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Biomedical subjects

F W Bazer

Publications and source records attributed to F W Bazer.

At least 271 records · Page 15Linked to original sources
PubMed1982

Comparison of glucose, fructose, ascorbic acid and glucosephosphate isomerase enzymatic activity in uterine flushings from nonpregnant and pregnant gilts and pony mares.

In Experiment 1, 40 gilts and 30 pony mares were used to characterize changes in glucose, fructose, ascorbic acid and glucosephosphate isomerase (GPI) enzymatic activity in uterine flushings collected either during the estrous cycle or early pregnancy. Total recoverable glucose was greater (P less than 0.01) in uterine flushings from pregnant gilts, but pregnancy status had no effect on total recoverable glucose in pony mare uterine flushings. Fructose was undetectable in uterine flushings from nonpregnant gilts and pony mares and pregnant gilts and pony mares prior to Day 14, but occurred in increasing amounts between Days 14 and 18 or 20 of pregnancy. In Experiment 2, it was demonstrated that the porcine conceptus is the primary source, if not the sole source of fructose. Total recoverable ascorbic acid in uterine flushings was not affected by pregnancy in gilts, but was greater (P less than 0.01) in pregnant versus nonpregnant pony mares. In both species, total recoverable ascorbic acid was affected (P less than 0.01) by day of the estrous cycle and pregnancy. The GPI enzyme allows for the interconversion of glucose-6-PO4 and fructose-6-PO4. GPI total and specific activities were greater (P less than 0.01) for pregnant than nonpregnant gilts and pony mares. The periods of greatest GPI activity were temporally associated with elevated estrogens of either ovarian or blastocyst origin. Results from Experiment 3 indicated a marked increase (P less than 0.01) in GPI activity in uterine flushings from gilts treated with estradiol valerate. Results of this study indicate that glucose (gilt only), fructose, ascorbic acid and GPI activity are increased in uterine flushings of gilts and pony mares during early pregnancy. The increase in these constituents may reflect increased carbohydrate metabolism in ways which are uniquely beneficial to conceptus development in ungulates.

Animals↗
PubMed1982

Placental transport and distribution of uteroferrin in the fetal pig.

Placental transport of uteroferrin (Uf), the progesterone-induced iron transport glycoprotein, and its distribution within the fetus were investigated by the peroxidase-antiperoxidase bridge (PAP) technique. In Experiment 1, Uf was localized in endometrial and placental tissues taken from gilts on Days 60, 75, 90 and 105 of pregnancy. Uteroferrin was observed within cells of the endometrial glands and surface epithelium adjacent to placental areolae but not in endometrial surface epithelium between areolae. Heavy staining for Uf was observed in cells of the areolae and was associated with both supra- and infranuclear cytoplasmic vesicles. Vesicles located within the infranuclear cytoplasm were occasionally observed to be releasing their contents into capillaries surrounding the areolae. In Experiment 2, Uf was measured by radioimmunoassay in blood samples taken from the umbilical vein and artery of fetuses on Day 75 of pregnancy. Uteroferrin concentrations were greater (P less than 0.07) in umbilical vein blood (79.8 +/- 13.1 ng/ml) than in umbilical artery blood (43.9 +/- 13.1 ng/ml). Uteroferrin binding by Day 75 fetal liver membranes was examined in Experiment 3. Binding of 125I-Uf increased linearly with increasing quantities of membrane protein and binding of 125I-Uf was competitively inhibited by adding unlabeled Uf to the assay. In Experiment 4, urine samples were taken from Day 75 fetuses and assayed for beta-mercaptoethanol activated acid phosphatase activity which is indicative of Uf. In addition, urine proteins were analyzed for Uf by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and Ouchterlony double immunodiffusion (ID). Acid phosphatase specific activity was 3.37 +/- 1.83 mumol substrate hydrolyzed/10 min per mg protein. Uteroferrin was detected in two of three urine samples by 2D-PAGE and in three of eight samples by ID. In Experiment 5, tissue distribution of Uf was determined by the PAP technique in liver and kidney tissue taken from fetuses on Day 75 of pregnancy. Staining for Uf was observed in collecting ducts and proximal tubules of kidney tissue, but staining was not observed in liver tissue. These results indicate that Uf is transported by the areolae into the chorioallantoic capillaries and to the fetus by the umbilical vein. Within the fetus Uf is either bound by the liver, probably to supply iron for hematopoiesis, or cleared by the kidney and transported within the urine to the allantoic sac to serve as a temporary iron storage reservoir.

