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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A brief electric pulse often produces a high rate of activation of recently ovulated oocytes. Some other efficient parthenogenetic stimuli, such as alcohol, however, disrupt the spindle apparatus and increase the incidence of aneuploidy. In this paper, we have determined whether electroactivation per se increases the incidence of chromosomal segregation errors in haploid parthenogenones as evidenced at first cleavage mitosis. Superovulated F1 hybrid female mice were killed at 15.5, 18.5, 22.5, and 25 h after the HCG injection. Batches of 10-12 cumulus-denuded oocytes were transferred to an electroactivation chamber containing mannitol which was connected to a high voltage pulse stimulator and the pulse was triggered once. A high proportion of oocytes activated following this treatment, but only the single-pronuclear haploid parthenogenones were incubated overnight in medium containing colcemid, to determine the incidence of aneuploidy as evidenced at first cleavage mitosis. "Sham" electroactivation groups were also examined for evidence of activation and aneuploidy as described above. In these cases, cumulus-denuded oocytes were put through the electroactivation chamber but the pulse was not triggered. A further group of oocytes was studied to determine the effect of handling and exposure to hyaluronidase on activation frequency and parthenogenetic pathways. Finally, the spontaneous rate of aneuploidy was examined in fertilised embryos of F1 hybrid female mice x Rb(1.3)1Bnr male mice at first cleavage mitosis. The results show that single pulse electroactivation does not increase the level of aneuploidy in single-pronuclear parthenogenous compared to the "sham" group or the spontaneous rate observed in 1-cell fertilised embryos, nor does aneuploidy appear to increase with postovulatory age.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Reprod Dev 1993 Mar
PMID:The incidence of aneuploidy after single pulse electroactivation of mouse oocytes. 847 Dec 52

A yeast artificial chromosome (YAC B30) with a 320 kb insert of genomic DNA which includes the HLA-A gene was used to screen a cDNA library of human duodenal mucosa. Seven cDNA clones were isolated which correspond to seven new non-HLA class I structural genes. These new genes are located within a region that may well contain the gene responsible for hemochromatosis and have therefore been named HCG I-VII (Hemochromatosis Candidate Gene). HCG I, III, V and VI are probably single copy genes, situated at 180, 155, 140 and 230 kb centromeric to HLA-A, respectively. HCG II, IV and VII present several copies: one copy of HCG II, one of HCG IV and one of HCG VII are centromeric to HLA-A (at 30, 70 and 100 kb respectively). Another copy of HCG IV is 20 kb telomeric to HLA-A. Each of the genes localized on the YAC B30 is associated with an CpG/HTF island.
Hum Mol Genet 1993 Jan
PMID:Localization of seven new genes around the HLA-A locus. 849 Jun 24

The role of angiotensin II (AngII) in ovarian steroidogenesis is not clearly understood. In order to study its action on progesterone synthesis and to determine which receptor subtype is involve, granulosa cells obtained from women undergoing in-vitro fertilization were cultured for 2 or 4 days and then incubated in the presence of AngII (10(-7) M) with or without human chorionic gonadotrophin (HCG, 10 IU/ml) for 3 or 18 h. In cells cultured for 2 days, incubation with AngII decreased progesterone secretion by 36%, and inhibited activity of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) by 87% (P < 0.05), although its expression was not significantly reduced. However, in cells cultured for 4 days, progesterone production was enhanced by incubation with AngII (38%), and no change was observed in 3 beta-HSD expression. Both inhibitory and stimulatory effects were dose-dependent. Progesterone secretion was increased (93%) by incubation with HCG of cells cultured for 4, but not for 2 days, and no potentiation was observed with AngII. Treatment with PD123177 completely blocked the action of AngII and decreased the HCG-stimulated secretion of progesterone by 27%. Angiotensin type-2 (AT2) receptor mRNA was expressed in cells cultured for 4 days. In conclusion, AngII showed a regulatory role in in-vitro progesterone production by human granulosa luteinized cells, modulating the activity of 3 beta-HSD. It is likely that these actions may be mediated via membrane receptors, possibly of the AT2 receptor family.
Mol Hum Reprod 1997 Aug
PMID:Regulatory role of angiotensin II on progesterone production by cultured human granulosa cells. Expression of angiotensin II type-2 receptor. 929 49

