Increased number of mast cells in the dominant follicle of the cow: relationships among luteal, stromal, and hilar regions

History, insights, and future perspectives on studies into luteal function in cattle

The corpus luteum (CL) forms following ovulation from the remnant of the Graafian follicle. This transient tissue produces critical hormones to maintain pregnancy, including the steroid progesterone. In cattle and other ruminants, the presence of an embryo determines if the lifespan of the CL will be prolonged to ensure successful implantation and gestation, or if the tissue will undergo destruction in the process known as luteolysis. Infertility and subfertility in dairy and beef cattle results in substantial economic loss to producers each year. In addition, this has the potential to exacerbate climate change because more animals are needed to produce high-quality protein to feed the growing world population. Successful pregnancies require coordinated regulation of uterine and ovarian function by the developing embryo. These processes are often collectively termed "maternal recognition of pregnancy." Research into the formation, function, and destruction of the bovine CL by the Northeast Multistate Project, one of the oldest continuously funded Hatch projects by the USDA, has produced a large body of evidence increasing our knowledge of the contribution of ovarian processes to fertility in ruminants. This review presents some of the seminal research into the regulation of the ruminant CL, as well as identifying mechanisms that remain to be completely validated in the bovine CL. This review also contains a broad discussion of the roles of prostaglandins, immune cells, as well as mechanisms contributing to steroidogenesis in the ruminant CL. A triadic model of luteolysis is discussed wherein the interactions among immune cells, endothelial cells, and luteal cells dictate the ability of the ruminant CL to respond to a luteolytic stimulus, along with other novel hypotheses for future research.

Male and female gonadal ageing: its impact on health span and life span

Ageing is linked to changes in the hypothalamic-pituitary-gonadal axis and a progressive decline in gonadal function. While women become infertile when they enter menopause, fertility decline in ageing men does not necessarily involve a complete cessation of spermatogenesis. Gonadal dysfunction in elderly people is characterized by morphological, endocrine and metabolic alterations affecting the reproductive function and quality of life. With advancing age, sexuality turns into a critical emotional and physical factor actually defining the number of years that ageing people live a healthy life. Gonadal ageing correlates with comorbidities and an increased risk of age-related diseases including diabetes, kidney problems, cardiovascular failures and cancer. This article briefly summarizes the current state of knowledge on ovarian and testicular senescence, explores the experimental models used in the study of gonadal ageing, and describes the local pro-inflammatory, oxidative and apoptotic events and the associated signalling pathways that take place in the gonads while people get older. Overall, literature reports that ageing exacerbates a mutual crosstalk among oxidative stress, apoptosis and the inflammatory response in the gonads leading to detrimental effects on fertility. Data also highlight the clinical implications of novel therapeutic interventions using antioxidant, anti-apoptotic and anti-inflammatory drugs on health span and life span.

Mast cells and Kurloff cells - Their detection throughout the oestrous cycle in normal guinea pig ovaries and in guinea pigs with cystic rete ovarii

Mast cells (MCs) and Kurloff cells (KCs) were detected in guinea pig ovaries in the follicular and luteal phases of the oestrous cycle. The samples of ovaries were fixed in Mota's basic lead acetate. Toluidine blue was used for detection of MCs and periodic acid-Schiff for detection of KCs. The percentage of KCs in a differential leukocyte count was determined in blood smears stained according to the Pappenheim method. Non-pregnant females with normal ovaries and with cystic rete ovarii were included in the study and the numbers of MCs and KCs were compared in these two groups and in follicular and luteal phases of the oestrous cycle. MCs' distribution in ovaries was different in the guinea pig in comparison to previously studied species: MCs were found exclusively in the superficial layers of cortical stroma and no significant difference was found between the number of MCs in the follicular and luteal phases, neither in normal ovaries, nor in ovaries with cystic rete ovarii. Significantly lower numbers of MCs were found in ovaries with cystic rete ovarii (P < 0.01) in contrast to normal ovaries. A significantly higher percentage of KCs in the peripheral blood was found in the follicular phase (P < 0.05), whereas no significant difference was found in relation to the presence of cystic rete ovarii. Interestingly, no KCs were found in the samples of ovaries (either in the follicular or luteal phase, and with or without cysts). Thus, the expected role of KCs in ovarian physiology or in the aetiology of the cystic rete ovarii can be excluded.

