Various Stages Of Estrous Cycle Research Articles

Differential Size Distribution and Estrogen Receptor Cargo of Oviductal Extracellular Vesicles at Various Stages of Estrous Cycle in Mice

Oviductal extracellular vesicles (OEVs) play an important role in fertilization and embryo development. However, it remains largely unknown whether the size and protein cargo of OEVs change during the estrous cycle in mice. This study analyzed the changes in the size distribution and protein cargo of OEVs at four stages of the estrous cycle in mice. The distribution widths of OEVs according to the estrous cycle stage were as follows: proestrus, 20–690 nm in diameter, with two peaks at 50 and 250 nm; estrus, 22–420 nm in diameter, with two peaks at 40 and 200 nm; metestrus, 30–70 nm diameter, with a single peak at 40 nm; and diestrus, 10–26 nm diameter, with a single peak at 20 nm. The estrogen receptor (ER) level in OEVs at the proestrus stage differed significantly from that at estrus (P = 0.013) and diestrus (P = 0.005). The levels of CD9 and Hsc70 fluctuated across the four stages, although with no significant differences. Furthermore, OEVs were observed among the cilia and microvilli of epithelial cells at the proestrus, estrus, and diestrus stages, but not at the metestrus stage. The number of observed OEVs was the highest at the proestrus stage, followed by the estrus, and the diestrus stage. Endosomes were also observed at the estrus and diestrus stages. The change of the OEV size and ER cargo is associated with the estrous cycle in mice. Our findings increase the understanding of the physiological characteristics of OEVs, which may have clinical applications.

Acoustic features of vocalization as a tool for estrus detection in Murrah buffaloes

Twelve Murrah buffaloes were selected from the institute herd and acoustic features like call duration, amplitude, total energy, mean pitch, mean intensity, formants (F1, F2, F3, F4, and F5), and N/H (Noise to Harmonic) ratio were analyzed. Call duration was significantly higher on day of estrus (1.52 ± 0.07 s) and proestrus (1.44 ± 0.07 s) than in metestrus (1.241 ± 0.04 s) and diestrus stages (0.981 ± 0.05 s). Total energy (0.121 ± 0.01 P2s), mean pitch (226.67 ± 14.11 Hz), maximum amplitude (0.959 ± 0.01 P), and mean intensity (85.05 ± 0.26 dB) was more (p < 0.05) in proestrus than in other stages. F1 (1131.94 ± 11.85 Hz) and F5 formants (6567.74 ± 12.62 Hz) were significantly higher (p < 0.05) during estrus, while F2 (2238.46 ± 26.53 Hz), F3 (3435.00 ± 19.33 Hz), and F4 formants (5127.71 ± 25.90 Hz) were higher (p < 0.05) in proestrus in comparison to other stages of estrous cycle. The identified acoustic features of voice in Murrah buffaloes were signficantly different in various stages of estrous cycle. These could be used as a tool for estrus detection management in buffaloes which have probems of silent estrus.

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Emerging evidence suggests that Bone Morphogenetic Proteins (BMPs), which belong to the Transforming Growth Factor-β (TGF-β) super-family, are known to be involved in the follicular growth and steroid production in different species. This study describes BMP6 bearing in corpus luteum over various stages of estrous cycle. The bubaline CL was classified into four stages according to the morphology and progesterone (P4) concentration. The real time PCR and immunoblot studies revealed that BMP6 was significantly (P<0.05) unregulated during the mid stage of CL that was consistent with immunohistochemical localization in the luteal cells. The transcriptional and translational expressions of BMP6 in the early and late CL were comparable and significantly (P<0.05) lower than that of mid CL. In conclusion, BMP6 expression is dependent on the stage of CL in the buffalo.

ALTERATIONS IN CONCENTRATIONS OF INHIBIN IN RELATION TO FSH AND STEROIDS HORMONE DURING ESTROUS CYCLE IN EGYPTIAN BUFFALOES

Seven Egyptian buffaloes were used to study the plasma changes of inhibin, FSH, estradiol-17b and progesterone concentrations during the at estrous cycle. These hormones were determined at estrous and two interval until day twenty two of estrous cycle. Plasma inhibin estimated by enzyme-linked immunoasorbent assay (ELISA). Both FSH, estradiol-17β and progesterone were estimated by radioimmunoassay (RIA). In order to elucidiate the feedback system controlling mentioned hormones during estrous cycle, variations in the levels of hormones and their inter-relationshpis were studied. Plasma inhibin levels ranged between 439.28 and 584 pg/ml during various stages of estrous cycle, peak of inhibin level was at day of estrous by an average of 584 pg/ml. Follicle stimulating hormone levels were higher at day of estrous (25.48 ng/ml), decreased and fluctuated towards end of estrous cycle and then increased at twenty two days of estrous cycle. Peak of estradiol-17β was 18.54 pg/ml at day of estrous, while the peak of progesterone was 4.39 ng/ml at twelfth day from the start of estrous. It could be concluded that each of inhibin and estradiol-17b seems to have a feedback regulatory effect on FSH secretion in buffaloes. Key words: Inhibin, FSH, estradiol-17b, progesterone, estrous cycle, buffalo.

