Hormones Flashcards
What is the typical result of phosphorylate a gene regulatory protein on the reaction’s kinetics? What enzyme can do that?
⬆️ Vmax (add more enzyme to the cell). PKA phosphorylate CREB.
What are the two intracellular ways to relax the smooth muscle resulting in vasodilation?
Atrial Natriuretic receptor ▶️ guanylate cyclase activity
NO ▶️ 🔛 soluble guanylate cyclase
What G protein couple the alfa-2 adrenergic receptor of epinephrine and what is its effect?
Gi ➡️ inhibit adenylate cyclase ➡️ ⤵️ insulin release from B cells of pancreas
What is the mechanism by which glucagon and insulin antagonizes each other via intracellular phosporylation?
*Glucagon ▶️ 🔛 PKA ➡️ phosphorylate enzymes
*Insulin ▶️ 🔛 Protein phosphatase ➡️ dephosphorylating enzymes
Ex; glycogen phosphorylase and synthase, and same antagonizes for TG synthesis and degradation, and other pathways
Named two consequences of gene amplification in the case of some mutated oncogenes and other genes.
- over expression of oncogen (⬆️ number of enzymes and ⬆️ Vmax) In tumor cells
- resistance to drugs (ex; amplification Dihydrofolate reductase ➡️ resistance to methotrexate
What type of water-soluble receptor don’t use second messengers for protein kinase activation?
Those with intrinsic protein kinase activity (often tyrosine kinases). Ex; insulin receptor, growth factors
How does the caffeine favor the glucogenolysis and gluconeogenesis?
Inhibit the cAMP phosphodiesterase (PDE) ▶️ ⬆️ cAMP ▶️ 🔛 PKA ▶️ 🔛 glycogen phosphorylase
Look for the target of gluconeogenesis….
Why the PIP2 pathway by activation of phospholipase C can cause smooth muscle contraction?
PIP2 ➡️ IP3 ➡️ release Ca from ER ➡️ contraction
What is the effect of the ADP-ribosylation in Gs Alfa subunit? What can do that?
- ⬆️ cAMP ▶️ chloride secretion from intestinal mucosal cells (cholerae toxin causing diarrhea)
- same E. coli heat labil toxin (traveler’s diarrhea)
How and what toxin can reduce the responsiveness of the Gi protein to its receptor?
Bordetella pertussis exotoxin ▶️ ADP-ribosylation Gi Alfa subunit ▶️ ⬆️ cAMP (not known how does it relate with whooping cough)
How does the caffeine favor the glucogenolysis and gluconeogenesis?
Inhibit the cAMP phosphodiesterase (PDE) ▶️ ⬆️ cAMP ▶️ 🔛 PKA ▶️ 🔛 glycogen phosphorylase
Look for the target of gluconeogenesis….
Why the PIP2 pathway by activation of phospholipase C can cause smooth muscle contraction?
PIP2 ➡️ IP3 ➡️ release Ca from ER ➡️ contraction
What is the effect of the ADP-ribosylation in Gs Alfa subunit? What can do that?
- ⬆️ cAMP ▶️ chloride secretion from intestinal mucosal cells (cholerae toxin causing diarrhea)
- same E. coli heat labil toxin (traveler’s diarrhea)
How and what toxin can reduce the responsiveness of the Gi protein to its receptor?
Bordetella pertussis exotoxin ▶️ ADP-ribosylation Gi Alfa subunit ▶️ ⬆️ cAMP (not known how does it relate with whooping cough)
