The effect of dietary administration with essential unsaturated fatty acids, linoleic acid [18:2 (n-6)], a mixture of oleic acid [18:1 (n-9)], linoleic acid and γ-linolenic acid [18:3 (n-6)], or α-linolenic acid [18:3 (n-3)], on early embryo development of pubertal female pigs in summer was examined. Safflower oil was supplemented to a concentrated diet (the control diet) at the rate of 5% (Safflower oil-diet). The concentration of linoleic acid was 3.75 g/100 g in the Safflower oil-diet. Fatty acids-enriched mold dried cell was supplemented to the control diet at the rate of 20% (Mold dried cell-diet). The concentration of γ-linolenic acid was 5.32 g/100 g in the Mold dried cell-diet. Mold dried cell also contains oleic acid and linoleic acid at concentrations of 7.28 g/100 g and 2.98 g/100 g, respectively. Perilla oil was supplemented to the control diet at the rate of 7.5% (Perilla oil-diet). The concentration of α-linolenic acid was 4.125 g/100 g in the Perilla oil-diet. Each diet was given daily to five crossbred pubertal gilts for approximately 4 months. From at least 70 days after the start of the experimental diets, embryo collections were performed. The control embryos were obtained from the same breed, 10 pubertal gilts, given only the control diet. Embryos were collected on day 6 (day 1=the last day of estrus) and assessed morphologically. Embryo collection was repeated twice for each pig fed the diet supplemented with essential unsaturated fatty acids. The mean number of corpora lutea was greater in gilts given Mold dried cell-diet than in gilts given Safflower oil-diet (P<0.05) or Perilla oil-diet (P<0.01). The mean number of ova recovered in gilts given Mold dried cell-diet was also greater than that in gilts given the control diet (P<0.05), Safflower oil-diet (P<0.05) or Perilla oil-diet (P<0.01). Furthermore, both the mean number and the proportion of embryos showing normal morphology in gilts given Mold dried cell-diet were significantly higher than in gilts given the control diet, Safflower oil-diet or Perilla oil-diet. These results indicate that the unsaturated fatty acids-enriched mold dried cell may be beneficial for improving ovulation rate and embryo quality.

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Mechanisms responsible for a daily increase in plasma gonadotropins during lactation of golden hamsters (Mesocricetus auratus) were investigated. A daily afternoon (1700 h) increase in plasma luteinizing hormone (LH), follicle-stimulating hormone (FSH) and progesterone was observed until at least day 15 of lactation (day 0 of lactation = day of parturition). On the other hand, plasma estradiol did not show any significant change at 1100, 1700 and 2300 h. Such increases occur in hamsters nursing 8 pups. In hamsters nursing 2 pups, however, only a daily increase in LH was noted on day 5 of lactation and the diurnal rhythm of LH was difficult to see because of the increase in basal levels of LH on day 10 and 15 of lactation. The diurnal increases in plasma LH and FSH disappeared within 2 days after removal of the litter on day 10 of lactation and by day 14 of lactation (4 days after litter removal) most animals had resumed ovulating. Ovariectomy on day 2 of lactation did not affect the profile of plasma LH on subsequent days. In contrast, the basal levels of plasma FSH increased, suggesting the absence of an inhibitory ovarian signal (probably inhibin). A negative relationship existed between plasma estradiol and the daily surges of LH and FSH at 1700 h; the daily rise in gonadotropins occurred when plasma levels of estradiol were low. The afternoon increases in plasma LH and FSH were prevented by treatment with physiological levels of estradiol, comparable to those observed in the cyclic hamster. Antiserum against LHRH injected at 1100 h on day 10 of lactation completely suppressed the daily rise of plasma LH and FSH. These results indicate that during lactation low levels of estradiol are required for the expression of diurnal increase in plasma LH and FSH in the hamster. Moreover, the low levels of estradiol results in the daily release of LHRH.

