Study on the thyroid function of thoroughbred females in varying stages of pregnancy, using "in vitro” tests 125I-T3 and 125I-T-4

Abstract

The author has studied sera of 26 thoroughbred female equines, aged between five through 12 years, collected in five different pregnancy stages. We have performed five bleedings: the first from the group between 49 and 90 days pregnancy; the second between 103 and 167; the third between 158 and 222; the fourth between 216 and 280; and the last between 271 and 335 days of pregnancy. As average results of T3 and T4 for 125I-lyothyronine retention in resin and of thyroxin per 100 ml of serum, We found 44.22% and 2.13 meg in the first collection; 44.02% and 2.21 mcg in the second; 46.67% and 2.60 mcg in the third; 43.51 % and 2.56 mcg in the fourth; and, finally, 41.14% and 1.94 mcg in the fifth collection. A sixth group was formed, composed of females from the first group that were between 49 and 55 days pregnant, for which we registered values 46.27% for T3 Test and 0.93 mcg of T4 Test. We have also performed the variance analysis of the results obtained in tests T3 and T4 in the six groups, the first with females between 49 and 55 days of pregnancy and the others, each represented by six animals choosen by allotment, with 62 through 90, 138 through 167, 193 through 222, 251 through 280, and 306 through 335 days of pregnancy. Analysing the results of T3 Test we have found statistical significance for the animal group and verified, by Tukey’s test that only one animal was responsible for the significance. The data referring to the variance analysis applied to the results obtained with the help of T4 Test showed statistical significance for the varying periods; and Tukey’s test revealed that such fact occurred because the first group differed from the others.