title: Development of thyroidal responsiveness to  estrogen in the maturing rat (38471).
abstract: The incidence of thyroid disorders around the time of puberty is frequent in human females. The  influence of estrogen on thyroid function during this period has been controversial. Female rats hypophysectomized at 21, 30 or 50 days of age were treated with either 17beta-estradiol (E-2) or TSH or a mixture of E-2 and TSH. Determinations were then made of thyrodial 131I-uptake, organic 131I, and 131I excretory patterns. In 21-day old animals, E-2 alone had no effect on thyroidal 131 I uptake, whereas in 30-day or older animals E-2 significantly increased 131I uptake. TSH or TSH-E-2 combinations markedly increased 131I uptake in both groups. Thyroidal 131I was shown to be almost exclusively protein-bound in each instance. No difference was observed between 21 and 30-day old rats with respect to 131I excretory patterns,except for decreased urinary output in the TSH-E-2 groups; this decrease, however, appeared to be partially attributable to an increased thyroidal uptake of iodine in these animals. The results suggest that the thyroid gland becomes responsive to estrogen only at or around the time of puberty.
mesh_terms: D000367:Age Factors; D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D005243:Feces / Q000032:analysis; D005260:Female; D007455:Iodine / Q000032:analysis / Q000378:metabolism* / Q000652:urine; D007457:Iodine Radioisotopes; D011485:Protein Binding; D051381:Rats; D013961:Thyroid Gland / Q000378:metabolism*; D013972:Thyrotropin / Q000494:pharmacology
chemical_list: D007457:Iodine Radioisotopes; D004958:Estradiol; D013972:Thyrotropin; D007455:Iodine