Plasma Growth Hormone Studies in Normal Individuals and Acromegalic Patients

A radioimmunoassay for HGH employing 125I-labeled HGH and a precipitating goat anti-rabbit gamma globulin antiserum has been used to measure the plasma growth hormone (PGH) concentrations in normal individuals, and in acromegalic patients before and after treatment with alpha particles to the pituitary. The assay requires no extraction or dilution of the unknown plasma. It was observed with this assay that nonfasted normal females on cyclic estrogen-progestin therapy often have extremely high PGH concentrations, whereas plasma from normal males, taken under the same conditions, reveals extremely low values with a relatively narrow range. In addition to clinical signs of improvement in acromegaly after alpha particle irradiation to the pituitary, objective evidence of improvement was obtained in all such treated patients in terms of their PGH levels. After treatment of acromegalic patients, the fasting PGH level may be the best assessment of the effectiveness of the treatment.