Reference intervals for bone marrow cells in juvenile and young adult cats bone marrow cytology.

BACKGROUND: The current bone marrow (BM) reference intervals (RI) are based on a limited number of cats. Age-related changes in BM variables might be important,possibly affecting the interpretation of the results. OBJECTIVES: Establish BM cytologic reference intervals (RIs) and association of age and sex on these findings, in healthy juvenile and young adult cats. METHODS: BM aspirates of cats deemed healthy based on history and clinical, CBC, serum chemistry findings, and negative retrovirus serology were obtained and examined cytologically. The examination included a 1000-nucleated differential cell count and cell morphologic assessment. RIs were calculated using parametric, robust, and nonparametric methods. The cytologic findings were examined for associations with sex and age. RESULTS: The study included 40 cats (females, 22 [55%]; males, 18 [45%]) with a median age of 1.5 years (range 0.5-5). Most calculated RIs were similar to those previously reported. BM plasma cell and monocyte counts were weakly and positively correlated with age (rs, .312 and .373, respectively; P < .05). Metarubricytes were higher infemales (mean, 25.1%; SD, 6.0%) than males (mean, 21.2%; SD, 6.0%; P < .05). CONCLUSIONS: The BM differential cell counts determined in this study can serve as RIs for cats aged 0.5-5 years.

Laboratory and clinical findings and their association with viral and proviral loads in cats naturally infected with feline leukemia virus.

This study was conducted to correlate clinical, laboratory, and bone marrow (BM) changes in cats naturally infected with feline leukemia virus and their association with viral loads in blood and BM and proviral loads in BM. Cats were classified into five groups based on antigenemia, clinical and/or laboratory findings and viral/proviral loads, according to a prospective study: symptomatic progressive (GI); asymptomatic progressive (GII); regressive (GIII); unclassified (GIV); or healthy (GV). |Correlations between these five groups and viral/proviral loads were evaluated. High viral and proviral loads were detected in GI and GII and viral loads were significantly associated with laboratory signs. Proviral loads detected in BM were significantly lower in GIII and GIV. GI cats were more likely to develop hematopoietic disorders than those from the other groups. Hematological and clinical disorders and disease severity are related to higher viral blood and proviral BM loads.

Synthesis and Charaterization of Silica-Based Aldehyde Chitosan Hybrid Material for Biodiesel Purification.

This study concerns the development and charaterization of Silica-based aldehyde Chitosan hybrid material as an adsorbent for biodiesel purification. This biocomposite was prepared by sol-gel route and oxidation with periodate, and then characterized. FTIR experiments showed that the hybrid formed presents absorption bands similar to those of Chitosan-Silica, with the exception of the vibrations at 1480 cm-1 and 1570 cm-1 attributed to the symmetrical angular deformation in the N-H plane, and possess large N2 Brunauer-Emmett-Teller (BET) surface areas. Thermogravimetric analysis (TG) and scanning electron microscopy (SEM) was also carried out. Adsorption studies of bioadsorbents involving the analysis of free glycerol, soap, acidity, diglycerides, triglycerides, and fluorescence spectroscopy showed that silica-based aldehyde chitosan has a good affinity for glycerol and a good purification process.

Musculoskeletal health of subjects with hemophilia A treated with tailored prophylaxis: Canadian Hemophilia Primary Prophylaxis (CHPS) Study.

