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[HGH secretion after oral application of L-dopa and L-carbidopa (author's transl)]
Insights
L-Dopa and L-Carbidopa effectively stimulate human growth hormone (HGH) secretion in children. Two blood samples, taken 40 and 90 minutes after administration, are sufficient to assess HGH levels and rule out deficiency.
Area of Science:
- Pediatric Endocrinology
- Pharmacology
Background:
- Human Growth Hormone (HGH) deficiency can impact a child's growth.
- Assessing HGH secretion requires reliable stimulation tests.
Purpose of the Study:
- To evaluate the efficacy of L-Dopa and L-Carbidopa (Nacom) in stimulating HGH secretion in children.
- To determine optimal timing for blood sampling to assess HGH response.
Main Methods:
- 12 children (aged 6-14 years) received an oral dose of 250 mg L-Dopa and 25 mg L-Carbidopa.
- Serum HGH concentrations were measured at regular intervals post-administration.
- Subjects were grouped based on the time to peak HGH levels.
Main Results:
- All participants exhibited a significant increase in HGH secretion, with a mean peak of 19.6 ng/ml.
- Two distinct response patterns emerged: peak HGH at 20-40 minutes and 60-90 minutes.
- A two-sample blood draw at 40 and 90 minutes post-ingestion proved sufficient for evaluation.
Conclusions:
- L-Dopa and L-Carbidopa are effective agents for stimulating HGH release in pediatric subjects.
- A 40 and 90-minute sampling protocol can reliably aid in excluding HGH deficiency.
- Further discussion addresses the physiological mechanisms underlying L-Dopa/L-Carbidopa-induced HGH secretion.
Abstract:
The stimulatory effect of L-Dopa and L-Carbidopa (Nacom) on HGH secretion was determined in 12 children of normal height aged from 6 to 14 years. Each child received a standard dose of 250 mg L-Dopa and 25 mg L-Carbidopa p.o. HGH concentration in the serum was determined at standard intervals. All subjects showed a sufficient increase of HGH. The mean value was 19.6 ng/ml. According to the maximum values of the HGH concentration the sample can be divided into two groups; the first group reached the highest values after 20--40 min, the second one after 60--90 min. On evaluation of the curve of the mean values it appears that 2 blood samples taken 40 and 90 min after the ingestion of L-Dopa and L-Carbidopa are sufficient in order to exclude HGH deficiency. The theoretical background for HGH secretion after stimulation by L-Dopa and L-Carbidopa is discussed.