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  #1  
Old 08-02-2010
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Pancreas Chloroquine effect on pancreatic beta cells

Chloroquine is a weak base that neutralizes acidic organelles. In a pancreatic beta cell, which of the following would be a direct effect of chloroquine treatment?
A. Increased proinsulin content in secretory vesicles
B. Increased release of C peptide
C. Increased number of amylase-containing secretory vesicles
D. Reduced translation of glucagon mRNA
E. Increased stability of insulin mRNA
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  #2  
Old 08-02-2010
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is the answer A?
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Old 08-03-2010
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No sure about that but as Chloroquine causes "hypoglycemia" i would go with option

A. Increased proinsulin content in secretory vesicles
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Old 08-03-2010
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same
i think also A
concerning with intracellular transport of proinsulin in beta cells.

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Old 11-21-2011
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what is the right answer here??
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Old 11-21-2011
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Hey dr.muhamad I dont think its A, cause why would it increase the amount of insulin in the vesicle? Mustnt that be fairly constant? i would go with increased release of C-peptide, since this means equimolar release of insulin. what do u think?
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Old 11-21-2011
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The answer is: A. Increased proinsulin content in secretory vesicles

Chloroquine treatment inhibits the conversion of proinsulin to insulin, resulting in decreased formation of insulin within secretory vesicles. Chloroquine neutralizes acidic compartments such as the secretory vesicles. Acidification causes concentration of the contents of secretory vesicles, facilitates breakdown of the contents of phagosomes and lysosomes, and is involved in the cleavage of prohormones to their active forms (e.g., proinsulin to insulin). The acidification process functions through a vacuolar H+-proton pump that is present in the membranes of most endocytic and exocytic vesicles, including those of the phagosomes, lysosomes, secretory vesicles, and some compartments of the Golgi. Ribosomes are not dependent on a proton pump mechanism and are, therefore, less sensitive to chloroquine. Gene and message expression and message stability are also not targets for chloroquine. Note that pancreatic beta ( ) cells synthesize insulin. Proinsulin is split into C peptide + insulin in secretory vesicles. In vivo, C-peptide release can be used to measure production of insulin by a patient's pancreatic beta cells. This is particularly useful in patients who are receiving insulin. Glucagon is synthesized by alpha ( ) cells, and amylase is an exocrine pancreatic product produced by the acinar cells.
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Old 11-21-2011
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Default should be A

reason i think is that if something neutralises acidity it'll decrease the cleavage of pro to active component and thus only increase pro not the components of cleavage
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