BACKGROUND: Full-dose prophylaxis is very effective at minimizing joint damage but is costly. Tailored prophylaxis has been proposed as a way of reducing costs while still protecting joints. OBJECTIVE: To report detailed findings in index joints of 56 subjects with severe hemophilia A entered into the Canadian Hemophilia Prophylaxis Study, and treated with tailored prophylaxis, after 13 years. METHODS: Boys with severe hemophilia A (< 2% factor) and normal joints were enrolled between the ages of 1 and 2.5 years. Initial treatment consisted of once-weekly factor infusions, with the frequency escalating in a stepwise fashion when breakthrough bleeding occurred. During the first 5 years, subjects were examined every 3 months using the modified Colorado Physical Evaluation (PE) scale; subsequently, every 6 months. The Childhood Health Assessment Questionnaire (CHAQ) was administered at each visit. RESULTS: Median age at study entry was 19 months (range 12-30 months); median follow-up was 92 months (range 2-156). The median PE score was 2, 3 and 3 at ages 3, 6 and 10 years. Persistent findings were related to swelling, muscle atrophy and loss of range of motion. The median score for each of these items (for the six index joints) was 0 at ages 3, 6 and 10 years. The median overall CHAQ score was 0 at ages 3, 6 and 10 years, indicating excellent function. CONCLUSIONS: Canadian boys treated with tailored primary prophylaxis exhibit minimal joint change on physical examination and minimal functional disability.

A qualitative study identifying the knowledge, attitudes and behaviours of young men with mild haemophilia.

The Canadian Physiotherapists in Hemophilia Care (CPHC) sought to learn about attitudes and behaviours of young male adults with mild haemophilia towards their condition and care. Semi-structured in-person or telephone interviews were conducted with 18 young men from and across Canada. This report summarizes the participants' attitudes towards their haemophilia, previous injuries, perceived barriers to seeking treatment, as well as their decision-making process when self-assessing injury. The interviews demonstrated that communication between the young adults and the health care team was not optimal, with common reference to the ineffectiveness of lecture style education. Gaps in knowledge also emerged regarding bleed identification and management.

Experimental evidence that changes in oocyte growth influence meiotic chromosome segregation.

BACKGROUND: It is well known that the fidelity of meiotic chromosome segregation is greatly reduced with increasing maternal age in humans. More recently, direct studies of human oocytes have demonstrated a striking age-related increase in oocytes exhibiting gross disturbances in chromosome alignment on the meiotic spindle. This abnormality, termed congression failure, has been postulated to be causally related to human non-disjunction and to result from subtle alterations in folliculogenesis that develop with advancing reproductive age. METHODS: Immunofluorescence staining, conventional cytogenetic analysis and spectral karyotyping of oocytes from mouse models were used to investigate the hypothesis that changes in the regulation of folliculogenesis induce meiotic defects. RESULTS: Mutations that affect oocyte growth were found to increase the frequency of congression failure at first meiotic metaphase. Importantly, increased congression failure was correlated with meiotic non-disjunction, suggesting a cause-and-effect relationship. CONCLUSIONS: Our findings support the hypothesis that congression failure results from disturbances in the complex interplay of signals regulating folliculogenesis and that these changes subtly alter the late stages of oocyte growth, increasing the risk of a non-disjunction error. These findings have important implications for human aneuploidy, since they suggest that it may be possible to develop prophylactic treatments for reducing the risk of age-related aneuploidy.

Immortalization of equine trophoblast cell lines of chorionic girdle cell lineage by simian virus-40 large T antigen.

