Biomedical subjects

W W Thatcher

Publications and source records attributed to W W Thatcher.

At least 199 records · Page 11Linked to original sources

PubMed1986

Inhibition of uterine prostaglandin-F2 alpha production by bovine conceptus secretory proteins.

The effect of bovine conceptus secretory proteins (CSP) on uterine prostaglandin (PG)-F2 alpha production was evaluated in dairy cattle following injection of estradiol-17 beta. Intrauterine injections of dialyzed serum proteins (Control, n = 5) or CSP (n = 5) were administered from days 15 through 18 post-estrus. Following intrauterine treatments on day 18, all cows were injected with E2 (3 mg) to stimulate uterine PGF2 alpha production. Plasma concentrations of progesterone (P4) and 15-keto-13,14-dihydro-PGF2 alpha (PGFM) were determined by RIA. The PGFM responses following E2 challenge were decreased (p less than 0.01) for cows receiving CSP versus serum proteins into the uterine lumen. Individual PGFM, P4 and cycle length responses are discussed. Data suggest that proteins secreted by the bovine conceptus suppress uterine PGF2 alpha production during pregnancy recognition in the cow.

Animals↗

PubMed1986

Concentration of phenylbutazone (PBZ) and 13, 14-dihydro-15 keto PGF(2alpha) (PGFM) in blood and seminal plasma of stallions treated with PBZ.

Three stallions, 3 to 5 yr old and approximately 550 kg bodyweight, were used in a switchback experimental design to study the effect of daily, oral administration of 3g PBZ on the concentrations of PBZ and PGFM in blood (plasma) and seminal plasma (SP). Control and treatment periods were each 24 days' duration. Blood and semen samples were simultaneously collected every three days during these periods. Each stallion served consecutively as a control, treated, control, and treated subject for 24 days in each of the four periods. Concentrations of PBZ were obtained using HPLC and PGFM by specific RIA. Concentrations (mean +/- SE) of PBZ averaged 9.2 +/- 0.12 ug/ml in plasma but were undetectable in SP following the treatments. There was no significant difference in the plasma levels of PGFM between pre- and post- treatment values. However, there was a significant difference (P<0.001) in PGFM concentrations of seminal plasma before and after treatment. Results of this study suggest that daily, oral adminisration of 3g PBZ for 24 days to mature stallions can significantly decrease seminal plasma concentrations of PGFM. The physiological significance of this observation remains speculative.

Journal Article↗

PubMed1986

Relationship between estrone sulfate in plasma and litter size at farrowing for sows and gilts.

A positive association (P < 0.01) was detected between estrone sulfate (ES) concentrations in maternal plasma at Day 30 of pregnancy and litter size at parturition in swine. This relationship was best described by a fifth order regression equation (R(2) = 0.5) which indicated that as ES increased from 1 to 7.5 ng/ml on Day 30, litter size increased from 0 (nonpregnant) to 18 piglets farrowed. Day of sampling (P < 0.02), month (P < 0.04) and parity (P < 0.08) were major sources of variation in the model. This indicated that effects of environmental factors such as heat stress, which influence conception rate and embryonic survival, are reflected in changes in maternal ES. Also, larger litter size associated with parous sows is reflected in increased ES in maternal plasma. We conclude that measurement of ES early in gestation may be useful in reproductive management to identify nonpregnant gilts and sows as well as those with small litters.

Journal Article↗

PubMed1986

Interrelationships between uterus and conceptus to maintain corpus luteum function in early pregnancy: sheep, cattle, pigs and horses.

Processes associated with "Maternal Recognition of Pregnancy" are reviewed extensively from the ovine, bovine, porcine and equine species. Comparisons among these species indicate that CL maintenance is achieved primarily by a predominant antiluteolytic-anti PGF effect, and there is strong evidence for antiluteolytic-luteoprotective and luteotropic controls that complement this basic system. The nature of the chemical signals (steroids, prostaglandins and proteins) to regulate these processes among the species are described. Common to all of the species reviewed is a change in vascular dynamics to and from the uterus and ovary during early pregnancy. The dialogue between endometrial epithelium and trophectoderm of the developing conceptus is described. The consequence of these various physiological and biochemical responses of early pregnancy is maintenance of the CL to provide a sustained embryotrophic environment. Either in the absence of or death of a conceptus, an efficient and acute system is operational to terminate this progestational environment via regression of the CL through uterine production of PGF.

