Early preantral follicles of the domestic cat express gonadotropin and sex steroid signaling potential.

Key biomolecular processes, which regulate primordial ovarian follicle dormancy and early folliculogenesis in mammalian ovaries, are not fully understood. The domestic cat is a useful model to study ovarian folliculogenesis and is the most relevant for developing in vitro growth methods to be implemented in wild felid conservation breeding programs. Previously, RNA-sequencing of primordial (PrF), primary (PF), and secondary follicle (SF) samples from domestic cat implicated ovarian steroidogenesis and steroid reception during follicle development. Here, we aimed to identify which sex steroid biosynthesis and metabolism enzymes, gonadotropin receptors, and sex steroid receptors are present and may be potential regulators. Differential gene expression, functional annotation, and enrichment analyses were employed and protein localization was studied too. Gene transcripts for PGR, PGRMC1, AR (steroid receptors), CYP11A1, CYP17A1, HSD17B1 and HSD17B17 (steroidogenic enzymes), and STS (steroid metabolizing enzyme) were significantly differentially expressed (Q values of ≤0.05). Differential gene expression increased in all transcripts during follicle transitions apart from AR which decreased by the secondary stage. Immunohistochemistry localized FSHR and LHCGR to oocytes at each stage. PGRMC1 immunostaining was strongest in granulosa cells, whereas AR was strongest in oocytes throughout each stage. Protein signals for steroidogenic enzymes were only detectable in SFs. Products of these significantly differentially expressed genes may regulate domestic cat preantral folliculogenesis. In vitro growth could be optimized as all early follicles express gonadotropin and steroid receptors meaning hormone interaction and response may be possible. Protein expression analyses of early SFs supported its potential for producing sex steroids.

Role of sex steroids and prostaglandins during the luteal life cycle in domestic cats and lynxes.

Although lynxes and domestic cats are both felids, their luteal life cycles differ. As in many species, corpora lutea (CLs) of domestic cats regress after pregnancy or pseudopregnancy. By contrast, CLs of lynxes do not functionally regress following the cycle of their formation. They stay physiologically active and persist for several years. To obtain an improved understanding of the life cycle of both species, we comparatively studied the CLs of these species in detail. In this review, we summarize the similarities and differences of their CLs regarding sex steroid and prostaglandin generation and receptors. The most evident differences were visible in the CLs of lynxes, which persist from previous cycles, compared with CLs of lynxes and domestic cats from the recent luteal cycle. We assume that these differences could indicate processes ensuring long-term luteal survival and functionality, for example, by high estrogen production/metabolism or by antioxidative effects.

The antioxidative enzyme SOD2 is important for physiological persistence of corpora lutea in lynxes.

Corpora lutea (CL) are transient endocrine glands supporting pregnancy by progesterone production. They develop at the site of ovulation from the remaining follicle, are highly metabolically active and undergo distinct, transformative processes during their lifetime. In contrast to other species, CL of lynxes do not regress at the end of cycle, but remain functionally active (persist) for years. Reactive oxygen species (ROS) and anti-oxidative enzymes are described to be important for the functionality of CL. We examined ten anti-oxidative enzymes in fresh and persistent CL of lynxes as well as in domestic cat CL of different luteal stages. The gene expression profiles, especially those of SOD1 and SOD2, showed some remarkable differences between CL stages during non-pregnant and pregnant cycles of domestic cats and between fresh and persistent CL of lynxes. Lynx gene expression profiles of SODs were confirmed by western blot analysis, immunohistochemistry and activity assays. SOD2 was characterized by a conspicuous high expression and enzyme activity exclusively in persistent CL. We suggest that SOD2 is required to detoxify potential elevated superoxide anion levels by producing H2O2 in the physiologically persistent CL. This product might also act as a signaling molecule, securing the CL from apoptosis and insuring long-term luteal cell survival.

Brilliant cresyl blue staining allows the selection for developmentally competent immature feline oocytes.