Immortalized cell lines have many potential experimental applications including the analysis of molecular mechanisms underlying cell-specific gene expression. We have utilized a recombinant retrovirus encoding the simian virus-40 (SV-40) large T antigen to construct several immortalized cell lines of equine chorionic girdle cell lineage - the progenitor cells that differentiate into the equine chorionic gonadotropin (eCG) producing endometrial cups. Morphologically, the immortalized cell lines appear similar to normal chorionic girdle cells. Derivation of the immortalized cell lines from a chorionic girdle cell lineage was verified by immunological detection of cell-surface antigens specific to equine invasive trophoblasts. The cell lines differed, however, from mature chorionic girdle cells or endometrial cup cells in that they did not produce eCG and did express MHC class I molecules. Thus, these cell lines appear to have been arrested at a stage of development prior to final differentiation into endometrial cup cells. It was also determined that some of these cell lines as well as endometrial cups express the estrogen receptor-related receptor beta gene, but not the glial cell missing gene (GCMa) both of which are expressed in the murine and human placenta. Among these cell lines, three (eCG 50.5, 100.6 and 500.1) express eCG alpha mRNA. Since regulation of eCG alpha subunit gene is largely unknown, we investigated the signal transduction pathways regulating the eCG alpha subunit gene. Both activators of protein kinase A (PKA) and protein kinase C (PKC) induced the expression of eCG alpha subunit expression 3.2 (P<0.05)- and 1.9 (P<0.05)-fold respectively, in the eCG 500.1 cell line. However, activation of these pathways failed to induce eCG beta subunit expression. In conclusion, lines of equine trophoblast cells have been immortalized that display markers characteristic of those with the equine chorionic girdle and endometrial cup cell lineage. A subset of these cells expresses the eCG alpha subunit gene which is responsive to activators of the PKA and PKC signal transduction pathways.

AR suppresses transcription of the alpha glycoprotein hormone subunit gene through protein-protein interactions with cJun and activation transcription factor 2.

Previously, we reported that the AR directly suppressed transcription of the alpha glycoprotein hormone subunit (alphaGSU) gene in a ligand-dependent fashion while ER had no effect. Mutagenesis studies of the alphaGSU promoter indicated that two elements were required for AR-mediated suppression: the alpha basal element and tandem cAMP response elements (CREs). Because several members of the bZip family of transcriptional proteins can bind the CREs, we used several functional assays to determine whether AR interacts selectively with cJun, activation transcription factor 2 (ATF2), or CRE binding protein (CREB). When tested by cotransfection with AR, cJun and ATF2 specifically rescued androgen-mediated suppression of the alphaGSU-reporter construct in a gonadotrope-derived cell line. In contrast, cotransfected CREB displayed no activity in this rescue assay. In fact, overexpression of CREB alone diminished activity of the alphaGSU promoter, suggesting that the transcriptional activity normally conferred by the tandem CREs in gonadotropes requires their occupancy by cJun/ATF2 heterodimers. Binding assays carried out with a glutathione-S-transferase-AR fusion protein indicated that the receptor itself also displayed a clear preference for binding cJun and ATF2. Furthermore, we ruled out the possibility that AR suppressed activity of the alphaGSU promoter by reducing synthesis of these bZip proteins. Additional experiments suggested that phosphorylation of AR or histone acetylation are unlikely requirements for AR suppression of alphaGSU promoter activity. Thus, our data suggest that AR suppresses activity of the alphaGSU promoter through direct protein-protein interactions with cJun and ATF2.

AR suppresses transcription of the LHbeta subunit by interacting with steroidogenic factor-1.

Synthesis of LH is suppressed by feedback from gonadal steroids. Previously, we demonstrated that 779 bp of the bovine LHbeta promoter was sufficient to target expression of a chloramphenicol acetyltransferase reporter gene specifically to the pituitary in transgenic mice, and found that it was appropriately suppressed after administration of T or E2. In this study, we report that ligand-bound AR, but not ligand-bound ER, directly suppressed activity of the bovine LHbeta promoter when examined in a gonadotrope-derived cell line. Additional studies with mutated bovine LHbeta promoter constructs focused on the proximal 5'-flanking region because of the presence of several cis-acting elements that are highly conserved across all mammals. These include regulatory elements that bind steroidogenic factor 1 (SF-1), Egr-1, and Pitx1. When tested by cotransfection with AR, overexpression of Egr-1, Pitx1, and constitutively active steroidogenic factor 1 (SF-1DeltaLBD) each individually rescued androgen-mediated suppression of the bovine LHbeta promoter. This suggested a functional interaction between each of these transcription proteins and AR. In contrast, overexpression of full-length SF-1 was incapable of relieving the bovine LHbeta promoter from the suppressive effect imposed by AR. This suggested that the ligand-binding domain of SF-1 plays an important role in functional interactions that occur between this protein and AR. This notion was further supported by binding assays performed with glutathione-S-transferase-AR: these identified SF-1 as a key interactive partner and localized this interaction to the ligand-binding domain of the protein. Additional binding studies indicated that protein interactions between SF-1, Pitx1, and Egr-1 interfere with formation of a binary complex that contains AR and SF-1. Thus, we conclude that AR suppresses activity of the bovine LHbeta promoter through protein-protein interactions with SF-1 and that the degree of this interaction can be modified by the presence of Egr-1 and Pitx1.

