General Hormonal Stuff

Question 1

What are the main type of hormones in humans?

Answer 1

Protein/polypeptide hormones-short polypeptides (longer called proteins)-made as pro-hormones and cleaved
Steroid hormones (made from cholesterol)
Miscellaneous (not in either categories)

Question 2

Describe protein/polypeptide hormones with an exemple

Answer 2

Protein hormones are made from DNA-from their specific cell
eg: Corticotrophs produce ACTH
mRNA of POMC is transcribed and translated into RER
Then into golgi, and into vesicles-packaged their with enzymes that will transform POMC to ACTH. Then vesicles with active hormone sit near the membrane and wait to be activated-then will be released by exocytosis

Question 3

Descibe steroid hormones synthesis with an exemple

Answer 3

Steroids are main from cholesterol, uptaken from blood (LDL), then usually stored as Cholesterol ester in Fatty acid ester vesicles.
The proteins to make the chol are in to mitochondria. eg: Released from FAE by esterase, then transported into mito by StAR enzyme => ACTH increases those through PKA
Once cortisol is made,freely diffuse across membranes and into circulation

Question 4

How are both main types of hormones transporter?

Answer 4

Protein hormones are just transported in the blood and pass until their receptor
Steroid hormones actually are mainly bound by plasma proteins (eg: Albumin, CBG (binds cortisol), and othess (specific for each steroid hormone)). MOST steroid hormones are bound-like 90/99%. But dynamic equilibrium, and as free hormone production increase, bind more, etc-always same amount remains available (eg free horm down->prortein release more, vice versa)
If protein binding up, then increase hormone synth and level available

Question 5

Explain how protein hormones and steroid hormones signal

Answer 5

protein hormones act on extraceullar receptors.
eg: Insulin acts of EGFRL, ACTH acts on GCPR (Gs adnylyl cyclase, PKA, increase esterase and stAR effects->more cortisol)
Steroid hormones can freely diffuse into membranes-intracellular receptors (cytosol or nucleus), which one bind the hormone move to nucleus and increase trasncription of target genes

Question 6

Can you explain very general hormones homeostatis (ein relation to ACTH and cortisol)

Answer 6

Homones are on tight feedback, usually negative (some positive ofc)
Usually they are their own feedback, or their direct effects cause feedback
ACTH acts on the adrenal glands to produce cortisol-which can act on the adenohypophysis to reduce ACTH production -classic
TSH->TRH->T3/T4 => all products inhibit makers