Modification of 24-hour growth hormone secretion after continuous subcutaneous infusion of growth hormone-releasing hormone (GHRH (1-29)NH2) in short children with low 24-hour growth hormone secretion.

Six short children with low 24-hour growth hormone (GH) secretion were treated with continuous subcutaneous infusion of GHRH (1-29)NH2 for 3 weeks using a portable infusion pump. Restoration of pulsatile GH secretion was observed in all three children treated with 40 micrograms/kg/day of GHRH, but in only one of the three children treated with 20 micrograms/kg/day. All parameters of 24-hour GH secretion increased, but in five children the magnitude of the GH response was greater on day 1 than on day 21 of GHRH treatment. This decrease was not observed in the single child who responded to a low dose of GHRH (20 micrograms/kg/day); on the contrary, the response in this patient was greater after 21 days of GHRH treatment. Plasma levels of GHRH (1-29)NH2 were significantly higher on day 21 than on day 1 of treatment, suggesting altered pharmacokinetics over time. The effect of GHRH treatment on growth could not be determined because of the short duration of the study, but the data obtained on 24-hour GH secretion and GHRH metabolism suggest that a long-acting analogue of GHRH could be useful for the treatment of GH deficient or insufficient children.