The outcome of in-vitro-maturation and in-vitro-fertilization of feline oocytes depends on the selection of high quality oocytes, and is often restricted to morphological criteria. The aim of this study was to test whether the Brilliant cresyl blue (BCB) staining is suitable for pre-selection of feline oocytes before in-vitro-maturation. Cumulus-oocytes-complexes (COC) were released from domestic cat ovaries obtained after ovariectomy and were subjected to BCB staining. BCB+ stained oocytes were characterized by a violet/pale blue staining of the ooplasma, BCB- oocytes remained unstained. Transmission electron microscopy indicated for a slightly advanced stage of BCB- oocytes within the maturation process. After 24 h in-vitro-maturation, almost 75% of BCB+ and 21.5% of BCB- oocytes were able to reach metaphase II. Also, after in-vitro-fertilization, significantly more oocytes developed to morulae (19.2%) if oocytes were preselected for BCB staining, although 8% of unstained COC still reached advanced embryo stages. Prolonged storage of ovaries before COC retrieval for 16-20 h at 4 °C was accompanied by reduced number of BCB+ oocytes (96 of 210, 45.7%) in comparison to freshly isolated COC (151 of 225, 67.1%), and impaired cleavage rate (19.8%) and morula rate (9.4%) of BCB+ oocytes but the rate of embryos which developed to advanced stages remained unchanged (∼50%). To conclude, BCB staining is a very useful tool to preselect immature COC of feline species ensuring higher developmental rates.

Diet changes alter paternally inherited epigenetic pattern in male Wild guinea pigs.

Epigenetic modifications, of which DNA methylation is the most stable, are a mechanism conveying environmental information to subsequent generations via parental germ lines. The paternal contribution to adaptive processes in the offspring might be crucial, but has been widely neglected in comparison to the maternal one. To address the paternal impact on the offspring's adaptability to changes in diet composition, we investigated if low protein diet (LPD) in F0 males caused epigenetic alterations in their subsequently sired sons. We therefore fed F0 male Wild guinea pigs with a diet lowered in protein content (LPD) and investigated DNA methylation in sons sired before and after their father's LPD treatment in both, liver and testis tissues. Our results point to a 'heritable epigenetic response' of the sons to the fathers' dietary change. Because we detected methylation changes also in the testis tissue, they are likely to be transmitted to the F2 generation. Gene-network analyses of differentially methylated genes in liver identified main metabolic pathways indicating a metabolic reprogramming ('metabolic shift'). Epigenetic mechanisms, allowing an immediate and inherited adaptation may thus be important for the survival of species in the context of a persistently changing environment, such as climate change.

Model for Hormonal Emergency Contraception (HEC) in cycling and mated guinea pigs - Studies with the Progesterone Receptor Modulators (PRM) Ulipristal Acetate (UPA/CDB2914) and EC317.

A guinea pig model for new HEC methods is proposed. Two targets for HEC (Hormonal Emergency Contraception), ovulation and conception (post-mating study), were investigated using adjusted PRM treatments: (a) Ovulation inhibition study: Injections on cycle days 10-17, study of ovarian histology on day 18; (b) post-mating study: Injections on cycle days 1 and 2; rate of pregnant females was recorded at autopsy on day 18. P plasma levels permitted assessment of effects on ovulation in non-conceiving animals. RESULTS: (a) All controls had recently ovulated. Statistically significant anti-ovulatory effects (p < 0.05, Fisher's Exact Test) were seen at 10 mg UPA (ulipristal acetate, CDB2914) and ≥0.3 mg EC317; 100% inhibition was found for EC317 at 10, 3, and 1 mg/day. No dosage of UPA was 100% effective. (b) In post-mating studies, 16 of 30 controls were pregnant. Both PRMs (progesterone receptor modulator) exerted inhibitory effects on conception, none on imminent ovulation; 1 of 10 animals had living conceptuses after 10 mg UPA, none following 10 and 1 mg EC317/day, respectively. At pairwise comparison with controls, 10 mg was the lowest effective dosage for UPA (p < 0.05), and 1 mg for EC317 (p < 0.01). P plasma levels: Significantly lower P (p < 0.05) in subsequently pregnant vs non-pregnant controls was found on cycle day 3 or 4; this difference disappeared on day 8 or 9. This stage thus appears vulnerable to hormonal constellations and possibly PRM effects. HEC model: Effects on ovulation and conception were seen at the same dose levels of both PRM. Superior and more consistent effects of EC317 vs UPA (factor ≥10) suggest higher efficacy using EC317 for HEC.