Animals↗

PubMed1986

Prostaglandin F2 alpha as the luteolysin in swine: VI. Hormonal regulation of the movement of exogenous PGF2 alpha from the uterine lumen into the vasculature.

To test the endocrine-exocrine theory of maternal recognition of pregnancy in the pig 16 gilts were assigned randomly to a 2 X 2 factorial involving pretreatment with sesame oil (SO) or estradiol valerate (5 mg; EV) injected on Days 11 through 14 of the estrous cycle and an intrauterine injection of saline (5 ml; SA) or prostaglandin F2 alpha (50 micrograms; PGF) on Day 14. Peripheral blood samples were collected for 120 min postinjection and analyzed for 15-keto-13,14-dihydro-PGF2 alpha (PGFM). PGFM concentrations were lower in EV than SO gilts (438 vs. 844 pg/ml; p less than 0.05). There was heterogeneity of regression between EV and SO gilts (p less than 0.01), with EV gilts having a slower release of PGF from the uterine lumen into the vasculature. Prostaglandin F2 alpha did not increase mean PGFM concentrations (p greater than 0.10), but resulted in an altered temporal pattern of PGFM (p less than 0.05) compared to SA gilts. There was an interaction between the two treatments over time, with EV-PGF gilts demonstrating a slower, more gradual release of PGFM than SO-PGF gilts. To test whether prostaglandins of the E series were involved in this mechanism, gilts were assigned to two 4 X 4 latin squares balanced for residual effects and treated with saline or flunixen meglumine (Banamine). Each gilt was treated with four PGE:PGF infusion sequences (SEQ) in each uterine horn: phosphate-buffered saline (PBS; PBS-SEQ), PGE1 (50 micrograms), PGE2 (50 micrograms), and PGE1 (25 micrograms) + PGE2 (25 micrograms) (PGE-SEQ), with each infusion followed 15 min later by PGF (25 micrograms).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Proteins secreted by the sheep conceptus suppress induction of uterine prostaglandin F-2 alpha release by oestradiol and oxytocin.

In Exp. I, 0.5 mg oestradiol or vehicle (0.5 ml absolute ethanol + 0.5 ml 0.9% NaCl) was injected i.v. at 08:00 h on Day 14 (onset of oestrus = Day 0). Blood samples were obtained via a jugular catheter at 30 and 1 min before oestradiol and every 30 min for 10 h afterwards. Plasma was obtained and assayed for 15-keto-13,14-dihydro-PGF-2 alpha (PGFM) by radioimmunoassay. Before oestradiol, PGFM basal values were higher (P less than 0.01) in pregnant (N = 10) than nonpregnant (N = 6) ewes (193 +/- 30 vs 67 +/- 8 pg/ml). However, at 4-10 h after oestradiol, pregnant ewes (N = 5) had less variable (P less than 0.01) PGFM values than did nonpregnant ewes (N = 5). In Exp II, conceptus secretory proteins (CSP) were obtained by pooling medium from cultures of Day-16 sheep conceptuses (N = 40). Ewes received 750 micrograms CSP + 750 micrograms plasma protein (N = 6) or 1500 micrograms plasma protein (N = 6) per uterine horn at 08:00 h and 18:00 h on Days 12-14. All ewes received 0.5 mg oestradiol at 08:00 h on Day 14 and blood samples were collected as in Exp. I and assayed for PGFM. On Day 15, 3 ewes in each group received 10 i.u. oxytocin and 3 received saline i.v. at 08:00 h and blood samples were taken continuously from 10 min before to 60 min after treatment. Mean PGFM response to oestradiol was suppressed (P = 0.05) in CSP- vs plasma protein-treated ewes (371 +/- 129 vs 1188 +/- 139 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Role of conceptus secretory products in establishment of pregnancy.

Conceptuses produce steroids, prostaglandins, proteins and possibly other unidentified agents which may play a role in the establishment and maintenance of pregnancy. A key event in this process is protection of the corpus luteum (CL) from the luteolytic activity of prostaglandin (PG) F-2 alpha of uterine origin. Oestrogens produced by the pig conceptuses between Days 11 and 16 appear to exert an antiluteolytic effect resulting in the sequestering of PGF-2 alpha within the uterine lumen. Failure of the pregnant uterus to release PGF-2 alpha in an endocrine fashion, therefore, allows for maintenance of CL function. Conceptuses of sheep and cattle produce proteins which, when introduced into the uterine lumen of nonpregnant ewes and cows, suppress the ability of oestradiol and oxytocin to stimulate uterine production of PGF-2 alpha. These conceptus secretory proteins appear to exert an antiluteolytic effect by inhibiting uterine production of luteolytic amounts of PGF-2 alpha. The horse conceptus produces both oestrogens and proteins during early pregnancy when uterine production of PGF-2 alpha is suppressed. Co-culture of horse endometrium and conceptus inhibits endometrial production of PGF-2 alpha. Conceptuses of pigs, sheep and cattle undergo elongation to achieve apposition between trophectoderm and endometrium but the horse embryo migrates rapidly and consistently throughout the uterus to achieve endometrial contact.

