Journal of Reproduction and Development
Online ISSN : 1348-4400
Print ISSN : 0916-8818
ISSN-L : 0916-8818
Volume 43, Issue 3
August
Displaying 1-12 of 12 articles from this issue
Original Articles
  • Qing-Yuan SUN, Hui LIU, Da-Yuan CHEN
    1997 Volume 43 Issue 3 Pages 189-197
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The effect of protein kinase inhibitors on the activation events of mouse eggs at different ages and the dependence on Ca2+ were studied. Inhibition of protein kinase(s) by staurosporine with concentration over 2 μM first induced the destruction of meiotic spindle and then the nuclear formation in metaphase II eggs, but did not stimulate the cortical granule exocytosis; staurosporine with concentration below 0.2 μM and protein kinase C inhibitor sphingosine at concentrations of 10-100 μM did not activate mouse eggs. The activation of mouse eggs by staurosporine was egg age-dependent, but calcium-independent. The number of nucleoli in the formed nucleus or naked nucleoli in the ooplasm was dose- and egg age-dependent. To further evaluate the nuclear and cytoplasmic activation by staurosporine, interphase eggs were processed for electron microscopy and it was found that most nucleoli were highly condenced like those in the pronucleus, but vacuolated or ring-shaped ones also appeared, which implied the activation of egg genome. In addition, staurosporine also induced the formation of Golgi complexes around the nucleus. The nuclear formation induced by staurosporine was completely overcome by okadaic acid. These results suggest that inhibition of staurosporine-sensitive protein kinase(s) other than protein kinase A and C is responsible for the transition from metaphase to interphase in an egg age-dependent but calcium-independent manner in mouse eggs.
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  • Hiroshi NAGASAWA, Hiroyuki INOUE, Mitsutaka YASUDA, Kazutoshi YAMAMOTO
    1997 Volume 43 Issue 3 Pages 199-204
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The effects of coffee cherry (CC), the residue left after the removal of coffee beans from the fruit, on the lactation of SHN mice were examined. Free access to drinking water with 0.01 % and 0.025 % solutions of the water extract of CC between days 1 and 12 of lactation improved the pup growth rate used as an index of lactational performance. The treatments affected little any of mother weight, mammary gland contents of DNA, RNA and lactose, serum levels of prolactin, growth hormone and non-esterified free fatty acid and major endocrine organ weights. The period of time spent by the mother mice in the nest was significantly elongated in the experimental mice given CC compared to the control. The results strongly suggest that CC can stimulate the growth of pups through its improvement of the nesting behavior of mother mice.
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  • Yoko KATO, Miho TANIMURA, Yukio TSUNODA
    1997 Volume 43 Issue 3 Pages 205-211
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    Glucose phosphate isomerase (GPI)-1AA and GPI-1BB homozygotes were produced by natural mating of CD-1 strain mice and the several reproductive characteristics of both homozygotes were compared. The pregnancy rate, period required for copulation and litter size were essentially the same. The developmental ability of GPI-1AA zygotes and 2-cell embryos in vitro was significantly lower than that of GPI-1BB (60 vs 75% and 75 vs 98%, respectively). After preservation at 4C for 24 h, the proportion of the GPI-1AA-2-cell embryos developed to blastocysts was significantly low (28 vs 57%). After transfer of GPI-1AA embryos to recipient mice, the developmental potential into fetus was similar or significantly superior to that of GPI-1BB (19 vs 24% and 47 vs 14%, respectively). When both embryos were aggregated at the 8-16-cell stage and transferred to recipients, 76% of the young (13/17) was chimeras and both isozymes types were observed in most tissues analyzed. In conclusion, both GPI-1AA and GPI-1BB embryos of the CD-1 strain mice were equally useful for researches in developmental biology and biotechnology, their features being basically the same.