Mitochondrial characteristics in oocytes of the domestic cat (Felis catus) after in vitro maturation and vitrification.

CONTENTS: The objective of this study was to evaluate mitochondria in immature and in vitro-matured domestic cat oocytes and to assess for the first time the effect of vitrification on mitochondrial traits. Mitochondrial distribution and aggregation were assessed using confocal microscopy after staining with the fluorescent dye-MitoTracker® Red CMXRos. Only cells at the germinal vesicle and the metaphase II stages of nuclear development, representing immature and mature oocytes, respectively, were included in our study. Our study shows that 80% of immature and 100% of mature oocytes exhibit a peripheral pattern of mitochondria distribution, indicating that, in contrast to the situation in other species, the mitochondria of cat oocytes are not dispersed throughout the cell after in vitro maturation but instead maintain a strong affinity for the oocyte periphery near the membrane. However, a loss of aggregation was observed during in vitro maturation-78% of immature oocytes showed homogeneous granulation versus only 18% of mature oocytes (p < .001). The increased intensity of MitoTracker® Red CMXRos staining after in vitro maturation (p < .05) may be tentatively attributed to an increase in mitochondrial activity but could likewise reflect a concomitant appearance of sulphhydryl groups in cytoplasm (known to be targeted by the dye). Mitochondrial distribution did not change upon vitrification; however, dye intensity decreased (p < .05) and mitochondrial aggregation was intensified in both immature and mature vitrified cat oocytes.

Metabolism of prostaglandin F2alpha in Eurasian lynx (Lynx lynx) and Asian leopard cat (Prionailurus bengalensis euptilura).

Methods for monitoring endocrine status are useful tools for reproduction management. In particular, successful captive breeding of endangered feline species requires reliable methods for pregnancy diagnosis. In many species, uterine and placental prostaglandin-F2α (PGF2α) is involved in the regulation of reproductive processes. PGF2α is metabolized to 13,14-dihydro-15-keto-PGF2a (PGFM) during the first passage through the lungs. Immunoreactive PGFM is elevated in pregnant felids during the last trimester and is used for pregnancy diagnosis, although authentic PGFM is excreted in negligible amounts. To investigate the metabolism of PGF2α, a radiometabolism study was performed in two individuals of two feline species, Eurasian lynx and leopard cats, by injection of tritiated PGF2α and collection of faecal and urinary samples. All samples were extracted and subjected to HPLC separation. Radioactivity and immunoreactivity towards PGFM were determined in each HPLC fraction. The radio- and immunogramms differ slightly between the two species, and radiolabelled PGFM was present only in minor amounts. One major eicosanoid metabolite was found in all urine and faecal samples analysed, and also in previous studies in faecal samples of several pregnant feline species. Its polarity was similar, but not identical to PGF2α. We hypothesized that PGF2α is metabolized to more polar dinor and tetranor metabolites. First mass spectrometric analyses favoured a dinor metabolite as major compound of PGF2α metabolism in felids. Following identification and validation in the studied species, we aim to use these metabolites to improve pregnancy detection in other felids and probably other carnivores.

Analysis of gene expression in granulosa cells post-maturation to evaluate oocyte culture systems in the domestic cat.

