Composition Of Oviductal Fluid Research Articles

Porcine oviductal extracellular vesicles facilitate early embryonic development via relief of endoplasmic reticulum stress.

The key to successful in vitro embryo production (IVEP) is to mimic the natural in vivo oviductal microenvironment. Although the chemically defined media in extensive use for the in vitro culture of mammalian embryos is based on the composition of oviductal fluid, the IVEPsystems in current use must still bypass the oviduct to produce embryos in vitro. Extracellular vesicles (EVs) in the oviduct are versatile intercellular delivery vehicles for maternal-embryo communication, and a lack of them can be associated with failed early embryonic development under in vitro culture conditions. Herein, we isolated EVs from porcine oviduct fluid and confirmed that oviductal EV supplementation improves the embryonic development of parthenogenetically activated (PA) embryos in terms of blastocyst formation rates and total cell numbers. Our experiments also revealed that a beneficial effect of oviductal EVs on PA embryos was achievable, at least in part, by relieving endoplasmic reticulum stress. These results suggest that the maternal-embryo communication mediated by oviductal EVs benefits early embryonic development. Given the contribution of oviductal EVs to early embryonic development, these findings offer novel insights for the optimization of current IVEP systems.

Influence of metabolic status and genetic merit for fertility on proteomic composition of bovine oviduct fluid†.

The oviduct plays a crucial role in fertilization and early embryo development providing the microenvironment for oocyte, spermatozoa, and early embryo. Since dairy cow fertility declined steadily over the last decades, reasons for early embryonic loss have gained increasing interest. Analyzing two animal models, this study aimed to investigate the impact of genetic predisposition for fertility and of metabolic stress on the protein composition of oviduct fluid. A metabolic model comprised maiden Holstein heifers and postpartum lactating (Lact) and non-lactating (Dry) cows, while a genetic model consisted of heifers from the Montbéliarde breed and Holstein heifers with low- and high-fertility index. In a holistic proteomic analysis of oviduct fluid from all groups using nano-liquid chromatography tandem-mass spectrometry analysis and label-free quantification, we were able to identify 1976 proteins, among which 143 showed abundance alterations in the pairwise comparisons within both models. Most differentially abundant proteins were revealed between low fertility Holstein and Montbéliarde (52) in the genetic model and between lactating and maiden Holstein (19) in the metabolic model, demonstrating a substantial effect of genetic predisposition for fertility and metabolic stress on the oviduct fluid proteome. Functional classification of affected proteins revealed actin binding, translation, and immune system processes as prominent gene ontology (GO) clusters. Notably, Actin-related protein 2/3 complex subunit 1B and the three immune system-related proteins SERPIND1 protein, immunoglobulin kappa locus protein, and Alpha-1-acid glycoprotein were affected in both models, suggesting that abundance changes of immune-related proteins in oviduct fluid play an important role for early embryonic loss.

70 Effect of Ovulation Stimulus on Biochemical Composition of the Oviduct of Alpaca (Vicugna pacos)

Experiments were designed to determine the effect of ovulation stimulus on the biochemical composition of oviduct fluid in alpacas (Vicugna pacos). Twenty-four adult females were used to determine profiles of protein, albumin, glucose, cholesterol, and triglycerides in oviduct fluid. The animals were stimulated with 1 mL of seminal plasma (SP), 0.042 mg of a gonadotropin-releasing hormone (GnRH) analogue (buserelin acetate; Conceptal, Intervet, Holland), or PBS as control group. The oviduct was removed inmediately after slaughter on Day 2 or 4 after ovulation induction and washed with 3 mL of PBS solution. Determination of the biochemical composition was carried out with specific kits from the FAR Diagnostics Italia laboratory using a semiautomatic biochemical analyzer of the Sinowa China brand, which is based on spectrophotometric evaluation. The results are presented in Table 1. Our results suggest that the method of induction of ovulation affected the biochemical composition of oviduct fluid, including concentrations of albumin, cholesterol, total protein, triglyceride, and glucose. Table 1.Biochemical composition of oviduct fluid (mean ± SEM).

