Fate of Insulin
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Insulin is distributed only extracellularly. It is a peptide; gets degraded in the g.i.t. if given orally. Injected insulin or that released from pancreas is metabolized primarily in liver and to a smaller extent in kidney and muscles.
FATE OF INSULIN
Insulin is distributed only extracellularly.
It is a peptide; gets degraded in the g.i.t. if given orally. Injected insulin
or that released from pancreas is metabolized primarily in liver and to a
smaller extent in kidney and muscles. Nearly half of the insulin entering
portal vein from pancreas is inactivated in the first passage through liver.
Thus, normally liver is exposed to a much higher concentration (4–8 fold) of
insulin than are other tissues. As noted above, degradation of insulin after
receptor mediated internalization occurs to variable extents in most target
cells. During biotransformation the disulfide bonds are reduced—A and B chains
are separated. These are further broken down to the constituent amino acids.
The plasma t½ is 5–9 min.
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