Showing papers by "Fuller W. Bazer published in 1984"

Ovine Trophoblast Protein 1, an Early Secreted Blastocyst Protein, Binds Specifically to Uterine Endometrium and Affects Protein Synthesis*

Abstract: Ovine trophoblastic protein-1 (oTP-1), an early secretory protein of the sheep blastocyst, was purified after culturing day 14–16 conceptuses for 24 h in vitro. The localization of oTP-1 in the pregnant day 16 sheep uterus was determined immunocytochemically. The protein was associated with trophectoderm cells of the elongated blastocyst and with the surface and upper glandular epithelium of the maternal uterus. Receptors that bound oTP-1 with high affinity (Kd = ∼2 × 10−10 M) were present in crude membrane preparations derived from homogenates of endometria from day 12 nonpregnant and anestrous ewes. Uterine infusion of 125I-labeled oTP-1 into day 12 nonpregnant ewes showed that the majority of the radioactivity was retained in the uterus, and only very small amounts of intact protein appeared to enter the maternal vasculature. There was no significant association with the corpora lutea, ovaries, or other tissues tested. oTP-1 failed to compete with ovine PRL for rabbit mammary gland receptors or with hC...

prolong luteal maintenance when introduced into the uterine lumen of cyclic ewes

Abstract: Experiments were performed to determine whether proteins, produced and released into the incubation medium by Day 15-16 sheep conceptuses cultured for 24-48 h, could prolong the functional lifespan of the corpus luteum (CL) when infused into the uterine lumen of cyclic ewes. Beginning on Day 12 (oestrus = Day 0) either a concentrated (2 ml) solution of total conceptus culture medium protein (2.2 mg) or diluted sheep serum (2.2 mg protein) was introduced daily via an indwelling catheter into the uterine lumen of 3 ewes for 7 days (Days 12-18). Peripheral blood samples were collected daily for 14 days (Days 12-25). On Day 25 all ewes were laparotomized and ovaries observed to determine whether CL previously marked with India ink were maintained. All controls had ovulated and formed new CL. By contrast none of the conceptus protein-treated ewes had ovulated, and their peripheral progesterone levels remained elevated. One ewe maintained a functional CL until Day 52 when she was hysterectomized. Light microscopy of histological sections prepared from the endometrium revealed glandular development comparable to that in the endometrium of cyclic animals during late dioestrus. The cells of the CL were similar to those from cyclic animals during mid- to late dioestrus. Ovine trophoblast protein ( oTP -1), a major protein secreted by the sheep conceptus between Days 13 and 21 of pregnancy, was purified from conceptus incubation medium and injected (0.2 mg protein/day) into the uterine lumen of 3 animals. Plasma progesterone concentrations indicated that oTP -1-treated animals maintained luteal function 4 days longer than did control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Proteins released by cultured Day 15-16 conceptuses prolong luteal maintenance when introduced into the uterine lumen of cyclic ewes.

Abstract: Experiments were performed to determine whether proteins, produced and released into the incubation medium by Day 15-16 sheep conceptuses cultured for 24-48 h, could prolong the functional lifespan of the corpus luteum (CL) when infused into the uterine lumen of cyclic ewes. Beginning on Day 12 (oestrus = Day 0) either a concentrated (2 ml) solution of total conceptus culture medium protein (2.2 mg) or diluted sheep serum (2.2 mg protein) was introduced daily via an indwelling catheter into the uterine lumen of 3 ewes for 7 days (Days 12-18). Peripheral blood samples were collected daily for 14 days (Days 12-25). On Day 25 all ewes were laparotomized and ovaries observed to determine whether CL previously marked with India ink were maintained. All controls had ovulated and formed new CL. By contrast none of the conceptus protein-treated ewes had ovulated, and their peripheral progesterone levels remained elevated. One ewe maintained a functional CL until Day 52 when she was hysterectomized. Light microscopy of histological sections prepared from the endometrium revealed glandular development comparable to that in the endometrium of cyclic animals during late dioestrus. The cells of the CL were similar to those from cyclic animals during mid- to late dioestrus. Ovine trophoblast protein ( oTP -1), a major protein secreted by the sheep conceptus between Days 13 and 21 of pregnancy, was purified from conceptus incubation medium and injected (0.2 mg protein/day) into the uterine lumen of 3 animals. Plasma progesterone concentrations indicated that oTP -1-treated animals maintained luteal function 4 days longer than did control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Uteroferrin has N-asparagine-linked high-mannose-type oligosaccharides that contain mannose 6-phosphate