Sperm selection in the female mammalian reproductive tract. Focus on the oviduct: Hypotheses, mechanisms, and new opportunities

Research over the past 3 decades has caused a major shift in the way that the oviduct, or fallopian tube, is perceived. Previously, it was regarded as little more than the anatomic site for fertilization, where spermatozoa and oocytes meet as they travel in opposite directions. However, this view has been radically altered by the realization that both spermatozoa and oocytes elicit changes in the biochemical composition of oviductal fluid through the induction of novel gene expression. Moreover, it has also been shown that only a privileged sperm population, selected on the basis of multiple criteria, is permitted to enter the oviduct, where they are subjected to even more selection processes that control their motility and capacitation status, thus either inhibiting or facilitating their progress toward the oocyte. Even more recently, it has become apparent that the oviduct has some ability to differentiate the genetic signatures of X- and Y-bearing spermatozoa. Although how exactly this is achieved is unknown, it prompts us to speculate that the oviduct may also be capable of distinguishing other genetically encoded properties of individual spermatozoa and that there must ultimately be a huge payoff in terms of selective animal breeding.

69 DIFFERENTIAL AND QUANTITATIVE ANALYSIS OF DOG OVIDUCTAL FLUID

The major reproductive peculiarity of the bitch is that ovulation releases prophase I (germinal vesicle, GV, immature) oocytes. Resumption of meiotic maturation, as well as fertilisation and embryonic development to the morula stage occur in the oviduct. Because the dog is a biomedical model for human diseases and also a model for endangered canid species, the development of assisted reproduction techniques would be of great interest. To date, in vitro-produced canine embryos remain exceptional and no puppy has been born. The main limiting factors of in vitro embryo production are the low oocyte maturation rates, the poor oocyte quality and the high polyspermy. A better knowledge of the composition of oviductal fluid during the periovulatory period may help to mimic the in vivo conditions for in vitro oocyte culture and, thereafter, their fertilisation and embryonic development. The objective of this study was to analyse the oviductal fluid by a label-free quantitative proteomic workflow based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) protein separation, nano-scale liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) analysis and quantitative method using spectral counting. Ovarian cycles were followed by vaginal smears, ultrasonography and progesterone blood assays. Oviductal fluids were collected from 3 beagle bitches, after ovariectomies performed 3.5 days after ovulation. After dissection, the ampulla and isthmus were separated and flushed with 50 μL of PBS. Oviductal fluids were submitted to 1D SDS-PAGE and all bands were digested with trypsin. Peptide extracts were analysed on an Ettan multidimensional LC (MDLC) system coupled to a linear ion trap quadrupole (LTQ) mass spectrometer. After protein identification using Mascot server and with Swiss-Prot and National Center for Biotechnology Information (NCBI) databases, bioinformatic processing of data and statistic analysis (t-test with P < 0.05) were performed using the spectral counting quantitative module of the Scaffold software. Using this strategy, 427 proteins were qualitatively identified in canine oviductal fluid. Three proteins were specific of the ampulla, 10 specific of the isthmus and 414 were found in both oviductal parts. Among these common proteins, some were differentially expressed, from 1.25 to 9 times higher (HV303_Human, RLA2_Horse, SPRL1_Human, SODC_CANFA, PROF1_Human, ARF4_Bovin and TRXR1_Bovin). The gene ontology analysis displayed biological pathways specific to the biology of reproduction (6 proteins; RUVB1_Human, OVGP1_Pig, STAT3_Human, PLAK_Human, GPX3_Rat and DYL1_Human). These candidate proteins and especially oviduct-specific glycoprotein and glutathione peroxidase, will now be validated by immunodetection methods.