Animals↗

PubMed1986

Proteins secreted by day-16 to -18 bovine conceptuses extend corpus luteum function in cows.

Corpus luteum function, interoestrous interval and spontaneous uterine PGF-2 alpha (PGF) production were evaluated in 9 cyclic Holstein cows (3/group) after intrauterine injections of pooled conceptus secretory proteins, 5 beta-pregnan-3 alpha-ol-20-one, or homologous serum proteins on Days 15.5 through 21 after oestrus. A significant extension of corpus luteum lifespan and interoestrous interval were detected in cows treated with conceptus secretory proteins compared to the other 2 groups. CL lifespan and interoestrous interval were not different (P greater than 0.25) between 5 beta-pregnan-3 alpha-ol-20-one and control groups. Evaluation of spontaneous PGF responses suggested that proteins synthesized and secreted by the bovine conceptus accommodate luteal maintenance during early gestation via an attenuation of endometrial PGF production.

Animals↗

PubMed1986

Ovarian follicular development during early pregnancy in cattle.

On the day of oestrus (Day 0), 23 cows were assigned randomly to 4 groups in a 2 X 2 factorial experiment. Main effects were cow status [pregnant (P) versus non-pregnant (NP; not mated)] and day (Day 17 versus Day 34) when cows were slaughtered and ovaries collected; i.e. Groups NP-17 (N = 6), NP-34 (N = 5), P-17 (N = 6) and P-34 (N = 6). To mimic CL maintenance associated with presence of a conceptus in Group P-34, cows assigned to Group NP-34 were hysterectomized between Days 4 and 6 after oestrus. Pregnancy in Groups P-17 and P-34 (recovery of conceptus) and CL maintenance between day of surgery and Day 34 in Group NP-34 were confirmed. In Group NP-17, all cows except one were slaughtered before luteolysis. CL-bearing ovaries were serially sectioned (10 microns) and follicles (greater than 0.15 mm) were counted and measured using routine histological techniques. For each size class of follicles, the percentages of follicles were similar (P greater than 0.1) on Days 17 and 34. The percentage of non-atretic follicles (less than 4 pycnotic bodies) was lower (P less than 0.002) in pregnant than non-pregnant groups in the smallest class of antral follicles (0.16-0.28 mm) but was higher (P less than 0.03) in larger classes (0.68-3.67 mm) for pregnant groups. Percentages of atretic follicles were 3.7 and 4.9 (P greater than 0.1) for follicles of 0.16-0.67 mm, 91.1 and 78.9 for follicles of 0.68-3.67 mm (P less than 0.04) and 5.1 and 16.1 (P less than 0.05) for follicles of 3.67-78.56 mm in pregnant and non-pregnant groups respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1985

Characterization of proteins produced in vitro by periattachment bovine conceptuses.

Bovine conceptuses from Days 16 (n = 4), 19 (n = 6), 22 (n = 3), and 24 (n = 4), and chorion from Day 69 (estrus/mating = Day 0) were cultured for 24 h in modified minimum essential medium (MEM) in the presence of radioactive L-leucine [( 3H] leucine) to characterize de novo synthesis and release of proteins. Proteins released into MEM were identified by two-dimensional polyacrylamide gel electrophoresis, fluorography, and gel and ion exchange chromatography. Major polypeptides identified in MEM were different from those identified in conceptus and chorionic tissues. Both uptake of [3H] leucine and quality of polypeptides produced de novo and released into MEM were related to stage of conceptus development. Percent retention of [3H] leucine in MEM was lowest (P less than 0.01) in Day 16 cultures (1.2 +/- 4.1%), increased in Days 19 (16.8 +/- 3.7%) and 22 cultures (20.9 +/- 5.8%), and decreased (P less than 0.07) in Day 24 cultures (6.9 +/- 4.1%). Complexity of polypeptides increased after Day 16. Days 16, 19, 22 and 24 conceptus culture MEM was enriched in low-Mr, acidic polypeptides (Mr/isoelectric point ranges: 22K-26K/6.5-5.6, 20K-26K/5.5-5.4, and 16K-20K/5.0-4.5), which were not prominent products of Day 29 and 69 tissues. A high-Mr (Mr +/- SEM; 735K +/- 22K) glycoprotein was produced by all conceptus and chorionic tissues. The transient nature of production of low-Mr polypeptides suggests that they may be required during the periattachment period.

