IHDC Flashcards
What are the three groups of hormones?
→Steroids – lipid soluble small molecules e.g. testosterone
→Peptide / proteins e.g. insulin
→Modified amino acids / amine hormones e.g. adrenaline
What are steroid hormones synthesised from?
→cholesterol
Where are corticosteroids synthesised?
→adrenal cortex
Where are androgens and oestrogens synthesised?
→gonadal tissues
Which cancers are common for men and women?
→women= breast →men= prostate
What does the steroid-nuclear receptor complex bind to?
→to specific DNA sequences called response elements
→located in the promoters of steroid responsive genes
What are the key characteristics of nuclear receptors?
→Ligand binding domain (LBD)
→DNA binding domain (DBD)
→Activation function domain (AF1 & 2)- forms part of activation signal
What is the activation function domain of nuclear receptors?
→Recruits gene activation machinery,
→some receptors have a secondary AF2 domain towards the C-terminal
What does binding of steroids to steroid receptors cause?
→physical restructuring of the polypeptide chains in the receptor, activating it
what happens when ligands bind to the ligand binding site of receptors?
→shift in an a-helix, activating the receptor
→Receptor dimerises
→moves into the nucleus and binds to specific DNA sequences
→recruits DNA modifying enzymes e.g. histone deacetylases, other transcription factors and RNA polymerase to promoters of hormone responsive genes
What does the DNA binding domain contain?
→2 zinc fingers domains
→Interaction with the DNA phosphate backbone
What are hormone response elements?
→specific DNA sequences found in the promoters of hormone responsive genes
What is characteristic of hormone response elements?
→Many are palindromic
How many nuclear receptor genes in humans?
→48 nuclear receptor genes
What do steroid receptors share and differ in?
→high homology in the DNA binding domain
→differ in ligand binding domains, and differ in N-terminal activation domains
What type of gland is the breast?
→apocrinegland
What is the breast composed of?
→glands and ducts
What are lobes in the breast?
→milk-producing part of the breast
→15-20 sections
Where are lobules found?
→lobes
What is the difference between endocrine and exocrine glands?
→Exocrine glands – secrete substances out onto a surface or cavity, via a ductal structure.
→Endocrine glands – secrete substances directly into the bloodstream
What type of glands are apocrine glands?
→specialised exocrine gland in which a part of the cells’ cytoplasm breaks off releasing the contents
What are the two cell types in mammary epithelium?
→luminal
→basal
What are luminal cells in mammary epithelium?
→form a single layer of polarized epithelium around the ductal lumen, luminal cells produce milk during lactation
What are basal cells in mammary epithelium ?
→cells that do not touch the lumen
→in contact with the basement membrane
→also known as myeoepithelium
Which cells in mammary epithelium contracts during lactation?
→ basal
Which cells in mammary epithelium produces milk?
→luminal
What are the two phases of mammary gland development?
→hormone-independent from embryonic development up to puberty
→hormone-dependent during puberty, menstrual cycle and pregnancy
What does hormone dependent mammary development result in?
→ductal elongation
→triggers side branching
Which hormone switches on the progesterone receptor?
→oestrogen
What is the effect of progesterone on ducts?
→branching of the ducts
→together with prolactin hormone