Ion, Protein, Phospholipid and Energy Substrate Content of Oviduct Fluid During the Oestrous Cycle of Buffalo (Bubalus bubalis)

The aim of this research was to analyse the composition of oviduct fluid (ODF) in buffalo cows at different oestrous cycle phases to fulfil the requirements of buffalo embryos in vitro. ODF was collected by chronic cannulation from three cows that were synchronized by administering a synthetic prostaglandin. Based on hormonal profiles, the pre-ovulatory, ovulatory, post-ovulatory and luteal phases of the oestrous cycle were defined. The volume of ODF produced (ml/24 h) was influenced by the oestrous cycle, with values (mean ± SE) around ovulation (1.0 ± 0.2) greater (p < 0.05) than in both the luteal (0.4 ± 0.1) and the post-ovulatory phases (0.5 ± 0.1), but not different from the intermediate values in the pre-ovulatory phase (0.8 ± 0.2). Among cycle phases, no differences were found in sodium, potassium, calcium and magnesium concentrations (130.0 ± 1.1, 5.1 ± 0.3, 2.8 ± 0.1 and 0.59 ± 0.04 mmol/l respectively). Interestingly, the chloride secretion (μm/24 h) was higher (p < 0.05) at ovulation (150.2 ± 16.5) than during both the luteal (73.7 ± 22.0) and the post-ovulatory phases (63.7 ± 11.2), with intermediate values in the pre-ovulatory phase (113.4 ± 23.5). Glucose concentration (mmol/l) was higher (p = 0.056) in the pre-ovulatory phase (0.06 ± 0.02) than in the luteal (0.02 ± 0.01) and post-ovulatory (0.02 ± 0.01) phases but not different from values in the ovulatory phase (0.04 ± 0.02). Concentrations of pyruvate and lactate among oestrous cycle phases were similar (0.08 ± 0.01 and 1.0 ± 0.1 mmol/l respectively). The total quantity of phospholipids (μmol/24 h) was greater (p < 0.05) at ovulation (0.21 ± 0.02) compared with the luteal, pre-ovulatory and post-ovulatory phases of the cycle (0.09 ± 0.02, 0.13 ± 0.02 and 0.09 ± 0.01 respectively). No differences were found in either the protein concentration (1.8 ± 0.3 mg/ml) or the quantity of proteins secreted in 24 h (1.8 ± 0.4 mg) among oestrous cycle phases. In conclusion, this study provides the first characterization of buffalo ODF during the oestrous cycle, showing species-specific differences that may be useful for developing suitable media for buffalo in vitro embryo production.

Modulation of The Oviductal Environment by Gametes

The notion of a gamete recognition system that alerts females to the presence of gametes in their reproductive tract profoundly influences our understanding of the physiology of events leading to conception and the bearing of offspring. Here, we show that the female responds to gametes within her tract by modulating the environment in which pregnancy is initially established. We found distinct alterations in oviductal gene expression as a result of sperm and oocyte arrival in the oviduct, which led directly to distinct alterations to the composition of oviductal fluid in vivo. This suggests that either gamete activates a cell-type-specific signal transduction pathway within the oviduct. This gamete recognition system presents a mechanism for immediate and local control of the oviductal microenvironment in which sperm transport, sperm binding and release, capacitation, transport of oocytes, fertilization, and early cleavage-stage embryonic development occur. This may explain the mechanisms involved in postcopulatory sexual selection, where there is evidence suggesting that the female reproductive tract can bias spermatozoa from different males in the favour of the more biologically attractive male. In addition, the presence of a gamete recognition system explains the oviduct's ability to tolerate spermatozoa while remaining intolerant to pathogens.

