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Biomedical subjects

F W Bazer

Publications and source records attributed to F W Bazer.

At least 289 records · Page 16Linked to original sources
PubMed1980

Effect of the conceptus on quantitative and qualitative aspects of uterine secretion in pigs.

Endometrial explants were removed from uteri of animals pregnant and pseudopregnant (5 mg oestradiol valerate on Days 11--15) for 60 days, from the gravid and non-gravid horns of unilaterally pregnant pigs at Day 60 of pregnancy and fron non-pregnant animals at Day 12 of the oestrous cycle. The tissues were cultured in the presence of L-[34S]methionine for 24 h, and the tissues and medium were then analysed separately by two-dimensional polyacrylamide gel electrophoresis. Radioactive polypeptides were identified by autoradiography of dried gels. Tissues from all all except the cyclic animals released an identical group of polypeptides into the culture medium: the major radioactive products were 4 acidic polypeptides of low molecular weight and several basic proteins, which included the purple phosphatase uteroferrin, and lysozyme. In separate experiments explants from 3 unilaterally pregnant pigs were cultured with L-[3H]leucine, and, on a fresh weight basis, the tissue from the non-gravid horn released significantly less radioactive macromolecular material into the medium in 24 h than did tissue from gravid horns. It therefore appears that although the nature of the secretion produced by the pregnant uterus is a consequence of maternal hormonal regulation alone, the tissue underlying a conceptus is quantitatively more active than that from unoccupied regions of a uterus.

Acid Phosphatase↗
PubMed1979

Resonance Raman scattering from uteroferrin, the purple glycoprotein of the porcine uterus.

Uteroferrin, a purple-colored, iron-containing glycoprotein, purified from the uterine fluid of progesterone-stimulated pigs, owes its natural purple color to a broad absorption band centered at 545 nm. Laser excitation within the visible absorption band of uteroferrin results in an intense resonance Raman spectrum which bears a striking resemblance to that reported for Fe(III)-transferrin, the iron transport protein of serum. Excitation profiles for the four resonance-enhanced bands of uteroferrin were obtained from 4579 A to 6741 A, using lines from Ar+ and Kr+ lasers. Each of the profiles have maxima near 545 nm. The spectral similarities of uteroferrin and Fe(III)-transferrin lead to the belief that the Fe(III) binding sites of the two proteins must be, at least in some respects, quite similar. In particular, it is concluded that, as in Fe(III)-transferrin, the metal binding site of uteroferrin contains a tyrosine ligand and that the visible absorption spectrum of uteroferrin results from a phenolate to Fe(III) charge transfer.

Animals↗
PubMed1979

Actions of hormones on the uterus and effect on conceptus development.

The process of reproduction in the mammalian female involves interactions between gonadal and placental steroids and, possibly, protein hormones such as placental lactogen, and the uterine endometrium. These interactions are discussed relative to available data from pigs and with the understanding that the concepts presented may not be directly applicable to other species. Swine embryos enter the uterus for continued development beyond the early blastocyst stage and, within the uterus, the spherical blastocyst, of about 2 mm diameter on day 12, undergoes rapid elongation to an organism of about 1 m in length by day 15 of pregnancy. During this period of elongation, the blastocyst appears to provide the chemical signal, presumably unconjugated estrogens, that allows for corpora lutea (CL) maintenance (luteostatic effect) and, therefore, continued production of progesterone by the CL which is essential for pregnancy. Estrogens from the blastocyst may exert their luteostatic effect on the uterus by causing prostaglandin F2 alpha, the presumed porcine uterine luteolysin, to be secreted in an exocrine (toward the uterine lumen) rather than an endocrine (toward the endometrial stroma and vasculature) direction during pregnancy. Consequently, prostaglandin F2 alpha is sequestered in the uterine lumen and does not become available, via the utero-ovarian vasculature, to exert its luteolytic effect. The potential steroid precursor(s) available to the trophoblast for estrogen synthesis appear to be produced through endometrial conversion of progesterone to unconjugated androgens, e.g., androstenedione and testosterone, and conjugated estrogens, e.g., estrone-sulfate and estradiol-sulfate. The estrogens may, in concert with progesterone and possibly other hormones, placental lactogen for example, act locally, i.e., at the site of placentation to: result in a luteostatic effect; increase uterine blood flow; enhance water, electrolyte and substrate (carbohydrate and amino acid) transport to the site of placentation and across the placenta; affect synthesis and secretion of macro-molecules (histotroph) by the uterine glands that serve as enzymes and (or) carrier molecules and control or modulate physiological and (or) biochemical events essential to placental and fetal development that are not understood.