Changes in the mast cell distribution in the canine ovary and uterus throughout the oestrous cycle

This is the first study describing the relation between the phase of the oestrous cycle and the number of mast cells (MCs) in the canine ovaries and uterine horns. The total number of MCs was counted in cortex ovarii, medulla ovarii, endometrium and myometrium. The number of MCs was compared in all of these areas among the bitches in the early follicular phase, luteal phase and anoestrus. MCs were the most numerous in the early follicular phase and in the luteal phase; however, they were significantly less numerous during anoestrus. Based on the results, it was concluded that the number of MCs in ovaries and uterine horns fluctuates during the oestrous cycle. The results of this study may contribute to clarifying the role of MCs in the reproductive organs of bitches.

Intrafollicular melatonin concentration is elevated in patients with ovarian hyperstimulation syndrome (OHSS) and can serve as an important predictor of OHSS

PURPOSE

Melatonin is an important factor in regulating numerous processes in human female reproduction. The aim of the present study was to compare melatonin levels in the follicular fluid (FF) of ovarian hyperstimulation syndrome (OHSS) women with those of non-OHSS women undergoing in vitro fertilization (IVF)-embryo transfer and to evaluate the relationship between FF melatonin levels and IVF outcomes in these women.

METHODS

We determined FF melatonin levels in 20 OHSS women and 23 non-OHSS women on oocyte retrieval day.

RESULTS

OHSS patients had significantly higher melatonin levels as compared to the non-OHSS women (P < 0.001). In addition, melatonin levels of the patients were significantly positively correlated with antral follicle count (AFC), serum anti-Müllerian hormone (AMH) levels, serum estradiol (E₂) levels on human chorionic gonadotropin (HCG) administration day, number of retrieved oocytes, total fertilized oocytes, normally fertilized oocytes, cleaved zygotes, top quality embryos on day 3, blastocysts obtained and embryos suitable for transplantation (day 3 embryos + day 5/6 blastocysts) (P < 0.05). While, the intrafollicular melatonin levels were significantly negatively correlated with age, basal serum follicle-stimulating hormone (FSH) levels, serum FSH levels on HCG administration day (P < 0.01). Since younger women with more AFC, higher AMH levels, higher serum E₂ levels and larger number of retrieved oocytes are much easier to encounter OHSS, while FF melatonin levels are significantly correlated with these five indices in our study, we propose that intrafollicular melatonin concentration can also be an important predictor of OHSS.

CONCLUSIONS

This is the first demonstration that FF melatonin levels were significantly higher in OHSS patients than in non-OHSS group and FF melatonin levels may serve as an important predictor of OHSS.

Cresyl Violet Stains Mast Cells Selectively: Its Application to Counterstaining in Immunohistochemistry

The thiazine dye toluidine blue (TB) is well known to stain mast cells and hyaline cartilage metachromatically, and thus is mostly often used for their identification. However, TB is not suitable for counterstaining in immunohistochemistry, because of its high-background staining in the cytoplasm of other cell species and in extracellular structures. To expand the knowledge about dyestuffs staining mast cells in consideration with their usage in immunohistochemistry, we determined the stainability of several thiazines and oxazines, which are structurally related compounds to TB, using sections of mast cell-containing tissues. We found that all azine dyes used metachromatically stained mast cells and cartilage. Among these dyes, an oxazines cresyl violet (CV) stained mast cells with lower background, suggesting that those are useful for detecting mast cells and for counterstaining in immunohistochemistry. To ascertain its utility, CV was used in immunostaining of bHSDs in sections from adult rat ovary. Immunopositive signals reflected by DAB development in brown were clearly detected even after CV staining. We conclude that, similar to thiazines, oxazines stain mast cells metachromatically, and that of these, CV is more useful as a counterstain in immunohistochemistry than TB.