Preliminary results on the composition of oviductal fluid in buffalo

The aim of this study was to determine if qualitative and quantitative differences exist in energy substrates and ionic components of buffalo cow oviductal fluid during dioestrus, pre-ovulatory and ovulatory phases of the oestrous cycle. Ten multiparous Italian Mediterranean Buffalo (Bubalus Bubalis) cows at 15 days in milk were used. Cannulation of oviduct was performed as previously described by Kavanaugh et al.(1992) for cattle, adapting the technique to the smaller dimension of buffalo reproductive tract. We evaluated daily secretion rates, energy substrates and ions concentration during the three phases. Oviductal fluid secretion rates (ml/24h) and glucose concentration were significantly greater in the ovulatory phase (P<0.01) and in the pre-ovulatory phase (P<0.05) than in dioestrus. No significant differences were detected between oestrous phases for the other parameters analyzed.

Gametes Alter the Oviductal Secretory Proteome

The mammalian oviduct provides an optimal environment for the maturation of gametes, fertilization, and early embryonic development. Secretory cells lining the lumen of the mammalian oviduct synthesize and secrete proteins that have been shown to interact with and influence the activities of gametes and embryos. We hypothesized that the presence of gametes in the oviduct alters the oviductal secretory proteomic profile. We used a combination of two-dimensional gel electrophoresis and liquid chromatography-tandem mass spectrometry to identify oviductal protein secretions that were altered in response to the presence of gametes in the oviduct. The oviductal response to spermatozoa was different from its response to oocytes as verified by Western blotting. The presence of spermatozoa or oocytes in the oviduct altered the secretion of specific proteins. Most of these proteins are known to have an influence on gamete maturation, viability, and function, and there is evidence to suggest these proteins may prepare the oviductal environment for arrival of the zygote. Our findings suggest the presence of a gamete recognition system within the oviduct capable of distinguishing between spermatozoa and oocytes.

HISTROTROPHIC NUTRITION AND EARLY EMBRYO DEVELOPMENT

Histrotrophic nutrition was manipulated in adult Merino ewes during the course of a single reproductive cycle. From 18 days before until 6 days after ovulation. The effect of his relatively short-term exposure to high feed intake (H: 1.5 × maintenance ration), maintenance intake (M: 1× mainrenance ration) or low feed intake (L:0.5 × maintenance) was examined on embryo development, composition of oviductal fluid and pregnancy outcome in the ewes that either ovulated naturally or were induced to superovulate. Live weight was significally (p<0.05) reduced in sheep on L-compared with a M- or H- feed intake regime. The mean number of embryo collected, the mean number of corpora lutea (CL), and the proportion of embryos/CL recovered, was not influenced significally by differences in feed intake. However,embryos from sheep with an L feed intake during the peri-conceptional period consistently contained a significally (P<0.05) increased number of cells, resulting from a specific increase in the number of trophectoderm (TE) cells. Manupulating feed intake across the pre- vs.post-ovulatory periods revealed that exposure to a low feed inake in the 6-days post-ovulatory period caused this increase in the number of TE cells. Overall, these studies indicate that short-term changes in feed intake can significantly alter embryo development with potential consequences for subsequent fetal development. The way in which these short term changes influences development has not been resolved, but a number of exciting avenues are presented for further investigation. The findings are relevant to both human and animal and to improving our understanding of basic development process in reproduction.

HISTROTROPHIC NUTRITION AND EARLY EMBRYO DEVELOPMENT

Histrotrophic nutrition was manipulated in adult Merino ewes during the course of a single reproductive cycle. From 18 days before until 6 days after ovulation. The effect of his relatively short-term exposure to high feed intake (H: 1.5 × maintenance ration), maintenance intake (M: 1× mainrenance ration) or low feed intake (L:0.5 × maintenance) was examined on embryo development, composition of oviductal fluid and pregnancy outcome in the ewes that either ovulated naturally or were induced to superovulate. Live weight was significally (p<0.05) reduced in sheep on L-compared with a M- or H- feed intake regime. The mean number of embryo collected, the mean number of corpora lutea (CL), and the proportion of embryos/CL recovered, was not influenced significally by differences in feed intake. However,embryos from sheep with an L feed intake during the peri-conceptional period consistently contained a significally (P<0.05) increased number of cells, resulting from a specific increase in the number of trophectoderm (TE) cells. Manupulating feed intake across the pre- vs.post-ovulatory periods revealed that exposure to a low feed inake in the 6-days post-ovulatory period caused this increase in the number of TE cells. Overall, these studies indicate that short-term changes in feed intake can significantly alter embryo development with potential consequences for subsequent fetal development. The way in which these short term changes influences development has not been resolved, but a number of exciting avenues are presented for further investigation. The findings are relevant to both human and animal and to improving our understanding of basic development process in reproduction.