The effect of human chorionic gonadotropin (hCG) on the expression of immediate early genes (IEGs) including all members of fos and jun family, and c-myc was studied using mouse Leydig cell line (MA-10 cells) by Northern blot analyses. In addition, the induction of ref-1 which enhances DNA binding of fos/jun proteins was also analyzed. HCG induced a rapid and transient expression of c-fos, fosB, c-jun, junB, junD and c-myc with a peak at 30 min to 1 h. In contrast, induction of fra-1 mRNA was delayed with a peak at 3 hr. However, fra-2 mRNA was immediately increased by hCG with a peak at 1 h. The ref-1 mRNA was expressed before the stimulation and its level was not altered by hCG at least for 8 hr. The differential induction of IEGs and continuous expression of ref-1 mRNA suggest an important role of their gene products on the regulation of Leydig cell function by hCG.
Biochem Mol Biol Int 1998 Feb
PMID:Inductions of immediate early genes (IEGS) and ref-1 by human chorionic gonadotropin in murine Leydig cell line (MA-10). 953 May 5

Oocyte meiosis is sensitive to endogenous and exogenous perturbations that upset the temporal sequence of biochemical reactions during oocyte maturation (OM) and predispose oocytes to aneuploidy. Nicotine is an alkaloid that has been reported to disrupt the rate of OM, reduce ovulation and fertilization rates, and increase diploidy. The objective of this study was to test the hypothesis that nicotine perturbs the rate of OM and induces aneuploidy in mouse oocytes in vivo and in vitro. Female mice were given 7.5 IU pregnant mare's serum and either 0, 5.0, 7.5, or 10 mg/kg nicotine in vivo at -3, 0, and +3 h relative to a 5 IU injection of HCG. Oocytes were also cultured in vitro in the presence of 0, 1.0, 5.0, or 10.0 mmol/l nicotine. In vivo, significant (P < 0.05) differences in the proportions of oocytes with premature centromere separation and premature anaphase were found at 10.0 mg/kg nicotine suggesting that the rate of OM was advanced. Also, at this dose the proportion of ovulated oocytes was reduced by approximately 50% relative to controls. In vitro, only non-significant differences were found among the parameters measured. Although nicotine reduced the ovulation rate and perturbed the rate of OM in vivo, these data show that the rate of aneuploidy was not significantly elevated.
Mol Hum Reprod 2000 Mar
PMID:Sensitivity of mouse oocytes to nicotine-induced perturbations during oocyte meiotic maturation and aneuploidy in vivo and in vitro. 1069 70

The present study was designed to determine whether progesterone might have a role in gonadotrophin-induced pituitary adenylate cyclase-activating polypeptide (Pacap) gene expression in rat ovary. Northern blot analysis revealed that treatment of pregnant mare's serum gonadotrophin (PMSG)-primed immature rats with the progestin antagonist RU486 or an inhibitor of 3beta-hydroxysteroid dehydrogenase epostane, 1 h before HCG, resulted in a dose-dependent inhibition of the HCG-induced Pacap gene expression. In-situ hybridization demonstrated that the number of pre-ovulatory follicles expressing Pacap mRNA in their granulosa cells was greatly reduced in ovaries treated with RU486. Moreover, the suppressive effect of RU486 or epostane on the LH-induced Pacap gene expression in cultured pre-ovulatory follicles was reversed by co-treatment with the synthetic progestin R5020. We further cloned the 5'-flanking region of the rat Pacap gene and identified the presence of a consensus progesterone receptor element. When luciferase fusion genes containing Pacap gene promoter were transiently transfected into granulosa cells of pre-ovulatory follicles, luciferase activity was markedly stimulated by LH. Treatment with RU486 or epostane resulted in partial suppression of LH-stimulated PACAP promoter activity. Taken together, these results indicate that progesterone, acting through progesterone receptors, plays a role in gonadotrophin induction of Pacap gene expression in granulosa cells of pre-ovulatory follicles, and thereby may be involved in the process of ovulation.
Mol Hum Reprod 2000 Mar
PMID:Involvement of progesterone in gonadotrophin-induced pituitary adenylate cyclase-activating polypeptide gene expression in pre-ovulatory follicles of rat ovary. 1069 71

Rat sarcomas, induced by subcutaneous injections of 7,12-dimethylbenz[a]anthracene (DMBA), were studied with the objective of identifying critical chromosome regions associated with tumorigenesis. We employed three genomewide screening techniques-cytogenetics, CGH, and allelotyping-in 19 DMBA-induced sarcomas in F1 (BN/Han x LE/Mol) rats. The most conspicuous finding in the cytogenetic analysis was a high incidence of trisomy for rat chromosome 2 (RNO2). Signs of gene amplification (hsr) were also seen in several tumors. The CGH analysis revealed that gains in copy number were much more common than losses. The gains mostly affected RNO2 (10/19), RNO12q (7/19), and RNO19q (5/19), as well as the proximal part of RNO4 (8/19) and the distal part of RNO7 (7/19). Reduction in copy number was seen in RNO17 (2/19). For the allelotyping, we used 318 polymorphic microsatellite marker loci covering the entire genome. We identified regions of allelic imbalance affecting most of the rat chromosomes. The highest incidences of recurrent allelic imbalance were observed at loci in certain regions in RNO1, 2, 4, and 7 and at lower incidences in parts of RNO12, 16, 18, and 19. The combined results suggested that genetic alterations detected in RNO2 and RNO12 usually corresponded to complete or partial trisomy, whereas those in RNO1 and RNO7 seemed to involve regional deletions and/or gains. Furthermore, we could confirm that copy number gains occur proximally in RNO4, where a previous study showed amplification of the Met oncogene in a subset of these tumors.
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PMID:Genomewide assessment of genetic alterations in DMBA-induced rat sarcomas: cytogenetic, CGH, and allelotype analyses reveal recurrent DNA copy number changes in rat chromosomes 1, 2, 4, and 7. 1082 3

