Notes: S1H is a synthetic peptide mimetic of human growth hormone amino acids 36-51 and an antagonist of the growth hormone receptor.{68518} It adopts an α-helical structure in solution and decreases STAT5 phosphorylation induced by human growth hormone in SK-MEL-28 and MALME-3M melanoma cell lines, as well as by prolactin in IM-9 B cell lymphocytes, when used at concentrations of 100 and 200 nM.