Regulation of Sertoli Cell α2-Macroglobulin and Clusterin (SGP-2) Secretion by Peritubular Myoid Cells1

Self Cite

Results of previous in vitro and in vivo studies have illustrated that the expression of testin by Sertoli cells is tightly associated with the disruption of Sertoli-germ cell junctions. In the present study, treatment of rats with cadmium chloride (CdCl(2)), which disrupted the inter-Sertoli tight junctions, failed to induce any changes in testicular testin expression. In contrast, lonidamine, an antispermatogenic drug that rearranges the Sertoli cell membrane microfilament structure causing a disruption of Sertoli-germ cell adhesion junctions, induced a drastic increase in testicular testin expression when administered orally. Lonidamine-induced Sertoli cell testin expression involved both ongoing RNA and de novo protein synthesis. Basal testin expression remained stable during the 27-h incubation with actinomycin D but required de novo protein synthesis in vitro. An inhibitor of protein kinase A, Rp-cAMPS, caused a 50% inhibition of Sertoli cell testin expression at 10 microM within 24 h. A biphasic response was noted in testin expression when forskolin was included in the Sertoli cell culture, and high concentrations of cAMP analogues (1 mM) rapidly reduced testin expression. However, lonidamine can abolish the inhibitory effect of cAMP analogues on Sertoli cell testin expression. These results illustrate that the induction of testin expression may involve several signal transduction pathways.

Section: Discussionmentioning

confidence: 99%

Testin Induction: The Role of Cyclic 3′,5′-Adenosine Monophosphate/Protein Kinase A Signaling in the Regulation of Basal and Lonidamine-Induced Testin Expression by Rat Sertoli Cells1

Grima

Cheng

2000

Self Cite

“…Glucocorticoid receptors decrease with age in Sertoli cells. Glucocorticoids increase androgen binding protein mRNA in Sertoli cells from 19-day-old rats [45] and increase a-2 macroglobulin secretion at high concentrations [46]. Neither effect has been shown to be transcriptionally regulated, however.…”

Section: Discussionmentioning

confidence: 99%

Both Sertoli and Peritubular Cells Respond to Androgens with Increased Expression of an Androgen Response Element Reporter1

Ku¹,

Loose-Mitchell

Sanborn

1994

To explore the ability of androgens to affect gene expression in Sertoli and peritubular cells in vitro, constitutively expressed pSV2-Luc and a regulated reporter containing an androgen response element (MMTV-Luc) were transiently transfected into these cells. Reporter expression was markedly affected by cell density and maturational age. Mibolerone-stimulated MMTV-Luc expression increased in Sertoli cells with animal age between 15 and 25 days, consistent with the developmental increase in androgen receptor concentration, but was not markedly age-dependent in peritubular cells. The antiandrogen hydroxyflutamide inhibited stimulation of MMTV-Luc expression by 1 and 10 nM testosterone in both Sertoli and peritubular cells, consistent with an androgen receptor-mediated event. In contrast, dexamethasone at 1 and 10 nM elicited no effect in Sertoli cells, but stimulated MMTV-Luc expression in peritubular cells. In this study, the androgen receptor/glucocorticoid receptor ratio was 2.4 and 0.06 in Sertoli and peritubular cells, respectively. Cotransfection of Sertoli and peritubular cells with a plasmid expressing the rat androgen receptor further increased the androgen-stimulated expression of MMTV-Luc. These data demonstrate the functionality of the androgen receptors in both Sertoli and peritubular cells in culture. Receptor expression appears to be a limiting factor in the response. The data are consistent with potential roles for both Sertoli and peritubular cells in androgen-mediated transcriptional events in the testis.

“…Preparations of these testicular cells from Sprague-Dawley were performed as previously described [10][11][12]. About 3 Rg of total RNA was reverse-transcribed to DNA by use of 1 Rtg of oligo(dT)-15 primer (Promega Biotec, Madison, WI) at 42°C for 60 min together with 8 U of AMV-reverse transcriptase (Promega), 10 units of RNasin (Promega), 2.5 1 of dNTP (10 mM each of dATP, dGTP, dCTP, and dTITP), 2.5 u1l of DT (dithiothreitol, 100 mM) and sterile water in a final reaction volume of 25 1 as previously described [13].…”

Section: Testin Mrna Amplification By Sequential Use Of Reversetranscmentioning

confidence: 99%

Cyclic and Postnatal Developmental Changes of Testin in the Rat Seminiferous Epithelium—An Immunohistochemical Study1

Zong¹,

Zhu

Grima

et al. 1994

Testin is an authentic Sertoli cell secretory protein consisting of two molecular variants designated testin I (M(r) 35 000) and testin II (M(r) 37 000). N-Terminal amino acid sequence analysis revealed that testin I is identical to testin II except that testin II has three extra N-terminal amino acids of threonine-alanine-proline (TAP). Earlier studies by immunoflorescence microscopy have shown that testin is detected in the seminiferous epithelium consistent with localization in the junctions between Sertoli cells as well as Sertoli-germ cells, and that it appears to be a component of junctional complexes in the testis. In the present study, we have examined the localization of testin in different stages of the spermatogenic cycle of the adult rat testis when germ cells migrate from the basal portion of the seminiferous epithelium to the tubular lumen. In stages I-IV, testin was localized mainly in the basement laminae in the junctional complexes between adjacent Sertoli cells as well as between Sertoli cells, spermatogonia, and pachytene spermatocytes. When elongated spermatids were embedded into the seminiferous epithelium in stage VII of the cycle, testin was detected predominantly on the concave side of the elongated spermatids, but relatively few testin reaction products were seen in the round spermatids. In the beginning of stage VIII of the spermatogenic cycle, intense testin immunoreactive substances were detected around the heads of the elongated spermatids; these substances were virtually undetectable in late stage VIII after the release of the mature sperm into the tubular lumen, suggesting that testin may be a novel marker to divide stage VIII into stages VIIIa and VIIIb.(ABSTRACT TRUNCATED AT 250 WORDS)