Urinary excretion of catechol metabolites particularly MHPG in children. Relation to age, body mass indices and...

Determinations of noradrenaline (NA), adrenaline (A), vanillylmandelic acid (VMA), metanephrines (MN), homovanillic acid (HVA) and 3-methoxy-4-hydroxy-phenylglycol (MHPG) were performed in 24 h urine samples of three groups of children: 26 normal children, 7 cases of congenital myxedema (not treated for at least one month) and 8 obese children to whom a short (9-14 days) course of thyroid extract was administered. No sex difference was noted in any group. The results in the control group (mean +/- SE) were as follows: NA 23.8 +/- 2.18 micrograms, A 6.2 +/- 0.35 micrograms, VMA 1.58 +/- 0.22 mg, NM 0.526 +/- 0.079 mg, HVA 1.24 +/- 0.142 mg, MHPG, 1.60 +/- 0.232 mg. The excretion of MHPG was significantly (cor)related to NA (p less than .05) and completely unrelated to the other derivatives. Significant equations and curves were obtained from linear regression analysis of MHPG excretion to age (p less than .025), weight (p less than .025), body surface (p less than .05), and creatinine excretion (p less than .05) but not to height and Quetelet index. No significant change was encountered in both myxedema or thyroid extract-treated obese group in any urinary metabolite determined. It was concluded that in children the urinary MHPG excretion is closely correlated to NA excretion and is linearly dependent on age, weight and creatinine extraction. Thyroid activity seems to have no evident effect on urinary excretion of various catechol metabolites. Suggestion is made that the MHPG (cor)relation(s) found originate(s) in corresponding change(s) of noradrenergic receptor sensitivity within the brain.