24-HOUR PROFILE OF GROWTH-HORMONE IN CYCLIC NOCTURNAL TOTAL PARENTERAL-NUTRITION

Objective. To detect the effect of the loss of alimentation rhythmicit y on a circadian rhythm of human growth hormone (HGH) secretion, a 24- hour profile of HGH was studied in a growing child on cyclic nocturnal total parenteral nutrition (TPN). Twenty-four-hour profiles of substr ates and metabolic hormones were also studied to evaluate the efficien cy of cyclic nocturnal TPN on childhood growth. Study Design. Periodic blood samples from a child with megacystis-microcolon-intestinal-hypo peristalsis syndrome were obtained on five occasions, at ages 6, 7, 8, 9, and II, when she was on cyclic nocturnal TPN. Results. Peak HGH se cretion appeared with the onset of deep sleep despite the concomitant hyperglycemia and hyperinsulinemia induced by TPN at night. Smaller pe aks of HGH were also observed during the noninfusion period during the day. Twenty-four-hour profiles of substrates and metabolic hormones i ndicated a switch from glucose use during the infusion phase to an oxi dation of lipids during the noninfusion period. Conclusion. The fact t hat the patients growth curve remains within normal limits suggests th at cyclic nocturnal TPN would be an efficient method of nutritional su pport. During cyclic nocturnal TPN, regular rhythm of HGH secretion oc curs, and normal childhood growth is achieved.