Placenta detachment: unexpected high concentrations of 5-hydroxytryptamine (serotonin) in fetal blood and its mitogenic effect on placental cells in bovine

The purpose of this study was twofold: (1) to determine whether there is a profile of 5-hydroxytryptamine (5-HT, serotonin) concentrations in fetal bovine blood and tissues during pregnancy, parturition and the early neonatal period and (2) to determine whether 5-HT has a 'mitogenic' effect on cultured placentome cells in bovine. Results revealed a 5-HT concentration profile in fetal blood. Overall concentrations of 5-HT in fetal blood were 6.6 times (P< 0.001) that of adult cows and 2.8 times (P< 0.001) that of blood collected during caesarean section (from umbilical veins) and from 18-72 h old calves. Mid-term and full-term pregnancy fetuses were not statistically different from each other. Overall concentrations of 5-HT in the intestinal wall of the fetus were 4.4 times higher (P< 0.05) than in the 24 h calf. Concentration of 5-HT in full-term muscle was 3.5 times higher than in mid-term muscle and 2.8 times higher than in 24 h old calf muscle (P< 0.05). Concentrations of 5-HT in mid-term and full-term cotyledon were 4.4 times higher (P< 0.05) than in post partum cotyledon. Characterized trophoblast cells and a heterogeneous population of bovine cotyledon cells treated with 5-HT (2.5, 5.0 and 10.0 microm) incorporated between 2.0 and 3.0 times more(3)[H]-thymidine than untreated controls, indicating a dose-dependent (r=0.94) positive mitogenic effect of 5-HT. Both groups of cultured cells responded equally. Five-HT treatment did not affect either cell number or cell size. It was concluded that a 5-HT concentration profile exists in fetal bovine blood and tissues and that 5-HT has the ability to act as a mitogen in bovine placental cells.

Reduced cortisol potentiates the exercise-induced increase in corticotropin to a greater extent in trained compared with untrained men

We examined the effect of acute exercise and reduced cortisol on pituitary and adrenal responsiveness and the impact of reduced plasma cortisol on maximal oxygen consumption (VO2max) in eight trained (T) and eight untrained (UT) males. Subjects completed two graded maximal exercise tests (GXT), each preceded by either overnight metyrapone (MET) or placebo (PLA) administration. Blood samples were collected before and after GXT. With PLA, resting corticotropin (ACTH) levels were higher in T versus UT men; however, cortisol and 11-deoxycortisol were similar between groups. Following GXT on PLA, cortisol was unchanged but 11-deoxycortisol increased in both groups; however, ACTH increased only in UT men. For both groups, cortisol, 11-deoxycortisol, and ACTH were different post-GXT with MET versus PLA. Furthermore, following GXT with MET, the ACTH response was greater in T versus UT subjects. VO2max was not altered by MET in either group. We conclude that (1) at rest, only ACTH levels differed between T and UT men; (2) individually, the GXT and MET provide a similar ACTH response in UT but not in T subjects; (3) when GXT and MET are superimposed, they provide a stronger stimulus to pituitary and adrenal reserve than either test alone; (4) the combination of MET and GXT elicits a greater ACTH response in T compared with UT men; and (5) an acute reduction in plasma cortisol does not alter VO2max.

Evaluation of inhibitory effects of doxorubicin on collagenase using a bovine placentome model

The chemotherapeutic antibiotic doxorubicin (Adriamycin) was reported to inhibit bacterial collagenase activity when tested on both a synthetic substrate and intact collagen. Our objective was to establish whether doxorubicin would inhibit bacterial collagenase activity on a bovine placentome model. Metabolically active, isolated bovine placentomes were infused, via umbilical vessels, with a mixture of bacterial collagenase and doxorubicin. Six experimental groups were used. Group (1) comprised of saline controls; (2), collagenase at 1,200 U/cc; (3, 4, and 5), collagenase (1,200 U/cc) plus doxorubicin at 0.04 mg/cc, 0.02 mg/cc, 0.01 mg/cc, respectively; (6), doxorubicin at 0.02 mg/cc. After 5 hrs of incubation (39 degrees C), manometric pressure (needed to separate caruncle and cotyledon), caruncle-cotyledon interface hydroxyproline (collagenolysis), and total protein (proteolysis) were determined. Results indicated no (P > 0.01) inhibition of collagenase by doxorubicin. We concluded that doxorubicin (at above dosages) is not an inhibitor for bacterial collagenase when tested on bovine placentomes.

The potential of collagenase as a new therapy for separation of human retained placenta: hydrolytic potency on human, equine and bovine placentae

The purpose of this study was to determine to what degree bacterial collagenase may digest human placentae compared to equine and bovine placentae. Placenta samples from human, equine and bovine were incubated with bacterial collagenase solution at various concentrations. The degree of hydrolysis and collagen breakdown was measured by the release of total proteins and hydroxyproline into the incubation media. Also, whole placentae were injected via umbilical cord arteries with collagenase solution (200 U/ml, 200 ml total volume in human and 1000 ml in equine) and hydrolysis determined chemically and subjectively. Human and equine placental collagens were the most sensitive to collagenase digestion. Overall mean collagenase activity determined by the release of hydroxyproline from human placenta was 1.6 times and in equine placenta three times greater than in bovine placenta, while the breakdown of non-collagenous proteins remained negligible. When injected into whole placenta, the collagenase digested placentae evenly within 6-12 h. At 24 h, placentae were liquefied, although, umbilical blood vessels resisted collagenase digestion. Bacterial collagenase was highly effective in breaking down human placenta collagen. Intraplacental injections of collagenase via umbilical cord arteries may help to detach retained placenta in women as it does in mares and cows.

