Identification of iodothyronines in plant tissues

   It has become widespread knowledge that many signaling molecules are common to organisms of different groups. This is likely to be valid for such important metabolism regulators as iodothyronines. A number of studies have confirmed the presence of thyroid hormone activity in compounds of plant origin. However, these studies do not explain whether the compounds under consideration are iodine derivatives of thyronine, similar to animal and human thyroid hormones, or whether they are mimetics of thyroid hormones. In this work, we aim to verify the presence of iodothyronine analogs with different degrees of iodization in plant tissues.   We also aim to determine iodine concentrations in plant tissue lysates and to compare them with the theoretically calculated values in order to test the assumption about the identity of their structure to human thyroid hormones.   It was shown that tetraiodothyronine (T4) and triiodothyronine (T3) analogs are simultaneously present in potato tubers and wheat leaves. In potato tubers at dormancy, the concentration of T4 was 118 ± 16 nmol/L (n = 15), while the concentration of T3 in the same samples was 4.01 ± 0.96 nmol/L. T4 and T3 concentrations in wheat leaf lysates were 60.24 ± 79 and 6.76 nmol/L (n = 15), respectively. According to the results of inductively coupled plasma mass spectrometry, the studied samples contain iodine in the amounts consistent with the assumption about the presence of tetraiodinated tyronine derivatives.