Effects of metamorphosis and captivity on the in vitro sensitivity of thyroid glands from the tiger salamander, Ambystoma tigrinum, to bovine thyrotropin
The sensitivity of thyroid glands from the tiger salamander, Ambystoma tigrinum, to bovine thyrotropin (bTSH) was tested in vitro. Thyroids were taken from subjects representing metamorphic stages I (premetamorphic larvae), II (onset of climax), and VII (completion of gill resorption), as well as from captivity control larvae. Exogenous TSH reduced the cumulative uptake of /sup 125/I in vitro by thyroids from stage I larvae after 24 and 48 hr. The capacity of thyroids to release thyroxine (T4) in vitro was used subsequently as a measure of their responsiveness to TSH. Baseline levels of T4 release in vitro were variable but did not differ significantly among developmental stages. A low dose of bTSH (5 X 10(-6) IU/ml) did not increase in vitro T4 release compared with that of controls. A larger dose (5 X 10(-4) IU/ml) caused greater increases in T4 release from thyroids of stage II and VII subjects than from those of controls. This dose produced only a small response by thyroids from captivity-control subjects. The results suggest that the thyroids of Ambystoma increase in their capacity to respond to TSH during the process of metamorphosis.
- Research Organization:
- Univ. of Colorado, Boulder
- OSTI ID:
- 6017827
- Journal Information:
- Gen. Comp. Endocrinol.; (United States), Vol. 67:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
IODINE 125
UPTAKE
THYROID
RADIONUCLIDE KINETICS
SENSITIVITY
THYROXINE
SECRETION
TSH
BIOLOGICAL FUNCTIONS
CATTLE
DOSE-RESPONSE RELATIONSHIPS
IN VITRO
IODIDES
METAMORPHOSIS
SALAMANDERS
TRACER TECHNIQUES
AMINO ACIDS
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
BETA DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
FUNCTIONS
GLANDS
HALIDES
HALOGEN COMPOUNDS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE COMPOUNDS
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY HORMONES
RADIOISOTOPES
RUMINANTS
THYROID HORMONES
VERTEBRATES
560162* - Radionuclide Effects
Kinetics
& Toxicology- Animals
Plants
Microorganisms
& Cells