Biomedical subjects

I Ben-Shlomo

Publications and source records attributed to I Ben-Shlomo.

At least 37 records · Page 2Linked to original sources

PubMed1999

Ovarian interleukin-1 receptor antagonist in rats: gene expression, cellular localization, cyclic variation, and hormonal regulation of a potential determinant of interleukin-1 action.

It is hypothesized that the intraovarian interleukin (IL)-1 system plays a prominent role in the regulation of follicular development and ovulation. A central component of the intraovarian IL-1 system is the IL-1 receptor antagonist (IL-1RA), a protein acting as a pure IL-1 receptor antagonist and one for which intracellular (icIL-1RA) and secretory (sIL-1RA) varieties have been described. It was the objective of this study to explore rat ovarian IL-1RA gene expression, to establish the identity and relative abundance of its alternative transcripts, to study its cellular localization, to determine its cyclic variation, and to assess its hormonal regulation. Protected IL-1RA cDNA fragments corresponding to either sIL-1RA or icIL-1RA were barely detectable in untreated whole ovarian tissue of immature rat origin. However, sIL-1RA transcripts reached a maximal value (3.3-fold increase over untreated control values; p < 0.05) 12 h after hCG administration (time of projected ovulation). In situ hybridization localized IL-1RA to mural, antral, and cumulus granulosa cells. Modestly intense staining was also apparent in oocytes. The basal pattern of sIL-1RA expression by cultured whole ovarian dispersates was characterized by a spontaneous increase to a peak value at 4 h. The early (4 h) sIL-1RA burst proved IL-1-, nitric oxide-, and protein biosynthesis-independent. However, treatment with IL-1beta led to a secondary sIL-1RA peak at 48 h, an effect that was substantially reversed by IL-1RA. This stimulatory effect of IL-1beta on IL-1RA expression proved relatively specific, and nitric oxide independent, but contingent upon de novo protein biosynthesis. The in vitro expression of icIL-1RA was barely detectable. Taken together, these in vivo and in vitro observations 1) document the rat ovary as a site of IL-1RA (sIL-1RA > cIL-1RA) expression, 2) localize the relevant transcripts to the granulosa cell, 3) disclose peak expression at the time of ovulation, and 4) establish IL-1 dependence.

Animals↗

PubMed1999

Rat ovarian interleukin-1alpha: interleukin-1-dependent in vitro expression.

Evidence exists supporting the possibility that intraovarian interleukin-1 (IL-1) may play an intermediary role in the periovulatory cascade. Although the existence of a mammalian intraovarian IL-1 system has been convincingly demonstrated, most efforts have focused on the possibility that the mammalian ovary is a site of IL-1b production, reception, and action. The objective of this study was to explore the possibility of ovarian IL-1a expression, characterize its pattern of expression by cultured ovarian cells, and study its hormonal regulation. The basal in vitro expression of IL-1a by cultured whole ovarian dispersates from immature rats increased spontaneously, reaching a peak (sixfold increase over untreated controls) at 4 h. Treatment with an IL-1 receptor antagonist (IL-1RA), human chorionic gonadorropin, or IL-1b failed to attenuate the initial 4-h burst of IL-1a expression. By contrast, treatment of whole ovarian dispersates with IL-1b for 48 h resulted in significant upregulation of IL-1a transcripts (60-fold increase). This IL-1b effect was completely blocked by cotreatment with IL-1RA, thereby suggesting mediation via a specific IL-1 receptor. The IL-1b effect proved to be protein biosynthesis and eicosanoid dependent, nitric oxide independent, and relatively specific in that it was not reproduced by a select series of other granulosa cell agonists.

Animals↗

PubMed1999

Transforming growth factor-beta1 is a potent inhibitor of interleukin-1beta action in whole ovarian dispersates.

