Endocrinology Flashcards
What are some forms of regulatory control?
Secretion (feedback)
Targeted cellular response (receptor)
Built in cellular amplification system
What is the first messenger to a cellular response?
A signal extracellularly
What are the second messengers to cellular response?
Cellular messengers to effectors
What is a hormone?
Substance produced in one tissue or organ and released into the blood and carried to other organs where it acts to produce a specific response
What do most hormones act as?
Cell surface receptors
What is cellular effector?
Molecule which modulates cellular activity
What is signal transduction?
How an external signal becomes an internal response
Relay molecules is the signal pathway
What are some therapeutic targets?
Receptors, second messengers or effector proteins
What are endocrine hormones?
Released by specialized tissues
Transported via bloodstream
Influence remote region of the body
What are paracrine hormones?
Influence neighboring cells/tissues
Local
What are autocrine hormones?
Affect the same cell they were secreted from
What are neuroendocrine hormones?
Secreted by neurons into bloodstream
Affect distant targets
What are the 7 classic endocrine organs?
Pituitary, thyroid, parathyroid, testes, ovary, adrenal cortex/medulla and endocrine pancreas
What are some other “endocrine” organs?
CNS, GI tract, heart, kidney
What is an ectopic endocrine organ?
Tumor - neoplastic hormone production
What the peptide hormones?
Anterior pituitary hormones (GH, LH, FSH, TSH, ACTH, PRL)
Posterior pituitary hormones (ADH/vasopressin, oxytocin)
Pancreatic hormones: insulin and glucagon
Parathyroid: PTH
What are the steroid hormones?
Gonadal: estrogens, androgens, prosgestins
Adrenal cortex: cortisol, aldosterone
What are the amine hormones?
Adrenal medulla: catecholamines (EPI, NE)
Thyroid: thyroid: T4 and T3
Which endocrine hormones are water soluble?
Peptides, catecholamines
Dissolved in plasma
Mostly acute, short-term action
What endocrine hormones are somewhat water-soluble?
Steroids, thyroid hormones
How must somewhat water-soluble endocrine hormones move in the plasma?
90% circulate bound to plasma proteins like albumin
Sex hormone binding globulin
Free hormones go into tissues (hormone reservoir)
What endocrine hormones are lipophilic and how to they travel?
Thyroid hormones, gonadal and adrenal steroids
Intracellular receptors
Activate transcription/ protein synth
Membrane receptors
What is the “G” in the G-protein receptor coupling?
GTP-binding protein: amplified response
How does G-protein receptor coupling work?
Couple receptor activation to effector activity
Heterotrimeric structure: alpha and beta-gamma subunits
How is the G-protein receptor shut off?
GTPase activity of alpha unit to deactivate
What does phosphorylation do?
Alters protein activity
What is Gs?
Stimulatory G-protein
What is the secondary messenger to G-protein receptors?
Cyclic AMP
What does cAMP amplify?
pKa (?)
