What is a hormone?
- Chemical messenger
- Produced and secreted by specialised endocrine gland
- Transported in blood
- Distant target organ
- Where is elicits a physiological response
What is paracrine and autocrine signalling?
- Local hormones
- Autocrine is when a cell does it to itself
- Paracrine is when a cell does it to neighbouring cells
What are the three types of hormone?
Which are hydrophobic and which are hydrophilic?
- Protein/Peptide - e.g. Growth hormone
- Cholesterol Derivatives - e.g. Steroids and Vitamins
- Modified Amino Acids - e.g. Adrenaline, Thyroid Hormones
How are hormone signalling pathways regulated?
- Regulation of hormone
- → secretion and processing of prehormones
- Regulation of receptor
- → Isoform - same hormone different receptor form elicits different response
- → expression - same receptor but on different tissue with different intracellular proteins
- → number - down-regulation removes receptors, up-reg adds
- → affinity of receptor - open/closed conformation
- Regulation of intracellular signalling pathway
What is amplification?
- Small intracellular molecules (e.g. Ca2+, cAMP)
- → produced in large amounts as response to extracellular signal
- → activate downstream signalling molecules
What are the hormones produced by the posterior pituitary?
- Vasopressin (ADH → anti-diuretic hormone)
What are the hormones produced by the anterior pituitary?
- Single polypeptide chain hormones:
- ACTH - Adrenocorticotrophic hormone
- GH - Growth hormone
- PRL - Prolactin
- Multi-subunit polypeptide chain hormones: Common alpha unit, different beta unit
- LH - Luteinizing hormone
- FSH - Follicle stimulating hormone
- TSH - Thryoid stimulating hormone