Retention of the biological potency of human pituitary growth hormone after reduction and carbamidomethylation.

The reduced alkylated derivative of human pituitary growth hormone was prepared by reacting the native hormone in 8M urea solution, first with mercaptoethanol and then with iodoacetamide. On the basis of amino acid analyses, the product isolated after gel filtration on Sephadex G-100 is completely devoid of unreduced cystine but otherwise has a composition identical to that of the native hormone. When assayed in both the rat tibia test and the pigeon crop-sac assay,it appears that the full potency of the native hormone is retained in the reduced alkylated derivative.