Effect of elevated systemic concentrations of ammonia and urea on the metabolite and ionic composition of oviductal fluid in cattle.

High dietary protein leads to elevated systemic concentrations of ammonia and urea, and these, in turn, have been associated with reduced fertility in cattle. The effect of elevating systemic concentrations of ammonia and urea on the concentrations of electrolytes and nonelectrolytes in bovine oviductal fluid were studied using estrus-synchronized, nulliparous heifers (n = 25). Heifers were randomly assigned to 1 of 3 treatments consisting of jugular vein infusion with either ammonium chloride (n = 8), urea (n = 8), or saline (n = 9). Oviducts were catheterized, and fluid was recovered over a 3-h period on either Day 2 or 8 of the estrous cycle. No difference (P > 0.05) was found in the concentrations of any electrolyte or nonelectrolyte between oviducts ipsi- or contralateral to the corpus luteum. Plasma and oviductal concentrations of urea were increased by infusion with urea (P < 0.001) and ammonium chloride (P < 0.05) but not by saline (P > 0.05). Plasma and oviductal concentrations of ammonia were elevated by infusion with ammonium chloride (P < 0.001) but not by infusion with urea or saline (P > 0.05). No effect (P > 0.05) of treatment was found on oviductal or plasma concentrations of glucose, lactate, magnesium, potassium, or sodium or on plasma concentrations of insulin or progesterone. The concentration of calcium in oviductal fluid was reduced by urea infusion and was negatively associated with systemic and oviductal concentrations of urea. Oviductal concentrations of sodium were higher on Day 8 than on Day 2 (P < 0.05). No effect of sample day was found on any of the other electrolytes or nonelectrolytes measured (P > 0.05). Elevated systemic concentrations of ammonia and urea are unlikely to reduce embryo survival through disruptions in the oviductal environment.

Formation of Fallopian tubal fluid: role of a neglected epithelium.

Fluid produced and secreted by the Fallopian tube provides the environment in which gamete transport and maturation, fertilization and early embryo development occur. This review describes the composition of oviductal fluid in terms of ions and nutrients such as glucose, lactate, pyruvate and amino acids. The function of oestrogen-specific glycoprotein is discussed. The mechanisms of fluid secretion and agents known to influence fluid production and secretion are described. Clinical implications of abnormal oviductal fluid production and secretion in hydrosalpinx and pelvic inflammatory disease are also discussed.

What is the relationship between the metabolism of preimplantation embryos and their developmental competence?

What is the relationship between the metabolism of preimplantation embryos and their developmental competence?

Electrophoretic characterization of proteins in oviduct fluid of cows during the estrous cycle

This study was undertaken to examine the in vivo protein composition of the bovine oviduct during the estrous cycle. Oviduct fluid was collected daily from four oviduct-cannulated dairy cows for a total of four complete estrous cycles. Fluid secretion followed a definite cyclic pattern, with maximum secretion occurring at estrus in all cycles. Protein concentration fluctuated during the cycle and varied among animals. In general, protein concentration was lower at the time of estrus. Total protein in oviduct fluid, however, was higher around estrus, indicating increased transudation or secretion by the oviduct. One-dimensional SDS-PAGE separation revealed the protein pattern of oviduct fluid to be generally similar to that of blood serum and follicular fluid. Two proteins appeared to be oviduct-specific. The first, a protein of approximately 47 kDa, was evident in oviduct fluid throughout the estrous cycle. The second protein, evident as a broad diffuse staining band above albumin, appeared for only 3-4 days at or near ovulation. This protein had a molecular weight of 80-95 kDa and stained positive for carbohydrate with periodic acid-Schiff reagent. These studies indicate that the in vivo protein composition of oviduct fluid varies with the estrous cycle, and that around estrus, an oviduct-specific glycoprotein is present.

