ABSTRACT
This book is primarily concerned with L-tryptophan. However, two major derivatives of tryptophan, serotonin and melatonin, have gained prominence in recent years and appear to have overshadowed L-tryptophan. For example, during the last 35 years (1965 to 2000) the total citations on the Medline database were as follows: tryptophan, 17,106; serotonin, 44,841; and melatonin, 8,130. In Medline literature citations, serotonin has by far (2-to 3.5-fold) outnumbered L-tryptophan continuously from 1961 until the present time (Figure 10.1). Also, it is interesting to note that melatonin citations have gradually climbed from 1961 to the present and now equal those of tryptophan (Figure 10.1). The citations refer to total citations, which include all subcategories of each of the three categories.
