Somatostatin reduces 3H-thymidine incorporation and c-myc, but not thyroglobulin ribonucleic acid levels in human thyroid follicular cells in vitro.
The action of somatostatin (SRIH) on 3H-thymidine (thy) incorporation and on c-myc and thyroglobulin RNA levels in a suspension of follicles from normal and goitrous human thyroid was examined. SRIH, at 10(-7) M concentration, inhibited basal thy incorporation (maximally by 4 h lasting for up 24 h), which effect was greater in goiter than in normal thyroid and was also detected in growing adherent epithelial cells. Moreover, in a follicle suspension SRIH prevented TSH-stimulated thy incorporation, both in normal and in goitrous thyroid. Basal expression of c-myc RNA was not affected by SRIH in either tissue, whereas the TSH-stimulated c-myc RNA level was significantly reduced in goiter. No effect of SRIH was observed on basal or TSH-stimulated thyroglobulin RNA levels. SRIH did not alter basal cAMP concentrations in normal or goitrous follicles, but it significantly reduced TSH-stimulated cAMP accumulation both in normal thyroid and in goiter. Overall, our data indicate a direct inhibitory action of SRIH on growth, but not on differentiation, of human thyroid, probably by a mechanism not entirely cAMP dependent.
degli Uberti
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EC
Sezione di Endocrinologia dell'Istituto di Medicina Interna, Università degli Studi di Ferrara, Italy.
Hanau
S
S
Rossi
R
R
Piva
R
R
Margutti
A
A
Trasforini
G
G
Pansini
G
G
del Senno
L
L
D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D006042:Goiter / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics*; D012313:RNA / Q000378:metabolism*; D012016:Reference Values; D013004:Somatostatin / Q000494:pharmacology*; D013936:Thymidine / Q000378:metabolism*; D013954:Thyroglobulin / Q000235:genetics*; D013961:Thyroid Gland / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D014316:Tritium
D016271:Proto-Oncogene Proteins c-myc; D014316:Tritium; D013004:Somatostatin; D012313:RNA; D013954:Thyroglobulin; D000242:Cyclic AMP; D013936:Thymidine