Animals↗
PubMed1979

Hormonal and physical changes associated with bovine conceptus development.

Conceptus (placental membranes, fetal fluids and fetus) development was characterized between Days 27 and 111 of gestation. Progestagens, oestrone, oestradiol, oestrone sulphate and prostaglandins (PG) F were measured in maternal plasma and allantoic and amniotic fluids. Protein concentrations are described for fetal fluids. The early increase in placental membrane weight from 1.12 g (27 days) to 58.45 g (50 days) was associated with oestrogen production presumably of conceptus origin. Oestrogens increased significantly in allantoic and amniotic fluids throughout the period studied with oestrone being the primary free oestrogen, rising from 2 pg/ml (Day 33) to 144 ng/ml by 111 days in allantoic fluid. Changes in plasma oestrogens of the maternal circulation were not detected until after Day 70 at which time oestrone concentration was greater than that of oestradiol. Fetal fluid concentrations of progestagens, oestrone sulphate and PGF were not related to maternal plasma levels and a sequestration of these hormones by the allantois is postulated.

Allantois↗
PubMed1979

Luteolytic effect of oestrone sulphate on cyclic beef heifers.

The action of oestrone sulphate on luteal function was tested in cyclic beef heifers. Once daily injection of 28 or 56 mg oestrone sulphate in corn oil beginning on Day 10 of the cycle had a significant luteolytic effect as compared to corn oil-treated controls.

Animals↗
PubMed1979

Method for obtaining ovine uterine secretions from unilaterally pregnant ewes.

Development of the ovine conceptus was confined to the uterine horn ipsilateral to the corpus luteum (CL) by placing a ligature around that uterine horn at a point near the uterine body on day 5 of pregnancy. On day 140 of gestation, seven of 10 ewes were still pregnant and from 21 to 815 ml of uterine fluid (488 +/- 94 ml, X +/- SEM) were collected from the nongravid uterine horn. Total recoverable protein (X +/- SEM) was 13.4 +/- 3.4 grams. Polyacrylamide gel electrophoresis of the reduced proteins in presence of sodium dodecyl sulfate indicated that protein composition of uterine fluid was distinct from that of colostrum, serum, amniotic fluid, and allantoic fluid, and revealed the presence of two major polypeptides with molecular weights of about 57,000 and 58,500, respectively, plus numerous other minor components. Gel filtration on columns of Sephadex G-200 and Sepharose CL-6B suggested that these polypeptides formed a series of aggregates of high molecular weight when kept under nonreducing conditions. Glucose (.18 +/- .03 mg/ml), but not fructose, was present in uterine fluid. In addition, high levels of prostaglandin F (451.4 +/- 83.3 ng/ml) were present.

Allantois↗
PubMed1979

An investigation of the uterine luminal environment of non-pregnant and pregnant pony mares.

Uterine flushings were collected from 30 non-pregnant Pony mares on Days 8, 12, 14, 16, 18 or 20 after oculation. Mares were allowed a recovery period of one oestrous cycle and were mated at the next oestrus. They were then ovario-hysterectomized on days which corresponded to the day of the oestrous cycle to which they were assigned. Uterine flushings were analysed for total recoverable protein and acid phosphatase activity. Least squares analysis indicated a status X day interaction for total protein (P less than 0.10) and acid phosphatase activity (P less than 0.005) in which the latter was higher in uterine flushings during pregnancy. Peripheral plasma oestrone and oestradiol concentrations were measured by radioimmunoassay and results indicated that plasma oestrone concentrations in pregnant and non-pregnant mares were not different, and oestradiol was lower (P less then 0.005) in the peripheral plasma during pregnancy. conceptus membranes were incubated in vitro for 120 min in a chemically defined medium. Incubation medium was then assayed to assess oestrone and oestradiol production capacilities at Days 8, 12, 14, 16, 18 and 20 of pregnancy. Conceptus membrane production of oestradios (pg/5 ml/h) increased (P less than 0.05) from Day 8 (243 pg/5 ml) to Day 20 (108 763 pg/5 ml). A similar trend, but of lower magnitude, existed for oestrone production.