Transforming growth factor beta1 (TGFbeta1) acts as an inhibitor of the actions of interleukin-1beta (IL-1beta) in various organ systems. In order better to understand the inter|P-actions between these polypeptides in the ovary, we evaluated the effect of TGFbeta1 co-treatment on various IL-1beta-mediated actions in cultures of whole ovarian dispersates. Treatment with IL-1beta enhanced media accumulation of nitrites (4.8-fold), prostaglandin E2 (PGE2, 3. 9-fold) and lactate (2.0-fold), and enhanced glucose consumption (2. 1-fold). Treatment with TGFbeta1 alone did not significantly affect any of these parameters. However, the addition of TGFbeta1 inhibited IL-1beta-stimulated nitrite (100%), PGE2 (44%) and lactate (78%) accumulation and inhibited IL-1beta-stimulated glucose consumption (74%) in a dose-dependent manner. The addition of TGFbeta1 also suppressed the steady-state levels of IL-1beta-stimulated IL-1beta, type I IL-1 receptor and IL-1 receptor antagonist transcripts (98, 67 and 83% inhibition respectively). These data suggest that TGFbeta1 is capable of inhibiting several IL-1beta-stimulated endpoints. Since IL-1 has been identified as a possible proinflammatory mediator of ovulation and TGFbeta has been implicated as a promotor of fibrosis and healing, we speculate that IL-1 and TGFbeta might play antagonistic roles in the normal ovulatory sequence.

Animals↗

PubMed1998

Resistance to activated protein C and the leiden mutation: high prevalence in patients with abruptio placentae.

OBJECTIVE: The Leiden mutation, a point mutation in the gene encoding coagulation factor V, is associated with a high frequency of thromboembolic phenomena. It has recently been connected with adverse outcomes of pregnancy. We carried out this study to define its connection with abruptio placentae. STUDY DESIGN: Twenty-seven women who had abruptio placentae and 29 control subjects matched for age, parity, and ethnic origin were studied. We studied all women for possible hypercoagulation defects. All women demonstrating resistance to activated protein C were studied for the presence of the factor V Leiden mutation. RESULTS: Seventeen of 27 case patients had an activated protein C ratio </=2.5, compared with 5 of 29 control subjects (odds ratio 8.16, 95% confidence interval 3.6-12.75, P =.00125). Participants with activated protein C ratios </=2.5 underwent deoxyribonucleic acid analysis. Eight case patients were found to have the factor V Leiden mutation (5 heterozygous and 3 homozygous, 29.6%), compared with 1 heterozygote among the control subjects who were tested (3.4%). CONCLUSION: Factor V Leiden mutation was found quite frequently in patients with abruptio placentae.

Abruptio Placentae↗

PubMed1998

Transvaginal sonography as the ultimate diagnostic tool for the management of ectopic pregnancy: experience with 840 cases.

OBJECTIVE: To evaluate the efficacy of transvaginal sonography and serum beta-hCG levels as diagnostic tools for deciding whether to perform operative laparoscopy in the treatment of presumed ectopic pregnancy (EP). DESIGN: A prospective protocol for the evaluation and treatment of women with presumed EP. SETTING: Department of Obstetrics and Gynecology, Haemek Medical Center, Afula, Israel. PATIENT(S): Eight hundred forty women with presumed EP who were seen in our emergency department from January 1988 through December 1995. INTERVENTION(S): On the basis of specific sonographic signs and beta-hCG levels, we performed immediate operative laparoscopy in patients with demonstrable extrauterine fetal heart activity or >100 mL of fluid in the pelvic cavity. We followed up all other patients, using defined criteria for laparoscopic intervention. MAIN OUTCOME MEASURE(S): The accuracy of transvaginal sonography in predicting EP was evaluated as part of the described protocol. RESULT(S): Overall, 380 patients were found to have EP. Of these, 331 were identified positively by transvaginal sonography and 49 were not. In 27 of 358 laparoscopies, no EP was found. The sensitivity of transvaginal sonography for the prediction of EP was 87% and the specificity was 94%. The positive and negative predictive values were 92.5% and 90%, respectively. CONCLUSION(S): In this protocol, which invariably captured the true location of the products of conception, using transvaginal sonography as the primary modality in the evaluation of patients with presumed EP resulted in the use of laparoscopy mainly as a treatment tool. This approach is both safe and economical.

Adolescent↗

PubMed1998

Glucocorticoids suppress basal (but not interleukin-1-supported) ovarian phospholipase A2 activity: evidence for glucocorticoid receptor-mediated regulation.