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  • Shigeo TAKAMORI, Kunio SHIOTA, Tomoya OGAWA
    1997 Volume 43 Issue 3 Pages 213-219
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    Hormone-secreting cells in the anterior pituitary (AP) gland can be categorized into two groups with respect to spontaneous release. One line of evidence has suggested relatively high spontaneous release of GH and PRL compared to other hormones. We previously reported that brief pretreatment of AP cells with trypsin severely decreased the spontaneous release of GH and PRL, but increased that of ACTH and TSH, and had no apparent effect on that of LH and FSH. The cell-type specific alteration of spontaneous release indicates involvement of trypsin-sensitive-membrane-proteins (TSMPs) in the mechanism of hormone release in the AP gland. In this study, we examined secretagogue- and high-K+ stimulated release of AP hormones from trypsin-pretreated cells by using a superfusion system. TRH and high K+ did not provoke increased PRL release. Each of the secretagogues and high K+ caused a corresponding elevation of other hormones, i.e., TSH, ACTH, LH, and FSH, suggesting that the TRH receptor and voltage-sensitive Ca2+ channel remained functional. In addition, GRF and high K+ did not result in a corresponding increase in GH release. We concluded that the GH/PRL cell lineage has distinct secretory mechanisms including TSMPs.
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  • Kiyoshi YAMAUCHI, Shinichiro HAMASAKI, Yukari TAKEUCHI, Yuji MORI
    1997 Volume 43 Issue 3 Pages 221-226
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The annual profiles of gonadal steroid hormone secretion in male and female sika deer (Cervus nippon) were examined by means of fecal steroid analysis as a non-invasive method for monitoring the reproductive status. Fecal samples were collected weekly from three female and one male captive deer throughout a year, with more frequent sampling at 1-2 days intervals in the female deer during the breeding season. Fecal samples were dried thoroughly and extracted with diethyl-ether. Progesterone and testosterone concentrations were measured by radioimmunoassays, and expressed as ng per g of dried feces. At the time of each fecal sampling, we observed the reproductive behavior to examine its relevance to the endcrine profile. Fecal progesterone concentrations of female deer represented cyclic changes of 12-13 days intervals during the breeding season which extended from October to January, and the estrous behavior was consistently observed at the nadir of fecal progesterone concentrations. One hind got pregnant following the mating and its fecal progesterone showed a gradual increase to the level which were several times higher as compared with those in the other two non-pregnant hinds. In the buck, on the other hand, there was a clear annual change of fecal testosterone with the peak preceding the onset of ovarian cyclicity in the females. From these results, it is suggested that the reproductive endocrine status of sika deer can be successfully monitored by means of fecal steroid analysis without disturbing the focused animals.
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  • Sang-Yoon NAM, Hwa-Young YOUN, Kenji OGAWA, Masamichi KUROHMARU, Yoshi ...
    1997 Volume 43 Issue 3 Pages 227-234
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    Mitochondrial capsule selenoprotein (MCS) has been known as a structural protein of the mitochondrial sheath in spermatozoa. In this study, to investigate whether or not the expression of MCS mRNA in testes is affected by aging or selenium (Se) deficiency, the cDNA clone of MCS was isolated from the testes of 8-week-old ICR mice by reverse transcription-polymerase chain reaction. The nucleic acid sequence analysis confirmed that the cloned cDNA is an open reading frame of the MCS and contains 3 in-phase TGA codons that recognize specifically the selenocysteine in selenoprotein. According to Northern blot analysis, the MCS mRNA in testes greatly increased at 8 weeks old and then began to increase with aging. As compared with that of 8-week-old mice, the signal increased about 2.4-fold in the testes of 80-week-old mice. On the other hand, we generated Se-deficient and Se-sufficient mice by feeding weanling male mice (3 weeks old) with either a Se-deficient or a Se-sufficient diet for 11 weeks. MCS mRNA decreased about 21-fold in the testes of Se-deficient animals as compared with that of Se-sufficient animals. The present study provides a novel evidence that MCS mRNA level in testes increases with aging, but remarkably decreases due to Se deficiency.
