Lecture 47 + 48 Flashcards
(26 cards)
Beta cells in the pancreas respond to both glucose AND ____ acids.
AMINO
____2 receptors are abundant in the liver for glucose uptake and the uptake is not rate limiting, so the liver plays an important role in quickly clearing circulating glucose.
GLUT2 receptors are abundant in the liver
Three Glycolysis enzymes (Hexokinase, PFK-1, and Pyruvate Kinase) that catalyze essentially irreversible steps are ____ by insulin and ____ by glucagon.
ACTIVATED by insulin and INHIBITED by glucagon
Insulin activates ____ and _____ _____ pathway in Adipose tissue.
Insulin activates GLYCOLYSIS and PENTOSE PHOSPHATE pathway in adipose tissue
In muscle and adipose tissues, insulin up-regulates expression of _____ receptors (High affinity/low Km,) whereas the liver, kidney, pancreatic beta-cells, and the brain and many other tissues use _____ receptors (Low affinity/High Km) to take up glucose.
In muscles and adipose, insulin up-regulates expression of GLUT4, whereas liver, brain and other tissues use GLUT2
Tyrosine kinase domains activate VERY rapidly. Not just insulin, but ____ growth factor and ____ growth factor (to name a few) also bind RTKs.
EPIDERMAL growth factor and NERVE growth factor.
_____ proteins recognize and bind the phosphorylated regions of the RTKs and relay the signal to the cell by activating monomeric ____ proteins (i.e. Ras) that are active when bound to GTP.
ADAPTOR proteins recognize the phosphorylated regions of the RTKs and relay the signal to the cell by activating monomeric G-proteins
TGFbeta receptors, unlike insulin receptors which are Tyrosine kinases, are _____ kinases.
SERINE
Another receptor with intrinsic enzymatic activity is the Receptor _____ cyclase that directly generates the second messenger ____. It can be activated by ___ natriuretic peptide.
Receptor GUANYLYL cyclase.
cGMP
ATRIAL natriuretic peptide.
During long term starvation, the ____ becomes an important site for gluconeo (it can produce up to 40% of the body’s glucose in a long-term starvation state.)
KIDNEY
Type I diabetes is characterized as an autoimmune disease that destroys pancreatic Beta cells leading to an absolute _____ in Insulin.
absolute DEFICIENCY
Type II diabetes is characterized by a decreased _____ to insulin.
Decreased RESPONSE to glucose
There is a ____ genetic predisposition to Type I diabetes vs a _____ genetic predisposition to Type II.
MODERATE genetic predisposition to Type I vs a HIGH genetic predisposition to Type II
____ is common in Type I, but is rare in Type II. Similarly, _______ is common in Type I, while hyperosmolar coma is common in Type II.
KETOSIS
Ketoacidosis
Maturity Onset Diabetes of the Young (MODY) is considered Genetic Diabetes, and can arise from issues with _____ factors, _____ enzymes, or _____ defects.
TRANSCRIPTION factors, METABOLIC enzymes, or SIGNALING defects
Metformin (drug to treat Type II diabetes) activates AMP-Activated Protein Kinase (AMPK) which promotes ____ in the liver and glucose uptake in the ____, but inhibits _____ acid synthesis and gluconeo.
AMPK promotes GLYCOLYSIS in the liver and glucose uptake in the MUSCLES, but inhibits FATTY acid synth and gluconeo
Normal HbA1c levels are about ____-____%
4-6%
Cytokines, EPO, interferons, prolactin, and other ligands bind receptors with _____ enzymatic activity, whereby the enzymatic activity is carried out by a protein that is distinct from the receptor itself (i.e. JAK kinase.)
ASSOCIATED
If Erythroid progenitor cells have EPO receptors but are not stimulated by EPO, they undergo _____
Apoptosis
Interferons increase _____ resistance, Interleukins control ____ and ____ cell differentiation, and GMCSF increases _____ and _____ production.
Interferons increase VIRUS resistance, Interleukins control B and T cell differentiation, and GMCSF increases GRANULOCYTE and MACROPHAGE production
In the case of cytoline receptors, _____ kinase is activated via a conformational change in the intracellular domain of the receptor it’s associated with. It then phosphorylates itself and the receptor, at which point ____ binds the phosphorylated receptor and becomes phosphorylated itself.
JAK kinase.
STAT (Signal Tranducer and Activator of Transcription.)
Albright hereditary Osteodystrophy (AHO) is a type of ______ (PHP) characterized by short stature, round face, obesity, and subcutaneous ossification of soft tissue. In AHO, the ____ subunit of the trimeric Gs protein is defective. Keep in mind, Parathyroid hormone normally increases cAMP .
PSEUDOHYPOPARATHYROIDISM.
In AHO, the ALPHA subunit of the Gs Protein is defective.
Inflammatory cytokines signal via _____ cleavage. They can cause the phosphorylation and _____ of an inhibitor protein (signaling it for degradation by a proteosome) bound to a transcription factor (i.e. NF-kapaB.) The transcription factor is only active when freed from its inhibitor.
Proteolytic cleavage. They can cause the phosphorylation and UBIQUITINATION of an inhibitor protein bound to a transcription factor (i.e. NF-kapa.)
Wnt receptors (implicated in colon cancer), Hedgehog receptors (implicated in basal cell carcinoma), and Notch receptors (implicated in T-cell acute lymphoblastic leukemia and calcific aortic disease) are also examples of receptors that cause irreversible protein _____.
CLEAVAGE