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We evaluated the influence of the administration of a synthesized heterocyclic pyrimidine compound, 2-piperadino-6-methyl-5-oxo-5, 6-dihydro(7H) pyrrolo-[3, 4-d] pyrimidine (MS-818), which has promoting activity of basic fibroblast growth factor(bFGF)-induced angiogenesis, on the number of ovulations in mice (Jcl:ICR strain) superovulated with pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG). When injected with PMSG and hCG, ovulation failed to be induced in 13.5% of mice, but all of those injected with MS-818 in addition to PMSG and hCG, responded to the stimulation and superovulated. There was also a significant increase in superovulatory response in the mice injected with MS-818 compared with those injected with saline. The mean actual number of ovulations for mice injected with 0 (saline) or 50 μg of MS-818 for 3 days was 13.1 ± 2.1 and 26.9 ± 4.2, respectively, indicating that MS-818 affected the actual number of ovulations. Subcutaneous injection of MS-818 resulted in more actual ovulations than intraperitoneal injection. There was no difference between the control (saline) and MS-818-injected groups in the proportion of ova fertilizing and cleaving to the blastocyst stage in vitro.

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In our previous study, using a bovine β-casein/human lactoferrin hybrid gene, transgenic mice were generated to target the expression of human lactoferrin (hLF) into the mammary glands. Here, we report the fidelity of transgene expression by eleven transgenic mice and their progeny. Expression of hLF in lactating mice was demonstrated by northern and western blots, ELISA, and immunohistochemical staining. Northern blot analysis in five different tissues revealed that the transgene was expressed in the mammary gland. hLF was expressed in five of eight transgenic mouse lines analyzed by ELISA. The expression level of hLF in milk at day 10 of lactation ranged from 2.5 to 200 μg/ml. The apparent molecular weight of the recombinant hLF was indistinguishable from the native form upon immunoblotting. Immunohistochemical staining revealed that hLF in transgenic mice was exclusively expressed in the epithelial cells of mammary gland. The transgenic mice produced in this study provide a model for the eventual generation of transgenic farm animals producing high levels of hLF in their milk.

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The effect of the protein secretion inhibitor, brefeldin-A on the development of mouse 4-cell embryos was investigated. Four-cell embryos of various ages (0, 2, 3, 4, 5, 6, 7, and 8 h post division to the 4-cell stage) were cultured continuously in a medium containing 5 μg/ml brefeldin-A, and the embryos were observed for the evidence of cell division. Developmental rates to the 8-cell stage were significantly lower in embryos cultured with brefeldin-A from 0, 2, 3, 4 and 5 h post division to the 4-cell stage (16.4%, 25.0%, 42.9%, 56.7% and 56.9%, respectively). The embryos placed in BFA from 6, 7 and 8 h post division to the 4-cell stage cleaved normally (85.5%, 94.0% and 100%, respectively). Some of the embryos in which cell division did not occur consisted of 2 or 3 blastomeres that were binucleate. However, when the brefeldin-A application was limited to 6 h, the ability of cell division was reverted (more than 80%). Most of these embryos formed blastocoel cavity by 40 h post division to the 4-cell stage as normal embryos.

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ACTH challenge tests for the assessment of stress on the first and third week postpartum and bacteriologic examination of uterine swabs on the second and fourth week, were conducted in dairy cows following clinically normal (n=12) and abnormal (n=21) puerperium. Postpartum ovarian activity and uterine involution were also investigated. The basal plasma cortisol concentrations (mean ± S.E.) during the first and third week postpartum were 3.1 ± 0.9 ng/ml and 3.4 ± 1.1 ng/ml in normal cows, and 6.5 ± 1.9 ng/ml and 4.9 ± 1.2 ng/ml in abnormal cows, respectively. The mean basal plasma cortisol values of abnormal cows were elevated and significantly higher (P<0.05) during the first week postpartum. Bacterial organisms were isolated from the uterus of 33.3% of normal and 61.9% of abnormal cows during the second week postpartum and in 33.3% of normal and 23.8% of abnormal cows during the fourth week. Resumption of ovarian activity was neither affected by puerperal disorders nor uterine bacterial infection. Uterine involution at 4 weeks postpartum was completed in all cows with normal puerperium and delayed in 23.8% of abnormal cows. The results indicate that cows with abnormal puerperium had significantly higher basal cortisol levels, and had higher occurrence of uterine bacterial infection during the second week when compared with normal cows.

