ELUCIDATION OF THYRO-MODULATORY PATHOPHYSIOLOGICAL ACTIONS FOLLOWING PROLONGED CO-EXPOSURE TO EXCESS CALCIUM AND MAGNESIUM: A DURATION - DEPENDENT STUDY

Abstract

Calcium and magnesium, indispensable minerals for survival, are the two chief components of hard water. Previous in vivo (dose and duration-dependent) as well as in vitro studies with high calcium and magnesium invidually had already established the adverse effects caused by these 2 individual minerals. However, the effects of hard water as a combination of calcium and magnesium on thyroid physiology are still unconvincing and scanty. Experimental animal (rat) models were developed to study the intricate details of CaCl2 - MgSO4 co-exposure induced effects in a duration - dependent study protocol. Adult, male, albino Wistar strain rats were subjected to CaCl2 - MgSO4 co-exposure for 15, 30 and 60 days with each group receiving 1.5g CaCl2-1.5g MgSO4/100 g diet/day, against respective controls. Daily food consumption, body weight gain%, absolute and relative thyroid weight, histologic and histometric analyses, enzyme activity patterns including thyroid peroxidase (TPO), thyroidal Na+-K+-ATPase, thyroidal 5’ -deiodinase type I (DI), hormone profiles including total & free T4, total & free T3, TSH were studied. Significant (P< 0.05) alterations were found in almost all parameters, in the Ca - Mg treated groups in a duration -dependent fashion when compared to their respective control groups. So, it can be suggested that, prolonged, excess CaCl2 - MgSO4 co-exposure produces marked structural and functional alterations of thyroid physiology and thus contributes in the thyroid pathophysiological development.