Tetrahydrobiopterin in the Treatment of Infantile Hypertrophic Pyloric Stenosis

Evidence is emerging that reduced nitric oxide production may be involved in the pathogenesis of hypertrophic pyloric stenosis. Nitric oxide synthase (NOS) requires tetrahydrobiopterin (BH₄) for activity. Four infants with hypertrophic pyloric stenosis were treated with oral BH₄(10 mg/kg/day) for 2.5 days. Although plasma total biopterin increased significantly at 3, 27, and 51 h after BH₄administration, there was no effect on the production of plasma cGMP, nitrite, nitrate, or citrulline. Ultrasound investigations before and after the ingestion of BH₄revealed no changes in the hypertrophic pyloric stenosis. We conclude that oral BH₄, in the dose utilized in our investigations, does not modify the cause of hypertrophic pyloric stenosis, presumably because it did not restore nitric oxide production in the nonadrenergic noncholinergic nerves of the enteric nervous system.