A single Pitx1 binding site is essential for activity of the LHbeta promoter in transgenic mice.

Reproduction depends on regulated expression of the LHbeta gene. Tandem copies of regulatory elements that bind early growth response protein 1 (Egr-1) and steroidogenic factor 1 (SF-1) are located in the proximal region of the LHbeta promoter and make essential contributions to its activity as well as mediate responsiveness to GNRH: Located between these tandem elements is a single site capable of binding the homeodomain protein Pitx1. From studies that employ overexpression paradigms performed in heterologous cell lines, it appears that Egr-1, SF-1, and Pitx1 interact cooperatively through a mechanism that does not require the binding of Pitx1 to its site. Since the physiological ramifications of these overexpression studies remain unclear, we reassessed the requirement for a Pitx1 element in the promoter of the LHbeta gene using homologous cell lines and transgenic mice, both of which obviate the need for overexpression of transcription factors. Our analysis indicated a striking requirement for the Pitx1 regulatory element. When assayed by transient transfection using a gonadotrope-derived cell line (LbetaT2), an LHbeta promoter construct harboring a mutant Pitx1 element displayed attenuated transcriptional activity but retained responsiveness to GNRH: In contrast, analysis of wild-type and mutant expression vectors in transgenic mice indicated that LHbeta promoter activity is completely dependent on the presence of a functional Pitx1 binding site. Indeed, the dependence on an intact Pitx1 binding site in transgenic mice is so strict that responsiveness to GnRH is also lost, suggesting that the mutant promoter is inactive. Collectively, our data reinforce the concept that activity of the LHbeta promoter is determined, in part, through highly cooperative interactions between SF-1, Egr-1, and Pitx1. While Egr-1 can be regarded as a key downstream effector of GnRH, and Pitx1 as a critical partner that activates SF-1, our data firmly establish that the Pitx1 element plays a vital role in permitting these functions to occur in vivo.

Effects of estradiol-17beta administration on steady-state messenger ribonucleic acid (MRNA) encoding equine alpha and LH/CGbeta subunits in pituitaries of ovariectomized pony mares.

The process of sexual recrudescence in the springtime in mares is characterized by renewal of follicular growth and acquisition of steroidogenic competence. Concomitant with renewal of follicular steroidogenesis is re-establishment of LH biosynthesis and secretion. Research results from our laboratory indicate that increased estradiol and LH secretion occur in close temporal association before the first ovulation of the year. Therefore, the hypothesis tested in this experiment was that estrogen administration to ovariectomized pony mares during the equivalent time of early vernal transition would enhance LH biosynthesis as monitored by messenger ribonucleic acid (mRNA) encoding for the pituitary subunits of LH (alpha and LH/CGbeta). Mares were administered either sesame oil vehicle control, or estradiol (5 mg i.m. twice daily in sesame oil) for 3, 6 or 9 days, beginning on February 2. The pituitary glands were harvested, and examined for LH subunit mRNA by Northern Blot and slot blot analysis. There was a significant increase in LH secretion after 6 days of estradiol secretion compared with control vehicle administration. Similarly, there was a significant increase in both alpha and LH/CGbeta subunit mRNA when estradiol was administered for 9 days. These data indicate that estrogen stimulates LH subunit formation in mares during early equivalent vernal transition. These data do not, however, discriminate between a direct pituitary effect of estrogen, and a hypothalamic effect. Whether the surge of estradiol just prior to the first ovulation of the year is essential for the renewed biosynthesis of LH subunits cannot be determined from these data. However an important role of estrogen in the final stages of sexual recrudescence is indicated.

