Stimulation of growth hormone secretion by levodopa-propranolol in children and adolescents.

Levodopa, 0.5 gm/1.73 sq m, and propranolol, 0.75 mg/kg, were administered orally to 23 children with short stature and 10 children suffering from various disorders. Glucose and insulin tolerance tests and arginine infusions were also utilized in some of these subjects to determine growth hormone (GH) response. Seventeen subjects with short stature had a GH peak greater than 5 ng/ml to the combined levodopa-propranolol provocative test (DPPT). The mean GH peak concentration obtained in this group was 19.6 +/- 1.8 (SEM) ng/ml, and in 94.1% of these children the peak was obtained at either 30, 60, or 90 minutes following the administration of the two drugs. Six subjects with short stature who failed to respond to the DPPT had abnormal responses to at least two other stimulatory tests and were classified as GH-deficient. Two subjects among the ten suffering from various disorders failed to respond to the DPPT. The first was a case of chromophobe adenoma of the pituitary gland with primary amenorrhea and luteinizing hormone deficiency, and the second a case of Hand-Schüller-Christian disease. The DPPT appears to be a reliable, safe, and easy-to-perform test to determine GH reserve.