PHAR 300 Lecture Notes - Lecture 8: Anterior Pituitary, Adrenal Gland, Cholesterol Side-Chain Cleavage Enzyme
10 Oct 2018
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Document Summary
A messenger is released in the bloodstream to affect a distal receptor. A hormone is a chemical messenger that circulates in the body and has effect on distance cells. The endocrine system: hypothalamus, pituitary, thyroid, parathyroids, pancreas, adrenal glands, ovaries, testes. 3 levels: hypothalamus, anterior pituitary, organ functions. The hypothalamus produces crh (corticotrophin-releasing hormone), a 41 aa peptide. Crh acts on gpcrs in anterior pituitary to stimulate pomc synthesis: actually a propeptide, targets receptors in pituitary, proopiomelanocorticotropin. So there is post-translational processing as well to control how much of the message is carried. Regulates the production of glucocorticoids in the adrenal glands: zonae fasciculata/reticularis. The synthesis is in the adrenal cortex. Increase delivery of cholesterol to inner mitochondrial membranes for the synthesis of steroids. Increase the transcription of the enzyme in charge of side-chain cleavage p450 enzyme called cyp11a1. Cleaves the side-chain of cholesterol, making pregnenolone, which is the precursor for most steroid products.