The contribution of the maternal immune system to the establishment of pregnancy in cattle

Immune cells play an integral role in affecting successful reproductive function. Indeed, disturbed or aberrant immune function has been identified as primary mechanisms behind infertility. In contrast to the extensive body of literature that exists for human and mouse, studies detailing the immunological interaction between the embryo and the maternal endometrium are quite few in cattle. Nevertheless, by reviewing the existing studies and extrapolating from sheep, pig, mouse, and human data, we can draw a reasonably comprehensive picture. Key contributions of immune cell populations include granulocyte involvement in follicle differentiation and gamete transfer, monocyte invasion of the peri-ovulatory follicle and their subsequent role in corpus luteum formation and the pivotal roles of maternal macrophage and dendritic cells in key steps of the establishment of pregnancy, particularly, the maternal immune response to the embryo. These contributions are reviewed in detail below and key findings are discussed.

New developments of the effect of melatonin on reproduction

In the past decades, a lot of advances in understanding the biochemistry and physiology of the pineal gland have been made. There is evidence that it interacts with many endocrine as well as non-endocrine tissues to influence their metabolic activity modulating many organs and functions. Melatonin is secreted by the pineal gland in the brain and plays an important role in regulating the neuroendocrine system. This hormone is one of the major role players in the regulation of the circadian sleep-wake cycle. It is normally released from the pineal gland during the night in response to environmental changes in light. Studies have shown that melatonin plays a role in the regulation of many reproductive processes such as puberty, gonadal function, and pregnancy. Beside these, melatonin has been shown to be able to directly neutralize a number of free radicals and reactive oxygen and nitrogen species. The main objective of this review is to provide comprehensive information about the new developments in melatonin research regarding its role in reproduction. A review of international scientific literature was done and a question-and-answer format was used in an attempt to convey comprehensive information in a simple manner. This review discusses evidence currently available relating to the effect of melatonin on reproductive processes. It deliberates the mechanism of action of melatonin, its effect on puberty, testicular and ova function, pregnancy, and oxidative stress. A growing body of scientific evidence is suggesting that melatonin plays an important role in reproductive function. It is therefore imperative to highlight the beneficial effects of this hormone in improving the reproductive processes.

The role of melatonin as an antioxidant in the follicle

Melatonin (N-acetyl-5-methoxytryptamine) is secreted during the dark hours at night by pineal gland, and it regulates a variety of important central and peripheral actions related to circadian rhythms and reproduction. It has been believed that melatonin regulates ovarian function by the regulation of gonadotropin release in the hypothalamus-pituitary gland axis via its specific receptors. In addition to the receptor mediated action, the discovery of melatonin as a direct free radical scavenger has greatly broadened the understanding of melatonin's mechanisms which benefit reproductive physiology. Higher concentrations of melatonin have been found in human preovulatory follicular fluid compared to serum, and there is growing evidence of the direct effects of melatonin on ovarian function especially oocyte maturation and embryo development. Many scientists have focused on the direct role of melatonin on oocyte maturation and embryo development as an anti-oxidant to reduce oxidative stress induced by reactive oxygen species, which are produced during ovulation process. The beneficial effects of melatonin administration on oocyte maturation and embryo development have been confirmed by in vitro and in vivo experiments in animals. This review also discusses the first application of melatonin to the clinical treatment of infertile women and confirms that melatonin administration reduces intrafollicular oxidative damage and increase fertilization rates. This review summarizes our recent works and new findings related to the reported beneficial effects of melatonin on reproductive physiology in its role as a reducer of oxidative stress, especially on oocyte maturation and embryo development.

