Transgenerational Effects of Di-(2-Ethylhexyl) Phthalate (DEHP) on Stress Hormones and Behavior.

Exposure to di-(2-ethylhexyl) phthalate (DEHP) has been linked to male reproductive abnormalities. Here, we assessed transgenerational actions of DEHP on several behaviors and stress responses. We used 2 doses of DEHP (150- and 200-mg/kg body weight) and a treatment regimen previously shown to produce transgenerational effects on male reproduction.

Transgenerational effects of di-(2-ethylhexyl) phthalate on testicular germ cell associations and spermatogonial stem cells in mice.

Recent evidence has linked human phthalate exposure to abnormal reproductive and hormonal effects. Phthalates are plasticizers that confer flexibility and transparency to plastics, but they readily contaminate the body and the environment. In this study, timed pregnant CD1 outbred mice were treated with di-(2-ethylhexyl) phthalate (DEHP) from Embryonic Day 7 (E7) to E14.

Immunoprotective properties of primary Sertoli cells in mice: potential functional pathways that confer immune privilege.

Primary Sertoli cells isolated from mouse testes survive when transplanted across immunological barriers and protect cotransplanted allogeneic and xenogeneic cells from rejection in rodent models. In contrast, the mouse Sertoli cell line (MSC-1) lacks immunoprotective properties associated with primary Sertoli cells. In this study, enriched primary Sertoli cells or MSC-1 cells were transplanted as allografts into the renal subcapsular area of naive BALB/c mice, and their survival in graft sites was compared.

Activity of retinoic acid receptor-alpha is directly regulated at its protein kinase A sites in response to follicle-stimulating hormone signaling.

Retinoic acid receptor-alpha (RARA) is crucial for germ cell development in the testis, as shown by the degenerated testis in Rara gene knockout mice, which are sterile. Similarly, FSH is known to regulate Sertoli cell proliferation and differentiation, indirectly controlling the quantity of the spermatogenic output. Interestingly, FSH inhibited, via activation of FSH receptor, cAMP, and protein kinase A (PKA), the nuclear localization and transcriptional activity of RARA.

Disulfide isomerase glucose-regulated protein 58 is required for the nuclear localization and degradation of retinoic acid receptor alpha.

Retinoic acid receptor alpha (RARA) is critical for spermatogenesis, as shown by a sterility phenotype observed in Rara knockout mice. RARA is important in both Sertoli and germ cells of the testis. Here, we demonstrate that a disulfide isomerase glucose-regulated protein 58 (GRp58) participates in the nuclear import and degradation of RARA in Sertoli cells.

Retinoic acid modulates the subcellular localization of small ubiquitin-related modifier-2/3 (SUMO-2/3) in the testis.

Covalent attachment of small ubiquitin-related modifier (SUMO) to target proteins is an important posttranslational mechanism controlling diverse cellular functions. Recently, hypo- or hyper-sumoylation by SUMO-2/3 was shown to play a crucial role in male reproduction. However, the regulation of SUMO-2/3 in the testis remains unknown.

Temporal profiling of rat transcriptomes in retinol-replenished vitamin A-deficient testis.

At least in mammals, retinoic acid is a pivotal factor in maintaining the functionality of the testis, in particular, for the progression of germ cells from mitosis to meiosis. Removal of dietary vitamin A or a targeted deletion of retinoic acid receptor alpha gene (Rara), the receptor for retinoic acid, in mice, led to testicular degeneration by a dramatic loss of germ cells and a loss of control of the spermatogenic cycle. The germ cells that remained in the vitamin A deficient (VAD) rat testis were spermatogonia and a few preleptotene spermatocytes.

Small ubiquitin-like modifier-2 modification of retinoic acid receptor-alpha regulates its subcellular localization and transcriptional activity.

The retinoic acid receptor-alpha (Rara) gene is critical for germ cell development in the testis, as demonstrated by infertile Rara knockout male mice. The encoded protein for Rara (RARA) is expressed in both Sertoli cells and germ cells, but it is not always in the nucleus. Previously, all-trans retinoic acid (ATRA) was shown to increase the nuclear localization and transcriptional activity of RARA in Sertoli cells.

Potential functions of retinoic acid receptor A in Sertoli cells and germ cells during spermatogenesis.

Elucidation of the retinoid signaling circuitry in the testis is critical to understanding how male germ cells develop to spermatozoa. Retinoic acid receptor A protein (RARA) is an essential mediator of retinoid signaling in the testis, as shown by a sterility phenotype observed for retinoic acid receptor A gene (Rara) knockout male mice. The seminiferous tubules of Rara knockout mice showed varying degrees of germ-cell degeneration.

Retinoic acid regulation of eye and testis-specific transcripts within a complex locus.

We previously used a yeast-based enhancer trap to identify a strong, retinoic acid response element (RARE). We have now characterized testis and eye transcripts that are adjacent to this regulatory element. Bioinformatics analysis of expressed sequence tag (EST) clones and RNase protection, reverse transcription-PCR, and Northern blot assays indicate that these two RNAs are transcribed from the same locus on opposite template strands.

Sarcosine1, glycine8 angiotensin II is a functional AT1 angiotensin receptor antagonist.

