Influence of indomethacin and of polyphloretin phosphate fractions on in vivo secretion of thyroid hormone in mice
Melander, A.; Westgren, U.; Ingbar, S.H.
Acta Endocrinologica 86(2): 330-335
1977
ISSN/ISBN: 0001-5598 PMID: 578623 Document Number: 117552
Previous in vivo studies in mice have shown that polyphloretin phosphate (PPP), a polyionic polyester of phosphoric acid and the dihydrochalcone phloretin, can inhibit thyroid hormone secretion induced by TSH -pre-treated mice. When given alone, neither indomethacin nor PPP or its subfractions reduced the BRI levels. Instead, small increments were seen in occasional experiments. Indomethacin did not inhibit the BRI increase in response to any of the thyroid-stimulating agents, but rather enhanced the responses in occasional experiments. PPP and some of its high MW subfractions reduced the BRI increases in response to TSH but not those to 5-HT or IPNE. The findings do not support the concept that de novo synthetized PG mediates TSH activation of thyroid hormone secretion, but they favor the view that PPP inhibits the action of TSH at its receptor site.