Alternans and the onset of ventricular fibrillation.

Ventricular fibrillation (VF) remains a major cause of death in the industrialized world. Alternans (a period-doubling bifurcation of cardiac electrical activity) have recently been causally linked to the progression from ventricular tachycardia (VT) to VF, a more spatiotemporally disorganized electrical activity. In this paper, we show how alternans and thus VT degenerate to chaos via multiple, specific dynamical routes, largely associated with spatial components of VF dynamics, explaining failures of many recently proposed antiarrhythmic drugs. Identification of dynamical mechanisms for the onset of VF should lead to the design of future experiments and consequently to more effective antiarrhythmic drugs.

Chronic hypersecretion of luteinizing hormone in transgenic mice disrupts both ovarian and pituitary function, with some effects modified by the genetic background.

When the pituitary or hypothalamus becomes resistant to steroid negative feedback, a vicious cycle ensues, resulting in chronic hypersecretion of luteinizing hormone (LH) from the pituitary and steroids from the ovaries. In women, LH hypersecretion is implicated in infertility, miscarriages, and development of granulosa cell tumors. Progress in defining the underlying mechanisms of LH toxicity, however, has been limited by the lack of well-defined animal models. To that end, we have developed a new transgenic mouse model (alpha-LHbetaCTP) wherein LH hypersecretion occurs chronically and results in several dire pathological outcomes. Chronic hypersecretion of LH was achieved by introducing a transgene containing a bovine alpha subunit promoter fused to the coding region of a chimeric LHbeta subunit. The alpha subunit promoter directs transgene expression only to gonadotropes. The LHbeta chimera contains the carboxyl-terminal peptide (CTP) of the human chorionic gonadotropin beta subunit linked to the carboxyl terminus of bovine LHbeta. This carboxyl extension extends the half-life of LH heterodimers that contain the chimeric beta subunit. In intact alpha-LHbetaCTP females, serum LH is elevated five- to ten-fold in comparison to nontransgenic littermates. Levels of testosterone (T) and estradiol (E2) also are elevated, with an overall increase in the T-to-E2 ratio. These transgenic females enter puberty precociously but are anovulatory and display a prolonged luteal phase. Anovulation reflects the absence of gonadotropin-releasing hormone (GnRH) and the inability to produce a pre-ovulatory surge of LH. The ovaries are enlarged, with reduced numbers of primordial follicles and numerous, giant, hemorrhagic follicles. Despite the pathological appearance of the ovary, females can be superovulated and mated. Although pregnancy occurs, implantation is compromised due to defects in uterine receptivity. In addition, pregnancy fails at midgestation, reflecting a maternal defect presumably due to estrogen toxicity. When the transgene is in a CF-1 background, all females develop granulosa cell tumors and pituitary hyperplasia by five months of age. They die shortly thereafter due to bladder atony and subsequent kidney failure. When the transgene is placed in other strains of mice, their ovaries develop a luteoma rather than a granulosa cell tumor and the pituitary develops pituitary hyperplasia followed by adenoma. In summary, alpha-LHbetaCTP mice provide a direct association between abnormal secretion of LH and development of a number of ovarian and pituitary pathological responses.

An NF-Y binding site is important for basal, but not gonadotropin-releasing hormone-stimulated, expression of the luteinizing hormone beta subunit gene.

