Abstract: Novel synthetic peptides of the general formula ##STR1## and the corresponding reduced, linear form. The cyclic form of the peptide is produced by oxidation of the corresponding linear compound thereby providing the divalent dithio group --S--S-- joining the beta carbon of each of the cysteine moieties. In the above formula X is serine (SER) or lysine (Lys), and Y is OH or Thr-Glu-Gly-Phe. The obtained synthetic peptides, in either form, are useful in promoting growth of cells of mammalian tissues.

Abstract: A synthetic decapeptide, L-pglutamyl-L-histidyl-L-tryptophanyl-L-seryl-L-tyrosyl-glycyl-L-leucyl-L- arginyl-L-prolyl-glycinamide having the hormonal activity of the luteinizing hormone releasing hormone (LRH) of the hypothalamus gland of mammals is provided by utilizing, as key starting materials, the amino acids, pyroglutamic acid, histidine, tryptophan, serine, tyrosine, glycine, leucine, arginine, proline. Synthesis of the decapeptide is accomplished by coupling, in appropriate protected forms, all of the remaining amino acids, individually or in combination, to the starting amino acid, or amino acid group or to the terminal amino acid resulting from combinations with one or more other amino acids, bound to a resin or carrier followed by release of the decapeptide from the carrier as the amide or other form which is converted to the amide, L-pglutamyl-L-histidyl-L-tryptophanyl-L-seryl-L-tyrosyl-glycyl-L-leucyl-L- arginyl-L-prolyl-glycinamide.

Abstract: A synthetic decapeptide, L-pglutamyl-L-histidyl-L-tryptophanyl-L-seryl-L-tyrosyl-glycyl-L-leucyl-L- arginyl-L-prolyl-glycinamide which has the hormonal activities of the luteinizing hormone releasing hormone (LRH) of the hypothalamus gland of mammals is produced by utilizing as the key starting materials, the amino acids, glutamic acid or pyroglutamic acid, histidine, tryptophan, serine, tyrosine, glycine, leucine, arginine, and proline. Synthesis of the decapeptide is accomplished by coupling, in appropriate combinations of appropriate protected forms of the amino acids, and finally deprotecting to yield the amide, L-pglutamyl-L-histidyl-L-tryptophanyl-L-seryl-L-tyrosyl-glycyl-L-leucyl-L- arginyl-L-prolyl-glycinamide.