Growth Hormone (GH) Secretion in Patients with an Inactivating Defect of the GH-Releasing Hormone (GHRH) Receptor Is Pulsatile: Evidence for a Role for Non-GHRH Inputs into the Generation of GH Pulses (original) (raw)

2001, The Journal of Clinical Endocrinology & Metabolism

GH secretion is regulated by the interaction of GHRH and somatostatin and is released in 10–20 pulses in each 24-h cycle. The exact roles in pulse generation played by somatostatin, GHRH, and the recently isolated GH-releasing peptide, Ghrelin, are not fully elucidated. To investigate the GHRH-mediated GH secretion in human, we investigated pulsatile, entropic, and 24-h rhythmic GH secretion in two young adults (male, 24 yr; female, 23 yr) from a Moroccan family with a novel inactivating defect of the GHRH receptor gene. Data were compared with values in age- and gender-matched controls. Plasma GH concentration were measured by a sensitive immunofluorometric assay, with a detection limit of 0.01 mU/L. All plasma GH concentrations in the female patient were measurable; in the male patient 30 of 145 samples were at or below the detection limit. GH secretion was pulsatile, with 21 and 23 secretory episodes/24 h in the male and female patients, respectively. The fraction of basal to tot...