GROWTH-HORMONE ALTERS LYMPHOCYTE SUBPOPULATIONS AND ANTIBODY-PRODUCTION IN DWARF RATS IN-VIVO

Female dwarf rats at different ages were treated with recombinant porc ine GH or with a potent sheep anti-rat GH serum. Body weight and splee n weight increased with GH and decreased with anti-GH treatment (p < 0 .001). Neither GH nor anti-GH treatment resulted in a change in circul ating WBCs, but GH decreased, while anti-GH increased, RBC counts (p < 0.001). Similarly, GH treatment tended to decrease the ratio of CD4():CD8(+) T-cells while anti-GH increased (p < 0.05) the ratio. Anti-GH treatment also enhanced the animals' ability to produce specific IgG in response to KLH injection. These results indicate that GH may have a physiological role in suppressing humoral immune function but may en hance cell-mediated immunity.