Evaluation of intraplatelet and urinary 5-hydroxytryptamine (5-HT), and urinary 5-hydroxyindoleacetic acid (5-HIAA) levels in patients with toxemia of pregnancy.

Toxemia of pregnancy is considered to represent a disorder of activated blood coagulation. To identify possible indicators for evaluating the clinical course of toxemia, we measured the intraplatelet and urinary levels of 5-HT and its urinary metabolite, 5-HIAA in 25 patients with toxemia vs. 29 non-toxemic pregnant women. 5-HT and 5-HIAA were assayed by high performance liquid chromatography (HPLC). During the 24-34 weeks of gestation, the toxemic patients and the non-toxemic women each had low intraplatelet levels of 5-HT which didn't differ significantly. A significant (p < 0.05) decrease in intraplatelet 5-HT was observed in the toxemic patients vs. the non-toxemic women after the 35th week of gestation until delivery. The untake of exogenous 5-HT by platelets was increased in the toxemic patients, and their urinary (5-HT+5-HIAA) value increased significantly (p < 0.05) as compared with the non-toxemic women after the 35th week of gestation until delivery. A decrease in the intraplatelet level of 5-HT and an increase in the urinary level of (5-HT+5-HIAA) were observed in the toxemic patients, findings that paralleled the progression of this disorder. Serial measurements of intraplatelet and urinary levels of 5-HT and urinary levels of 5-HIAA in the toxemic patients revealed a significant correlation between disease activity and those levels. These observations support the concept that the measurement of intraplatelet and urinary levels of 5-HT and of urinary levels of 5-HIAA may be useful in following the clinical course of the toxemic patients.