Ovulation may constitute a cyclic, inflammatory-like process, wherein the increased expression of interleukin (IL)-1 and the biosynthesis of prostaglandins may be established corollaries. In this communication we hypothesize that glucocorticoids, potent anti-inflammatory principles, may exert an antiovulatory effect by interfering with ovarian IL-1-driven prostaglandin biosynthesis. To test this hypothesis, we examined the effect of treatment with dexamethasone on the activity of ovarian phospholipase A2 (PLA2), the event-limiting enzyme in prostaglandin biosynthesis, and on the gene expression pattern of secretory and cytosolic PLA2 (sPLA2 and cPLA2, respectively). Whole ovarian dispersates from immature rats were cultured under serum-free conditions for 48 h in the absence or presence of dexamethasone. At the conclusion of this culture period, PLA2 activity was determined in cell sonicates and conditioned media. Parallel probing for sPLA2 and cPLA2 transcripts was also undertaken using a solution hybridization/RNAse protection assay. Treatment of whole ovarian dispersates with dexamethasone produced a significant (P < 0.005) decrease in basal cellular and extracellular PLA2 activity to 27 and 40% of controls, respectively. A 5-fold decrease in the basal steady state levels of sPLA2 (but not cPLA2) transcripts was also noted. Co-treatment with dexamethasone produced complete inhibition of IL-1-stimulated cPLA2 transcripts but not of IL-1-supported cellular and extracellular PLA2 activity or sPLA2 transcripts. A glucocorticoid receptor antagonist (RU486), blocked the ability of dexamethasone to inhibit basal sPLA2 transcripts and extracellular PLA2 activity. The inhibitory effect of dexamethasone proved glucocorticoid-specific in that aldosterone and 17beta-estradiol were without effect. Taken together, these observations suggest that dexamethasone is capable of inhibiting basal (but not IL-1-supported) ovarian PLA2 activity, a glucocorticoid receptor-mediated effect due, in part, to a decrease in sPLA2 gene expression. Our findings further suggest that sPLA2 and cPLA2 are differentially regulated and that they may well differ in their relative contribution to ovarian prostaglandin biosynthesis in general and to PLA2 activity in particular. To the extent that IL-1 plays a central role in the ovulatory process, these findings argue against the view that the chronic anovulatory state induced by glucocorticoid excess is due, if only in part, to suppression of ovarian IL-1-dependent PLA2 activity.

Animals↗

PubMed1998

Laparoscopic resection of ovarian benign cystic teratomas: experience with 84 cases.

Laparoscopic treatment of benign cystic teratoma of the ovary has been recommended following the study of relatively small numbers of patients. We reviewed our experience with a prospective ongoing protocol for the treatment of benign ovarian teratomas, between January 1990 and December 1996. Sonography established the diagnosis, and biochemical markers were used to screen for possible malignancy. Surgery consisted of resecting the cyst and conserving the ovary if appropriate. The resected cyst was aspirated of its contents following insertion into an EndoCatch bag. Removal was accomplished via the narrowest incision possible by pulling the bag's margins through the incision and grasping the solid parts with conventional surgical instruments. The diameter of the cysts ranged from 2 to 15 cm. Cystectomy was performed in 47, and oophorectomy in 37, patients. Spillage occurred in 11 cases, but none developed peritonitis or fever. The mean duration of post-operative stay was 0.9 days (range 0.5-2). We conclude that laparoscopic resection of benign teratomas of the ovary is safe, well tolerated, and shortens hospital stay.

Adolescent↗

PubMed1997

The midcycle increase in ovarian glucose uptake is associated with enhanced expression of glucose transporter 3. Possible role for interleukin-1, a putative intermediary in the ovulatory process.