Maturation of oocytes is a prerequisite for successful embryo development. The fertilization competence of in vivo derived oocytes is significantly higher than that of oocytes matured in vitro. Commonly evaluated morphological criteria for oocyte maturation do not reflect the complexity and quality of maturation processes. Oocytes and granulosa cells are communicating closely in a bidirectional way during follicular growth and maturation. Assessing the mRNA expression of specific genes in granulosa cells could be a non-invasive way to evaluate the conditions of in vitro oocyte maturation. The objective of this study was to elucidate the influence of two different FSH additives on the in vitro maturation rate and gene expression of cumulus-oocytes complexes in domestic cat. Feline oocytes were matured in a medium, supplemented with LH and 0.02 IU/ml porcine FSH versus 0.02 IU or 1.06 IU/ml human FSH. Granulosa cells were separated from oocytes directly after 24 hr of maturation or after additional 12 hr of in vitro fertilization. Gene expression levels were analysed by quantitative PCR for aromatase, antimullerian hormone, follicle stimulating hormone receptor (FSHR), luteinizing hormone/choriogonadotropin receptor (LHCGR) and prostaglandin E synthase. Neither oocyte maturation rate nor gene expression levels differed after 24 or 36 hr in all three groups. However, variations were discovered in correlations of expression levels, for instance for FSHR and LHCG, indicating differences in the fine-tuning of in vitro maturation processes under varying FSH supplementations. We suppose that correlation between gene expressions of selected genes suggests a superior maturation quality of feline oocytes.

Research on reproduction is essential for captive breeding of endangered carnivore species.

Assisted reproductive technology (ART) has great potential for conservation, but its successful application in captive breeding programmes of endangered species is often compromised by limited background on species' biology. Although carnivore species benefit from knowledge obtained in domesticated species (dogs, cats and ferrets), the focus of research is different. In pet animals, research in reproduction has mainly been focused on ovarian function and contraception, although substantial progress has also been made in the field of in vitro embryo production, transgenic embryos and cloning to aid relevant medical models. In endangered species, however, research should focus on characterizing reproductive traits (cyclicity and seasonality) to unravel species-specific endocrine principles of reproduction physiology. Based on this knowledge, it is crucial to enhance the ability to manipulate female reproductive cycles, especially those of embryo recipients. Furthermore, research conducted on molecular and cellular mechanisms of gamete and embryo development, as well as on cryopreservation protocols of gametes and embryos, is required for successful implementation of advanced ART to wild carnivores. This review will provide a summary on the state of the art with focus on ART contributing to conservation breeding of endangered carnivores.

Expression of steroidogenic enzymes and steroid receptors in foetal gonads of domestic cat-Sex similarities and differences.

Foetal gonads already produce steroid hormones and by this influence the further development of external and internal genitalia as well as of the brain. Beside this, foetal gonads themselves can be influenced by foetal or maternal hormones. The time course of foetal gonadal development can differ between species. As knowledge on processes in domestic cats is very limited, the steroidogenic enzyme expressions as well as these of steroid receptors were analysed in foetal gonads of domestic cats. We investigated a period from beginning of the second half of pregnancy to the beginning of the third trimester; a phase, where also gonadal development proceeds. The mRNA expression of most of the steroidogenic enzymes was remarkably higher in male gonads compared to female ones on all analysed days. The enzyme mRNA expression in female gonads shows a tendency for an increase towards the beginning of the third trimester, except that of aromatase gene CYP19A1-it shows the opposite trend. CYP19A1 was detectable just in female gonads, indicating that only female foetal gonads are capable of producing oestrogens. Gene expressions of genomically and non-genomically acting steroid receptors for progesterone, androgen and oestrogen reception were observed in gonads of both genders. Slightly higher expressions of some receptors were detected in female compared to male gonads; only for the non-genomically oestrogen receptor GPER, we observed the opposite. The protein staining for progesterone receptor membrane component 1 (PGRMC1) exposed a potential function of it on steroid-producing cell and/or cells that suppose early oogenesis.

Cryopreservation of feline oocytes by vitrification using commercial kits and slush nitrogen technique.