Changes in phospholipids, cholesterol and protein content of oviduct fluid of cows during the oestrous cycle

The oviducts of 4 cows were cannulated and oviduct fluid was collected daily from the exteriorized cannulas for a total of 5 oestrous cycles. Daily serum samples were assayed for oestradiol-17 beta and progesterone to monitor the oestrous cycle. Data for each cycle were compared for oviduct fluid collected during the non-luteal phase (serum progesterone less than or equal to 1.5 ng/ml) and the luteal phase (serum progesterone greater than 1.5 ng/ml). During the non-luteal phase oviduct fluid volume was higher and the osmolality was lower than during the luteal phase. Total protein, cholesterol and phospholipid secreted daily was greater during the non-luteal phase. Cholesterol and protein concentrations were generally lower during the non-luteal phase, but phospholipid concentrations were generally higher. About 40% of the phospholipid in oviduct fluid was phosphatidylcholine and lysophosphatidylcholine, while phosphatidylinositol and lysophosphatidylinositol accounted for 20%. The ratio of 1-acyl-phospholipid to diacylphospholipid increased during the non-luteal phase. An increased cholesterol to phospholipid ratio, and a decreased cholesterol to protein ratio in oviduct fluid also were associated with the non-luteal phase. Changes in the lipid composition of oviduct fluid during the oestrous cycle may play a role in the preparation of gametes for fertilization.

Composition of oviduct fluid kept at two temperatures during collection from sheep.

It has never been established that fluid collected from the oviducts of rabbits (Clewe & Mastroianni, 1960), ewes (Black, Duby & Riesen, 1963; Restall, 1966; Perkins, Goode, Wilder & Hensen, 1965; Iritani, Gomes & VanDemark, 1969), cows (Carlson, Black & Howe, unpublished data) and monkeys (Mastro¬ ianni, Shah & Abdul-Karim, 1961) is comparable with the fluid normally present in the oviduct. The results of Holmdahl & Mastroianni (1965) suggest that it may not be comparable since they found that fluid held at low tempera¬ tures during collection from rabbits contained more glucose and less calcium than fluid collected at room temperature. A similar experiment was therefore carried out in sheep. Fourteen ewes of the Dorset and Shropshire breeds were used in the experi¬ ment. They were placed in individual stalls, given 1 lb of grain, hay or silage, and unrestricted water. Oestrus was detected with the aid of a ram. Animals to be cannulated for the collection of oviduct fluid were anaesthe¬ tized with Equithesin (Jen-Sal Labs) and the reproductive tract was exposed through a ventral incision anterior to the mammary glands. A silicone rubber (Silastic-Dow Corning) cannula (0-217 cm outer diameter, 0-102 cm inner diameter, 61 cm long) was inserted through the infundibulum of one oviduct and into the ampulla for about 1 cm. The cannula was retained within the oviduct by two ligatures of synthetic suture material, care being taken not to occlude the lumen. The position and patency of the cannula were determined by forcing a small amount of air into the oviduct. After ligating the uterine end of the cannulated oviduct to prevent passage of oviduct fluid into the uterus, the distal end of the cannula was brought out through the right flank and attached to a plastic test-tube cap which had an opening for air. The cap fitted tightly on the sterile plastic test-tubes in which the oviduct fluid was collected. The wound was closed in the usual manner and the animal allowed to regain full conscious¬ ness before being returned to its stall. Each ewe was fitted with a canvas blanket in which there was a pocket in the right side to hold the test-tube and container. The temperature within the collection vials was controlled by circulating

Effect of an intrauterine device on sheep oviduct fluids: chemical composition and stimulation of spermatozoan respiration in vitro.

