels along and binds
to its target cell.
Comparing to neurotransmission, in both cases there is packaging of peptides into
vesicles, the peptides are released and then the peptides interact with their
receptors.
With regards to neurotransmission the release point of the peptides is very close to
where the receptors are, resulting from neurosecretion of a neurotransmitter.
The receptor doesn’t know whether the agonist has come from a few nm away from
an axon terminal or from many micrometres away via the circulation. The receptor
binding is the same.
Nerve cells mainly synapse with other neurones, but many do synapse with effector
cells e.g. gland cells.
Finally there is neuroendocrine transmission, this is a combination of both neural
and endocrine signaling.
Here, we can see a conventional nerve cell, that receives excitation and generates APs
which travel down the axon and when they reach the axon terminal they cause
, release of a signaling molecule. But here instead we have release of a hormone into
the blood. So it is a neurohormone.
Then in the blood it circulates around acting like a normal hormone. In this process
there has been transduction of an electrical signal to a chemical one.
Below can be seen other related signaling mechanisms
When we release something from a cell that just diffuses locally and affects
neighbouring cells, this is paracrine transmission.
Autocrine is when cells release things and what it has released affects its own
growth.
Intracrine is something that happens entirely within the cell.
Neuroendocrine cells are neurosecretory cells that release signal molecules
(hormones) from their synaptic terminal into the blood. This is controlled via
synaptic transmission from presynaptic neurones – neuroendocrine integration.
Hypothalamo-Pituitary Axis
The pituitary we always consider part of the hypothalamus, the hypothalamo-
pituitary axis.
The hypothalamus contains two main types of neurosecretory cells, the
magnocellular (meaning large cells) and parvocellular (meaning small cells).
The pituitary gland itself is bi-lobed consisting of an anterior and posterior lobe. The
anterior is larger and posterior smaller.
