THE PARADOXICAL RESPONSE OF GROWTH-HORMONE (GH) TO THYROTROPIN-RELEASING-HORMONE (TRH) IN CONSTITUTIONALLY TALL CHILDREN INVOLVES A CHOLINERGIC PATHWAY
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Date
1989
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Abstract
To investigate whether or not a cholinergic pathway is involved in the paradoxical response of GH to TRH in constitutionally tall children, we studied 8 healthy prepubertal children aged 42/12 - 7 10/12 yr, whose heights were over the 95th percentile of the NCHS tables. We defined as "paradoxical" a GH increment greater than 5 ng/ml in response to TRH. Five out of 8 children showed a paradoxical response of GH to TRH (mean GH peak after TRH of 10.7 .+-. 1.1 ng/ml). Pretreatment with atropine (0.01 mg/kg IM 30 min prior to the TRH administration) abolished the TRH induced GH rise (peak GH after TRH of 1.5 .+-. 1.0 ng/ml, p < 0.01) but did not modify the TSH response (peak TSH after TRH: basal conditions 8.7 .+-. 0.8 .mu.U/ml, post atropine: 9.5 .+-. 1.4 .mu.U/ml, p > 0.05). Our results demonstrate that a cholinergic pathway is involved in the paradoxical response of GH to TRH in constitutionally tall children.