Molecular characterization and bioinformatics analysis of Ncoa7B, a novel ovulation-associated and reproduction system-specific Ncoa7 isoform

In the present work, we employed bioinformatics search tools to select ovulation-associated cDNA clones with a preference for those representing putative novel genes. Detailed characterization of one of these transcripts, 6C3, by real-time PCR and RACE analyses led to identification of a novel ovulation-associated gene, designated Ncoa7B. This gene was found to exhibit a significant homology to the Ncoa7 gene that encodes a conserved tissue-specific nuclear receptor coactivator. Unlike Ncoa7, Ncoa7B possesses a unique and highly conserved exon at the 5' end and encodes a protein with a unique N-terminal sequence. Extensive bioinformatics analysis has revealed that Ncoa7B has one identifiable domain, TLDc, which has recently been suggested to be involved in protection from oxidative DNA damage. An alignment of TLDc domain containing proteins was performed, and the closest relative identified was OXR1, which also has a corresponding, highly related short isoform, with just a TLDc domain. Moreover, Ncoa7B expression, as seen to date, seems to be restricted to mammals, while other TLDc family members have no such restriction. Multiple tissue analysis revealed that unlike Ncoa7, which was abundant in a variety of tissues with the highest expression in the brain, Ncoa7B mRNA expression is restricted to the reproductive system organs, particularly the uterus and the ovary. The ovarian expression of Ncoa7B was stimulated by human chorionic gonadotropin. Additionally, using real-time PCR, we demonstrated the involvement of multiple signaling pathways for Ncoa7B expression on preovulatory follicles.

Distribution and heterogeneity of mast cells in female reproductive tract and ovary on different days of the oestrus cycle in Angora goats

The physiological distribution of mast cells (MCs) in the reproductive tract and ovary of 12 Angora goats was determined using light microscopic histochemical techniques. Uterus (corpus uteri and cornu uteri), uterine cervix, uterine tubes (isthmus and ampulla) and ovary samples were obtained by laparatomy from groups of animals during metoestrus, dioestrus and proestrus (days 5, 10 and 16 of the oestrous cycle). Tissues were fixed in Mota's fixative (basic lead acetate) for 48 h and embedded in paraffin. Six-micrometre-thick sections were stained with toluidine blue in 1% aqueous solution at pH 1.0 for 5 min and alcian blue-Safranin at pH 1.0 for 30 min. MCs were generally associated with blood vessels in all reproductive organs. In the uterus, they were concentrated mainly in the close of the uterine gland and deep stroma in the endometrium. Higher MC numbers were observed by toluidine blue staining in the uterus, uterine cervix and uterine tubes on days 10 (corpus uterine: 4.7 +/- 3.8 and cornu uterine: 4.9 +/- 3.5) and 16 (corpus uterine: 5.9 +/- 4.5 and cornu uterine: 5.4 +/- 2.4) of the oestrous cycle compared with day 5 (p < 0.05). Mast cells were not observed in the follicles, the corpus luteum and the underside of the surface epithelium of the ovarian cortex, but were observed in the interstitial cortical stroma and the ovarian medulla. In the ovary, MC numbers were significantly higher on day 16 of the oestrous cycle (cortex: 3.4 +/- 2.4 and medulla: 5.7 +/- 4.5, p < 0.05). Safranin-positive connective tissue MCs were not observed in the uterine tube on any occasion. These results indicate oestrous cycle-related changes in the number and location of MCs in goat reproductive organs.

Pathology of the corpus luteum of cows

The corpus luteum (CL) is a transient endocrine organ which can manifest a number of pathologic conditions such as cysts, inflammation, adhesions, dysfunction and neoplasia. Luteal and follicular cysts are the most commonly encountered abnormalities and need to be distinguished from cysts within a normal CL. Inflammatory lesions are also frequently encountered and can be caused by viral, bacterial, or iatrogenic causes. If inflammation is severe, adhesions and subfertility/infertility can result. Luteal dysfunction is a broad classification of another pathologic condition encountered in the cow. Generally this results in abnormal production of progesterone or abnormal luteal lifespan resulting in infertility. Neoplasms are relatively rare in the CL but include both primary and metastatic tumors. Understanding the pathologic conditions that occur within the CL will allow a more accurate clinical assessment of these very dynamic endocrine structures.

