Identification of somatogenic binding sites in liver microsomes from normal mice and transgenic mice expressing human growth hormone gene.

Somatogenic binding sites were detected and characterized in microsomal preparations from livers of normal mice and mice expressing metallothionein-I/hGH (mMT/hGH) hybrid gene, using 125I-labelled bovine or human GH, or a photoreactive derivative of hGH (125I-AP-hGH1). Specific binding of 125I-bGH was detected in liver microsomes from both normal and transgenic mice with an apparent Kd of 2 nM. 125I-hGH was partially displaced by bGH. 125I-AP-hGH1 was covalently bound to the microsomal preparations, and bGH prevented the formation of the 130 kDa species with no appreciable effect on 63 kDa and 70 kDa lactogenic complexes.