Sheep oviduct fluids were studied to determine whether the presence of an IUD had any effect on the chemical composition of the fluids. The effect of oviduct fluids on ram sperm was also studied. IUD presence did not affect either volume or composition of oviduct fluid. Oviduct fluid from IUD-bearing sheep did not stimulate sperm respiration more than control oviduct fluid. There was a statistically significant (p less than .01) correlation between lactate content of oviduct fluid and sperm respiration. No histological changes were noted in IUD-bearing uteri.

Failure of scopolamine, pilocarpine or phenoxybenzamine to influence the rate of oviduct secretion in the rabbit.

The innervation of the oviduct is primarily adrenergic although parasympathetic fibres may also be present (see Brundin (1965) for a review of the literature). While the neural control of the oviduct musculature has received much attention, little is known of the effect of the nervous system on the rate of formation or composition of oviduct fluid. Bishop (1956) reported that pilocarpine injections increased both the rate of oviduct fluid secretion and secretory pressure. He concluded from his experiments that pilocarpine stimulated fluid production by way of the cholinergic innervation of the oviduct. He further concluded that pilocarpine caused the release of secretory materials from the oviduct epithelium since oviduct fluid after pilocarpine was cloudy and contained cellular d\l=e'\bris. The aim of this experiment was to determine whether the rate of oviduct fluid production could be altered by injections of pharmacological agents known to affect the sympathetic and parasympathetic nervous system. Eight adult, New Zealand rabbits (about 3 kg) were prepared for continuous collection of oviduct secretions by the method described by Clewe & Mastroianni (1960). The collection device was slightly modified by encasing the glass collecting coil in an aluminium cassette provided with a removable cover. Approximately 1 1/2weeks was allowed between surgery and the beginning of the study. During this time, oviduct fluid was withdrawn from the collection device each morning and evening and the volume of secretion recorded. The experimental period for each drug was 5 days. Each day during the 5-day experimental period, four observations on secretion rate were made at 2-hr intervals. The drug to be studied was given only on the 3rd day, 2 days being allowed between experimental periods. The drugs used (in the order of their use) were scopolamine, pilocarpine and phenoxybenzamine. All drugs were dissolved in 0-9% sterile sodium chloride solution immediately before use and injected subcutaneously. Scopolamine (100 mg/ml) was administered at the rate of 120 mg per animal every 2 hr to give a total dose of 480 mg. One injection of pilocarpine (1-0 mg in 1-0 ml

Effects of Stage of the Estrous Cycle and Exogenous Hormones upon the Volume and Composition of Oviduct Fluid in Ewes

Protein, lactic acid and alkaline phosphatase activity were determined in oviduct fluid collected from ewes during various periods of natural and synchronized estrous cycles. Average values were: protein, 3.02 gm./100 ml.; lactic acid, 44.13 mg./100 ml. and alkaline phosphatase, 32.88 units of activity/ml, per hour. The progesterone-PMS treatment used to regulate estrus had no significant effect upon these constituents. Protein and lactic acid did not change significantly during the estrous cycle, but alkaline phosphatase activity was higher (P<.01) during estrus than during other periods of the cycle. A significant (P<.05) period-by-treatment interaction was obtained with protein. Only traces of reducing sugars, ranging from 0.0 to 1.03 mg./100 ml., were found in oviduct fluid, and concentration did not vary with hormone treatment or stage of estrous cycle. Oviduct fluid contained cellular debris, leucocytes and unidentified particles which ranged from 0.2 to 0.5 µ in diameter. Bacterial growth was not obtained when agar plates and broth cultures were inoculated with oviduct fluid. The presence of a cannula in the oviduct did not affect ovarian activity or length of estrous cycle. Observations on the volume of fluid secreted by the oviduct showed that the period of maximum secretion occurred on the first or second day after the onset of natural estrus, but was delayed until the third day when estrus was regulated with progesterone-PMS.