Dependency of maximum goitrogenic response on some minimal level of thyroid hormone production
Thyroidal activity was studied in chicks given dietary thiouracil in conjunction with daily doses of thyroxine and with diets adequate and deficient in iodine. DL-thyroxine administered at doses up to 1.0 microgram per day for 10 to 12 days had no effect or slightly increased thyroid weight. Both the epithelial and colloid components of the thyroid gland were increased in response to thiouracil and to thiouracil in combination with low dosages of exogenous thyroxine. Radioiodine uptake was increased above the control with thiouracil and with thiouracil in conjunction with .5 and 1.0 microgram DL-thyroxine given daily. Birds receiving thiouracil, with and without exogenous thyroxine, showed a different pattern of radioiodine uptake and release than the control birds. Thiouracil-treated birds showed a rapid uptake of iodine following its administration, which was followed by a rapid decline immediately after peak accumulation, whereas in control birds thyroidal radioiodine concentration reached a plateau at the maximum concentration attained. The goitrogenic response to thiouracil was much greater when the diet was supplemented with iodine than when the diet was iodine-deficient. Thyroids under iodine deficiency contained greater percentages of epithelial tissue than with iodine-supplemented diets. Thyroid glands of chicks given thiouracil in an iodine-supplemented diet contained much more colloid than glands from iodine-deficient chicks with or without thiouracil. DL-thyroxine at a dosage of .5 microgram per day to chicks given thiouracil in an iodine-adequate diet increased, whereas higher dosages decreased thyroidal colloid. It is concluded that some minimal concentration of thyroid hormone is required for maximum goitrogenic response. It is not clear whether the response is entirely due to an effect on thyrotropin production or whether there is an effect of thyroid hormone on the thyroid gland itself.
- Research Organization:
- Department of Poultry Science, The University of British Columbia, Vancouver
- OSTI ID:
- 5513210
- Journal Information:
- Poult. Sci.; (United States), Journal Name: Poult. Sci.; (United States) Vol. 60:4; ISSN POSCA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of iodide, methimazole, and thyroxine on thyroidal accumulation of radioiodide in immature domestic fowl
EFFECT OF VARIOUS FACTORS ON PROCESSES OF BIOLOGICAL SYNTHESIS OF THYROXINE IN THYROID
Related Subjects
550901* -- Pathology-- Tracer Techniques
551001 -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
ANTIMETABOLITES
ANTITHYROID DRUGS
AZINES
BIOCHEMISTRY
BIOSYNTHESIS
BIRDS
BODY
CARBOXYLIC ACIDS
CHEMISTRY
CHICKENS
DIAGNOSTIC USES
DIET
DISEASES
DRUGS
DYNAMIC FUNCTION STUDIES
ENDOCRINE DISEASES
ENDOCRINE GLANDS
FOWL
GLANDS
GOITER
HETEROCYCLIC COMPOUNDS
HORMONE ANTAGONISTS
HORMONES
HYDROXY COMPOUNDS
IODINE ISOTOPES
ISOTOPES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PATHOLOGY
PEPTIDE HORMONES
PYRIMIDINES
SYNTHESIS
THIOLS
THIOURACIL
THYROID
THYROID HORMONES
THYROXINE
URACILS
USES
VERTEBRATES