Elimination of apoptotic granulosa cells by intact granulosa cells and macrophages in atretic mature follicles of the guinea pig ovary.

Phagocytic cells disposing of dying granulosa cells in the atretic ovarian follicles were morphologically studied in guinea pig ovaries at various stages of estrous cycle. Epon embedded semithin sections stained with toluidine blue were observed with a light microscope, and ultrathin sections were examined under a transmission electron microscope. Frozen sections were processed for acid phosphatase histochemistry and MR-1 (a monoclonal antibody against guinea pig macrophages) immunohistochemistry. In animals during the estrus period (days 1 and 2) as well as the second half of the estrous cycle (days 11 and 16), there were numerous mature follicles in which massive groups of granulosa cells were undergoing apoptosis. Two kinds of phagocytic cells were identified in these follicles of the initial stage of atresia: one was intact granulosa cells ingesting neighboring dead granulosa cells, and the other was large round cells identified as macrophages due to their strong acid phosphatase activity and MR-1 immunoreactivity. Mature follicles of the advanced stage of atresia were frequently recognized during the metestrus period (days 4 and 5). Small stellate cells were regarded as surviving granulosa cells, while large round cells showing intense reactions for acid phosphatase and MR-1 were identified as macrophages. This study demonstrates that both intact granulosa cells and macrophages participate in the elimination of apoptotic granulosa cells in atretic mature follicles of the guinea pig ovary, and remain even in the advanced stages of atresia.

Biochemical characterization and sex dimorphism of muscarinic receptors in rat adenohypophysis.

The ligand binding properties of muscarinic receptors present in rat adenohypophysis were studied using the tritiated antagonists N-methyl-4-piperidyl benzilate, 3-quinuclidinyl benzilate, and methylscopolamine. Equilibrium analysis of antagonists binding as well as competition experiments with several agonists were used to probe the nature of binding sites. The nature of antagonist binding in the adenohypophysis points to heterogeneity of binding sites, in contrast to other brain regions, in which homogeneous populations of muscarinic receptors were detected. Some of the binding properties, e.g. affinity constants, population of high affinity agonist binding sites, etc., clearly indicated differences between male and female rats as well as differences in female rats at various stages of estrous cycle. The nature of these receptors and their possible physiological role are discussed.

Conversion of progesterone to 5 alpha-pregnane-3,20-dione and 3 alpha-hydroxy-5 alpha-pregnan-20-one by rat medical basal hypothalami and the effects of estradiol and stage of estrous cycle on the conversion.

Tissue slices of rat medial basal hypothalami (MBH’s) from various stages of estrous cycle were incubated with 3H-progesterone. Regardless of the stage of the estrous cycle, most of the recovered tissue radioactivity was present in the 1000 × g pellet after subcellular fractionation. The radioactivity associated with the 1000 × g pelletafter subcellular fractionation. The radioactivity associated with the 1000 X g pellet was isolated and identified on the basis of reverse isotopic dilution techhniques by purification to a constant specific activity. With all incubations the 2 major metabolites identified were 5α-pregnane-3,20-dione and 3αhydroxy- 5α-pregnan-20-one. Other metabolites of progesterone, if any, appear to be present in very small amounts (2–3%). Although no qualitative changes in metabolism of progesterone were observed with respect to the stage of the estrous cycle, quantitative variations were evident. Higher accumulations of 3H-5αpregnane- 3,20-dione as compared to 3H-3α-hydroxy- 5α-pregnan...

LH Release by LH-Releasing Hormone in Golden Hamsters at Various Stages of Estrous Cycle

SummaryStimulation of LH release by administration of natural or synthetic luteinizing hormone-releasing hormone (LH-RH) was studied at different stages of the estrous cycle in the golden hamster. The animals were pretreated with phenobarbital to prevent a spontaneous preovulatory surge of LH. In these animals serum LH levels after saline injection remained low throughout the estrous cycle. Intravenous injection of 0.1 or 0.4 μg LH-RH significantly increased serum LH levels compared to appropriate controls. The greatest response to LH-RH was observed during proestrus. The smallest response was observed on the day 1 of diestrus, and in most of the animals, at estrus. The pituitary response to LH-RH on day 2 of diestrus was smaller than during proestrus, and greater than that observed during day 1 of diestrus and estrus. The results indicate that pituitary responsiveness to LH-RH varies at different stages of estrus cycle in the golden hamster.The authors are indebted to Drs. G. D. Niswender and H. Papkoff ...