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Biomedical subjects

A Rostagnat

Publications and source records attributed to A Rostagnat.

4 recordsLinked to original sources
PubMed1977

Comparison of adiphenine and TRH effects on TSH release by rat pituitary in vitro.

The mechanism of action of adiphenine on in vitro rat anterior pituitary TSH release was compared to that of the physiological stimulator TRH. The comparative study showed that adiphenine and TRH were able to increase TSH release in a dose-dependent manner, had similar time courses of action for equipotent stimulating concentrations and produced similar aspects of stimulated TSH cells. However, there were several differences between the effects of adiphenine and TRH. Adiphenine action was inhibited by 20 mM K+; was not calcium dependent; was inhibited by neither thyroid hormones nor somatostatin; was little affected by energy depression. It is concluded that adiphenine probably acts near the ultimate steps of the TSH release pathway and could be a useful pharmacological tool for studying the mechanism of TSH release.

Animals↗
PubMed1977

Thyroxine secretion by isolated hog thyroid cells: a cyclic AMP independent pathway.

The release of 131I-labeled thyroxine (T4) from isolated hog thyroid cells was increased 1.5--2-fold by thyrotropin (TSH). Dibutyryl cyclic AMP failed to reproduce this TSH action. In this in vitro system another cell activity, T4 synthesis, was stimulated in an essentially identical fashion by TSH and dibutyryl cyclic AMP (time course of action, dose-response relationship). 3-Isobutyl-1-methylxanthine (IBMX), 0.5 mM, did not alter the basal [131I]T4 release whereas it enhanced the [131I]T4 synthesis. TSH, 60 MU/ml, increased the intracellular cyclic AMP concentration 3-4-fold. Chlorpromazine (5 X 10(-4)M) abolished the TSH stimulation of cyclic AMP accumulation but did not alter the TSH-induced increase in [131I]T4 secretion. It is concluded that the TSH action on [131I]T4 secretion by isolated thyroid cells is not mediated by the adenylate cyclase-cylic AMP system.

Animals↗