This study characterizes the rat ovary as a site of hormonally dependent glucose transporter (Glut) expression, and explores the potential role of interleukin (IL)-1, a putative intermediary in the ovulatory process, in this regard. Molecular probing throughout a simulated estrous cycle revealed a significant surge in ovarian Glut3 (but not Glut1) expression at the time of ovulation. Treatment of cultured whole ovarian dispersates from immature rats with IL-1beta resulted in upregulation of the relative abundance of the Glut1 (4.5-fold) and Glut3 (3.5-fold) proteins as determined by Western blot analysis. Other members of the Glut family (i.e., Gluts 2, 4, and 5) remained undetectable. The ability of IL-1 to upregulate Glut1 and Glut3 transcripts proved time-, dose-, nitric oxide-, and protein biosynthesis-dependent but glucose independent. Other ovarian agonists (i.e., TNF alpha, IGF-I, interferon-gamma, and insulin) were without effect. Taken together, our findings establish the mammalian ovary as a site of cyclically determined Glut1 and Glut3 expression, and disclose the ability of IL-1 to induce the ovarian expression as well as translation of Glut1 and Glut3 (but not of Gluts 2, 4, or 5). Our observations also establish IL-1 as the first known regulator of Glut3, the most efficient Glut known to date. In so doing, IL-1, a putative component of the ovulatory process, may be acting to meet the increased metabolic demands imposed on the growing follicle and the ovulated cumulus-enclosed oocyte.

Animals↗

PubMed1997

Individual implantation rate: proposal for a new index for evaluation of assisted reproduction results.

OBJECTIVE: To assess whether implantation in assisted reproductive technology (ART) cycles is a random event. DESIGN: Retrospective analysis of results. SETTING: Division for Reproductive Endocrinology and ART, Department of Obstetrics and Gynecology, Haemek Medical Center, Afula, Israel. PATIENT(S): A cohort of all cycles reaching ET from July 1, 1995, through June 30, 1996, and a cohort of all pregnancies recorded from January 1, 1995, through October 31, 1996. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Rate of multifetal pregnancy in relation to overall pregnancy rate. The number of gestational sacs observed by sonography, out of transferred embryos in conception cycles, was defined as the individual implantation rate. RESULT(S): Of 367 ETs, 75 (20.4%) yielded pregnancies, of which 31 (41%) were multifetal. Considering the mean number of embryos transferred (3.67), if implantation would have been random, multifetal gestation rate should have been only 14.8%, significantly less than the observed rate. In 110 pregnancies recorded between January 1995 and October 1996, individual implantation rate was 49.4% +/- 27.1% in intracytoplasmic sperm injection cycles compared with 40.5% +/- 20.4% in IVF cycles. CONCLUSION(S): Embryo implantation is not a random event. The index of individual implantation rate may help shed light on mechanisms underlying implantation.

Cohort Studies↗

PubMed1997

Methotrexate as a possible cause of ovarian cysts formation: experience with women treated for ectopic pregnancies.

OBJECTIVE: To evaluate ovarian morphology after either salpingostomy or local injection of methotrexate (MTX) to cause regression of tubal pregnancies and to define potential correlation to other clinical parameters. DESIGN: Prospective longitudinal follow-up. SETTING: Department of Obstetrics and Gynecology, Haemek Medical Center, Afula, Israel. PATIENT(S): One hundred one women who were treated for tubal pregnancy: 58 by salpingostomy and 43 by local MTX injection. INTERVENTION(S): Serial blood sampling for beta-hCG and serial transvaginal sonographic evaluation. MAIN OUTCOME MEASURE(S): Appearance of cysts in the ovaries and their location with regard to the side in which the tubal pregnancy occurred. RESULT(S): In 6 of 42 (14.3%) patients who were treated with MTX, multiple (range, three to six) ovarian cysts occurred, as compared with 1 of 55 (1.8%) in those who underwent salpingostomy. The largest cyst was 9.4 cm in diameter. No relation of cyst occurrence to the side of the ectopic pregnancy was recorded. The women who developed cysts did not differ in either initial serum beta-hCG levels or in the rate of its subsequent regression. CONCLUSION(S): Multiple ovarian cysts may occur in 15% of patients who are treated with intra-amniotic MTX to cause regression of tubal ectopic pregnancy.

Adult↗

PubMed1997

Hypnotic effect of i.v. propofol is enhanced by i.m. administration of either lignocaine or bupivacaine.

We have compared the hypnotic requirements for i.v. propofol when combined with i.m. lignocaine or bupivacaine. Ninety women (ASA I, II) undergoing minor gynaecological surgery were allocated randomly to one of nine groups of 10 patients to receive propofol combined with i.m. lignocaine, bupivacaine or saline, respectively. Propofol was administered in bolus doses of 0.2 mg kg-1 every 30 s until loss of response to verbal command was achieved. Lignocaine and bupivacaine significantly enhanced the hypnotic effect of propofol in a dose-dependent manner. The maximum doses tested (lignocaine 3.0 mg kg-1 and bupivacaine 1.0 mg kg-1) reduced the hypnotic dose of propofol by 34.4% and 39.6%, respectively. We conclude that if lignocaine or bupivacaine is injected into soft tissue before induction of anaesthesia by propofol, the i.v. dose of the latter should be modified accordingly.

