Fig. 1.
Effect of cigarette smoking on plasma tryptophan levels. Values are mean ± SD of each group. Tryptophan levels were expressed as mg/dl. *Indicates a p < 0.001 is statistically significant between groups
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.