Effect of G-Gly and G-NH2 on cell growth. Effect of G17-NH2 (10−9 M), Leu15-G(2–17)-Gly (10−9 M), and both peptides together on [3H]thymidine incorporation in AR4-2J cells. Results are expressed as percent of control, unstimulated [3H]thymidine incorporation. Mean ± SD of six different experiments, each performed in sextuplicates. *p < 0.05 versus control and *p < 0.05 versus G-NH2.