Amino Acids↗

PubMed1985

Characterization of proteins produced in vitro by bovine endometrial explants.

Endometrial tissues were obtained from 17 pregnant (P, estrus/mating = Day 0; Day 16, n = 4; Day 19, n = 6; Day 22, n = 3; Day 24, n = 4) and six nonpregnant (NP; Day 16, n = 4; Day 19, n = 2) cattle, as well as from one cyclic (nonbred) cow (Day 4), one later-pregnant cow (Day 69), and both ligated and pregnant uterine horns of three unilaterally pregnant cattle (UP; Day 270). Tissues (approximately equal to 500 mg wet tissue/explant) were cultured for 24 or 48 h in modified minimal essential medium (MEM), in the presence of radioactive amino acid and/or amino sugar substrate(s) (L-[3H] leucine, L-[14C] leucine, and D-[3H] glucosamine), in order to characterize substrate uptake and de novo synthesis and release of proteins and polypeptides in vitro. Endometrial explants from all cattle produced proteins de novo from radiolabeled substrates. Chromatographic (gel filtration, cation, and anion exchange) and two-dimensional polyacrylamide gel electrophoretic analyses revealed complex patterns of primarily acidic radiolabeled polypeptides in dialyzed MEM, which were absent from endometrial tissue homogenates. No qualitative differences were noted in the array of proteins released into MEM associated with either pregnancy status (P vs. NP, UP) or stage of gestation (Days 16, 19, 22, 24, 69, and 270). Medium from all endometrial explants was enriched in polypeptides in four Mr (X 10(3)/pH classes (I, approximately equal to 14/greater than 7.2; II, 19-24/5.4-6.3; III, 28-31/6.9-7.3; and IV, greater than or equal to 150/less than or equal to 5.1).

Amino Acids↗

PubMed1985

Characteristics of prostaglandin F measurements in the ovarian circulation during the oestrous cycle and early pregnancy in the cow.

Holstein or crossbred beef cows were anaesthetized on Days 15 to 17 after oestrus; the ovarian artery (OA), ovarian (utero-ovarian) vein (OV) and a peripheral artery (PA), were catheterized for chronic blood sampling. Beginning on the day after surgery, 6 sequential blood samples were collected every 30-40 min twice daily from 8 cyclic and 6 pregnant cows during Days 16-20: 818 blood samples (including 216 OA and PA concurrent arterial pairs) were collected. Overall least squares means for PGF concentrations (pg/ml) in the OV, OA and PA of cyclic cows were 562, 228 and 106, respectively. A significant (P less than 0.01) OA-PA difference (122 pg/ml) suggests that a local transfer system, between uterine venous effluent and ovarian arterial affluent, is functional in the cow. A transfer efficiency of about 1% was estimated. In cyclic cows differences in OA-PA concentrations of PGF were minimal on Days 16-18 and increased to about 160 pg/ml during luteal regression (Days 19-20). In pregnant cows a biphasic OA-PA pattern of difference in PGF between days was detected, with a peak on Day 18 (136 pg/ml) which was not apparent on Days 19-20. Amplitude of PGF spikes in the OA was significantly higher in cyclic (725 pg/ml) than in pregnant cows (397 pg/ml). We suggest that pregnancy suppresses PGF delivery to the ovarian circulation, resulting in maintenance of the corpus luteum in pregnant cows.

Animals↗

PubMed1985

Periparturient endocrine changes of conceptus and maternal units in Holstein heifers bearing genetically different conceptuses.

