Effect of growth hormone-releasing hormone on human peripheral blood leukocyte chemotaxis and migration in normal subjects.

The effect of synthetic human growth hormone-releasing hormone (GHRH) on chemotactic response and migration inhibition of human peripheral blood leukocytes has been studied. In the assay performed by using modified Nelson methods, significant inhibition of chemotactic response was observed at 10(-6)M-10(-8) M concentrations of GHRH. There is a strong negative correlation (r = -0.519; p less than 0.001) between the chemotactic response of peripheral blood leukocytes and the concentration of GHRH. In contrast, GHRH tested at the same concentration range was not active in the migration inhibition assay. This finding provides additional evidence for the neuroimmunomodulatory action of GHRH.