Fundamental roles of reactive oxygen species and protective mechanisms in the female reproductive system

Controlled oxidation, such as disulfide bond formation in sperm nuclei and during ovulation, plays a fundamental role in mammalian reproduction. Excess oxidation, however, causes oxidative stress, resulting in the dysfunction of the reproductive process. Antioxidation reactions that reduce the levels of reactive oxygen species are of prime importance in reproductive systems in maintaining the quality of gametes and support reproduction. While anti-oxidative enzymes, such as superoxide dismutase and peroxidase, play a central role in eliminating oxidative stress, reduction-oxidation (redox) systems, comprised of mainly glutathione and thioredoxin, function to reduce the levels of oxidized molecules. Aldo-keto reductase, using NADPH as an electron donor, detoxifies carbonyl compounds resulting from the oxidation of lipids and proteins. Thus, many antioxidative and redox enzyme genes are expressed and aggressively protect gametes and embryos in reproductive systems.

Intratesticular morphometric, cellular and endocrine changes in dromedary bulls exhibiting azoospermia

Twenty bulls, aged 7-12 years and selected from six dromedary farms were used in this study. Fifteen previously fertile animals were divided into fertile (controls) and infertile groups on the basis of abnormal scrotal contents following palpation and azoospermic ejaculates collected by electroejaculation. An examination of the clinical and histological findings as well as the testicular patterns of oestradiol-17beta, testosterone and histamine indicated that three bulls displayed normal ranges comparable to the controls but with bilateral spermatocoeles in the caput epididymides in conjunction with the soft texture of the testicles. Seven bulls showed moderate testicular firmness and springiness, a marked increase in testicular oestradiol-17beta and histamine concentrations, and increases in surface area, density of mast cells and percentages of seminiferous tubules containing premeiotic spermatogenic cells as well as decreases in testicular testosterone concentrations, surface area of Leydig cells and diameter of the seminiferous tubules. The remaining five infertile animals had small hard testicles, supranormal testicular testosterone concentrations, baseline values of testicular oestradiol-17beta and histamine, decreased numbers of Sertoli and mast cells, with a predominance (98.2%) of seminiferous tubules containing spermatogonia resting on a thickened tubular basement membrane. The results provide information on the relationship between gonadotrophin, testicular oestrogen, androgens and histamine as well as spermatogenesis in normal and azoospermic dromedary bulls.

Increased endogenous level of melatonin in preovulatory human follicles does not directly influence progesterone production

OBJECTIVE

To study the role of follicular melatonin on steroid production by human preovulatory follicles.

DESIGN

In vivo comparative and in vitro culture studies.

SETTING

University hospital.

PATIENT(S)

Thirty-six patients with tubal and/or male, but not endocrinological, infertility factors.

INTERVENTION(S)

Follicular fluid collection during IVF. In vitro granulosa cell culture from luteinizing or growing Graafian follicles.

MAIN OUTCOME MEASURE(S)

Follicular melatonin, P, T, and E(2) concentrations. In vitro P production by granulosa cells.

RESULT(S)

There was a positive correlation between follicular melatonin and P concentrations. Melatonin did not stimulate in vitro P production by granulosa cells from luteinizing or growing follicles. Melatonin, P, and E(2) concentrations were significantly higher, but T concentrations were lower, in large follicles than in small follicles.

CONCLUSION(S)

Preovulatory follicles contain a high amount of melatonin compared with that in small immature follicles; melatonin may play an important, but indirect, role in P production by human granulosa cells.

The ovarian hyperstimulation syndrome

OBJECTIVE

To review the up-to-date literature concerning the pathogenesis of, risk factors for, prevention of, and therapy for the ovarian hyperstimulation syndrome, and to provide suggestions for management of this syndrome.