Abstract: Uteroferrin is an iron-containing, progesterone-induced, acid phosphatase that is secreted in large amounts by the uterine endometrium of pigs. During pregnancy, it transports iron across the chorioallantois (placenta) for use in fetal hematopoiesis. In this paper, it is reported that uteroferrin synthesized by cultured endometrial explants possesses N-linked, high-mannose, oligosaccharide chains that contain 6- phosphomannose units. The latter is regarded as a possible recognition marker whereby acid hydrolases are targeted to the lysosome. On uteroferrin, however, the majority of the phosphate is in single diester linkages between the mannose and a covering N-acetylglucosamine. It is suggested that uteroferrin is a lysosomal enzyme that has assumed a role in iron transport and metabolism and is secreted because the covering N-acetylglucosamine is not removed.

Endocrine Aspects of Early Pregnancy in Pony Mares: A Comparison of Uterine Luminal and Peripheral Plasma Levels of Steroids during the Estrous Cycle and Early Pregnancy*

Abstract: Comparisons of estrone, 17β-estradiol, and plasma progestin concentrations were made in uterine fluid and peripheral blood of nonpregnant and pregnant pony mares. Concentrations of these steroids were also measured within yolk sac fluid from blastocysts on days 12,14,16, and 18 of pregnancy to obtain more complete analyses of the uterine environment (uterine fluid plus yolk sac fluid) of early pregnancy. Thirty mares were randomly assigned to six treatment groups (n = 5/ group), and uterine fluid and peripheral blood samples were obtained on days 8, 12, 14, 16, 18, and 20 postovulation. After a recovery period of one estrous cycle, mares were bred at their next estrus. Animals were hysterectomized on the same treatment day to which they had previously been assigned in the nonpregnant phase of this study. Using this design, uterine fluid and peripheral blood samples were collected from each mare on equivalent days of the estrous cycle and pregnancy. Significant differences in day trends were found between ...

Suppression of phytohemagglutinin-stimulated lymphocyte blastogenesis by ovine uterine milk protein.

Abstract: Two basic glycoproteins (UTM-P) with molecular weights of 57,000 and 59,000 were purified from ovine uterine milk collected on Days 125 and 130 of pregnancy. The UTM-P were evaluated for immunosuppressive activity in phytohemagglutinin (PHA)-treated, mixed lymphocyte (MLC) and resting lymphocyte (RLC) cultures. For PHA and RLC cultures, UTM-P (2.5 to 800 micrograms UTM-P/ml) were added to 1 X 10(6) lymphocytes and 0.8 micrograms of PHA (for PHA cultures only), while for the MLC, UTM-P (50 to 1600 micrograms UTM-P/ml) were added to 5 X 10(5) lymphocytes combined from each of two ewes. Following [3H] thymidine addition, cells were later harvested for determination of thymidine incorporation. Lymphocyte blastogenesis was suppressed by UTM-P in PHA (R2 = 0.32 to 0.92, P less than 0.01 to 0.001), MLC (R2 = 0.8, P less than 0.001) and RLC (R2 = 0.65, P les than 0.01) experiments. To determine reversibility, PHA-treated lymphocytes were incubated with UTM-P for 6, 12 or 24 h, then washed to remove surface UTM-P. Incubation was continued in the presence of PHA as with other experiments. Exposure of lymphocytes to UTM-P for 6 or 12 h did not result in suppression of blastogenesis, whereas exposure for 24 h was sufficient for suppression (P less than 0.01). In an additional experiment, UTM-P were added to PHA-treated cultures at 0, 6, 12 or 24 h. Suppression (P less than 0.01) of blastogenesis was observed for each time period. Immunosuppressive activity was not mediated by overall cytotoxicity and was not affected by routine handling and storage of UTM-P. Data from these experiments provide one explanation for tolerance of the conceptus allograft during defined stages of ovine pregnancy.

Role of uteroferrin in placental iron transport: effect of maternal iron treatment on fetal iron and uteroferrin content and neonatal hemoglobin.

