Research Project
3652847
Growth hormone (GH) secretion is abnormal in children with malnutrition, showing high baseline levels which are not suppressed by carbohydrate administration. Conventional provocative stimuli do not further enhance this increased secretion of GH. The abnormal secretory dynamics usually resolve during the course of refeeding. The mechanism of this metabolic abnormality is not understood. Recently, GRF testing has been shown to be a useful probe to test GH secretory dynamics. Our purpose is to investigate the response of GH to GRF administration in children with malnutrition before and after refeeding, and to see what role GRF may play in this hypersecretion of GH. GRF testing, which directly stimulates the pituitary to release GH, probes this system in a different way from conventional tests of GH release, such as ITT. The ITT and ATT seem to work indirectly and result in higher CNS centers stimulating endogenous GRF release. GRF studies in malnourished infants would allow us to address the following questions: 1) Could the elevated maximal secretion of GH associated with untreated malnutrition be further enhanced by GRF administration, or would such infants prove to be as refractory to GRF as they appear to be to other growth hormone provocative stimuli? 2) What changes in the GH response to GRF would occur during refeeding? 3) How would changes in sensitivity to GRF change with the increase of somatomedin C levels during nutritional recovery? We propose to administer GRF to malnourished infants 6 months and older, refeed the children and repeat the GRF test.
