COMPARING THE MOLECULAR PROPERTIES OF ENVIRONMENTAL HORMONES WITH HEARTBEAT CHANGES IN DAPHNIA MAGNA

Rationale: Environmental hormones (EH) disrupt the integrity of the endocrine system. Many chemical compounds act as endocrine disruptors, such as insecticides, herbicides, plasticizers. If these chemical compounds spread outside their area of intended use, they can stay in the environment and flow down into local bodies of water and wreak havoc upon ecosystems in the area. So, understanding the underlying relationship of the EHs with the physiology of an organism may be important for the design of chemical structures that could minimize the adverse effects for the future compounds. Methods: For this study, we chose 10 environmental hormones of BFR, DMT, LCH, DMA, TTS, MLT, ANN, CFT, GPS and GCH to examine the acute cardiac effects for 30 minute incubation in 1:10 serial dilution solutions.   The heartbeat rates and their differences were evaluated at pre- and post-incubation, which was then converted into their heartbeat change% based on the pre-heartbeat rates.  Then, the heartbeat change % for the individual EH was put on a regression analysis with molecular properties such as molecular weight, XlogP, topological polar surface area (TPSA), complexity, solubility and heavy atom count. Results: The leading coefficient of polynomial function showed relationship with those molecular properties with regression coefficient R2 from 0.1163 to 0.3182. The study should be significantly recognized in that the relationship of acute cardiac effects to the molecular properties were able to quantify as a unique attempt to elucidate.  More study might be needed for in-depth clarification in the constants of the polynomial relationship.