NORMAL GROWTH IN A PATIENT WITH SEPTO-OPTIC DYSPLASIA DESPITE BOTH GROWTH-HORMONE AND IGF-I DEFICIENCY

A 17 year-old female with septo-optic dysplasia (SOD) and hypopituitar ism who has grown normally despite GH deficiency is presented, Her ser um was examined to test current hypotheses to explain the phenomenon o f growth without GH, The patient's serum possessed potent irt vitro gr owth-promoting activity (GPA) in an erythroid progenitor-cell clonal p roliferation assay consistent with the patient's normal growth perform ance, In contrast to previously reported cases of growth without GH, t otal IGF-I concentrations were very low in this patient, precluding IG F-I being responsible for the observed GPA and normal growth pattern, Furthermore, circulating free IGF-I was also low which is reported for the first time in such a case, A detailed picture of IGP-binding prot eins is also presented, To test the hypothesis that hyperinsulinemia m ight be responsible for the observed GPA, in vitro GPA experiments wer e performed before and after removal of insulin by immunodepletion, Ne ither partial nor complete removal of insulin abolished the in vitro c ell proliferation response, These data demonstrate that neither IGF-I nor insulin is the factor responsible for GPA in at least this patient with SOD and growth without GH.