Characterization of the expression and regulation of genes necessary for myo-inositol biosynthesis and transport in the seminiferous epithelium.
(2004)
Journal - Biology of reproduction (United States )
Abstract :
In many mammals, the concentration of myo-inositol in the fluid of the seminiferous tubules is dramatically higher than levels found in serum. Two enzymes involved in myo-inositol synthesis: myo-inositol-1-phosphate synthase (ISYNA1) and myo-inositol monophosphatase-1 (IMPA1), are known to have high activity in the testes. ISYNA1 is an isomerase that catalyzes the conversion of glucose-6-phoshate to myo-inositol-1-phosphate. IMPA1 then hydrolyzes the phosphate group to produce myo-inositol. Although no physiological role for the high concentration of myo-inositol has yet to be elucidated, it has been suggested that it could be involved in osmoregulation. Previous research on these enzymes in the testis has focused on enzyme activity. The objective of this study was to evaluate the expression of these genes and the myo-inositol transporter, Slc5a3, within the testis. Using Northern blot analyses, we found that all three genes, Impa1, Isyna1, and Slc5a3 are expressed in Sertoli cells. Isyna1 is highly expressed in two types of germ cells, pachytene spermatocytes and round spermatids. IMPA1 was expressed in round spermatids. Slc5a3 expression is upregulated when Sertoli cells are treated with 0.1 mM dibutyryl cAMP. When Sertoli cells were cultured in a hypertonic medium, there was an increase in the expression of Isyna1 and Slc5a3. We postulate that this upregulation is a result of the capability of the Sertoli cell to sense and then react to a change in osmolarity by increasing the transport and production of the osmolyte myo-inositol.
| ISSN : | 0006-3363 |
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| Mesh Heading : | Animals Blotting, Northern Bucladesine Follicle Stimulating Hormone Gene Expression Heat-Shock Proteins Hypertonic Solutions Inositol Male Membrane Proteins Mice Mice, Inbred Strains Myo-Inositol-1-Phosphate Synthase Phosphoric Monoester Hydrolases RNA, Messenger Seminiferous Epithelium Sertoli Cells Spermatids Spermatozoa Symporters metabolism pharmacology drug effects physiology metabolism pharmacology metabolism metabolism metabolism analysis cytology physiology enzymology enzymology metabolism |
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| Mesh Heading Relevant : | genetics biosynthesis metabolism genetics genetics genetics physiology genetics |
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Androgen-regulated genes in the murine epididymis.
(2004)
Journal - Biology of reproduction (United States )
Abstract :
The epididymis is an androgen-responsive tissue where spermatozoa mature and gain motility. The three major regions of the epididymis, caput, corpus, and cauda, are known to have different functions and exhibit varied gene expression. Specific genes within the different regions of the epididymis have been identified to be under the influence of androgens. The goal of this study was to begin to elucidate the profile of androgen-responsive genes that may be important for sperm maturation using the Affymetrix MGU74Av2 GeneChip oligonucleotide microarray platform. Adult mice (B6/129 strain) were castrated and treated 6 days after castration with two injections of 5 mg of dihydrotestosterone (DHT) or oil over a 48-h period. The mice were killed 48 h later and total RNA was purified from the caput, corpus, and cauda regions of the epididymis. Using GeneSpring 5.0 (Silicon Genetics) software, transcripts were identified that were upregulated 2-fold or more by DHT in the caput (33 transcripts), the corpus (8 transcripts), and the cauda (9 transcripts).
| ISSN : | 0006-3363 |
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| Mesh Heading : | Androgens Animals Dihydrotestosterone Epididymis Gene Expression Regulation Male Mice Mice, Inbred Strains Oligonucleotide Array Sequence Analysis Orchiectomy Reproducibility of Results Up-Regulation drug effects physiology standards |
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| Mesh Heading Relevant : | pharmacology pharmacology physiology drug effects methods |
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