Synthetic analogs of growth hormone-releasing factor with antagonistic activity [formula omitted

Abstract

Analogs of human and rat growth hormone-releasing factor (hGRF and rGRF), related to [D-Arg 2]hGRF(1–29)NH 2, were synthesized by solid phase methodology. Their capacity to inhibit growth hormone secretion stimulated by hGRF(1–44)NH 2 was tested on rat anterior pituitary cells in monolayer culture. Among the analogs of hGRF, [D-Arg 2,29,Arg 30]hGRF(1–30)NH 2 showed the highest antagonistic potency of 3.64 relative to [D-Arg 2]hGRF(1–29)NH 2 = 1. However, the most potent analog synthesized thus far was [N-Ac-His 1, D-Arg 2,Ala 15]rGRF(1–29)NH 2, which showed a relative potency of 27.7.