title: The effect of L-dopa with and without decarboxylase inhibitor on growth hormone secretion in children with short stature.
abstract: The efficiency of L-dopa alone and L-dopa plus a dopa-decarboxylase inhibitor (carbidopa) in provoking growth hormome (GH) secretion was studied 40 children with short stature. By preventing the extracerebral metabolism, carbidopa increases the availability of L-dopa to the brain. The study was designed as paired series of growth hormone stimulation tests in which the effect of L-dopa alone, in different dosage schedules, was compared with the same dose level of L-dopa plus carbidopa, When L-dopa was given in full dose (125-500 mg), there was no significant difference in the serum GH concentrations at any time of sampling. In the lower dose level, the stimulant effect of L-dopa alone tended to be exceeded by the combination of L-dopa and carbidopa. The serum GH responses to the different schedules indicate that an optimal hypothalamic dopamine concentration for GH release could be achieved with a considerably lower dose of L-dopa than those employed in previously reported studies. When L-dopa is combined with a dopa decarboxylase inhibitor, the children have the advantage of less side effects in the form of nausea and vomiting.
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D001827:Body Height; D002230:Carbidopa / Q000008:administration & dosage / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology*; D007980:Levodopa / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D012636:Secretory Rate / Q000187:drug effects
chemical_list: D006834:Hydrazines; D007980:Levodopa; D013006:Growth Hormone; D002230:Carbidopa