Adult↗

PubMed1997

Hypnotic effect of i.v. thiopentone is enhanced by i.m. administration of either lignocaine or bupivacaine.

We have compared the hypnotic requirements for i.v. thiopentone alone and in combination with i.m. lignocaine or bupivacaine. Ninety women, ASA I-II, undergoing minor gynaecological surgery were allocated randomly to nine groups of 10 patients to receive thiopentone combined with i.m. lignocaine, bupivacaine or saline, respectively. Thiopentone was administered in bolus doses of 0.5 mg kg-1 every 30 s until loss of response to verbal command. Lignocaine and bupivacaine significantly enhanced the hypnotic effect of thiopentone in a dose-dependent manner. The maximum doses tested (lignocaine 3.0 mg kg-1 and bupivacaine 1.0 mg kg-1) reduced the hypnotic dose of thiopentone by 39% and 48%, respectively. We conclude that if lignocaine or bupivacaine are injected into soft tissue before induction of anaesthesia by thiopentone, the i.v. dose of the latter should be modified accordingly.

Adult↗

PubMed1997

Insulin-like growth factor I affects the intraovarian interleukin-1 system: evidence for suppression of type I interleukin-1 receptor expression and enhancement of secretory phospholipase A2 expression and activity.

This study assessed the possibility that the intraovarian insulin-like growth factor I (IGF-I) system interacts with the intraovarian interleukin-1 (IL-1) system, the central role of which has been the subject of increasing attention. To this end, whole ovarian dispersates from immature rats were cultured for 48 h in the absence or presence of IGF-I or IGF-binding protein-3 (IGFBP-3), with or without IL-1beta. Cellular RNA content was subjected to a solution hybridization, RNase protection assay with gel-purified [32P]-UTP-labelled antisense riboprobes for rat IL-1beta, type I IL-1 receptor (IL-1R) and secretory phospholipase A2 (sPLA2). PLA2 activity in conditioned media was assayed by measuring the release of [3H]-labelled palmitic acid from the sn-2 position of [3H]-labelled phosphatidylcholine dipalmitoyl (PCDP) substrate. Treatment with IGF-I resulted in a significant (P< 0.01) decrease in type I IL-1R transcripts (an effect which was reversed by co-treatment with IL-1beta), was without effect on IL-1beta transcripts, and significantly (P < 0.05) increased sPLA2 gene expression (an effect which was further enhanced by co-treatment with IL-1beta). Treatment with IGF-I resulted in a significant increase in extracellular PLA2 activity over untreated control. These observations suggest that IGF-I may down-regulate ovarian IL-1 action by decreasing type I IL-1R gene expression, while up-regulating sPLA2 gene expression and activity. These findings are consistent with a role for IGF-I in suppressing IL-1 actions while promoting the generation of prostaglandins. It is tempting to speculate that IGF-I, an intraovarian regulator concerned with promoting folliculogenesis, may be also entwined with priming the prostaglandin-producing potential in anticipation of subsequent ovulation.

Animals↗

PubMed1997

Ovarian expression, cellular localization, and hormonal regulation of rat secretory phospholipase A2: increased expression by interleukin-1 and by gonadotropins.

