Meeting Abstract

P1.119  Friday, Jan. 4  Effects of rearing temperature and thyroid hormone inhibitor Methimazole (MMI) on eye development and general morphology in zebrafish REIDER, M*; CONNAUGHTON, VP; American University mreider888@gmail.com

Effects of rearing temperature and thyroid hormone inhibitor Methimazole (MMI) on eye development and general morphology in zebrafish Reider, M and Connaughton VP. mr3039a@american.edu. Biology. American University. Zebrafish development is a complex process that has been shown to be highly dependent on thyroid hormones (THs), an endocrine system that is highly conserved from fish to humans. MMI, the thyroid inhibitor used in this study, is a common medication used to treat hyperthyroidism in humans, and is also frequently used in animal research. The purpose of this study was to examine the effects of TH deprivation on larval development. We analyzed MMI and rearing temperature effects on various aspects of zebrafish growth: eye size, inter-eye distance, body length, and spinal curvature. Embryos were sampled hourly from 60-72 hpf, a critical time in thyroid development. Results indicate a significant temperature effect for all growth parameters examined (p < 0.01). Maximal inhibitory effects of MMI were found between 66-68hpf for the 31oC group and at 64-66hpf for the 28oC group for 3 of the 4 parameters tested. Interestingly, following each inhibitory peak, measurements recovered and were similar to control values, indicating feedback mechanisms may be established as early as 64hpf. Because MMI inhibits endogenous TH synthesis only, sensitivity to this chemical is presumably indicative of both a functional embryonic TH system and a need for THs in overall zebrafish growth. Additionally, significant temperature effects supports rearing temperature as a critical factor in development studies.