Cirrhosis - Identify

[scopusmount]

The two major secretory pathways A B C D (pathway I) and C E (pathway II) are illustrated in the figure. Albumin secretion by hepatocytes occurs by pathway II. In a patient with cirrhosis, the serum levels of albumin are reduced. Which one of the following is the most likely cause of the reduced secretion of albumin?
(Modified, with permission, from Avery JK. Oral Development and Histology. 3rd ed. New York, NY: Thieme Medical; 2001.)


A.
Reduced binding of "A" to receptors

B.
Reduced numbers of functional hepatocytes

C.
Down-regulation of "B" on hepatocytes

D.
Reduced activity of the cAMP-activated signal transduction system

E.
Increased cAMP levels

[Hitman]

Ans : B .........

[Evergreen]

Originally Posted by Hitman

Ans : B .........

Agree with that.... B might be correct.

Any comments?

[scopusmount]

Cirrhosis damages hepatocytes leading to a reduction in synthesis of serum proteins. Pathway II on the diagram (C E) is the constitutive (default) pathway, used by fibroblasts for synthesis of proteoglycans, fibronectin, and collagen; serum proteins (albumin, transferrin, and lipoprotein) synthesized by hepatocytes; and plasma-cell-derived immunoglobulins. Pathway I (A D) is the regulated pathway. It differs from constitutive secretion (C E) in its requirement for a secretagogue (substance that induces secretion from cells [answers a and c]), which binds to a cell-surface receptor. Secretion in the constitutive pathway is not regulated at the level of second messengers (answers d and e). Regulated secretion (pathway I) requires recognition of a receptor (B) for its ligand (A, resulting in secretagogue-receptor binding). The synthetic processes in the two pathways are similar until the Golgi. The vesicles that bud from the Golgi (D) in the regulated pathway are clathrin-coated and contain a receptor involved in the concentration of secretory product. The constitutive pathway shuttles proteins such as integral membrane proteins and lipids in vesicles to the apical and basolateral membranes. The vesicles are nonclathrin-coated in the constitutive pathway. Exocytosis requires vesicle fusion with the membrane in both regulated and constitutive pathways. Ras-superfamily GTPases, members of the protein kinase D family and tethering complexes, like the exocyst that link to microtubules, are involved in constitutive secretion.