Assisted reproductive techniques are a valuable tool for conservation breeding of endangered species. Cryopreservation methods are the basis of gamete banks, supporting genetic diversity preservation. Unfortunately, cryopreservation of feline oocytes is still considered an experimental technique. The aim of this study was to compare two commercial kits, with our protocol for vitrification of cat oocytes (IZW), which comprises a three-step method with ethylene glycol, DMSO, fetal calf serum, trehalose and Ficoll PM-70. Furthermore, we applied slush nitrogen (SN2 ) for ultra-rapid freezing to improve survival rates. Cumulus-oocyte complexes were collected from domestic cat ovaries by slicing and vitrified at immature stage using Cryotop as storage device. Vit Kit® Freeze/Thaw (n = 89) showed the lowest maturation percentage obtained after warming (10.1%). A significant difference in maturation percentage of oocytes was found between Kitazato® kit (38.7%, n = 137) and IZW protocol (24.5%, n = 143). The cleavage after ICSI of warmed and matured oocytes (20.7% and 28.6%, respectively) and the morula percentage (18. 2% and 22.5%, respectively), however, did not reveal any significant difference between the two methods. Application of SN2 did not result in any improvement of oocytes' cryopreservation. Maturation percentage of the oocytes vitrified by IZW method with SN2 (n = 144) decreased until 6.1%, without any cleavage after fertilization. For Kitazato® (n = 62), only 17.7% were able to undergo maturation and cleavage percentage dropped to 18.2%, not reaching morula stage. These data demonstrate that feline oocytes can be vitrified either by our IZW method or by commercial Kitazato® kit, but the use of SN2 is improving neither maturation nor cleavage percentages when combined with these procedures.

Seasonally different reproductive investment in a medium-sized rodent (Cavia aperea).

Pronounced seasonal variations in day length, temperature, and resource availability characterize the temperate regions and strongly influence the animals living in these environments. To survive and reproduce successfully, animals must allocate resources among competing physiological systems, and they usually adjust their time of breeding to the most adequate season. Here, we examined whether reproductive investment in the wild guinea pig (Cavia aperea) differs across seasons. We kept animals in combined indoor-outdoor enclosures under natural light and temperature year-round. We measured littering probability, litter size, and birth weight, as well as maternal weight loss during lactation. In addition, we measured ovulation rate as a parameter to adjust reproductive investment prenatally. Our data reveal strong seasonal variations in reproductive traits despite the fact that the animals reproduced year-round. The results show a reduced reproductive investment in winter, indicated by a lower litter size and birth weight of pups, whereas investment was highest in warm seasons (summer and autumn) with higher litter size and birth weight. Maternal weight loss in lactation was highest in cold seasons even if the litter size was lower. Furthermore, we found the regulation on the proximate level of the reproductive investment, the ovulation rate, to differ significantly between the seasons.

Expression profiles of relaxin family peptides and their receptors indicate their influence on spermatogenesis in the domestic cat (Felis catus).

Disturbed spermatogenesis is a common problem in felines. Studying spermatogenesis in the domestic cat can improve the understanding of the biological background and help to counteract fertility problems in other feline species. Here, we analyzed 3 relaxin family peptides (relaxin, relaxin-3, and INSL3) and their receptors (RXFP1, RXFP2, and RXFP3) as potential spermatogenic factors involving their expression in the testis at different stages of its development. It may be concluded from its stage-dependent expression that relaxin, together with RXFP1, appears to be involved in the first stage of spermatogenesis, whereas relaxin-3 via binding to RXFP3 influences spermiogenesis. Furthermore, correlations were observed between relaxin, relaxin-3, RXFP1, RXFP2 and RXFP3 messenger RNA expression, and the relative numbers of haploid cells in testes. The peptide INSL3 was highly expressed at all testis development stages. Because of the low and stage-independent expression of its receptor RXFP2, an auto- and/or paracrine function of INSL3 in spermatogenesis seems unlikely. In the adult testis, messenger RNA expression of relaxin, RXFP1, and RXFP3 predominantly occurs in the tubular testis compartment, whereas INLS3 is mainly expressed in the interstitium.

Characterization of fetal growth by repeated ultrasound measurements in the wild guinea pig (Cavia aperea).