Equine retained placenta: technique for and tolerance to umbilical artery injections of collagenase

Under laboratory conditions and in clinical experiments, bacterial collagenase has proven to be effective in hydrolyzing placenta and detaching cotyledon from caruncle in the bovine species. Laboratory studies in which placental samples were incubated with collagenase have also demonstrated that collagenase is 3.7 times more effective in hydrolyzing equine placenta than bovine placenta. This led to the hypothesis that collagenase may be a potential treatment for mares with retained placenta. However, that collagenase may hydrolyze the uterine wall and perforate the uterus was a concern. It was the purpose of this study thus to determine any adverse effects of collagenase on the equine uterus and to develop a method for intraplacental injection of collagenase. Three normally expelled intact placentas from Arabian mares, 10 cyclic mixed-breed mares, and 4 mares of various breeds with retained placenta were used. Fluoroscein dye and latex were used to study the placental vasculature and to determine a suitable dose of collagenase; placentas were hydrolyzed by collagenase solution in vitro. Bacterial collagenase solution (40,000 units, 200 ml) was infused into the uterine lumen of each cyclic mare. Uterine biopsies were obtained from the mares before collagenase infusion and again at 16 h and 26 d after infusion. In the mares with retained placenta, each placenta was infused via its umbilical cord vessels with 200,000 units of bacterial collagenase in 1 L of saline. Results showed that none of the uteri from cyclic mares were damaged by collagenase treatment. During a 4-wk period of monitoring (including endoscopy) mares with retained placenta did not show any abnormalities. Retained placentas were expelled in less than 6 h after collagenase treatment. It was concluded that intraplacental injections of collagenase are a safe and potentially effective treatment for retained placenta in mares.

Prevention of retained placenta by injection of collagenase into umbilical arteries of calves delivered by cesarean section: A tolerance study

In the cow, cesarean section delivery is often followed by retention of fetal membranes. Hypothetically, the retention of fetal membranes could be prevented by intraplacental injections of the enzyme collagenase. However, the infusion of this potent proteolytic enzyme into a uterus traumatized by surgery can lead to uterine damage, including perforation. Thus, the objective of this research was to evaluate tolerance of intraplacental treatment of bacterial collagenase. A cesarean section was performed on 10 experimental cows undergoing induced delivery or diagnosed with dystocia. During the surgical procedure, 200,000 units of bacterial collagenase in 1 L of saline were infused via the umbilical arteries. A cesarean section was also performed on control cows (n = 25) affected by dystocia, but these received no collagenase. The collagenase-treated cows showed no clinical or laboratory signs of abnormality over a 3- to 4-wk observation period post treatment. When membrane retention time was set at 36 h post surgery, 20% of the experimental cows and 60% of the control cows had retained the fetal membranes. It was concluded that intraplacental administration of collagenase during cesarean section is safe. However, treatment effectiveness and economic benefits for commercial application need further study.

Results of a combined dexamethasone suppression/thyrotropin-releasing hormone stimulation test in healthy horses and horses suspected to have a pars intermedia pituitary adenoma

OBJECTIVE

To evaluate results of a combined dexamethasone suppression/thyrotropin-releasing hormone (TRH) stimulation test in horses suspected clinically to have a pars intermedia pituitary adenoma (PIPA).

DESIGN

Case-control study.

ANIMALS

7 healthy adult horses and 5 horses suspected to have a PIPA.

PROCEDURE

A baseline blood sample was collected, and dexamethasone (40 micrograms/kg [18 micrograms/lb] of body weight, IV) was administered; a second blood sample was collected 3 hours later, and TRH (1.1 mg, IV) was administered; serial blood samples were collected 15, 30, 45, 60, and 90 minutes and 21 hours after TRH administration (24 hours after dexamethasone injection). Cortisol concentration was determined for all blood samples.

RESULTS

Baseline cortisol concentration was significantly lower in horses suspected to have a PIPA than in healthy horses. Cortisol concentration was suppressed by dexamethasone in both groups; however, after TRH administration, cortisol concentration returned to baseline values in horses suspected to have a PIPA, but not in healthy horses. Concentration was still less than the baseline value 24 hours after dexamethasone administration in healthy horses.

CLINICAL IMPLICATIONS

The combined dexamethasone suppression/TRH stimulation test may be a useful diagnostic test in horses suspected to have a PIPA. For clinical application, collection of a blood sample 30 minutes after TRH administration is recommended.

Evaluation of injections of collagenase and oxytetracycline via the umbilical artery as treatment for retained placenta in cattle

OBJECTIVES

To test whether oxytetracycline inactivates collagenase when combined as a potential treatment for retained fetal membranes in cattle and to determine whether oxytetracycline passes to blood from fetal membranes after intraplacental injection.