Acid Phosphatase↗
PubMed1982

Identification of stage-specific and hormonally induced polypeptides in the uterine protein secretions of the mare during the oestrous cycle and pregnancy.

Uterine secretions were obtained on Days 4, 8, 12, 14, 16, 18 and 20 of the oestrous cycle and early pregnancy. Acid phosphatase activity was significantly affected by day of the cycle, reaching a maximum at days 12-14 during the luteal phase and then declining to almost undetectable levels, by Day 20. In pregnant animals, activity continued to increase beyond Day 14. Two-dimensional polyacrylamide gel electrophoresis showed that albumin was a major component. However, a number of unique proteins of non-serum origin appeared in mid-cycle but had disappeared by Day 20. One of these was a basic protein indistinguishable in electrophoretic properties from the uterine acid phosphatase of the pig, uteroferrin, which is believed to be involved in iron transport from the uterine endometrial epithelium to the conceptus. These same polypeptides, including the putative uteroferrin, were also present in uterine flushings from pregnant animals until Day 20, and in flushings from ovariectomized mares treated with progesterone but not in those given only oestradiol-17 beta. Flushings from all ovariectomized animals contained a non-serum, acidic polypeptide (pI 5.3) of molecular weight 70 000. One basic polypeptide (molecular weight approximately 17 000) appeared by Day 4 of the oestrous cycle and disappeared by Day 16 but was maintained during pregnancy until Day 20. It was absent, however, in flushings from a Day 45 pseudopregnant mare. Like the sow, therefore, the mare possesses a number of proteins associated with cyclic changes in steroid hormones during the oestrous cycle and early pregnancy.

Acid Phosphatase↗
PubMed1982

Purification and properties of a major, low molecular weight protein released by the trophoblast of sheep blastocysts at day 13-21.

Sheep blastocysts (Day 13-21) incubated in a modified Minimum Essential Medium released proteins into the medium at an approximately linear rate over a 24-h period. Single Day-16 blastocysts converted 2-8% of the radioactivity supplied (100 muCi L-[3H]leucine) into non-dialysable macromolecules which were released into the medium. Two-dimensional polyacrylamide gel electrophoresis revealed that at Day 13 there was only one major product (Protein X), consisting of three closely similar isoelectric species of (pI of denatured polypeptides about 5.5), each with molecular weights of 17 000. Between Days 14 and 21 additional proteins were detected. One of these was of high molecular weight (greater than 660 000) and did not appear on the two-dimensional gels, but Protein X continued to predominate until Day 23 when it could not be detected. Explants of chorion from Day 30 of pregnancy failed to secrete Protein X. Protein X was released in significant quantities (50-100 micrograms per 24 h) by the trophoblast but not the yolk sac of Day-14 and Day-16 conceptuses, but was present in very low amounts in the tissues. Protein X from the incubation medium of Day-14 and Day-16 conceptuses was purified by successive DEAE ion exchange and Sephacryl S-200 gel chromatography. Because Protein X and some of the other proteins are produced transiently between Days 13 and 21, it is possible that they may play a role in maternal recognition of pregnancy in sheep.

Animals↗
PubMed1982

High molecular weight glycoproteins released by expanding, pre-attachment sheep, pig and cow blastocysts in culture.

Blastocysts isolated from sheep (Day 14--16), pigs (Day 16) and cows (Day 19) during the pre-attachment elongation phase were cultured for up to 30 h in a modified MEM medium in the presence of radioactive amino acids (L-[14C]leucine or L-[35S]methionine) to label protein and D-[3H]glucosamine to label complex saccharides. All the blastocysts released considerable quantities of non-dialysable radioactive material into the medium at an approximately linear rate over the course of the incubation. Ion-exchange chromatography on DEAE cellulose at pH 8.2 revealed that the major glucosamine-labelled product in the medium was a non-sulphated glycoprotein which eluted early in the salt gradient. None of the blastocysts produced any detectable glycosaminoglycan-like materials such as hyaluronic acid. The glycoprotein was purified by ion-exchange and gel filtration chromatography and had a molecular weight of greater than 660 000. Up to 100 micrograms of this material could be isolated from incubations of 2 sheep conceptuses. It was relatively resistant to protease hydrolysis and consisted of approximately 50% carbohydrate and 50% protein. The main monosaccharide constituents, as revealed by gas-liquid chromatography, were galactose and N-acetylglucosamine plus some mannose and fucose. No sialic acid was present. The linkages between the carbohydrate chains and the peptide appeared to be resistant to alkaline borohydride cleavage and were probably, therefore, N-glycosidic.