Fetal growth during pregnancy has previously been studied in the domesticated guinea pig (Cavia aperea f. porcellus) after dissecting pregnant females, but there are no studies describing the fetal growth in their wild progenitor, the wild guinea pig (C aperea). In this study, 50 pregnancies of wild guinea pig sows were investigated using modern ultrasound technique. The two most common fetal growth parameters (biparietal diameter [BPD] and crown-rump-length [CRL]) and uterine position were measured. Data revealed similar fetal growth patterns in the wild guinea pig and domesticated guinea pig in the investigated gestation period, although they differ in reproductive milestones such as gestation length (average duration of pregnancy 68 days), average birth weight, and litter mass. In this study, pregnancy lasted on average 60.2 days with a variance of less than a day (0.96 days). The measured fetal growth parameters are strongly correlated with each (R = 0.91; P < 0.001) other and with gestational age (BPD regression equation y = 0.04x - 0.29; P < 0.001 and CRL regression equation y = 0.17x - 2.21; P < 0.01). Furthermore, fetuses in the most frequent uterine positions did not differ in their growth parameters and were not influenced by the mother ID. Our results imply that ultrasound measurement of a single fetal growth parameter is sufficient to reliably estimate gestational age in the wild guinea pig.

Comparative metabolism of PGFM (13,14-dihydro-15-keto-PGF2α) in feces of felids.

Methods for monitoring endocrine activities are useful tools for reproduction management. In particular, captive breeding of endangered felid species is considered to be an important part of the species conservation efforts. Within breeding programs, reliable methods for pregnancy diagnosis are highly demanded to prevent peri- and postpartal losses, but pregnancy diagnosis based on gestagen metabolites in felids is hampered by pseudopregnancies. Recently, we described fecal PGFM as an indicator for pregnancy in several feline species, but peak levels of PGFM secretion differed dramatically between species. It is believed that prostaglandin composition and metabolism pathways may differ as well. Therefore, a study was devised to both compare various fecal immunoreactive PGFM metabolites and to identify prostaglandins in fecal extracts by liquid chromatography-mass spectrometry (LCMS). Our results confirmed that fecal metabolite patterns differ between feline species. The identity of PGFM was confirmed in six of eight felids. In Iberian lynx and the Sumatran tiger, PGFM did not exceed 5% of all immunoreactivities. The total number of immunoreactivities varied between two (e.g., domestic cat) and four (e.g., oncilla). Several prostaglandins were identified by LCMS; apart from PGFM, all LCMS-identified prostaglandins, including tetranor-PGFM, did not show any cross-reactivity with our PGFM-specific antibody. This indicates the existence of still unknown eicosanoids and further studies are needed to clarify the origin of the different metabolites. Although differing stages of pregnancy did not reveal significant differences in the composition of metabolites, we could not exclude the possibility that metabolites from other prostaglandins (e.g. PGE2) contributed to the fecal metabolite patterns.

Influence of culture medium composition on relative mRNA abundances in domestic cat embryos.

Different culture conditions have been used to produce domestic cat embryos. As part of the in vitro procedures, the medium composition significantly affects the quality of the embryo development also. Quality assessments based on cleavage kinetics and blastomere symmetry are useful, but embryos also can differ in their relative gene expression patterns despite similar morphological characteristics. The aim of this study was to compare cat embryos produced with two different in vitro culture systems routinely used in two different laboratories [Smithsonian Conservation Biology Institute, Washington D.C., USA (SCBI) and Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany (IZW)]. Specifically, relative mRNA expression patterns of critical genes for pre-implantation embryo development were assessed in both conditions. Embryos were produced in parallel in both culture systems by IVF using frozen-thawed ejaculated semen in the United States and fresh epididymal sperm in Germany. Success of embryo development in vitro was recorded as well as relative mRNA abundances [DNA methyltransferases 1 and 3A (DNMT1, DNMT3A), gap junction protein alpha 1 (GJA1), octamer-binding transcription factor 4 [OCT4], insulin-like growth factors 1 and 2 receptors (IGF1R, IGF2R), beta-actin (ACTB)] in pools of days 4-5 morulae by semi-quantitative RT-PCR assay. Percentages of cleaved embryos were similar (p > 0.05) between both culture systems, regardless of the location. OCT4 mRNA abundance was higher (p < 0.05) in embryos derived in the SCBI culture system compared with those from the IZW system when epididymal sperm was used for IVF. No clear correlation between the expression pattern and the culture system could be found for all other genes. It is suggested that OCT4 expression might be affected by the media composition in some conditions and can be the indicator of a better embryo quality.