Acid Phosphatase↗
PubMed1978

Uterine luminal prostaglandin F in cycling mares.

Prostaglandin F was measured by radioimmunoassay in uterine flushings of cycling mares on days 4, 8, 12, 14, 16, 18 and 20 post-ovulation. Prostaglandin F was significantly (P less than .05) affected by day of the estrous cycle and reached maximal levels on day 14. Least squares means for days 4, 8, 12, 14, 16, 18 and 20 were: .66, .81, 4.77, 14.31, 5.48, 3.68 and 2.97 ng/ml, respectively.

Animals↗
PubMed1978

A study of prostaglandin F2alpha as the lutbolysin in swine: IV An explanation for the luteotrophic effect of estradiol.

This study evaluated effects of estradiol valerate on synthesis, secretion and direction of movement of immunoreactive prostaglandin F2alpha (PGF) in swine. Gilts were randomly assigned to provide uterine flushings representing days 11, 13, 15, 17 and 19 of the estrous cycle (three gilts/day). The same gilts then were allowed one estrous cycle for recovery. During the second postoperative estrous cycle they were treated with estradiol valerate (EV) (5mg/day, SC) on days 11 through 15 and uterine flushings again were obtained on the same respective days with the same gilts represented within each day. Total recoverable PGF per uterine horn increased from day 11 (X - 1.98 ng) to day 17 (X = 210.20 ng) and then declined to day 19 (X = 66.20 ng) during the control period. Following EV treatment average total recoverable PGF was the control period. Following EV treatment average total recoverable PGF was 1.9, 4,144.3 and 4,646.7 ng on the same respective days. EV treatment also resulted in maintenance of elevated levels of total protein and acid phosphatase activity in uterine flushings. These data suggest that estradiol may exert its luteotrophic effect by preventing the release of PGF from the uterine endometrium into the uterine venous system (endocrine secretion) while maintaining the movement of endometrial secretions into the uterine lumen (exocrine secretion).

Acid Phosphatase↗
PubMed1978

Development of the conceptus in the bovine.

Growth of fetuses, fetal membranes, and fetal fluids was characterized by least squares analysis for 254 conceptuses ranging from 25 to 278 days of gestation. Prior to 100 days of gestation, increases in allantoic fluid volume and chorio-allantoic membrane weight preceded those of fetal weight, amnio-allantoic membrane weight, and amniotic fluid volume. The relative rate of growth of components suggests a prerequisite of chorio-allantoic membrane expansion for subsequent fetal growth. Male fetuses were heavier than female fetuses as early as 100 days of gestation. Rate of growth of all fetuses was maximal at 230 days of gestation with a peak rate of greater than 200 g/day. Growth rate then declined to less than 100 g/day by term.

Allantois↗
PubMed1977

A study of prostaglandin F2alpha as the luteolysin in swine: II Characterization and comparison of prostaglandin F, estrogens and progestin concentrations in utero-ovarian vein plasma of nonpregnant and pregnant gilts.

Polyvinyl catheters were inserted into the right and left utero-ovarian veins (UOV) and saphenous vein (SV) and artery (SA) of six non-pregnant (O) and five pregnant (P) gilts on day 11 after onset estrus. Beginning on day 12, UOV blood samples were collected at 15-min intervals from 0800 to 1100 hr and 2000 to 2300 hr, and single samples were taken at 1200 and 2400 hrs. Peripheral blood (SA or SV) was sampled at 0800, 1200, 2000 and 2400 hr until gilts returned to estrus (X = 20.6 days) or day 24 of pregnancy. UOV plasma PGF concentrations (ng/ml; n = 1929) were measured by RIA. Status (P vs O) by day interactions were detected (P less than .01) but variances among treatments were heterogenous (P less than .01). Curvilinear day trends were detected for PGF in 0 gilts (P less than .01) but not P gilts. PGF peaks, defined as concentrations greater than two SD above the mean concentration for each gilt, occurred with greater frequency (chi2 = 16.4; P less than .01) in O than P gilts; and mean peak levels (X +/- SE) were 5.04 +/- .27 and 3.84 +/- .13 ng/ml, respectively. Progesterone concentrations were maintained in pregnant pigs and were indicative of luteal maintenance. Systematic differences in day trends of utero-ovarian venous plasma estradiol were detected between O and P pigs. These differences may be of paramount physiological importance and are discussed.

Animals↗