M. Aldegunde et al., UPTAKE OF TRYPTOPHAN INTO BRAIN OF RAINBOW-TROUT (ONCORHYNCHUS-MYKISS), The Journal of experimental zoology, 282(3), 1998, pp. 285-289
Brain and plasma levels of tryptophan, 30 min after intraperitoneal ad
ministration of increased doses of L-tryptophan (0, 12.5, 25, 37.5, 50
, 62.5, 75, 87.5, 100, 150, and 200 mg/kg body wt), D-tryptophan (0, 2
5, 50, 75, 150 mg/kg body wt) or the joint administration of L-tryptop
han and L-tyrosine (75 mg/kg body wt), were analyzed spectrofluorimetr
ically. The results show that the uptake of tryptophan into the brain
takes place through a stereospecific and saturable carrier, which is c
ommon for tyrosine and possibly other neutral aminoacids, in a way sim
ilar to that observed for mammals. On the other hand, the findings ind
icate that the uptake of tryptophan into brain of rainbow trout seems
to be little sensitive to the effects of competition with other amino
acids. (C) 1998 Wiley-Liss, Inc.