THE EFFECT OF TRYPAN BLUE ON THYROID FUNCTION IN THE RAT1<sup>1</sup>

Yamada, Takashi

doi:10.1210/endo-67-2-204

Cited by 15 publications

(2 citation statements)

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“…Effects of trypan blue on thyroid secretion were first discovered by Yamada (22), but interest waned because he concluded that the thyroid effects were indirect through decreased thyroxin binding and resulting suppression of TSH. In this report, we have not reexamined these peripheral effects of trypan blue but have demonstrated a direct effect of trypan blue on TSH-induced thyroid secretion during in vitro incubation whether the dye was administered in vitro or in vivo.…”

Section: Discussionmentioning

confidence: 99%

“…Trypan blue was first shown to decrease rat thyroid secretion by Yamada (22) in 1960 in studies employing in vivo administration of dye and following the rate of radioactive iodine release from the thyroid. In later work (16,21) an alteration in the serum protein electrophoresis pattern of treated animals and the requirement for an intact pituitary were demonstrated.…”

Section: Introductionmentioning

confidence: 99%

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Direct Effects of Trypan Blue on Thyroid Secretion

Peake¹,

Battle²,

Harrison³

et al. 1979

Horm Res

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Trypan blue directly inhibited in vitro thyroid secretion (butanol soluble ¹²⁵I release to the media) induced by both thyroid stimulating hormone (TSH) and dibutyryl cAMP. Intracellular colloid droplet counts were also decreased. Inhibition was directly proportional to dye concentration and could be overcome by supramaximal TSH and dibutyryl cAMP. Inhibition could be observed as early as 20 min of incubation, was not increased by preincubation, and could even be demonstrated after TSH in vivo. Trypan blue, in vivo, produced similar inhibition of thyroid secretion. Incubation of ¹²⁵I-thyroglobulin with lysosomal enzymes revealed inhibition with much lower concentrations of dye. Inhibition of lysosomal enzyme(s) would not appear to explain the marked decreases in colloid droplets, and this may represent two separate effects of trypan blue on thyroid secretion.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Direct Effects of Trypan Blue on Thyroid Secretion

Peake¹,

Battle²,

Harrison³

et al. 1979

Horm Res

View full text Add to dashboard Cite

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Passage of thyroid hormone across the placenta in intact and hypophysectomized rats

et al. 1962

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The studies were designed to determine whether thyroid hormone traverses the placenta of the rat.1. Pregnant rats were hypophysectomized on the twelfth day of the gestation period. The histological appearance and wet weights of the fetal thyroids at term were determined and found to be the same as that of fetuses of intact mothers. These results indicate that maternal TSH is not required for maturation of the fetal thyroid.2. Intact and hypophysectomized pregnant rats were provided with a diet supplemented with 0.2% propylthiouracil (PTU) added in powdered form starting on the fifteenth day of gestation until term. This treatment led to enlargement of thyroids of fetuses of intact and hypophysectomized mothers.3. Groups of intact and hypophysectomized pregnant rats given the same goitrogenic treatment as group 2 were injected daily with 100, 50, 25 and 12.5 fig of 1-thyroxin in suspension. Twenty-five pg of thyroxin were sufficient to inhibit goiter development in fetuses of hypophysectomized rats, while 50 pg was required to prevent the goiter formation in fetuses obtained from intact non-hypophysectomized pregnant rats.These results suggest that maternal thyroid hormone passes the placenta from mother to fetus. The effectiveness with which thyroid hormone passes from the mother to the fetal circulation is probably influenced in some way by the maternal pituitary.

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