Journal of Reproduction and Development
Online ISSN : 1348-4400
Print ISSN : 0916-8818
ISSN-L : 0916-8818
Volume 47, Issue 2
April
Displaying 1-8 of 8 articles from this issue
Review
  • Hirohito YAMAGUCHI, Kentaro NAGAOKA, Fuko MATSUDA, Ningchun XU, Ronald ...
    Article type: scientific monograph
    Subject area: none
    2001 Volume 47 Issue 2 Pages 69-82
    Published: 2001
    Released on J-STAGE: May 03, 2001
    JOURNAL FREE ACCESS
    In order for pregnancy to be established, the maternal system must recognize the presence of a conceptus(es) within the uterus. This physiological phenomenon, which subsequently causes the extension of the corpus luteum (CL) life-span, is known as maternal recognition of pregnancy. In ruminant ungulates, interferon-tau (IFNτ), produced by the conceptus, binds to the receptor located in the maternal endometrium in a paracrine manner. Its binding then affects levels of endometrial oxytocin receptor and estrogen receptor, which reduces pulsatile secretion of a luteolysin, prostaglandin F2α, resulting in the extension of CL function. Production of IFNτ seems to parallel the degree of trophoblast elongation and as the conceptus begins its attachment to the endometrium, IFNτ levels decline rapidly. Involvement of IFNτ in the process of implantation has long been suspected, but a role for IFNτ other than CL extension or transcriptional regulation of IFNτ genes has not been elucidated. In fact, several transcription factors that regulate the expression of IFNτ have been found, but none could explain its unique regulation. Recent findings related to maternal recognition of pregnancy are presented herein and a new insight into the potential regulation of IFNτ is discussed.
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Original Article
  • Hidehiko OGAWA, Masashi TAKAHASHI, Hitomi TAKAHASHI, Akira OKANO
    Article type: technical report
    Subject area: none
    2001 Volume 47 Issue 2 Pages 83-89
    Published: 2001
    Released on J-STAGE: May 03, 2001
    JOURNAL FREE ACCESS
    Postpartal changes of the endometrium in primiparous Meishan pigs during the process of uterine involution were examined by morphological and immunohistological methods. Reproductive organs were collected from lactating sows (Days 1, 13, 20 and 31 after parturition) and a weaned sow (weaned on Day 28 and sacrificed on Day 31 after parturition). Cryosectioned uterine tissues were stained with Mayer's hematoxylin and eosin for histological observations. To observe membranous extracellular matrix localization, samples were treated with antibodies against laminin and type IV collagen. The diameter of the uterine horn decreased dramatically by Day 13 and slightly decreased during Days 13 to 31 after parturition. Luminal and glandular epithelial cells were low and cuboidal during lactation but became highly columnar just after weaning. During lactation, laminin and type IV collagen were localized in a winding pattern in the basal lamina of the endometrial epithelium. After weaning, they were found in the basal lamina of the endometrial epithelium in a stratum. These results suggest that uterine involution is completed just after weaning.
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  • Christopher BISHONGA, Yoshiyuki TAKAHASHI, Seiji KATAGIRI, Masashi NAG ...
    Article type: technical report
    Subject area: none
    2001 Volume 47 Issue 2 Pages 91-96
    Published: 2001
    Released on J-STAGE: May 03, 2001
    JOURNAL FREE ACCESS
    This study determined the immunolocalization of transforming growth factor-β1 (TGF-β1) in the ovarian follicles of the adult mouse at diestrus, proestrus and estrus (10 and 12.5 h after treatment with hCG). The majority (≥72%) of the oocytes were stained positive in type 3b through to type 8 follicles. TGF-β1 staining in the granulosa and theca cells was first observed in type 5b follicles. The percentage of follicles with positively stained granulosa cells increased with follicular development from type 6 to 8 (13 to 82%). The percentage of follicles with positively stained theca cells did not show a clear trend (~30%) up to 10 h after hCG treatment, but increased in type 7 (79%) and unovulated type 8 (55%) follicles during the ovulation period (12.5 h after hCG). These results indicate that TGF-β1 is involved in follicular development and differentiation.
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  • Jun You LI, Kazumi SINOZAKI, Kazuhiko IMAKAWA, Masugi NISHIHARA, Toru ...
    Article type: technical report
    Subject area: none
    2001 Volume 47 Issue 2 Pages 97-103
    Published: 2001
    Released on J-STAGE: May 03, 2001
    JOURNAL FREE ACCESS
    Follicular growth of ruminant species occurs more than once during an estrous cycle either resulting in ovulation (ovulatory follicular wave) or not resulting in ovulation (latent follicular wave). Using Shiba-goats, we examined if ovulation could be induced from every latent follicular wave and if the resulting ova were fertile. Ovarian follicular development was monitored daily by transrectal ultrasonographic examination in 20 female goats for 2 consecutive estrous cycles. After the second spontaneous ovulation (day 0 = ovulation), all animals were each treated with a luteolytic dose of prostaglandin F2α (PGF 2α) on days 3 and 4,which resulted in ovulation from the first latent wave. Fertile males goats (n=2) were immediately introduced to the first group of animals (n=5), resulting in 4 pregnancies. For the second group of goats (n=9), 4 consecutive short estrous cycles were induced by the PGF2 α treatment at a mean interval of 6.5 ± 1.2 days with a range of 4-9 days. Five of 9 goats were allowed to mate following 4 consecutive short ovulatory cycles; normal behavioral estrus was observed at each estrus, and four of five animals became pregnant. The third group of goats (n=6), in addition to PGF2α treatment, received exogenous progesterone supplement which allowed latent follicular development to occur, but prevented ovulation until the effect of progesterone supplement subsided. These results suggest that female Shiba-goats possess physiological mechanisms for the final steps of follicular maturation and subsequent ovulation at short intervals when progesterone production from the newly developed corpus luteum is terminated.
