PLASMA TRYPTOPHAN IS ALTERED IN THE DAHL RAT MODEL OF HYPERTENSION

Increased dietary L-tryptophan (TRP) has been shown to blunt the devel opment of elevated blood pressure in several rat models of hypertensio n. Plasma TRP concentrations were measured in DS and Dahl salt-resista nt (DR) rats after 1, 4, and 6 weeks on a high salt diet which produce d a significant elevation in blood pressure in the DS rats after 4 and 6 weeks. Plasma TRP was significantly lower in the DS rats when compa red to the DR rats after 4 and 6 weeks on the high salt diet. Other pl asma large neutral amino acids in the DS and DR rats were not signific antly different after either 4 or 6 weeks on the high salt diet. No di fferences in plasma TRP were observed in DOCA salt-induced hypertensiv e, spontaneously hypertensive (SHR), stroke-prone SHR, or fructose-ind uced hypertensive rats compared to their normotensive controls. Theref ore, DS rats appear to have a selective salt-related defect in periphe ral TRP regulation.