Animals↗
PubMed1982

Nucleic acid, metabolic and histological changes in gilt mammary tissue during pregnancy and lactogenesis.

Changes in mammary gland histology, dry weights, nucleic acids and in vitro rates of substrate oxidation in incorporation into lipid were measured in mammary biopsies of three gilts each on d 30, 45, 60, 75, 90, 105 and 112 of pregnancy, and d 1 and 4 of lactation. Histological changes noted were progressive duct growth early in pregnancy followed by rapid lobulo-alveolar development between d 75 and 90 to complete mammogenesis. Colostrum and lipid were evident by d 105 with marked distension of alveolar lumina on d 112. Complete differentiation of the secretory process was apparent on the day of parturition. Concentrtion of dry, fat-free tissue (DFFT) and DNA changed little before d 60 but increased fourfold between d 75 and 90. No further increases in DFFT or DNA were noted. RNA concentrations paralleled DNA through d 90, after which they steadily increased. Rates of acetate and glucose oxidation increased transiently during midpregnancy then declined and remained low until initiation of lactogenesis. Substrate incorporation into lipid increased slightly at midpregnancy and again at d 105, after which it increased markedly. Collectively, results indicate that mammogenesis is complete by d 90, after which lactogenesis is initiated in a two-stage process. Metabolic rates expressed on a DNA basis indicated considerable rates of oxidation, but not of lipogenesis by proliferating mammary tissue. Preferential metabolism of acetate vs glucose near parturition suggests coordination of metabolism between the mammary gland and other maternal tissues.

Acetates↗
PubMed1981

Effect of estradiol-17beta on PGF and total protein content in bovine uterine flushings and peripheral plasma concentration of 13, 14-dihydro-15-keto-PGF(2alpha).

Two experiments were conducted to examine the effect of estradiol-17beta (E(2)-17beta) on content of immunoreactive prostagladin F(2)alpha (PGF, ng) and total protein (TUP, mg) in uterine flushings, as well as concentrations of 13, 14-dihydro-15-keto-PGF(2)alpha (PGFM) in plasma (Pg/ml). In experiment 1, Holstein heifers were utilized in a single reversal trial in which either E(2)-17beta (3 mg in 2 ml saline/ethanol 50:50; n=5) or vehicle alone (n=6) were given intravenously on day 14 or 15 of the estrous cycle (Period 1) following an induced estrus (day of estrus = day 0). Treatment (Trt) groups were reversed in Period 2 (Day 14 or 15 of the second estrous cycle). Jugular venous plasma was obtained before treatment (Oh), and at 5, 6, and 9h posttreatment (PT). Uterine flushings were collected nonsurgically in vivo , per cervix, via Foley catheter at 6h PT (20 ml of .9% saline per uterine horn). E(2)-17beta did not significantly alter (E(2)-17beta vs vehicle; x(-) +/- S.E.M.) PGF (1674 +/- .11 +/- 338.39 vs 1889.91 +/- 400.24 ng; P> .10) or TUP (33.25 +/- 2.57 vs 39.16 +/- 3.04 mg; P > .10). However, E(2)-17beta increased (P < .05) plasma PGFM (E(2)-17beta vs vehicle) after treatment (0h, 113.2 vs 163.8; 5h, 312.5 vs 203.9; 6h, 324.5 vs 198.0; 9h, 323.2 vs 246.8, pg/ml). In experiment 2, crossbred beef cattle received comparable treatments of either E(2)-17beta (n=5) or vehicle (n=5) on day 14 or 15 postestrus. Jugular venous plasma was obtained at 0h PT, and at 6h PT. Uterine flushings (1.9% saline, 20 ml per uterine horn) and peripheral plasma were collected at slaughter. Estradiol-17beta increased PGF (30.07 +/- 5.94 vs 8.46 +/- 2.01 ng; P> <.05) in uterine flushings as well as PGFM in plasma (E(2)-17beta : 55.82 +/- 19.13 pg/ml, at 0h and 89.31 +/- 14.02 pg/ml, at 6h, vs saline: 103.46 +/- 50.73 pg/ml, at 0h and 17.78 +/- 14.22, at 6h). Estradiol-17beta stimulated uterine production and release of PGF and protein as measured in flushings (experiment 2) as well as plasma PGFM responses (experiments 1 and 2). Uterine and/or cervical stimulation of experiment 1 may have masked uterine response to E(2)-17beta.

