Potential uses of human pancreatic growth hormone-releasing factor 1-44 amide.

A family of growth hormone releasing peptides have been isolated and characterized from human pancreatic islet cell tumours. We have compared the growth hormone release in normal volunteers and patients with various hypothalamo-pituitary disorders, following direct stimulation of the pituitary using 50 micrograms of the most potent homologue, hp GRF 1-44 amide i.v. with that following indirect stimulation using oral clonidine 0.15 mg/m2, which depends on intact hypothalamic mechanisms. These tests both produced a wide variation in GH response in normal volunteers, considerable GH release following hp GRF 1-44 amide but little after clonidine in idiopathic GH deficiency, and indistinguishable, negligible responses in patients with craniopharyngiomas and pituitary tumours associated with GH deficiency. Two untreated acromegalics showed GH increments in the normal range despite elevated basal levels. It is concluded that hp GRF 1-44 amide is of limited diagnostic value by itself, but may be of considerable therapeutic use in patients with idiopathic GH deficiency.