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Oocyte-cumulus complexes cultured in porcine follicular fluid exhibited a significant expansion of the cumulus oophorus. Porcine follicular fluid was fractionated by ultracentrifugation (220, 000 × g for 48 h) and resulted in four fractions named as Top, Second, Third and Bottom. Cumulus-oocyte complexes cultured in Top fraction showed a more marked degree of expansion than did other fractions. When the activity of Top fraction was compared with that of the original porcine follicular fluid, there was much more activity for cumulus expansion caused by Top fraction. When Bottom fraction was mixed with Top fraction, there was a significant decrease in the degree of expansion of the cumulus oophorus in vitro. In the same manner, when oocytectomized complexes were cultured in Top + Bottom fraction, the expansion activity of Top fraction was also suppressed. The arresting action can be altered when re-cultured in Top fraction, suggesting that it has a reversible action on cumulus expansion. The arresting activity was retained after dialysis in a tubing with a molecular cut off of 50 kDa.

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To test the hypothesis that seasonal variations in testicular morphology and function differ in Corriedale rams subject to different feeding levels, 24 spring-born Corriedale rams, aged 14-15 months at the beginning of the trial and raised under extensive grazing conditions in Uruguay, were allotted at random to two groups: Group H, that grazed on improved (sown) pastures, and Group L, the control, that grazed on natural pastures (range). Clinical data (live weight, scrotal circumference), semen, blood and tissue samples (testis, epididymis and seminal vesicle) were collected during each of four seasons (for one month/season) of the year. According to data measured, testicular form and function had its peak in autumn followed by a decline in winter and a subsequent recovery in spring and summer. Live weight loss during winter was significantly decreased in Group L but not in Group H. Scrotal circumference, seminiferous tubules diameter and seminal vesicle epithelial height decreased significantly during winter in both groups. Group H scrotal circumference returned earlier (spring) than Group L (summer) to autumn values. By summer, seminiferous tubules and seminal vesicle epithelial height had returned to autumn values in Group H, but not in Group L. Decrements of scrotal circumference in winter and spring were milder in Group H than in Group L animals. Group H testosterone values in autumn were higher than those from Group L in spring. In summary: 1) differences existed in seasonal variations in testicular morphology and function between Corriedale rams subjected to different feeding levels and, 2) the findings suggest that nutritional factors contributed, at least partly, to the differences in variations observed throughout the experiment.

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Previous research from our laboratory has shown that tumor necrosis factor (TNF)-α, administered either intravenously (iv) or intracerebroventricularly (icv), suppressed the electrical activity of hypothalamic gonadotropin-releasing hormone (GnRH) pulse generator in the rat. The present study was conducted to elucidate the possible roles of prostaglandins (PGs) and corticotropin-releasing hormone (CRH) in mediating the effect of TNF-α. Ovariectomized rats were fitted with chronically implanted electrode arrays in the mediobasal hypothalamus, and multiunit activity (MUA) was recorded under an unrestrained condition. Blood samples were withdrawn every 6 min through an indwelling atrial catheter for the determination of serum luteinizing hormone (LH) concentrations. During a pretreatment control period, characteristic increases (volleys) in MUA coincident with the initiation of each LH pulse were recorded. Indomethacin (1 mg/100 g BW, iv), a cyclooxygenase inhibitor, blocked the decrease in the frequency of MUA volleys induced by iv (1 μg) or icv (50 ng) injection of TNF-α. In contrast, icv injection of the CRH receptor antagonist (α-helical CRH, 100 μg) failed to block the suppressive effect of TNF-α on volley frequency. Neither indomethacin nor α-helical CRH alone affected the recurrence of MUA volleys. These results suggest that TNF-α suppresses GnRH pulse generator activity at least partially through PG-, but not CRH-, dependent mechanisms.

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