Holstein heifers (n = 21) were balanced across sires and assigned to three service-sire-breed groups in which heifers were inseminated artificially to either purebred Angus (n = 7), Holstein (n = 7) or Brahman (n = 7) bulls. Semen from four bulls was used for each service sire-breed group. Blood samples were collected from a jugular vein thrice weekly from d 160 to 265 of pregnancy, daily thereafter until 15 d postpartum, and then thrice weekly until d 60 postpartum. Concentrations of progesterone, estrone, estradiol, and estrone sulfate from 23 d prepartum to parturition, and of 15-keto-13,14-dihydro-prostaglandin F2 alpha (PGFM) from 2 d prepartum to d 15 postpartum were measured by radioimmunoassay. Heifers within the Brahman-service-sire group had longer gestations (P less than .05) than those of Holstein- or Angus-service-sire groups (285.0 vs 278.7), 279.0 d). Calf birth weight was lower (P less than .05) in Angus- than Holstein- and Brahman-service-sire groups (30.6 vs 36.1, 43.4 kg). Daily trends of prepartum maternal progesterone concentrations were approximately 1 ng/ml lower (P less than .01) in Angus- than Holstein- or Brahman-service-sire groups until luteolysis occurred. Heifers bearing crossbred Angus conceptuses had lower daily trends of prepartum estrogens concentrations (P less than .01), whereas heifers of the Holstein- and, even more dramatically, of the Brahman-service-sire groups had a higher magnitude and greater rise of plasma estrogens concentrations between d -10 and -1 prepartum (less than .01). Postpartum mean concentrations (P less than .05) and response curves of PGFM were lower (P less than .01) in the Angus- than in the Holstein- or Brahman-service-sire groups. Calf birth weights were correlated with least-squares means for maternal concentrations of prepartum estrone (r = .57), estradiol (r = .59) and estrone sulfate (r = .64) and postpartum maternal concentrations of PGFM (r = .56). Functional responses of the conceptus (e.g., estrogens) and maternal units (e.g., progesterone and PGFM) were influenced by conceptus genotype during the periparturient period.

Animals↗

PubMed1985

Carry-over effects of periparturient endocrine changes on postpartum reproductive function of Holstein heifers bred to genetically different service sires.

Effects of fetal sire on postpartum reproductive changes of the dam were studied in 21 Holstein heifers whose pregnancy had been initiated by either Angus (n = 7), Holstein (n = 7) or Brahman (n = 7) bulls. After parturition, all heifers were managed uniformly. Heifers in each service-sire-breed group were bled via jugular venipuncture thrice weekly from d 160 to 265 of pregnancy, daily thereafter until 15 d postpartum, and three times per week until d 60 postpartum. Ability of heifers to release prolactin (PRL) and luteinizing hormone (LH) was evaluated on d 10 postpartum after a simultaneous injection of thyrotropin releasing hormone (TRH; 100 micrograms) and gonadotropin releasing hormone (GnRH; 100 micrograms). Between d 5 and 60 postpartum, the reproductive tract of each heifer was examined rectally thrice weekly after collection of blood samples. Basal concentrations of LH from d 1 to 10 postpartum, as well as ability of the pituitary gland to release LH and PRL after the GnRH-TRH challenge, did not differ between service-sire-breed groups (P greater than .1). Means and profiles of progesterone concentrations during the first 60 d postpartum did not differ between service-sire-breed groups (P greater than .1). However, increases in progesterone concentrations following the GnRH-TRH challenge were synchronized more precisely in Angus (P less than .02) than in Holstein- and Brahman-service-sire groups. Daily rates of reduction in cervical and uterine horn diameters were higher (P less than .01) in Holstein- and Brahman- than in Angus-service-sire groups and were associated with higher profiles of postpartum 15-keto-13,14-dihydro-prostaglandin F2 alpha (PGFM) concentrations. Within-cow PGFM concentrations were correlated positively with cervical (r = .36) and uterine horn (r = .32) diameters. Postpartum ovarian responsiveness and uterine involution in Holstein heifers may be affected by genotypes of the conceptus they bore during pregnancy.

Animals↗

PubMed1985

Effects of climatic and management factors on conception rate of dairy cattle in subtropical environment.

Breeding records, representing 12,038 inseminations at Bassett's Dairy Farm (Monticello, FL), were analyzed to document effects of environmental and management factors on fertility of dairy cattle from January 1, 1975 to December 31, 1977. Conception rates of lactating cows decreased sharply when maximum air temperature on day after insemination exceeded 30 degrees C. In contrast, conception rates for heifers did not decline until 35 degrees C. Virgin heifers had higher conception rates for all services (50%) than lactating cows (34%) and suffered only slight depression of fertility during summer months. Heifers required 1.5 services per conception compared with 2.3 for lactating cows. Relationship between conception rate and rainfall on day after insemination was negative and curvilinear. Jerseys had higher conception rates (45%) than Holstein (39%) and Brown Swiss (41%). Services per conception were 1.7, 2.0, and 1.9. Substantial decreases of fertility were associated with advancing service number. Estrous status (standing; positive heat detection patch; mounting activity), inseminator, and year of service were related to variation of conception rate. Seasonal effects on fertility of lactating cows were marked. Thus, environmental management of the postpartum cow during hot summer months is warranted to maximize fertility.