Abstract: Uteroferrin, an Fe-containing, progesterone-induced glycoprotein is involved in maternal to fetal Fe transport in swine. These studies examined the effect of im Fe injection of dam on conceptus and piglet Fe stores. In Exp. I, eight gilts were bred and assigned to either treatment I (no Fe injections) or treatment II (total of 22 mg iron-dextran/kg body weight on d 40, 45, 50, 55 and 60 of gestation) and hysterectomized on d 90 to determine whether Fe injections increased Fe stores in the conceptus. Total Fe in allantoic fluid (P less than .10) as well as uteroferrin concentration (P less than .05) and total uteroferrin (P less than .05) in placentae were greater for gilts in treatment II. In Exp. II, 19 cross-bred sows were bred and assigned to treatments I and II (d 40, 50 and 60 of gestation), as in Exp. I, and treatment III (total of 22 mg iron-dextran/kg body weight on d 90, 100 and 110 of gestation) to determine effects of treatment on hemoglobin (Hb) values of the piglets at 8 +/- 1 h and d 4 postpartum. Piglets from treatment II had higher (P less than .01) Hb at 8 +/- 1 h, but not on d 4 postpartum. Experiment III was a replication of Exp. II except that Hb values were determined at 8 +/- 1 h, d 4 and d 7 postpartum. On d 7, piglets from treatment II had higher (P less than .05) Hb, but differences at 8 +/- 1 h and d 4 were not significant (P greater than .10).(ABSTRACT TRUNCATED AT 250 WORDS)

Uteroferrin: A protein in search of a function

Abstract: Uteroferrin, a purple-colored, iron-containing acid phosphatase, with many of the properties of a lysosomal hydrolase, transports iron from the mother to the conceptus in pregnant pigs. Uteroferrin, however, is but one member of what may be a broad class of iron-containing phosphatases with unusual spectral properties which result from a novel type of di-iron active site. The biological function of uteroferrin is unknown. We argue here that the in vivo function of uteroferrin, despite its undoubted ability to act as a potent acid phosphatase, is that of a transplacental iron transporter.

Yield and Composition of Milk and Weight Gain of Nursing Pigs from Sows Fed Diets Containing Fructose or Dextrose

Abstract: Yield and composition of milk and growth of nursing pigs in response to dietary treatment were estimated from 25 lactating sows during a 22-d period. Eight sows were fed 6 kg/d of a corn-soybean control diet (C sows). Nine were fed the control diet in which approximately 6.5 g X kg body weight (BW-1) X d-1 of carbohydrate was supplied by fructose corn syrup (F sows) and eight were fed the control diet containing equivalent carbohydrate supplied by powdered dextrose (D sows). Blood samples collected via jugular cannulae were analyzed for plasma concentrations of fructose, glucose and insulin. Concentrations of fructose and glucose from F sows were significantly higher throughout the study than that from D and C sows, while insulin concentration was approximately 2.5-fold lower. Milk yield from F sows on d 14 and 21 was significantly higher and pigs weaned on d 21 were heavier than those from D and C sows. Sows fed the diet containing fructose experienced significant BW loss during lactation. Coefficients of gross correlation across treatments showed milk yield and litter weight gain to be negatively associated with percentages of protein, lipids and total solids in milk, but positively associated with concentrations of lactose and gross energy. Nursing pig weight gain at weaning was more responsive to total yields of milk and milk nutrients than to composition. These data support the hypothesis that source of metabolizable energy (ME) affects milk yield, composition and efficiency at which the sow converts dietary nutrients into milk.

Acid phosphatase and leucine aminopeptidase activity in the uterine flushings of non-pregnant and pregnant gilts

Abstract: The activities of uteroferrin, measured as acid phosphatase (AP), and an aminoacylpeptidase (AA) were measured in uterine flushings collected from gilts on Days 6, 8, 10, 12, 14, 15, 16 and 18 of the oestrous cycle and pregnancy (N = 37). Changes in AP (P less than 0.05) were associated with day for both specific and total AP in non-pregnant and pregnant gilts. For pregnant and non-pregnant gilts, AP activity was greatest between Days 14 and 16 and then decreased to Day 18. The AA specific activity increased (P less than 0.01) between Days 10 and 12 of the oestrous cycle and pregnancy, but neither effects of pregnancy nor day by pregnancy status interaction were detected. The AA total activity was greater for pregnant gilts (P less than 0.01). These data suggest an inhibitory effect of oestrogens of blastocyst origin on synthesis and/or secretion of uteroferrin, but not AA.