Sarcosine1, glycine8 angiotensin II (SG Ang II) displayed unusual characteristics in early pharmacological studies. It was a potent antagonist of the dipsogenic actions of intracerebroventricularly administered Ang II in the rat, but showed low affinity for bovine cerebellar Ang II receptors. It has recently been shown that SG Ang II binds preferentially to the AT1 receptor.

Differential effects of phthalates on the testis and the liver.

Phthalates have been shown to elicit contrasting effects on the testis and the liver, causing testicular degeneration and promoting abnormal hepatocyte proliferation and carcinogenesis. In the present study, we compared the effects of phthalates on testicular and liver cells to better understand the mechanisms by which phthalates cause testicular degeneration. In vivo treatment of rats with di-(2-ethylhexyl) phthalate (DEHP) caused a threefold increase of germ cell apoptosis in the testis, whereas apoptosis was not changed significantly in livers from the same animals.

Retinoic acid inhibits rat XY gonad development by blocking mesonephric cell migration and decreasing the number of gonocytes.

Vitamin A (also called retinol) and its derivatives, retinoic acids (RAs), are required for postnatal testicular function. Abnormal spermatogenesis is observed in rodents on vitamin A-deficient diets and in retinoic acid receptor alpha (RARalpha) knockout mice. In contrast, RA has an inhibitory effect on the XY gonad development in embryos.

Tsp57: a novel gene induced during a specific stage of spermatogenesis.

Recently, we described the identification of a novel protein, nuclear receptor-associated protein 80 (RAP80), which is highly expressed in spermatocytes and appears to have a role in regulating gene expression. To identify proteins interacting with this protein, we performed yeast two-hybrid screening using full-length RAP80 as bait. This screen identified one in-frame clone encoding a novel testis-specific protein (Tsp), referred to as Tsp57.

Effects of ethanol on embryonic and neonatal rat testes in organ cultures.

Ethanol exposure in adult animals and humans has shown to elicit significant inhibitory effects on the function of male reproduction, but consequences of ethanol exposure on the embryonic and early postnatal testis development are not known. The current study investigated the effect of ethanol on embryonic and neonatal testis development using an organ culture technique. In embryonic day 13 (E13) testis organ cultures, ethanol had no effect on the testicular cord formation, the expression of Müllerian-inhibiting substance (MIS) in Sertoli cells or the number of gonocytes.

Effects of mono-(2-ethylhexyl) phthalate on fetal and neonatal rat testis organ cultures.

Di-(2-ethylhexyl) phthalate (DEHP) and its active metabolite, mono-(2-ethylhexyl) phthalate (MEHP), have been shown to cause reproductive toxicity in both developing and adult animals. In this study, we used organ cultures of fetal and neonatal rat testes to assess the in vitro effect of MEHP on seminiferous cord formation in Embryonic Day 13 (E13) testes and on the development of E18 and Postnatal Day 3 (P3) testes. Interestingly, MEHP had no effect on cord formation in the organ cultures of E13 testes, indicating that it has no effect on sexual differentiation of the indifferent gonad to testis.

Peroxisome proliferators disrupt retinoic acid receptor alpha signaling in the testis.

Peroxisome proliferators include a diverse group of chemicals, some of which have been demonstrated to be testicular toxicants. However, the mechanism by which peroxisome proliferators, such as phthalates, cause testicular damage is not clear. It is known that retinoic acid receptor alpha (RARalpha) and its retinoic acid ligand, the acid form of vitamin A, are required for spermatogenesis.

Trapping and characterization of novel retinoid response elements.

Retinoids, such as retinoic acid (RA), play a critical role in normal vertebrate development and physiology. However, embryonic exposure to excess retinoids also causes severe malformations. Retinoids bind RA receptors and retinoid X receptors, thus activating a plethora of genes.

Partial characterization of endothelial FGF receptor functional domain by monoclonal antibody VBS-1.

Polypeptide growth factors mediate their cellular responses by binding to and activating specific cell surface receptors. Monoclonal antibody (MAb) VBS-1, produced against native fibroblast growth factor receptor-1 (FGFR-1), inhibited the binding of fibroblast growth factor-2 (FGF-2) to its receptor on coronary venular endothelial cells (CVECs) as determined by 125I-FGF-2 Scatchard analysis and [3H]thymidine uptake assays (ED50 = 80 ng/mL). Enzyme studies demonstrated that MAb VBS-1 binds to a protein epitope.

Positive regulation of retinoic acid receptor alpha by protein kinase C and mitogen-activated protein kinase in sertoli cells.

Retinoic acid receptor alpha (RARalpha) is required for normal testis function. Similar to other steroid hormone receptors, RARalpha appears to undergo an activation process by which it translocates from the cytoplasm to the nucleus where it acts as a transcription factor. In this report, we demonstrate that RARalpha nuclear trafficking in Sertoli cells is positively regulated by phorbol-12-myristate-13-acetate-activated protein kinase C without the requirement of ligand, retinoic acid.

Synthesis and biological activity of the new 5-fluorocytosine derivatives, 5'-deoxy-N-alkyloxycarbonyl-5-fluorocytosine-5'-carboxylic acid.

A series of 5-fluorocytosine derivatives, 5'-deoxy-N-alkyloxycarbonyl-5-fluorocytosine-5'-carboxylic acid 6, were synthesized and evaluated for their antitumor activity.