Animal Husbandry↗

PubMed1985

Interrelationships of milk yield, body weight, and reproductive performance.

Records (2263) from a single north Florida herd for 3 yr were evaluated in a series of analyses. Environment was subtropical. Data set included only cows that had normal milk records and became pregnant. Holsteins and Jerseys averaged 6799 and 4504 kg milk, 587 and 418 kg postpartum body weight, 164 and 141 days open, and 2.3 and 2.1 services per subsequent pregnancy. Pooled within breed, repeatabilities and heritabilities of these performance measures were .37, .15; .53, .25; .20, .06; and .30, 0. Estimable genetic correlations were milk yield and body weight -.09, milk yield and services per conception .38, and services per conception and body weight .37; range of standard errors was .22 to .39. Substantial genetic antagonism may exist between milk yield and body weight, and efficient reproduction. If results of this research are verified elsewhere, breeders should be aware that selection for increased weight could lead to decreased reproductive efficiency.

Analysis of Variance↗

PubMed1984

Relationship of 15-keto-13,14-dihydro-prostaglandin F2 alpha concentrations in peripheral plasma with local uterine production of F series prostaglandins and changes in uterine blood flow during the early postpartum period of cattle.

Cows were prepared for surgery, either within 12 h after parturition (Day 0, n = 3), on Day 1 (n = 1) or on Day 2 (n = 1) postpartum. The previously gravid uterine horn was exposed through a high lumbar laparotomy, and catheters inserted into an uterine branch of the ovarian vein (UBOV) and in the main uterine artery (UA) via a branch of the main uterine artery. A blood flow transducer (8-13 mm, internal diameter) was placed around the UA. Starting 12-24 h following surgery, simultaneous blood samples were collected from UBOV and UA at 15-min intervals for 1 or 2 h daily from Days 1 to 10 postpartum (mean = 5.3 days). Concurrently, uterine blood flow (UBF) was recorded daily for 6 h. Mean concentrations of prostaglandin F2 alpha (PGF2 alpha) and 15-keto-13, 14-dihydro-PGF2 alpha (PGFM) were higher (P less than 0.01) in UBOV than UA (4.64 +/- 0.6, n = 96 vs. 0.08 +/- 0.02 ng/ml, n = 92 and 5.67 +/- 0.41, n = 98 vs. 1.02 +/- 0.09, n = 94, ng/ml, respectively). Concentrations of PGF2 alpha and PGFM in the UBOV increased (P less than 0.1) on Days 2 and 3 and decreased (P less than 0.01) thereafter. Mean UBF (ml/min) decreased (P less than 0.01) from 3079 +/- 683 on Day 1 to 602 +/- 56 on Day 2 and was 413 +/- 55 on Day 5.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1984

Source of F series prostaglandins during the early postpartum period in cattle.

In vivo and in vitro studies were conducted to determine the contribution of the bovine uterus to concentrations of 15-keto-13,14-dihydro-prostaglandin F2 alpha (PGFM) in peripheral plasma of postpartum cows. In Experiment 1, cows were assigned to three groups: untreated control (n = 4), hysterectomy following a manually induced prolapse of the uterus (n = 5) and sham operation (n = 3: prolapse of the uterus and replacement). Surgery was performed within 8 h of parturition, and blood samples collected frequently on the day of surgery and once (0800 h) or twice (0800 and 1700 h) daily from Day 1 to Day 15 postpartum. Following hysterectomy, PGFM concentrations decreased precipitously, became essentially undetectable by 5 h, and remained so for the rest of the experimental period. In contrast (P less than 0.01), PGFM concentrations, which remained elevated during the day of surgery in the sham-operated group, peaked on Day 2 (sham-operated group: 1339 pg/ml) or Day 3 (untreated control: 2143 pg/ml), and declined to a basal concentration between Days 10 to 15. In Experiment 2, in vitro metabolism of tritiated arachidonic acid ([3H] AA: 10 microCi) and production of PGF2 alpha and PGFM were studied in explants of early postpartum intrauterine tissues (myometrium, caruncle and intercaruncular endometrium). Extracts of [3H] AA metabolites released into the incubation medium were separated on Sephadex LH-20 column chromatography. Metabolites of [3H] AA, having the same chromatographic mobility as PGF2 alpha, PGFM and PGE2, were detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