Recombinant DNA-derived methionyl human growth hormone is similar in membrane binding properties to human pituitary growth hormone

N-terminal methionyl human growth hormone (met-hGH), expressed in Escherechia coli by recombinant DNA techniques, was compared to native human pituitary growth hormone in receptor-binding activity. Met-hGH was indistinguishable from pituitary hGH in binding to specific hGH receptors on cultured IM-9 lymphocytes and to "lactogenic" receptors on pregnant rat liver membranes. Additionally, met-hGH and pituitary hGH were equivalent in ability to induce hGH receptor loss in IM-9 cells, with an 80% decrease in membrane binding sites following 20 hour preincubation with 10 ng/ml of either met-hGH or pituitary hGH. We conclude that the receptor-binding activity of bacterially synthesized met-hGH and pituitary hGH are identical, suggesting a common tertiary structure.