We describe a reverse transcriptase-polymerase chain reaction (RT-PCR) for determination of human chorionic gonadotropin-beta (HCG beta) mRNA copies using the TaqMan system. To evaluate our quantitative assay, we analyzed HCG beta transcripts of all protein coding genes (HCG beta 5, 3, 8, and 7) in human RNA panels of different normal tissues and in glycodelin-A-stimulated trophoblast cell cultures. Absolute quantification using HCG beta TaqMan probe was found to be highly reproducible. Our study of RNA panels confirms recently published results that expression of HCG beta transcripts is a common feature of a great variety of different normal tissues. High levels of HCG beta mRNAs (> 1,000 molecules per 200 ng RNA) were detected in placenta, uterus, and testis. An increase of HCG beta mRNA expression (1.7-fold) was detected at 150 micrograms/mL glycodelin-A treatment in trophoblast cell culture. Time-dependence study showed that the increase in HCG beta mRNA level was evident at 60 min after glycodelin-A treatment. In summary, we have developed a highly sensitive one-tube, one-enzyme quantitative RT-PCR system that is time-saving and avoids postamplification procedures.
Mol Biotechnol 2000 Jan
PMID:Absolute quantification of human chorionic gonadotropin-beta mRNA with TaqMan detection. 4. 1091 14

Isolated ovarian follicles of greenback flounder Rhombosolea tapirina were incubated with a variety of gonadotropins (GtHs) and steroid precursors for periods of up to 42 h, and levels of free and glucuronated testosterone (T) and 17beta-estradiol (E(2)) in the medium, and free T and E(2) from inside follicles were measured by RIA. Short incubations (6 h) generated increases in T and E(2) in response to steroid precursors, but not human chorionic GtH (hCG), or salmon or carp GtH. At incubation times of 18 h, all GtHs stimulated T and, or E(2) production, whereas after 42-h incubation, GtH effects on E(2) production had disappeared. Steroid precursors remained effective at 18 and 42 h. T and E(2) glucuronides were formed in small quantities but did not account for loss of treatment effects at long incubation times. Instead, this could be explained by accumulation of E(2) in controls as a result of continued basal steroid production. Follicles absorbed substantial amounts of both endogenous and exogenous steroid from the medium, however, this did not appear to have any influence on changes in treatment effects with incubation time. Flounder follicles were most sensitive to hCG, followed by salmon and carp GtH at approximately 10-fold higher concentrations. Ovarian segments were not sensitive to any GtH but did convert exogenous steroid precursors indicating that tissue access by GtH may be a limiting factor under certain in vitro conditions. HCG augmented the conversion of 17-hydroxyprogesterone (17P) to T but not T to E(2), consistent with the relative GtH-insensitivity of aromatase in other species. Follicles converted a range of steroid precursors with equal competence, indicating that no step in the cleavage pathway is strongly rate-limited, and that choice of precursor is unlikely to affect the assessment of steroidogenic activity.
Comp Biochem Physiol A Mol Integr Physiol 2000 Oct
PMID:Characterization of parameters for in vitro culture of isolated ovarian follicles of greenback flounder Rhombosolea tapirina. 1106 85

One of the primary goals of ART is to achieve some degree of supraphysiologic ovarian stimulation. Too vigorous a response can lead to ovarian hyperstimulation syndrome (OHSS), which is potentially life threatening. The incidence of severe OHSS is low, yet global proliferation of ART suggests that the absolute number of cases will be increasing. The clinical course of OHSS is more severe in patients who conceive. Should gonadotropin therapy induce too great a response, OHSS can best be prevented via cycle cancellation and withholding HCG. An alternative, which would not forfeit oocyte retrieval, is to perform elective cryopreservation of all resulting pre-embryos. This requires a strategy to identify patients at risk accurately. Several centers have bypassed fresh embryo transfer to lessen the risk of OHSS. By consensus it appears that this approach reduces but does not eliminate the risk of severe OHSS. Chances of pregnancy are excellent in subsequent cryo thaw transfers.
Mol Cell Endocrinol 2000 Nov 27
PMID:Embryo freezing to prevent ovarian hyperstimulation syndrome. 1115 59


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