Neuroendocrine effects of toxic and low blood lead levels in children.

From 3 million to 4 million children in America have lead poisoning. This environmental toxin affects 1 in every 6 children younger than 6 years of age in the United States. The marked effects of lead toxicity on the central nervous system are well known, ie, lowering IQ and impairing memory, reaction time, and the ability to concentrate. Children are at greatest risk for the central nervous system effects of lead because the central nervous system is at its peak in development during the first few years of life. The negative correlation of stature and blood lead level (bPb) found in the National Health and Nutrition Examination Survey directed the authors to evaluate the possible neuroendocrine effects of this toxin in children. Twelve children were studied during toxic (greater than or equal to 40 micrograms/dL) and low bPb (less than 40 micrograms/dL). Classic provocative stimuli, L-dopa (15 mg/kg by mouth) and insulin (0.1 U/kg given intravenously), were used to determine human growth hormone (hGH) responses during toxic bPb and after chelation therapy in six of the subjects. An additional four subjects were studied during low bPb. In two patients LGH levels were determined every 20 minutes for 24 hours during toxic bPb. Thyroid-stimulating hormone and prolactin responses to thyrotropin-releasing hormone were also determined. All children studied showed growth retardation during toxic bPb. Mean peak hGH responses to provocative stimuli were lower during toxic bPb, but the responses were all within normal limits.(ABSTRACT TRUNCATED AT 250 WORDS)