Journal Article↗
PubMed1981

Progesterone-induced secretion of a retinol-binding protein in the pig uterus.

A retinol binding protein(s) of molecular weight about 17 000 has been demonstrated in uterine secretions from pigs in the luteal phase of the oestrous cycle. This protein was induced in ovariectomized sows treated with progesterone or progesterone plus oestradiol, but not in sows given oestradiol or corn oil. The vitamin A content of secretions from progesterone-treated animals also increased relative to those in controls. The apparent Kd of the binding protein for retinol was 2.6 X 10(-6) M. The protein had some affinity for retinoic acid and oleic acid, but did not bind retinyl esters of retinal. The protein probably comprises 5% or less of the total fraction of low molecular weight proteins induced by progesterone. A similar protein was found in allantoic fluid of pregnant animals, suggesting that, like uteroferrin, it serves to transport a water-insoluble nutrient from the maternal uterine endometrium to the conceptus.

Allantoin↗
PubMed1980

The novel "g' = 1.74" EPR spectrum of pink and purple uteroferrin.

Low temperature (T less than or equal to 20 K) EPR measurements have revealed the presence of a heretofore undetected signal in uteroferrin, a purple protein bearing a single iron atom per molecule. All three of its principal g values (1.923, 1.738, and 1.583) lie well below the free electron value of 2.0023. Magnetic susceptibility data from 2-77 K confirm that the novel EPR spectrum arises from a paramagnetic center with a single unpaired electron spin. Quantitative correlation of the EPR, susceptibility, and optical data point to chromophoric iron as the source of the rhombic EPR spectrum. Furthermore, close agreement between the concentration of iron and the integrated intensity of the rhombic EPR signal show that the iron in the paramagnetic center is mononuclear. Reduction of the protein to its pink form leaves the rhombic signal essentially unaltered. The previously reported g' = 4.3 EPR signal accounts for only a small fraction of the total iron in the protein and undoubtedly arises from adventitious iron. Collectively, these results strongly suggest that uteroferrin represents a new class of low spin iron proteins.

Acid Phosphatase↗
PubMed1980

A study of prostaglandin F2 alpha as the luteolysin in swine: V. Comparison of prostaglandin F, progestins, estrone and estradiol in uterine flushings from pregnant and nonpregnant gilts.

Uterine flushings were collected from 38 gilts representing Days 6,8,10,12,14,15,16 and 18 of the estrous cycle and pregnancy. The same group of gilts were represented within each of the respective days of the estrous cycle and pregnancy, i.e., three to six gilts per day per status. Uterine flushings (about 40ml) were assayed for prostaglandin F (PGF), estrone (E1), estradiol (E2), progestins (P) and protein. Nonpregnant gilts had higher (P < .01) concentrations of P in uterine flushings than pregnant gilts, but pregnant gilts had higher (P < .01) E1 and E2 concentrations. Significant day by status interactions were detected for E1 (P < .05), but not for E2 concentrations in uterine flushings. Total recoverable PGF and PGF concentrations in uterine flushings were greater (P < .01) in pregnant than nonpregnant gilts and significant (P < .01) day by status interactions were detected. In nonpregnant gilts, PGF increased between Days 12 and 16, i.e., during the period of corpora lutea (CL) regression. In pregnant gilts, PGF in uterine flushings increased markedly between Days 10 and 18. Total recoverable PGF on Day 18 of the estrous cycle was only 464.5 +/- 37.6 ng as compared to 22,688.1 +/- 1772.4 ng on Day 18 of pregnancy. Total recoverable protein was also higher (P < .01) in pregnant gilts. These data indicate that PGF synthesis and secretion by the uterine endometrium and/or conceptuses is not inhibited during pregnancy and suggest that PGF is sequestered within the uterine lumen of pregnant gilts, as is the total protein component of endometrial secretions referred to as histotroph.

Animals↗