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. Author manuscript; available in PMC: 2011 Mar 16.
Published in final edited form as: Neuropeptides. 2010 Nov 2;44(6):457–466. doi: 10.1016/j.npep.2010.08.003

Figure 5. Regulation of (Met)enkephalin in cathepsin L gene knockout mice.

Figure 5

(a) (Met)enkephalin (ME) levels in brains of knockout mice. ME levels in extracts of brain tissue from cathepsin L gene knockout mice (−/−) and wild-type control mice (+/+) were measured by RIA, shown as the mean + sem, with N = 10 for each group. A significant decrease (*) in enkephalin levels in knockout mice was observed (p < 0.013, two-tailed t-test).

(b) Elevated (Met)enkephalin production during cathepsin L expression. Elevation of cellular content of (Met)enkephalin in PC12 cells was observed after coexpression of cathepsin L (CL) and proenkephalin (PE). The radioimmunoassay (RIA) for (Met)enkephalin measures processed (Met)enkephalin since the RIA does not crossreact with PE. Controls included cells transfected with vector alone (no insert, control), PE alone, and cathepsin L (CL) alone. Experiments were conducted by transfection of triplicate wells of cells for each group, with RIA assay of (Met)enkephalin conducted in duplicate assays performed twice. Results are expressed as mean + standard error.