Early Life-Stage Effects in Medaka (Oryzias latipes) Following in Ovo Exposure to Polyamine Biosynthetic Inhibitors

Medaka, Oryzias latipes, were exposed in ovo to the polyamine (PA) biosynthesis inhibitors α-difluoromethylornithine (DFMO) and methylglyoxal bis(guanylhydrazone) (MGBG). In an additional group, spermine, the end product of the PA pathway, was added with DFMO and MGBG for a "rescue" treatment. At 4 days posthatch, length, DNA and RNA content, and swimming endurance were measured. The only parameter affected by treatment was swimming endurance which revealed decreased latent time to fatigue with increased dose, although not statistically significant. The rescue group, however, did demonstrate a statistically significant decrease in fatigue latency as compared to controls.