DESIGN

Literature review combined with on-site clinical experiences at the authors' institution of practice.

PATIENT(S)

Women who have risk factors for or manifest the ovarian hyperstimulation syndrome.

INTERVENTION(S)

Intravenous fluid management, thrombosis prevention techniques, paracentesis techniques, and critical care management protocols.

MAIN OUTCOME MEASURE(S)

Staging system of the ovarian hyperstimulation syndrome, criteria for outpatient versus hospitalization management, and indications for varying levels of interventional management.

RESULT(S)

The ovarian hyperstimulation syndrome, unique to the field of assisted reproductive technology, remains a largely elusive and unpredictable iatrogenic physiologic complication in the course of pharmacologic ovarian stimulation. Reliable information on risk factors, possible physiologic mechanisms, prevention techniques, and management is fortunately progressing, and overall advances are being made in this field. The present review is an attempt to summarize the modern literature regarding this syndrome and to use this current knowledge to provide a basis for acceptable management regimens.

CONCLUSION(S)

Ovarian hyperstimulation syndrome is a serious complication of assisted reproductive technology, with potential for critical morbidity and death. Physicians who prescribe medications known to be associated with this syndrome should be familiar with identifiable risk factors, means of prevention, and a system for staging and treating the disease and have a current knowledge base for putative models of pathogenesis.

Prospective study of the clinical and laboratory parameters of patients in whom ovarian hyperstimulation syndrome developed during controlled ovarian hyperstimulation for in vitro fertilization

OBJECTIVE

To compare patient characteristics and clinical and laboratory parameters in patients in whom ovarian hyperstimulation syndrome (OHSS) develops with those in whom it does not develop.

DESIGN

Prospective cohort study.

SETTING

Reproductive medicine unit at a university medical center.

PATIENT(S)

All patients undergoing IVF (n = 428) who received controlled ovarian hyperstimulation during a 6-month period.

INTERVENTION(S)

Prospective data collection.

MAIN OUTCOME MEASURE(S)

Patient characteristics (age, body mass index, medical history, smoking habits) and clinical and laboratory data obtained during controlled ovarian hyperstimulation were evaluated in patients who had severe OHSS, any degree of OHSS, or a significant risk of OHSS and compared with the remaining populations.

RESULT(S)

Severe OHSS developed in 18 patients (4.2%) and mild or moderate OHSS developed in 7.3%. As a group, all the patients with OHSS were significantly younger, received lower doses of gonadotropins, had ovaries containing a higher number of total and large follicles, had a higher number of retrieved oocytes, and had a higher pregnancy rate than the patients without OHSS. The patients with severe OHSS also had an increased prevalence of allergy (56% versus 21%) and were more likely to ultimately give birth.

CONCLUSION(S)

The observed differences may be useful in elucidating the pathophysiology of OHSS and identifying patients who are at increased risk for OHSS.

Distribution of histamine in laying hen ovary

In a laying hen, histamine was found to be present in all compartments of the ovary, i.e. stroma with follicles < 1 mm, small white (1-4 mm), large white (4-8 mm), atretic white, yellow preovulatory (8-35 mm) and postovulatory follicles. Stroma containing non-yolky follicles exhibited the highest histamine concentration (6080 +/- 331 ng/g wet wt. tissue) which differed significantly (P < 0.01) from histamine levels observed in all examined classes of ovarian follicles. High histamine concentration was found in small, large and atretic white follicles as well as in older postovulatory follicles whereas low levels of histamine contained yellow preovulatory and younger postovulatory follicles. Population of yolky white follicles presented significant (P < 0.01) differences in histamine level among small (4280 +/- 333), atretic (2940 +/- 193) and large (2010 +/- 110 ng/g) follicles. Within hierarchy of yellow preovulatory (F7-F1) follicles initial decrease in histamine concentration, from 859.3 +/- 51.5 ng/g in F7 follicle to 363.9 +/- 28.3 ng/g in F4 follicle, was followed by the increase as follicle matured, reaching the highest level in F1 follicle (711.4 +/- 35.9 ng/g). In postovulatory (P1-P5) follicles histamine concentration gradually increased as they were getting older, from 604.3 +/- 49.3 ng/g in P1 follicle to 2253 +/- 197 ng/g in P5 follicle. Determination of histamine in relation to ovulation revealed significant (P < 0.01) difference both in histamine concentration and content between the largest preovulatory F1 follicle and the largest postovulatory P1 follicle, being 0.5 h before and 0.5 h after ovulation, respectively. It is suggested that in chicken, ovarian histamine may play a role in the follicular development and/or the ovulatory process.

