Expression and Regulation of Δ5-Desaturase, Δ6-Desaturase, Stearoyl-Coenzyme A (CoA) Desaturase 1, and Stearoyl-CoA Desaturase 2 in Rat Testis
| Autor: | Thomas Sæther, Helge Rootwelt, Thien N Tran, Trine B. Haugen, Bjørn O. Christophersen |
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| Rok vydání: | 2003 |
| Předmět: |
Fatty Acid Desaturases
Male endocrine system DNA Complementary Coenzyme A Biology Dexamethasone Gene Expression Regulation Enzymologic Rats Sprague-Dawley chemistry.chemical_compound Delta-5 Fatty Acid Desaturase Testis Gene expression medicine Animals Insulin Tissue Distribution RNA Messenger Northern blot Epididymis chemistry.chemical_classification Regulation of gene expression Sertoli Cells Base Sequence Cell Biology General Medicine Sertoli cell Spermatozoa Rats Isoenzymes Stearoyl-CoA Desaturase medicine.anatomical_structure Reproductive Medicine chemistry Biochemistry lipids (amino acids peptides and proteins) Polyunsaturated fatty acid |
| Zdroj: | Biology of Reproduction. 69:117-124 |
| ISSN: | 1529-7268 0006-3363 |
| DOI: | 10.1095/biolreprod.102.014035 |
| Popis: | In mammalian cells, essential polyunsaturated fatty acids (PUFAs) are converted to longer PUFAs by alternating steps of elongation and desaturation. In contrast to other PUFA-rich tissues, the testis is continuously drained of these fatty acids as spermatozoa are transported to the epididymis. Alteration of the germ cell lipid profile from spermatogonia to condensing spermatids and mature spermatozoa has been described, but the male gonadal gene expression of the desaturases, responsible for the PUFA-metabolism, is still not established. The focus of this study was to characterize the expression and regulation of stearoyl-CoA desaturase 1 (SCD1), stearoyl-CoA desaturase 2 (SCD2), and Delta5- and Delta6-desaturase in rat testis. Desaturase gene expression was detected in testis, epididymis, and separated cells from seminiferous tubulus using Northern blot analysis. For the first time, SCD1 and SCD2 expression is demonstrated in rat testis and epididymis, both SCDs are expressed in epididymis, while testis mainly contains SCD2. Examination of the testicular distribution of Delta5- and Delta6-desaturase and SCD1 and SCD2 shows that all four desaturases seem to be localized in the Sertoli cells, with far lower expression in germ cells. In light of earlier published results showing that germ cells are richer in PUFAs than Sertoli cells, this strengthens the hypothesis of a lipid transport from the Sertoli cells to the germ cells. As opposed to what is shown in liver, Delta5- and Delta6-desaturase mRNA levels in Sertoli cells are up-regulated by dexamethasone. Furthermore, dexamethasone induces SCD2 mRNA. Insulin also up-regulates these three genes in the Sertoli cell, while SCD1 mRNA is down-regulated by both insulin and dexamethasone. Delta5- and Delta6-desaturase, SCD1, and SCD2 are all up-regulated by FSH. A similar up-regulation of the desaturases is observed when treating Sertoli cells with (Bu)2cAMP, indicating that the desaturase up-regulation observed with FSH treatment results from elevated levels of cAMP. Finally, testosterone has no influence on the desaturase gene expression. Thus, FSH seems to be a key regulator of the desaturase expression in the Sertoli cell. |
| Databáze: | OpenAIRE |
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