Effect of PACAP, VIP, and forskolin on in vitro megakaryopoiesis. (A) Flow cytometric analysis of day-6 (▩) and day-12 (■) differentiated MKs from cord blood–derived CD34⁺ cells in the presence of PACAP, VIP, or forskolin (FOR). Each point represents the mean amount of dual-stained CD41⁺ and CD61⁺ MKs plus or minus SD of 3 experiments. (B) The DNA ploidy distribution of CD61⁺ MKs in vitro–differentiated from CD34⁺ cells isolated from cord blood in the absence (NEG) or presence of PACAP, VIP, or FOR on day 12. Each point represents the mean number of CD61⁺ MKs of each ploidy level plus or minus SD of 3 experiments. *P < .05; **P < .01; #P < .001 by ANOVA.