Number and state of rat ovarian mast cells after exogenous administration of luteinizing hormone

Diestrous rats were treated with an injection of luteinizing hormone (LH), and their ovaries were examined for mast cell number and stage of degranulation at 2 and 4 hr post-injection. LH tripled the number of medullary mast cells at 2 hr. The source or origin of the additional mast cells is unknown. Comparison of the present results with other studies of rat ovarian mast cell dynamics suggests the occurrence of a reduction in mast cell number in early to mid-proestrus followed by an LH-induced increase in late proestrus.

Effects of cytokines on FSH-induced estradiol production by bovine granulosa cells in vitro: dependence on size of follicle

The objective of the present studies was to determine the effect of cytokines on FSH-induced estrogen production by granulosa cells from small (1-5 mm) and large (> or = 8 mm) bovine follicles. FSH-induced estradiol production by granulosa cells from large follicles (expressed as pg estradiol/10(5) cells/24 hr) was not affected (P > .05) by 10 or 100 ng/ml of interleukin (IL)-1 beta, 10 or 100 ng/ml of tumor necrosis factor-alpha (TNF alpha) or 100 ng/ml of IL-2. In contrast, 100 ng/ml of IL-1 beta, IL-2 or TNF alpha inhibited (P < .05) FSH-induced estradiol production by 31%, 55% or 72%, respectively in cells from small follicles. Interferon-alpha (IFN alpha; 100 U/ml) inhibited (P < .05) FSH-induced estradiol production by 61% and 20% in cultures of cells from small and large follicles, respectively. Interferon-beta (IFN beta; 100 U/ml), interferon gamma (IFN gamma; 100 U/ml) and bovine trophoblast protein-1 (bTP-1; 100 U/ml) inhibited (P < .05) estradiol production by 47%, 71% and 28%, respectively in cells from small follicles, but had no effect (P > .05) on FSH-induced estradiol production in cells from large follicles. TNF alpha binding protein-I blocked (P < .05) the inhibitory effect of TNF alpha on FSH-induced estradiol production by cells from small follicles. Viability of granulosa cells was not affected (P > .05) by the various cytokines. In summary, cytokines have little or no effect on FSH-induced estradiol production by bovine granulosa cells collected from large follicles, whereas cytokines (bTP-1 < or = IL-1 beta < IL-2 = IFN beta < IFN alpha < TNF alpha) have potent inhibitory effects on FSH-induced estradiol production by granulosa cells collected from small follicles. Thus, it appears that less differentiated granulosa cells (small follicles) are more responsive to cytokines than are highly differentiated granulosa cells (large follicles).

Distribution and characteristics of mast cells in the chick ovary

1. Distribution and characteristics of mast cells have been studied in the ovaries of 5 and 17 week old chickens. 2. Mast cells were mainly present in the stroma, hilum and theca of normal and atretic follicles. No significant age-related differences in percentage distribution of mast cells were observed in the stroma and hilar regions of the ovary. However, the percentage of mast cells associated with follicles in both age groups was significantly less compared to stromal and hilar regions. 3. The number of mast cells present in the theca of normal and atretic follicles of stage 301 to 500 microns increased significantly compared to the preceding stages in 17-week old chicken ovaries. Moreover, the number of mast cells associated with the follicles of this stage in 17-week old chick ovaries was also higher compared to 5-week old chicken ovaries. 4. The mast cells showing variable shapes were divided into two types: compact and degranulating. More degranulating mast cells were observed in the 17-week old chicken ovary compared to those observed at 5-weeks.

