Endocrine system Flashcards
What are the types of steroid hormones?
- Adrenal hormones (mineralocorticoids, glucocorticoids)
- Sex hormones (androgens, estrogens, progestogens)
What are the cholesterol derivates?
bile acids, vit D, steroid hormones (sex steroids, adrenal steroids)
What are the hormones that derivate from eicosanoids (20-C poly-unsaturated fatty acids)?
arachidonic acid (eicosanoid) is derivated to prostaglandins, leukotrienes and prostacyclins
I play a role in reproduction and inflammatory response
prostaglandins
What are GnRH, Oxytocin, TRH?
small peptide hormones
What are the differences between arginine vasopressin and oxytocin?
AA dif at positions 3 + 8
Vasopressin = water retention + vasoconstriction
Oxytocin = milk ejection + labor
What are examples of long polypeptide hormones?
GH and insulin
What are examples of AA hormones?
thyroid hormones (T3, T4) + adrenal medulla (epinephrine = from tyrosine, norepinephrine, dopamine)
Mass of secretory cells is called _____
Parenchyma
Endocrine hormones can be transient like ____
Ovarian follicles + placenta
What organelles are more present for peptide hormones?
rough ER bc of translation, smooth ER for steroid hormones
What are the steps in steroid hormones synthesizing?
- cholesterol stored in cytosol in lipid droplets
- cleavage of side chain in mitochondria = pregnenolone
- exported out of mitochondria into smooth ER
- transformation into hormone
- excreted out of cell (no vesicles bc lipophilic)
what can trigger hormone production?
- neural input
- hormonal stimulation/inhibition
- metabolic status
What is Addison Disease?
lack of cortisol and aldosterone = no -ve feedback on ACTH of pituitary gland = +++ production of ACTH in combination with melanocyte-stimulating hormone = +++ melanin = darkening of skin
What are the parts of the basic structure of a receptor?
- ectodomain (NH2 end)
- hydrophobic transmembrane domain (alpha helix)
- cytoplasmic domain (COOH end)
How hyperthyroidism is caused in Grave’s Disease?
TSH receptor’s ectodomain is cleaved off and stimulates antibodies production. Those antibodies act like TSH and bind to the receptors.
Which AAs at the cytoplasmic domain are responsible for phosphorylation of proteins?
- tyrosine
- serine
- threonine
What are the Ga subunits?
Gsa = activates adenylate cyclase Gia = inhibits adenylate cyclase Gqa = activates PLC Goa = activates ion channels G12/13a = regulates actin cytoskeleton (changes in cell shape)
TRUE or FALSE?
Hormones may use more than one G-protein?
True
What factors can affect the use of G-proteins?
- development
- hormone concentration
- tissue
What are the 3 steps after insulin binding?
- autophosphorylation of intracellulaire domain of receptor
- docking + phosphorylation of IRS-1 and 2 (insulin receptor substrate)
- activation of 2 major signal pathways (MAPK + PIP3)
What are the steps to MAPK pathway?
- insulin bonds to receptor
- phosphorylation of tyr
- phosphorylation of IRS-1
- binds to Grb2
- recruitment of Ras + Raf-1
- MEK
- ERK
- transcription factors activated
What are the steps to PIP3 pathway?
- IRS-1 phosphorylates PI3K
- PIP2 -> PIP3
- Activation of PKB -> activation of glut4
- inactivation of GSK3
- Glycogen synthase active
What are the steps to jak-stat pathway?
- bonding to receptor => dimerization and recruitment of JAK
- cross-phosphorylation of JAK
- JAK phosphorylates receptor
- recruitment of STAT
- JAK phosphorylates STAT
- STATs dissociate and dimerize
- STATs move to nucleus and bind to DNA
