Endothelin is a peptide with vasoactive and diuretic potential. Its re
lease has been demonstrated from endothelial and renal epithelial cell
s. Urinary excretion of endothelin, as shown by others, is thought to
reflect intrarenal production. We measured endothelin by RIA in a popu
lation of healthy children from Germany and Hungary (group 1), neonate
s (group 3) and children before and during forced diuresis (groups 2a
and 2b). Group 1 consisted of 24 children living in Germany and 13 chi
ldren resident in Hungary. The age range in this group was 2.9-17 year
s. Daily excretion correlated significantly with age (r = 0.48,p < 0.0
01), but endothelin excretion corrected for body surface area remained
constant with regard to the age group studied. This indicates that bo
dy or kidney size may influence endothelin excretion, respectively. Th
ere was no difference in endothelin excretion between the two countrie
s. In premature infants and neonates (group 3), daily excretion of end
othelin was highest in infants with very low gestational ages and decr
eased in full-term neonates to values not significantly different to t
he group of older children. The high values in premature infants may h
ave been influenced by mechanical ventilation of physical stress, whic
h cannot be differentiated in this study, however. In contrast to repo
rted results in adults, renal excretion of endothelin was correlated p
ositively to urine flow in all groups. Furthermore, the influence of f
orced diuresis was evaluated in 10 children with oncological disease b
efore (group 2a) and during (group 2b) forced diuresis with fluid load
(3 1/m(2); n = 4) and fluid load with furosemide injection (0.3-1.0 m
g/kg body weight; n = 6). During this diuretic state, endothelin excre
tion was enhanced significantly.