It has been suggested that ovulation may constitute a cyclic inflammatory-like process and that gonadotropin-inducible intraovarian interleukin (IL)-1, an established mediator of inflammation, may play a central role in this regard. In support of this hypothesis, our group has been able to document the ability of IL-1 to potently stimulate prostaglandin biosynthesis by cultured rat ovarian cells. Herein we explore the possibility that the prostaglandin-stimulating action of IL-1 is due, in part, to the enhanced expression of ovarian secretory phospholipase-A2 (sPLA2). A single sPLA2 transcript of 1.4 kilobases was noted in all extraovarian tissues of immature rat origin subjected to Northern blot analysis. However, only a barely detectable signal was apparent in ovarian tissue. In contrast, the more sensitive RNase protection assay revealed the unequivocal presence of ovarian sPLA2 transcripts. Cellular localization studies by way of in situ hybridization documented sPLA2 transcripts primarily in the granulosa cell of the periovulatory ovary. Molecular probing of untreated cultured whole ovarian dispersates disclosed spontaneous elaboration of sPLA2 transcripts as early as 20 h after the introduction of cells into culture. Treatment of cultured whole ovarian dispersates with IL-1beta for 48 h produced a 1.7-fold increase (over the value in untreated controls) in the relative expression of sPLA2 transcripts (p < 0.01) along with a 1.7-fold increase in media PLA2 activity (p < 0.01). A more marked increase was documented for IL-1beta-treated cultured isolated granulosa cells (12.5-fold increase, p < 0.001). Treatment of whole ovarian dispersates with an IL-1 receptor antagonist (IL-1RA) produced a reduction in the basal expression of sPLA2 transcripts (55% at the 5 microg/ml dose level; p < 0.01) and PLA2 activity (40%; p < 0.01), thereby suggesting basal endogenous IL-1-like bioactivity. Treatment of cultured whole ovarian dispersates with either hCG or FSH led to 2.6-fold (p = 0.056) and 3-fold (p = 0.029) increases in the abundance of sPLA2 transcripts, respectively, effects blocked by the concurrent presence of IL-1RA. These observations 1) document the immature rat ovary as a site of sPLA2 gene expression, 2) localize the relevant transcripts to the postovulatory granulosa cell, 3) confirm the presence of functional secreted ovarian PLA2 activity, 4) reveal PLA2 expression to be IL-1- and gonadotropin-dependent, and 5) suggest the existence of endogenous PLA2-stimulating IL-1-like activity. These findings also suggest that the ability of hCG or FSH to up-regulate ovarian sPLA2 transcripts may be due, in part, to the endogenous elaboration of IL-like activity.

Animals↗

PubMed1997

The rat ovarian phospholipase A2 system: gene expression, cellular localization, activity characterization, and interleukin-1 dependence.

We have previously demonstrated that interleukin-1 beta (IL-1 beta), a putative intermediary in the ovulatory process, is a potent stimulator of ovarian PG biosynthesis. In this communication, we examine the possibility that this IL-1 effect reflects in part the induction of arachidonic acid mobilization by phospholipase A2 (PLA2). Molecular probing of whole ovarian material revealed the immature rat ovary to be a site of modest secretory PLA2 (sPLA2) gene expression. However, no change in ovarian sPLA2 gene expression was noted during the periovulatory period. Comparable probing for cytosolic PLA2 (cPLA2) failed to disclose a quantifiable signal. However, in situ hybridization localized both sPLA2 and cPLA2 (sPLA2 > cPLA2) transcripts to the granulosa cell layer of the ovarian follicle. Treatment of cultured whole ovarian dispersates with IL-1 beta produced significant (P < 0.01) increments in the steady state levels of transcripts corresponding to both sPLA2 (1.7-fold increase) and cPLA2 (5-fold increase), an effect reversed by an IL-1 receptor antagonist, suggesting mediation via a specific IL-1 receptor. Treatment with cycloheximide, a protein synthesis inhibitor, resulted in significant attenuation of the ability of IL-1 beta to up-regulate sPLA2 and cPLA2 gene expression as well as medium PLA2 activity. Treatment with aminoguanidine, an inhibitor of inducible nitric oxide synthase, led to augmentation of the ability of IL-1 beta to up-regulate sPLA2 and cPLA2 gene expression as well as medium PLA2 activity. Total cellular PLA2 activity proved time, cell density, and calcium dependent, with an optimal pH of 8.0-9.0 and K(m) values in the low micromolar range (2-5 microM). Our observations 1) establish the rat ovary as a site of sPLA2 and cPLA2 gene expression, 2) localize the corresponding transcripts to the granulosa cell layer, and 3) establish IL-1 beta as an up-regulatory agent for ovarian sPLA2 and cPLA2 gene expression as well as for ovarian PLA2 activity. These findings also indicate that the IL-1 effect is 1) receptor mediated, 2) contingent in part upon de novo protein biosynthesis, and 3) inhibited by nitric oxide. These observations support the proposition that PLA2 may be a key component in the IL-1-stimulated biosynthesis of ovarian PGs.

