[Treatment of growth hormone deficiencies by GHRH]

Production of growth hormone is directly stimulated by a hypothalamic factor, called GHRH. This factor, that was first isolated in 1982, has now been synthetized and is under study for the treatment of growth hormone deficiencies due to hypothalamic dysfunction. A wide range of dosages have been used (3 to micrograms/kg/d); administration has usually been by subcutaneous injections, but continuous or pulse pump infusions have been used. In most series, GHRH treatment has been followed by increases in growth velocities; however, individual responses have varied widely, with some patients being "responders" and others "non-responders". No accurate criteria for differentiating responders from non-responders prior to treatment have as yet been identified. Studies of growth hormone secretion during treatment have usually evidenced a moderate increase both in the response to the GHRH test and in C/IGF I somatomedins. Investigations for anti-GHRH antibodies have been negative in most instances. GHRH treatment still raises many unanswered questions, including the effective dosage, exact indications, and mode of administration. Further studies are therefore needed before use of GHRH can become widespread.