Growth enhancement by dopaminergic therapy in children with intrauterine growth retardation

In a previous study we reported stimulation of growth velocity in hypopituitary children by dopaminergic therapy (DA), i.e. either L-dopa or bromocriptine. The purpose of the present study was to determine if DA stimulated endogenous GH release and growth in children with intrauterine growth retardation (IUGR), who also had microcephaly and psychomotor retardation. The effect of DA on serum LH, FSH, gonadal steroids, cortisol, T4, and TSH also was examined. Six prepubertal children [four girls and two boys; bone age (BA), 1.5-4 yr] with IUGR were divided into two study groups. Group I (n = 3) received L-dopa (15 mg/kg) orally every 6 h for 6 months. Group II (n = 3) received bromocriptine (1.25 mg) orally every 12 h for 6 months. At the end of the 6 months of DA therapy, both groups received human GH (hGH) (0.1 IU/kg) im thrice weekly for 6 months. The growth rate in group I was 6.5 +/- 0.1 (+/-SD) cm/yr after 6 months of DA compared with a pretreatment growth rate of 4.1 +/- 0.7 cm/yr. Individual increments ranged from 38-80%. All three children achieved normal growth rates for their BA. Similarly, the growth rate in group II increased to 7.7 +/- 0.9 cm/yr from a pretreatment growth velocity of 4.2 +/- 1.6 cm/yr. The growth increments of group II ranged from 43-133%. Two children of group II achieved normal growth rates for their BA, and all had a significant increase in height (P less than 0.05). Four of the six children achieved normal growth velocities after 6 months of hGH therapy. Five of the six children significantly increased their mean hGH responses to L-dopa or bromocriptine during chronic DA therapy compared with the pretreatment period. Maximum serum hGH values in group I increased from a pretreatment mean (and range) of 12 +/- 4 (+/-SE) ng/ml (5-18 ng/ml) to 46 +/- 12 ng/ml (21-64 ng/ml). The maximum hGH concentrations in group II increased from a pretreatment mean and range of 21 +/- 7 ng/ml (11-34 ng/ml) to 48 +/- 4 (42-56 ng/ml). Also, four of the six children had correspondingly increased somatomedin-C concentrations after DA therapy. The findings of this preliminary study indicate that dopaminergic therapy, i.e. L-dopa or bromocriptine, induced linear growth in patients with a form of IUGR associated with microcephaly and psychomotor retardation. DA therapy perhaps may be useful in treating other various forms of IUGR.