Adaptations to reduction of endometrial surface available for placental development in sheep.

Abstract: On Day 5 of pregnancy, before the blastocyst migrates to the uterus, one uterine horn was ligated to restrict the trophoblast to the lumen ipsilateral to the corpus luteum. The numbers of placentomes (caruncles and cotyledons) were reduced by half, but neither at 120 nor at 140 days of pregnancy (term 147 days) did the weights of placentae and fetuses of treated ewes differ significantly from those of control ewes. Amongst uterus-ligated animals prepared for chronic study, the rate of uterine blood flow (electromagnetic flow transducer, ml/min) to the pregnant horn was higher than in control ewes, as was the concentration of progestagens in maternal peripheral blood. There may be a compensatory response that causes hypertrophy of placentomes and that increases blood flow to the uterine horn containing placental tissue.

Response of Plasma Glucose, Fructose and Insulin to Dietary Glucose and Fructose in the Lactating Sow

Abstract: Twenty-two Hampshire-Yorkshire X Large White sows of second and third parity were allotted randomly to one of three dietary treatments. Five sows were fed 6.0 kg/day of a corn-soybean meal lactation diet (control diet). Twelve sows were fed the control diet in which 24% of the composition was supplied by corn syrup containing 72% fructose on a dry matter basis (fructose diet) and five sows were fed the control diet in which 24% of the composition was supplied by powdered dextrose (glucose diet). All diets were fed from days 1 through 21 of lactation. Blood was collected from all sows immediately prior to feeding and hourly for 6 hours postprandial via jugular vein cannulae following a single feeding on seven separate but nonconsecutive days during the 21-day period. Fructose was absorbed from the digestive tract of sows as evidenced by elevated (P less than 0.01) conventions of fructose in plasma. Sows fed the fructose diet also had higher (P less than 0.01) plasma glucose concentrations than did those fed the glucose and control diets. The concomitant elevated glucose concentration following ingestion of the fructose diet was not associated (P greater than 0.10) with increased insulin concentration. Fructose in plasma was associated with a slight but significant increase in insulin although the mean concentration of insulin in plasma was only one-third that measured in sows fed the glucose and control diets. These data suggest that fructose in vivo has a glucose-sparing effect presumably mediated through a physiological mechanism that lowers insulin concentration.

Biochemical interactions between blastocyst and endometrium in the large domestic animals

Abstract: In pigs, the blastocyst begins to elongate from a sphere to a long filamentous thread around day 10.5 of pregnancy. At about this time the endometrium secretes large quantities of protein into the uterine lumen. The synthesis of this material which is believed to be required for nutritional support of the conceptus is under the control of progesterone. The release of secretory protein appears to be triggered by the production of estrogens by the elongating blastocyst. Blastocyst estrogens are also involved in the phenomenon of maternal recognition of pregnancy in swine, and their interaction with the maternal system, by a mechanism as yet unknown, prevents a return to reproductive cyclicity. Maternal recognition of pregnancy in the sheep and cow occurs at around the time of blastocyst elongation. Here estrogens do not appear to be involved, and protein products secreted by the conceptus have been implicated. One product of the sheep, ovine trophoblast protein-1, which is produced only during a brief period (days 13–21) of pregnancy, has been purified. It appears to be a hormone whose target tissue is the uterine endometrium.

H1 histone synthesis by implanting pig blastocysts

Abstract: Histones were isolated from pig conceptuses on Days 8-18 of pregnancy, Acid-urea polyacrylamide gel electrophoresis (PAGE) was performed on samples of total histone and on PCA-soluble histone fractions (primarily histone H1). Conceptuses were also incubated for 24 h in vitro in the presence of [3H]lysine, and the histones analysed by autofluorography after PAGE. A minimum of two H1 histone bands was resolved in stained gels by these techniques. The autofluorographs indicate that both H1 histones are synthesized throughout the developmental period analysed. No shift in H1 histone subtype, as encountered in sea urchin development, was observed. The results suggest that such a shift, if it occurs, may have been made before Day 8.