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  • Maki MORITA, Hajime MIYAMOTO, Miki SUGIMOTO, Nami SUGIMOTO, Noboru MAN ...
    1997 Volume 43 Issue 3 Pages 235-241
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    We examined cell proliferation and morphological changes in the ampullar epithelium of mouse oviducts. Oviducts were labeled in vivo by administration of 5-bromo-2'-deoxyuridine (BrdU) on each day of the estrous cycle. The frequency of the ampullar S-phase epithelial cells labeled with BrdU changed according to the estrous cycle, with the highest proportion at proestrus. The morphology of the ampullar epithelia also changed during the estrous cycle. In estrus and metestrus, most of the ampullar epithelial cells were comprised of non-ciliated secretory cells. In diestrus and proestrus, however, the ciliated cells were dominant among the ampullar epithelial cells. Electron microscopic observations indicated that the ampullar non-ciliated secretory cells in metestrus had numerous secretory granules, and fusion of these granules with the plasma membrane, i.e. exocytosis, was evident. The present results indicate that cell proliferation and morphology of ampullar epithelia of mouse oviducts vary according to phase of the estrous cycle.
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  • Hisashi KISHI, Masahiro KONDO, Koji ARAI, Gen WATANABE, Kazuyoshi TAYA
    1997 Volume 43 Issue 3 Pages 243-250
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    Roles of ovarian inhibin and steroids in the regulation of basal secretion of follicle stimulating hormone (FSH) and luteinizing hormone (LH) were examined during pseudopregnancy in the rat. Bilateral or unilateral ovariectomy performed on either day 5 or 10 of pseudopregnancy (day 0; the day after copulation with a vasectomized male) produced a significant increase in plasma FSH concentrations within 6 h. During the subsequent 18 h, plasma FSH concentrations in unilaterally ovariectomized rats declined to a baseline level, and the gonadotropin concentrations in bilaterally ovariectomized rats remained significantly elevated above the value measured in sham-operated (control) animals. Plasma LH concentrations on either day 5 or 10 were not significantly altered by bilateral or unilateral ovariectomy. Plasma inhibin concentrations on both days 5 and 10 declined to an undetectable level within 6 h after bilateral ovariectomy. In unilateral ovariectomized rats, compared to control animals, a significant decrease in plasma inhibin concentrations was evident at 6 and 12 h, but not at 24 h, after the operation on both days 5 and 10. On day 5, administration of charcoal-treated porcine follicular fluid (an inhibin preparation) eliminated the increase in plasma FSH concentrations produced by bilateral ovariectomy within 24 h without affecting plasma LH concentrations. Plasma FSH and LH concentrations in rats bilaterally ovariectomized on day 5 were not significantly altered by administration of estradiol or progesterone alone, whereas both gonadotropin concentrations in these animals were slightly but significantly suppressed as late as 24 h after combined administration of estradiol and progesterone. In addition, in intact pseudopregnant rats, administration of antiserum against inhibin resulted in a marked increase in plasma FSH concentrations accompanied by a small but significant increase in plasma LH on day 5. These results collectively suggest that ovarian inhibin is a major regulator of FSH secretion during pseudopregnancy in the rat.
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Research Notes
  • Sueo NIIMURA, Takae ASAMI
    1997 Volume 43 Issue 3 Pages 251-256
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The activities of hydroxysteroid dehydrogenases (HSDs) and adenylate cyclase in parthenogenetic mouse blastocysts derived from the ova activated and diploidized by the treatment of ethanol and cytochalasin B were histochemically examined, and were compared with those in control blastocysts developed from fertilized ova. Although the activities of Δ5-3β-HSD with DHA and 17α-hydroxypregnenolone as the substrates, 17β-HSD with testosterone, 20α-HSD and 20β-HSD did not differ between parthenogenetic and control blastocysts, the activities of Δ5-3β-HSD with pregnenolone as the substrate, 17β-HSD with estradiol-17β and adenylate cyclase were significantly lower in parthenogenetic blastocysts. These results suggest that the metabolism of 17α-hydroxyprogesterone, 20α-hydroxyprogesterone, 20β-hydroxyprogesterone and androgen in parthenogenetic blastocysts is comparable to that in control blastocysts, whereas the metabolism of progesterone, estrogen and cyclic AMP in parthenogenetic blastocysts is low compared with that in control blastocysts. When parthenogenetic blastocysts were treated with hCG, the activities of Δ5-3β-HSD with pregnenolone as the substrate and 17β-HSD with estradiol-17β were stimulated, but were still lower than those of control blastocysts. The low potential of development in parthenogenetic embryos was discussed in relation to their steroid metabolism.
