Download Neuroendocrinology overview

Neuroendocrinology
Hormones
Endocrine hormones
Secreted directly into the blood
Controlled by pituitary (master gland)
and hypothalamus
Exocrine Hormones
Secreted into ducts
Not controlled by pituitary gland
or hypothalamus (e.g., gut hormones)
Hormones
released from endocrine cells
long latency, long duration of effect (mins/days)
delivered via blood
diffuse actions
Neurotransmitters
released from neurons
short latency, short duration of effect (msec)
released directly onto target cells
specific actions
This distinction has become blurred; e.g.
peptide neurotransmitters/neuromodulators,
release of 5-HT into ventricles, etc.
Pituitary Gland
(Hypophysis)
Anterior Pituitary
(Adenohypophysis)
Posterior Pituitary
(Neurohypophysis)
Control of
Adenohypophysial Hormones
neural inputs
Hypothalamus
Indirect
Loop
Short
Loop
Releasing
Factor
Adenohypophysis
Direct
Loop
Trophic
hormone
Endocrine Gland
Endocrine
hormone
Target tissues
All loops are negative feedback loops.
Increases in the amount of the substances monitored
reduces further secretion of those substances.
Sites of actions of hormones
1.
2.
3.
4.
nucleus--regulate transcription
protein synthesis
ribosomes--regulate translation
enzymes--turned on via cAMP, much like neurotransmitters
membranes--membrane receptor much like those for n.t.'s
Endocrine Hormones
Adenohypophysial hormones
Direct Actions
Somatotrophin (growth hormone; GH)
Prolactin
Melanocyte-stimulating hormone (MSH)
Indirect actions
Corticotrophin (ACTH)
Thyrotrophin (TSH)
Gonadotrophins
Luteinizing Hormone (LH)
Follicle-stimulating hormone (FSH)
Neurohypophysial hormones
Oxytocin
Vasopressin
Control of
Thyroid Hormones
neural inputs
Hypothalamus
Indirect
Loop
Short
Loop
TRF (TRH)
Adenohypophysis
Direct
Loop
TSH
Thyroid Gland
Thyroxine (T4)
Target tissues
All loops are negative feedback loops.
Increases in the amount of the substances monitored
reduces further secretion of those substances.
Control of
Sex Hormones
Hypothalamus
neural inputs
Gonadotrophin releasing hormone
(GnR)
Adenohypophysis
Luteinizing Hormone (LH)
Follicle Stimulating Hormone (FSH)
Testes (♂)
Ovaries (♀)
Testosterone (♂)
Estrogen/Progesterone (♀)
Target tissues
Control of
Adrenocortical Hormones
neural inputs
Hypothalamus
Indirect
Loop
Short
Loop
Corticotrophin
Releasing Factor
Adenohypophysis
Direct
Loop
Corticotrophin
or ACTH
Endocrine Gland
Cortisol and
Aldosterone
Target tissues
All loops are negative feedback loops.
Increases in the amount of the substances monitored
reduces further secretion of those substances.