Hormonal control of the in vitro uptake of [35S]sulfate by cartilage of Xenopus laevis tadpoles.
The influence of various mammalian hormones and growth factors on the skeletal growth in the clawed toad was examined in vitro by monitoring the uptake of [35S]sulfate by tadpole's hindlimbs. Autoradiographic studies demonstrated that the isotope was mainly incorporated into the cartilage. Sulfate uptake was significantly stimulated by 13 nM insulin-like growth factor I (IGF-I) in all experiments. The effect of 13 nM IGF-II was statistically significant only in approximately 50% of the experiments. Insulin was inconsistently effective. A significant stimulation was found using 1300 nM insulin. Neither prolactin and growth hormone nor the thyroid hormones thyroxine and triiodothyronine affected the [35S]sulfate uptake in vitro. The results indicate that cartilage growth in amphibians is mainly stimulated by IGF-I and to a less extended by IGF-II like in mammals.
Schneider
A
A
Department of Zoology II, University of Karlsruhe, Germany.
Hanke
W
W
D000818:Animals; D001345:Autoradiography; D002356:Cartilage / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013006:Growth Hormone / Q000494:pharmacology; D006614:Hindlimb; D006801:Humans; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007335:Insulin-Like Growth Factor II / Q000494:pharmacology*; D007814:Larva / Q000254:growth & development; D011388:Prolactin / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D013431:Sulfates / Q000378:metabolism*; D013462:Sulfur Radioisotopes; D013963:Thyroid Hormones / Q000494:pharmacology; D014982:Xenopus laevis
D007328:Insulin; D011994:Recombinant Proteins; D013431:Sulfates; D013462:Sulfur Radioisotopes; D013963:Thyroid Hormones; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D011388:Prolactin; D013006:Growth Hormone