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  • Kazufumi GOTO, Michihiro TANAKA, Shoji OOKUTSU, Yoshihiko NAKANISHI
    1997 Volume 43 Issue 3 Pages 257-260
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    Intracytoplasmic injection of a donor cell into an enucleated bovine oocyte was used to determine the in vitro and in vivo developmental capability of bovine cells derived from late morula-stage embryos. A single cell from late morula-stage embryos was directly injected into an enucleated activated oocyte cytoplasm. Development rates of nuclear transfer embryos to the 2- to 8-cell, morula, and blastocyst stages were 43.3 (13/30), 16.7 (5/30) and 6.7% (2/30) respectively. The viability of the nuclear transfer embryos was confirmed by the birth of a normal calf after transferring them into a recipient cow. The results indicated that the direct injection of a single cell into an enucleated activated oocyte may be an alternative to the oocyte-cell fusion method currently used for bovine nuclear transfer.
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  • Katsuhiro OHKOSHI, Masaki HATA, Yoko KATO, Yukio TSUNODA
    1997 Volume 43 Issue 3 Pages 261-265
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The effect of the age of a donor embryo on the developmental ability of bovine nuclear transferred eggs was examined. A blastomere of an in vitro fertilized embryo cultured for 3.5 to 6.5 days, or an inner cell mass cell (ICM) from a blastocyst cultured for 7.5 days was fused with an enucleated, preactivated oocyte matured in vitro by electrical stimulation. Fused eggs were co-cultured with cumulus cells for 10 days in vitro. The fusion rate of blastomeres from day 3.5 to 6.5 embryos with enucleated oocytes (78 to 88%) and the developmental ability of nuclear transferred eggs to blastocysts (6 to 10%) were not significantly affected by the age of the donor embryo. However, the fusion rate of the ICM cell was significantly low (28%). Although nuclear transferred eggs receiving an ICM cell developed to 2-cell (73%) and 8-cell (22%) stages at the same rates as those obtained in other groups (68 to 81% for 2-cell, 30 to 34% for 8-cell), none of them developed to blastocysts.
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  • Keitaro YAMANOUCHI, Akihiro IKEDA, Shigemi MATSUYAMA, Telhisa HASEGAWA ...
    1997 Volume 43 Issue 3 Pages 267-270
    Published: 1997
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The expression of inhibin α-subunit mRNA was examined in the corpus luteum (CL) of pregnant mares. Corpora lutea were obtained from pregnant mares at 50 h, 94 h after ovulation and on 30, 60, and 90 days of pregnancy. Northern blot analysis, using a cDNA specific to equine inhibin α-subunit as a probe revealed that the expression level of its transcript continued to decline until 30 days after ovulation. However, on day 60 of pregnancy, the level increased similar to that at 94 h after ovulation. On day 90 of pregnancy, the level declined again. The expression of inhibin α-subunit mRNA in the estrous cycle CL (7 days after ovulation) was also examined but the level was moderately low. Considering that serum concentration of equine chorionic gonadotropin (eCG) peaks at around day 60 of pregnancy, and the expression level of inhibin α-subunit in the CL of the pregnant mare also shows a peak on day 60 of pregnancy, it was suggested that, during pregnancy in equidae, the expression of inhibin α-subunit mRNA in the CL is stimulated by eCG.
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