Rapid responses to thyroxine in the testis: Active protein

D Menegaz, A Zamoner, C Royer, L D Leite, ZA Bortolotto, F R M B Silva

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

We investigated the involvement of protein synthesis in the stimulatory action of thyroid hormones on amino acid accumulation and characterized K(+) currents involved in the hyperpolarizing effect of thyroxine (T(4)) on Sertoli cells. Immature rat testes were incubated in Krebs Ringer-bicarbonate buffer (KRb) in the presence of [(14)C]methylaminoisobutyric acid with and without T(4), 3,5,3'-l-triiodothyronine (T(3)) and/or cycloheximide. Sertoli cells were monitored by intracellular recording in a chamber perfused with KRb with and without T(4), T(3) and/or blockers, and the membrane potential was monitored. T(4) and T(3) stimulated amino acid accumulation and protein synthesis. Treatment with cycloheximide diminished T(3) stimulatory actions on amino acid accumulation but had no effect on T(4) action. Both hormones elicited a hyperpolarization of the Sertoli cell membrane potential which involved K(+) channels, since TEA and apamin abolished this effect. These findings on rapid membrane actions of thyroid hormone in the testis suggest that some effects of T(4) are modulated by non-genomic mechanisms.
Translated title of the contributionRapid responses to thyroxine in the testis: Active protein
Original languageEnglish
Pages (from-to)128 - 134
Number of pages7
JournalMolecular and Cellular Endocrinology
Volume246
Publication statusPublished - Feb 2005

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