Regulated synthesis of luteinizing hormone (LH) requires coordinated transcriptional control of the alpha and LHbeta subunits in pituitary gonadotropes. Several cis-acting elements and trans-acting factors have been defined for control of the LHbeta promoter through heterologous cell culture models. In this report, we describe the identification of bipartite NF-Y (CBF/CP1) binding sites within the proximal bovine LHbeta promoter. When multimerized, one of these sites activates the heterologous, minimal HSV thymidine kinase promoter in the gonadotrope-derived cell line alphaT3-1. The functional role of the promoter-distal site in regulating the full-length bovine LHbeta promoter was assessed in vivo using transgenic mice harboring a mutant promoter linked to the chloramphenicol acetyltransferase reporter gene. While this element is important for conferring high level activity of the LHbeta promoter in pituitary, it does not appear to be essential for mediating gonadotropin-releasing hormone (GnRH) regulation. This is the first characterization of a cis-acting element within this GnRH-dependent promoter that is restricted to regulating basal expression and not GnRH-induced activity.

Elevated luteinizing hormone induces expression of its receptor and promotes steroidogenesis in the adrenal cortex.

Transgenic (TG) female mice expressing bLHbeta-CTP (a chimeric protein derived from the beta-subunit of bovine luteinizing hormone [LH] and a fragment of the beta-subunit of human chorionic gonadotropin [hCG]) exhibit elevated serum LH, infertility, polycystic ovaries, and ovarian tumors. In humans, increased LH secretion also occurs in infertility and polycystic ovarian syndrome, often concomitant with adrenocortical dysfunction. We therefore investigated adrenal function in LH overexpressing bLHbeta-CTP female mice. The size of their adrenals was increased by 80% with histological signs of cortical stimulation. Furthermore, adrenal steroid production was increased, with up to 14-fold elevated serum corticosterone. Primary adrenal cells from TG and control females responded similarly to ACTH stimulation, but, surprisingly, the TG adrenals responded to hCG with significantly increased cAMP, progesterone, and corticosterone production. LH receptor (LHR) expression and activity were also elevated in adrenals from female TG mice, but gonadectomized TG females showed no increase in corticosterone, suggesting that the dysfunctional ovaries of the intact TG females promote adrenocortical hyperfunction. We suggest that, in intact TG females, enhanced ovarian estrogen synthesis causes increased secretion of prolactin (PRL), which elevates LHR expression. Chronically elevated serum LH, augmented by enhanced PRL production, induces functional LHR expression in mouse adrenal cortex, leading to elevated, LH-dependent, corticosterone production. Thus, besides polycystic ovaries, the bLHbeta-CTP mice provide a useful model for studying human disorders related to elevated LH secretion and adrenocortical hyperfunction.

Luteinizing hormone induction of ovarian tumors: oligogenic differences between mouse strains dictates tumor disposition.

The use of fertility drugs has continued to grow since their introduction in the 1960s. Accompanying this increase has been the speculation that repetitive use of these drugs can cause ovarian tumors or cancer. We recently reported that transgenic mice with chronically elevated luteinizing hormone (LH), an analog of which is commonly used in fertility regimens, develop granulosa cell (GC) tumors. In this report we show that LH induction of these tumors is highly dependent on genetic background. In CF-1 mice, chronically elevated LH invariably causes GC tumors by 5 months of age. However, in hybrid mice generated by crossing CF-1 males with C57BL/6, SJL, or CD-1 females, elevated levels of this same hormone cause a completely different phenotype resembling a luteoma of pregnancy. We also show that three genes likely control these alternative hormonal responses. This clinical correlate of elevated LH reveals remarkably distinct, strain-dependent, ovarian phenotypes. In addition, these results support the rare incidence of GC tumors in the human population, and suggest that the ability of certain fertility drugs to cause ovarian tumors may depend on an individual's genetic predisposition.

Is the IDS glass half empty or half full?

