Diagram of hGH(human growth hormone) negative feedback loop Quizlet The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline GHK Cu may Prevent Oxidative Stress in Skin by Regulating Copper and Modifying Expression of Numerous Antioxidant Genes The tripeptide GHKCu complex ameliorates lipopolysaccharideinduced acute lung injury in mice Oncotarget Rigid flexible nanocarriers loaded with active peptides for antioxidant and anti inflammatory applications in skin ScienceDirect Feedback Loops Anatomy and Physiology I