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Research Note
  • Masahiro TAKAHASHI, Atsushi UEKI, Kyoko KAWAHATA, Taichi GOTO
    Article type: Introduction
    Subject area: none
    2001 Volume 47 Issue 2 Pages 105-108
    Published: 2001
    Released on J-STAGE: May 03, 2001
    JOURNAL FREE ACCESS
    The widths of metacarpus and metatarsus of 187 Holstein calves immediately after birth were measured to estimate the birth weight and the dystocia of Holstein calves to the term pregnancy, and the relationships between the widths and the birth weight or dystocia were investigated. A positive correlation was recognized in the width of metacarpus and the birth weight of Holstein calves. In the width of metatarsus, a positive correlation was also recognized. The greater the width of metacarpus or metatarsus was, the greater the dystocia rate was increased. Therefore, our results indicate that birth weight and dystocia are able to be estimated by the measurement of the width of metacarpus or metatarsus.
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  • Tetsuma MURASE, Koji MUKOHJIMA, Shin-ichi SAKAGUCHI, Tsuyoshi OHTANI, ...
    Article type: Introduction
    Subject area: none
    2001 Volume 47 Issue 2 Pages 109-112
    Published: 2001
    Released on J-STAGE: May 03, 2001
    JOURNAL FREE ACCESS
    This study examined differences in the penetration of various batches of mixed cervical mucus by bull spermatozoa. Mucus was collected from different numbers (2, 2, 3, 4 or 7) of cows or heifers in estrus and a part of the sample was individually, and the rest was mixed, and stored frozen. The distance traveled by the most advanced sperm cell in frozen-thawed mucus during incubation at 38 C for 10 min was measured (sperm penetration). Variation of sperm penetration in the individual mucus samples was reduced by mixing but the difference among the batches of mixed mucus was significant (p<0.0002). Nevertheless, the number of animals from which mucus was collected and mixed did not seem to influence the sperm penetration of the different batches. Unexpectedly it was observed that some individual and mixed mucus samples had reduced viscosity after freezing and thawing and sperm penetration in the mixed mucus samples showed a significant, negative correlation with the proportion of mucus of reduced viscosity contained in the batch (r=-0.969, p<0.01). These results suggest that the difference in the sperm penetration of mixed mucus may probably be rather independent of the number of mucus donors.
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Technical Note
  • Masayuki KOBAYASHI, Haruka SASAKI, Kyoko OGASAWARA
    Article type: Technical Note
    Subject area: none
    2001 Volume 47 Issue 2 Pages 113-118
    Published: 2001
    Released on J-STAGE: May 03, 2001
    JOURNAL FREE ACCESS
    Alamar Blue, an oxidation-reduction indicator, added to a culture medium is reduced in living cells as an intermediate electron acceptor in the mitochondrial electron transport system, so that the absorbance of alamar Blue at a specific wavelength changes with the progression of cell growth or the number of living cells. In order to rapidly and quantitatively evaluate the development of preimplantation mouse embryos cultured in vitro, a colorimetric assay with alamar Blue was applied. Two-cell embryos, obtained from CD-1 mice, were cultured in 4-well dishes with 1 ml of Whitten's medium containing 3 mg/ml of bovine serum albumin, and then transferred to 96-well plates (5, 10 or 20 embryos/well) with 100 μl of Whitten's medium containing alamar Blue (10%, v/v) and 3 mg/ml of bovine serum albumin. First, the effect of alamar Blue on the development of mouse embryos was examined. Although alamar Blue strongly inhibited the subsequent preimplantation development of the late 2-cell embryos, it had no significant effect on that of the 4- to 8-cell embryos. Changes in the absorbance of alamar Blue, with the progression of embryonic development and the number of embryos per well, were then monitored at 24-h intervals by measuring the absorbance using a microtiter plate reader. When the development of the 4- to 8-cell embryos was evaluated by the alamar Blue assay, the method required only 5-20 embryos per well of a 96-well plate and allowed daily monitoring of the proliferation for a period of 72 h, without compromising the sterility of the cultures. The absorbance of alamar Blue changed with the progression of embryonic development and correlated with the number of embryos per well. The stimulatory effect of EDTA on the development of zygotes obtained from CD-1 (5 or 10 embryos/well) was also determined by this method. The results indicate that the assay is useful for quantifying the development of mouse embryos cultured in vitro.
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  • Toru TAKAHASHI, Sanae HAMANAKA, Shoshichi IKEDA, Jin Kobayashi, Kazuyo ...
    Article type: Technical Note
    Subject area: none
    2001 Volume 47 Issue 2 Pages 119-123
    Published: 2001
    Released on J-STAGE: May 03, 2001
    JOURNAL FREE ACCESS
    A direct time-resolved fluorescent immunoassay (TR-FIA) system was developed and evaluated for measuring progesterone (P) concentrations in deer plasma. The minimum detectable level of this assay system was 0.25 ng/ml and ED 50 value of standard curve was 2.4 ng/ml. Intra- and inter-assay coefficients of variation were 8.8% and 15.7%, respectively. The direct TR-FIA revealed that the plasma P concentrations in sika deer expressed a diurnal pattern depending on their reproductive status. Results in the present study indicate that the TR-FIA system, that is specifically designed for humans if successfully utilized with slight modification, can be utilized for direct assaying of P in deer plasma. The plasma P profile in the sika deer appears to be consistent to that of other temperate deer expressing seasonal breeding characteristics.
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