Animals↗

PubMed1997

Interleukin-1 beta stimulates ovarian phosphoipase A2 (PLA2) expression and activity: up-regulation of both secretory and cytosolic PLA2.

Interleukin (IL)-1 beta has been shown to stimulate ovarian prostaglandin biosynthesis. We hypothesized that this effect entails the induction of phospholipase A2 (PLA2). Treatment of cultured whole ovarian dispersates of immature rat origin with IL-1 beta produced significant increases in [3H]arachidonic acid (AA) release and [3H]prostanoid accumulation as well as increases in cellular PLA2 activity and in secretory PLA2 and cytosolic PLA2 transcripts. Cotreatment with IL-1 receptor antagonist reversed IL-mediated (and basal) release of [3H]labeled AA and prostaglandin products, as well as cellular PLA2 activity. Treatment with IL-1 beta also promoted a significant decrease in the cellular content of [3H]phospholipids (apparently phosphatidylethanolamine but not phosphatidylcholine). These observations establish the ovary as a site of IL-1-dependent sPLA2 and cPLA2 gene expression, document the presence of a possible phosphatidylethanolamine-dependent PLA2 activity in cultured whole ovarian dispersates, reveal the up-regulatory, receptor-mediated action of IL-1 beta in this regard and suggest the existence of endogenous PLA2-stimulating/ IL-1-like bioactivity.

Animals↗

PubMed1997

Interleukin (IL)-1beta increases glucose uptake and induces glycolysis in aerobically cultured rat ovarian cells: evidence that IL-1beta may mediate the gonadotropin-induced midcycle metabolic shift.

This communication explores the possibility that interleukin (IL)-1beta, a putative intermediary in the ovulatory process, may take part in the gonadotropin-driven midcycle diversion of ovarian carbohydrate metabolism toward glycolysis. We examined the effect of treatment with IL-1beta on glucose metabolism in aerobically cultured whole ovarian dispersates from immature rats. Treatment with IL-1beta increased cellular glucose consumption/uptake, stimulated extracellular lactate accumulation and media acidification, and decreased extracellular pyruvate accumulation in a receptor-mediated, time-, dose- and cell density-dependent manner. Endogenous IL-1beta-like bioactivity was shown to mediate the ability of gonadotropins to exert these same metabolic effects. The IL-1beta effect was also (1) apparent over a broad range of glucose concentrations, inclusive of the putative physiological window; (2) relatively specific, because tumor necrosis factor-alpha and insulin were inactive; (3) contingent upon cell-cell cooperation (4) and reliant on de novo protein synthesis. Comparison of the molar ratios of lactate accumulation to glucose consumption in IL-1beta-replete vs. IL-1beta-deplete cultures suggests that IL-beta promotes the conversion of all available glucose to lactate but that other substrates for lactate production may also exist. However, no lactate was generated by cells grown under glucose-free conditions. Taken together, our data suggest that IL-1beta may act as a metabolic hormone in the ovary. Subject to the limitations of the in vitro paradigm, our data also suggest that IL-1beta may mediate the gonadotropin-associated midcycle shift in ovarian carbohydrate metabolism. By converting the somatic ovarian cells into a glucose-consuming glycolytic machinery, IL-1beta may establish glycolysis as the main energy source of the relatively hypoxic preovulatory follicle and the resultant cumulus-oocyte complex. The consequent oxygen sparing may conserve the limited supply of oxygen needed for vital biosynthetic processes such as steroidogenesis. This adaptational response may also provide the glycolytically incompetent oocyte with the obligatory tricarboxylic cycle precursors it depends on to meet the increased energy demands imposed upon it by the resumption of meiosis.

Aerobiosis↗

PubMed1996

Simplified riboprobe purification using translucent straws as gel tubes.

Gel purification of radioactive riboprobes enhances the quality of the ribonuclease protection assay. A simple and effective method for riboprobe purification is described. The method uses acrylamide gels in plastic tubes to achieve electrophoretic separation of the RNA polymerase products.

Animals↗