When the concept of integrated delivery began gaining popularity throughout the healthare field, some healthcare executies saw it as the solution for organizations struggling to contain rapidly rising costs. Others hoped that joining integrated delivery systems would help preserve smaller organizations that could not otherwise compete with larger providers in the same area. And many in healthcare thought that it had the potential to dramatically enhance quality of care and promote wellness. As integration becomes increasingly common, the practice is coming under heavy criticism from those who say it has not lived up to expectatations. At the same time, however, systems that are seeing success with integrated delivery are singing its praises. "The jury is still out on the effectiveness of integrated delivery systems," says Austin Ross, FACHE, a professor at the University of Washington's School of Public Health, Seattle. "So far, they have a spotty record. There have been some serious failures, but some positive things are taking place, too." Some experts say that integrated delivery systems are doomed; others believe there are good reasons to be optimistic. So is the glass half empty or half full?

Chronic hypersecretion of luteinizing hormone in transgenic mice selectively alters responsiveness of the alpha-subunit gene to gonadotropin-releasing hormone and estrogens.

Steroid hormones can act either at the level of the hypothalamus or the pituitary to regulate gonadotropin subunit gene expression. However, their exact site of action remains controversial. Using the bovine gonadotropin alpha-subunit promoter linked to an expression cassette encoding the beta-subunit of LH, we have developed a transgenic mouse model where hypersecretion of LH occurs despite the presence of elevated ovarian steroids. We used this model to determine how hypersecretion of LH could occur when steroid levels are pathological. During transition from the neonatal period to adulthood, the endogenous LHbeta subunit gene becomes completely silent in these mice, whereas the alpha-directed transgene and endogenous alpha-subunit gene remain active. Interestingly, gonadectomy stimulates expression of the endogenous alpha and LHbeta subunit genes as well as the transgene; however, only the endogenous LHbeta gene retains responsiveness to 17beta-estradiol and GnRH. In contrast, LH levels remain responsive to negative regulation by androgen. Thus, alpha-subunit gene expression, as reflected by both the transgene and the endogenous gene, has become independent of GnRH regulation and, as a result, unresponsive to estradiol-negative feedback. This process is accompanied by a decrease in estrogen receptor alpha gene expression as well as an increase in the expression of transcription factors known to regulate the alpha-subunit promoter, such as cJun and P-LIM. These studies provide in vivo evidence that estrogen-negative feedback on alpha and LHbeta subunit gene expression requires GnRH input, reflecting an indirect mechanism of action of the steroid. In contrast, androgen suppresses alpha-subunit expression in both transgenic and nontransgenic mice. This suggests that androgens must regulate alpha-subunit promoter activity independently of GnRH. In addition to allowing the assessment of site of action of sex steroids on alpha-subunit gene expression, these studies also indicate that chronic exposure of the pituitary to LH-dependent ovarian hyperstimulation leads to a heretofore-undescribed pathological condition, whereby normal regulation of alpha, but not LHbeta, subunit gene expression becomes compromised.

Transgenic mice with chronically elevated luteinizing hormone are infertile due to anovulation, defects in uterine receptivity, and midgestation pregnancy failure.

Elevated levels of LH have been associated with infertility and miscarriage in women. Previously, we have reported generating a transgenic mouse model that hypersecretes LH. Female transgenics exhibit extensive pathology including enlarged, cystic, and hemorrhagic ovaries; elevated testosterone:estradiol ratios; and infertility primarily due to anovulation. Here we show that anovulation can be reversed in transgenics and that, despite development within a pathological ovary, oocytes from transgenics are remarkably healthy. Fertilized ova from transgenics are capable of normal development to term when transferred into nontransgenic pseudopregnant recipients. However, reciprocal transfers of nontransgenic embryos into transgenic recipients failed due to lack of uterine receptivity. In addition, while superovulated and mated transgenics appear to have normal early pregnancy, embryos are resorbed at midgestation due to maternal hormonal defects. Transgenic infertility can be rescued by ovariectomy with progesterone and estradiol replacement. These studies are particularly intriguing in light of data indicating an increased rate of miscarriage among women undergoing infertility treatments who are diagnosed with polycystic ovarian syndrome.