CATECHOLAMINE (CA) SECRETION AND RESPONSE TO A STANDING POSITION IN NORMOTENSIVE CHILDREN

Abstract

Sulfoconjugation is a long time recognized metabolic pathway of CA, but its importance has only recently been appreciated. The degree of conjugation depends on the type of CA: epinephrine (E), norepinephrine (NE) and dopamine (DA). Basal free and conjugated (total) plasma CA levels (radioenzymatic method) were evaluated in 35 normotensive children (aged 6 nonths-5 years). In 16 of them a standing test was performed. Twenty-one normotensive adults were also studied. It was found a positive and significant correlation between total DA and total NE in both, children and adults (r=0.42, p<0.05; r=0.45, p< 0.05). The DA and NE conjugation degree were similar in all groups, meanwhile the E conjugation degree was significantly lower in the youngest children (6 months-5 years group, p<0.01). In response to standing, 10 out of 16 children showed an increase in free NE and DA (p<0.05 and p<0.01), while only an increase in free DA levels was observed in the rest of the groups. These data showed that the sulfooonjugation mechanisms are similar in children as in adults. Moreover, besides the already reported plasma NA response to standing, a significant plasma free DA increase was found.