The potential relevance of cytokines to ovarian physiology

Elucidating the secrets of intraovarian intercellular communication constitutes a central area of investigation. While most attention has been directed thus far at the somatic cellular components of the ovary, the potential role(s) and relative importance of the resident ovarian white blood cell have received relatively limited attention. Efforts are currently under way to reconcile traditional ovarian physiology with observations relevant to intraovarian components of the white blood cell series. In this connection, it is important to note that unlike some gonadal compartments, the ovary does not constitute an immunologically privileged site. Thus, resident ovarian representatives of the white blood cell series can be observed at various stages of the ovarian life cycle. Current concepts suggest that regulatory cellular networks formerly viewed in immune terms now fall within the broad domain of endocrinology. Viewed in this light, resident ovarian representatives of the white blood cell series may constitute potential in situ modulators of ovarian function acting in all likelihood through the local secretion of regulatory cytokines. As the flow of information is probably multi directional, the very same cells are probably targeted for steroidal and peptidergic input in keeping with the existence of multiple autocrine and paracrine loops.

New concepts in ovarian regulation: an immune insight

The purpose of the ovary is to produce eggs. In the human, oocyte production occurs cyclically at monthly intervals. The control of egg production is provided by both the endocrine and immune systems. Successful oocyte production is the result of sophisticated communication between the two systems. These interactions allow adaptive processes necessary for continuation of the species.

Quantitative and qualitative changes in blood leukocytes in the porcine ovary

The distribution of blood leukocytes in the preovulatory follicle (PO) and in the corpus luteum (CL) of the pig was studied by light microscopy. The number of macrophages increased in the freshly luteinized follicle, decreased subsequently in the developing and mature CL, and then increased again in the regressing CL. However, the relative proportion of macrophages as a percent of total blood leukocytes present did not change throughout the cycle. The increase in the number of lymphocytes was the greatest increase after ovulation as compared to all the other blood leukocytes observed. Even though the number of lymphocytes decreased thereafter, their numbers expressed as a percent of total blood leukocyte number remained high in the developing and mature CL. Eosinophils were the most prominent blood cell type present in thecal tissue of PO and in the regressing CL. In other stages of the CL, few eosinophils were observed. Neutrophil numbers remained moderate and unchanged throughout most of the estrous cycle except in the regressing CL, where the number of neutrophils was slightly increased. Low numbers of plasma cells were observed in all structures studied and no significant changes due to stage were apparent. The distribution of lymphocytes in the corpus hemorrhagicum (CH) and eosinophils in the regressing CL was different in different regions of the ovarian structure. In summary, blood leukocytes, most notably macrophages, lymphocytes and eosinophils, differentially migrate into specific structures of the ovary at specific stages of the estrous cycle of the pig. The possible involvement of these blood leukocytes in the modulation of ovarian events is discussed.

Mast cells in the testis, epididymis and accessory glands of the rat: effects of neonatal steroid treatment

Mast cells in the testis of control adult rats were found almost exclusively around subcapsular blood vessels. Discrete mast cells were distributed throughout the stroma of the epididymis and sex accessory glands. In neonatally estrogen-treated rats, a greater number of mast cells was present in the testicular interstitium, whereas no significant increase in the number of mast cells per square millimeter of stroma was found for the epididymis and sex accessory glands, despite stromal proliferation. On the other hand, androgen-treated rats did not have increased mast cell numbers in any organ. These results indicate that the increase in mast cell numbers was estrogen-dependent, specifically related to the testis and did not seem to be a consequence of the increase in the connective interstitial tissue.