The primary effect of T_3 and T_4 is to: decrease blood glucose. promote the release of calcitonin. promote protein anabolism resulting in heat-generating reactions (calorigenesis) stimulate the uptake of iodide by the thyroid gland. promote excretion of sodium ions in urine. Solution (C) Promote protein anabolism resulting in heat generating reactions (calorigenesis) Thyroid hormones T3 and T4 are responsible for metabolism which involves in the production of heat. Due to protein anabolism, the reactions tend to generate lot of heat and this is facilitated by T3 and T4 hormones due to increased metabolism activity..