Analysis of Sertoli cell efficiency allows the differentiation between two fundamentally different forms of feline teratospermia.

Teratospermia is a common phenomenon within felid species and has been attributed to reduction in genetic diversity. Testes from teratospermic domestic cats show enhanced spermatogenesis accompanied by remarkably reduced germ cell apoptosis. In the present study we investigated whether free-range teratospermic tom cats exhibit a similar testicular phenotype as proven permanently teratospermic males. Randomly collected teratospermic cats were compared with normal (normospermic; >60% morphologically normal sperm per ejaculate) and a well-characterized population of permanently teratospermic domestic cats, with respect to their spermatogenic potential. Histomorphologic assessment of testes from randomly collected teratospermic cats revealed no differences compared with normospermic donors. These two groups, however, were both different from permanently teratospermic cats, which exhibit fewer Sertoli cells and increased numbers of round spermatids per tubule cross-section resulting in a remarkably increased Sertoli cell efficiency (ratio of round spermatids to Sertoli cells). In conclusion, we can distinguish at least two fundamentally different forms of feline teratospermia. One subtype, found in most of the randomly collected tom cats, but not associated with altered quantitative spermatogenic parameters. Another subtype, found in all permanently teratospermic felids, is manifested by an impairment of Sertoli cell efficiency. We suggest that spermatogenic output should be analyzed before using random source domestic cats to study the phenomenon of teratospermia.

Using PGFM (13,14-dihydro-15-keto-prostaglandin F2α) as a non-invasive pregnancy marker for felids.

Understanding the complex endocrine interactions that control reproduction in felids is essential for captive breeding management. The most important demand is a quick and reliable pregnancy diagnosis. However, the occurrence of pseudopregnancies in felids complicates matters. We investigated whether the fecal prostaglandin metabolite (PGFM) recently suggested for pregnancy diagnosis in the lynx is suitable for all felid species. We found that increased levels of PGFM during the last trimester indicate pregnancy in seven of the eight main lineages of the carnivore family Felidae. PGFM levels in a sand cat (domestic cat lineage) were basal at mating and remained so until Day 40 post-mating. Day 41 marked the beginning of a distinct increase culminating in peak levels of 6.5 µg/g before parturition and decreasing again to baseline thereafter. Similar pregnancy profiles were obtained from the domestic cat, the leopard cat, the lynx, the ocelot and the caracal lineage, whereas in pseudopregnant individuals (sand cat, Iberian and Eurasian lynx) fecal PGFM remained at basal levels. In pregnant cheetahs (puma lineage) PGFM increased above basal following day ∼48 peaking before pregnancy but remained at baseline in pseudopregnant females. Discrepancies existed in the Panthera lineage. While Chinese leopard, Sumatran tiger, and the black panther showed marked increases of PGFM during the last weeks of pregnancy, only moderate increases in PGFM levels were found in the Indochinese tiger and the Persian leopard. Altogether, PGFM as tool for pregnancy diagnosis has been proven to be useful in breeding management of felids.

Life cycle of feline Corpora lutea: histological and intraluteal hormone analysis.

The corpus luteum (CL) is a transient hormone gland on the ovary that produces progesterone (P4) for the maintenance of pregnancy. It develops from residual follicular granulosa and theca cells after ovulation. Very little is known about the cellular and hormonal processes within CLs obtained from pregnant and pseudopregnant felids. Therefore, our aim was to review the luteal function in feline CLs of different reproductive stages in conjunction with our data obtained in domestic cats and Eurasian lynxes. Corpus luteum function in lynxes is of particular interest, as a post-partum luteal activity was suggested based on repeated ultrasonography and endocrine examinations. Histology of CL from pregnant and pseudopregnant domestic cats clearly reflects the luteal function. The formation of the CL after ovulation is characterized by transforming of theca and granulosa cells into steroidogenic luteal cells and is accompanied by increased intraluteal and circulating P4 levels. Luteal regression is steadily progressive; the first signs (coarsed vacuolization, increased proportion of non-steroidogenic cells) are visible already in CL from the second trimester of pregnancy.