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Results of experimental Cesarean sections in the cat at different stages of gravidity were compared with the recommendations given in the literature. 相似文献
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Rátky J Brüssow KP Egerszegi I Torner H Schneider F Solti L Manabe N 《The Journal of reproduction and development》2005,51(4):427-432
Only a very small amount of physiological data is available about the low fertility (mean litter size is 5.7+/-0.8) of Hungarian native breed, Mangalica (M), sows. The aim of the present paper is to reveal the differences in preovulatory follicle development and intrafollicular oocyte maturation between M and Landrace (L) gilts, with special reference to the peri- and postovulatory secretion and peripheral concentrations of estradiol-17beta (E2), progesterone (P4), and luteinizing hormone (LH). The number of preovulatory follicles was 6.8+/-1.4 and 19.6+/-6.6 in M and L gilts, respectively. A lower degree of cumulus expansion and a lower percentage of mature oocytes (TI/M II) was noted in M. Higher LH and E2 peak levels, a longer E2 to LH peak interval, and lower embryo survival was confirmed. Interestingly, despite the lower number of corpora lutea, a higher peripheral blood level of P4 was shown in M than in L gilts. Both diminished follicular development and protracted oocyte maturation may be involved in low fecundity in M, and the present findings may explain these reproductive phenomena. 相似文献
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Brüssow KP Schneider F Kanitz E Otten W Tuchscherer M 《The Journal of reproduction and development》2005,51(1):133-142
Prenatal stress has been seen as a reason for reproductive failures in pig offspring mostly originated or mediated by changed maternal functions. Experiments were conducted in pregnant gilts (n=32) to characterize effects of elevated maternal glucocorticoids on the secretion of reproductive hormones (LH, progesterone) during the 1st (EXP 1), 2nd (EXP 2) and 3rd (EXP 3) trimester of pregnancy (TP). Transiently elevated cortisol release was repeatedly achieved by application of 100 IU adenocorticotropic hormone (ACTH) (Synacthen Depot) six times every second day beginning either on day 28 (EXP 1), day 49 (EXP 2) or day 75 of pregnancy (EXP 3). Glucocorticoid concentrations were examined in umbilical blood vessels of fetuses which mothers were subjected to ACTH at 2nd and 3rd TP (EXP 4). Furthermore, the pituitary function of newborn piglets of EXP 2 was checked by a LH-RH challenge test. In sows, LH concentrations were at low basal level (0.1-0.2 ng/ml) but with pulsatory release pattern during each TP. The number of LH pulses/6 h (LSM +/- SE) of saline treated Controls increased with ongoing pregnancy and decreased to the 3rd TP (1.3 +/- 0.2 in EXP 1 vs. 2.0 +/- 0.1 in EXP 2 vs. 1.4 +/- 0.1 in EXP 3, p<0.05). After ACTH treatment the number of LH pulses left unchanged in Experiments 1 and 2 (1.3 +/- 0.2 and 1.5 +/- 0.1) and decreased in EXP 3 (0.8 +/- 0.2, p<0.05). Differences (p<0.05) were obtained comparing the LH pulse number of ACTH and saline treated sows at the 2nd and 3rd TP. Moreover, areas under the curve (AUC) of each LH pulse and of LH over baseline were significantly reduced by treatment. Levels of progesterone increased (p<0.05) for 150 to 170 min after each ACTH application both in EXP 1 and EXP 2, but not in EXP 3. The mean progesterone concentration was different between trimesters, and ACTH and Controls (1st TP: 30.0 +/- 0.9 and 24.4 +/- 0.7 ng/ml; 2nd TP: 35.5 +/- 0.9 and 29.1 +/- 1.0 ng/ml; 3rd TP: 13.6 +/- 0.2 and 13.1 +/- 0.1 ng/ml; p<0.05). In fetuses (n=87) recovered 3 h after ACTH or saline (EXP 4), the plasma cortisol concentrations were significantly increased in umbilical vein (93.7 +/- 5.5 vs. 47.0 +/- 5.3 nmol/l) and artery (95.7 +/- 5.4 vs. 66.4 +/- 5.4 nmol/l), and in periphery (46.8 +/- 5.3 vs. 27.1 +/- 5.3 nmol/l) compared to controls. Plasma ACTH concentrations, however, did not differ in fetuses of both treatment groups. Postnatal LH-RH challenge tests (1st and 28th day post partum) induced LH surges in female piglets (n=67) both of ACTH and saline treated sows, but did not differ between groups (1st day: 7.2 +/- 0.8 vs. 8.1 +/- 0.7 ng/ml; 28th day: 10.5 +/- 1.7 vs. 13.6 +/- 2.2 ng/ml). However, basal LH of piglets whose mothers were submitted to ACTH during 2nd TP was lower on 1st day (1.7 +/- 0.2 vs. 2.3 +/- 0.2 ng/ml, p<0.05) but not on 28th day (1.0 +/- 0.2 vs. 1.1 +/- 0.2 ng/ml). However in both groups, the basal LH was always higher on 1st as on 28th day (p<0.05). Thus, chronic intermittent ACTH administration is able to influence the release pattern of maternal reproductive hormones. However, these findings demonstrate that these effects are dependent on the stage of pregnancy. Furthermore, it was shown that maternal cortisol can cross the placenta during gestation and thus may affect maternal-fetal interactions and, as a result, reproductive function of offspring. 相似文献
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Brüssow KP Schneider F Tuchscherer A Egerszegi I Rátky J 《The Journal of reproduction and development》2008,54(6):431-438
The objective of this study was to evaluate luteinizing hormone (LH) and luteal progesterone (P4) secretion in systemic blood and blood near the ovaries in Mangalica (M) and Landrace (L) gilts by implanting catheters into the Vena jugularis and the Vena cava caudalis via the Vena saphena, respectively. Furthermore, leptin was analyzed in jugular vein blood. Blood was collected twice daily from day 7 to day 19 of the oestrous cycle and frequently (10-min intervals for 6 h) on day 9, day 12 and day 15 in M (n=3) and L gilts (n=4). L gilts had congruent pulsatile LH secretion in both veins, but the LH concentrations in M were always below the assay sensitivity during the luteal phase. In both breeds, episodic P4 secretion was found in the jugular and caval veins, and both sampling site and breed had an influence on P4 secretion (P<0.05). The mean concentration of P4 was higher (P<0.01) in utero-ovarian blood (75.8+/-5.3 in M; 49.6+/-4.2 ng/ml in L) than in the periphery (31.3+/-2.0 in M; 21.2+/-1.8 ng/ml in L). M pigs had a lower number of corpora lutea (9.7+/-2.3 vs. 20.5+/-4.4), and analysis of the P4 secretion ratio per corpus luteum revealed an influence of breed (P<0.01). This ratio was significantly higher in M (3.8+/-0.3 and 8.7+/-0.7 ng/ml) compared with the L gilts (1.4+/-0.1 and 2.8+/-0.3 ng/ml) in the jugular and caval veins, respectively. Blood sampling from the Vena cava caudalis is potentially more precise than from the Vena jugularis for evaluation of ovarian P4 secretion. Both the higher P4 concentration and increased leptin secretion (11.3+/-0.6 vs. 3.0+/-0.1 ng/ml, P<0.05) and consequently the altered LH secretion pattern in the Mangalica may contribute to the lower fecundity of this breed. 相似文献