DESIGN

Prospective, controlled study.

SAMPLE POPULATION

288 placentomes from 12 cows in their third trimester of pregnancy and 4 cows at term pregnancy.

PROCEDURE

8 experimental groups were established: saline control, collagenase, collagenase plus oxytetracycline at 3 dosages, and oxytetracycline at 3 dosages. Placentomes were infused through an umbilical vessel with the test solutions and incubated at 39 C for 4 hours. Immediately after incubation, the force needed to detach cotyledons from caruncles was measured by a manometric technique. Cotyledon-caruncle interface fluids were analyzed for hydroxyproline (collagen breakdown) and total protein contents. A combination of collagenase and oxytetracycline was injected via umbilical arteries of cows undergoing cesarean section and in cows with retained fetal membranes after natural delivery. Antibiotic residue in blood was determined by the Bacillus stearothermophilus disk assay.

RESULTS

There were no significant differences among collagenase and collagenase plus oxytetracycline groups in the amount of pressure needed to separate cotyledon from caruncle, amount of hydroxyproline released, and amount of total protein broken down. The 4 cows tested negative for oxytetracycline in the blood.

CLINICAL RELEVANCE

Oxytetracycline and collagenase may be a potential combination treatment for retained fetal membranes in cattle. In addition, the lack of antibiotic residue detection in blood may be of regulatory relevance.

Successful treatment of retained placenta with umbilical cord injections of collagenase in cows

Fetal membranes usually are released from the uterus between 2 and 6 postpartum hours. However, in a substantial percentage of cows (11%), fetal membranes are retained for several days. In part, failure of collagen breakdown seems to be related to retention of fetal membranes. Injections of 200,000 U of bacterial collagenase in 1,000 ml of physiologic saline solution via umbilical arteries (1 or 2) between 24 and 72 hours of retention caused release of retained fetal membranes in 23 of 27 cows (85%) with noninduced retained fetal membranes and in 10 of 14 cows (71%) with experimentally induced retained fetal membranes, within 36 hours after injection. Controls (n = 36) did not release retained fetal membranes within this time. Injections of collagenase via a jugular vein (2.2 x 10(6) U in 1,000 ml of physiologic saline solution), administered over a 30-minute period, caused release of retained fetal membranes within 36 hours in 3 of 6 cows with experimentally induced retained fetal membranes. Clinical complications did not follow treatments with collagenase. Umbilical injections of bacterial collagenase were highly effective in the treatment of retained fetal membranes in cows. The procedure is simple, safe, affordable, and can be completed in 25 minutes.

Bovine retained placenta: effects of collagenase and hyaluronidase on detachment of placenta

A significant percentage of cows (11%) fail to release the placenta within 12 h postpartum. Failure of collagen breakdown seems to be related to the retention of placentas. Sections of placentomes incubated with bacterial collagenase caused an increase in placentome proteolysis (6.6-fold) and placentome collagenolysis (94-fold) within 4 h in a dose-related fashion (r = 0.94). Injections of collagenase (825 U/cc) into the placentomes, via umbilical vessels, decreased the cotyledon-caruncle binding force (determined by manometry) to 30 +/- 5 mm Hg from 97 +/- 2 mm Hg, and increased proteolysis by 42% within 8 h (r = -0.95). Hyaluronidase at various concentrations (400-8 250 U/cc) and at various incubation times (up to 8 h) was not effective. Hyaluronidase (825 U/cc) and collagenase (825 U/cc) were not synergistic in loosening cotyledon-caruncle attachment. A single 15-min collagenase pulse, given prior to perfusion with collagenase-free blood, was as effective in loosening cotyledon attachment as was a sustained 2-h perfusion of blood with collagenase added. It was concluded that collagenase caused collagenolysis and loosening of cotyledon from caruncle, but collagenolysis and cotyledon-caruncle separation were not facilitated by the presence of hyaluronidase.

Fine structural aspects of postnatal development of feline lung

Lung development was studied in late prenatal, 1-, 7-, 14-, and 21-days postnatal and adult cats. Cats were born with a few alveoli, and the lungs appeared to have patches of primitive air spaces (saccules). The saccules of prenatal kittens were thick walled, very cellular, and lined by type II pneumocytes. Eosinophils were observed in the septum, intraepithelially, and in the alveolar space of growing cats. Secondary septa were flanked by a double capillary network and divided saccules into multiple shallow alveoli. Septation was irregular and time dependent and not completed by day 231 of postnatal life. Elastic fibers accumulated at the tip of the septa, seemingly playing an important role in alveolar formation. Type II pneumocytes were located at the base of the secondary septa in growing cats, thus strengthening secondary septa to withstand the stresses of respiration. Pores of Kohn were not observed in growing cats.

Clearance of exogenous carnitine in bovine semen: Potential diagnosis of epididymal function and patency of the ductus deferens

Carnitine content in the ejaculate depends mainly on the capability of the epididymis wall to transfer carnitine from the blood and on the patency of ejaculatory ductus systems. An elevation of carnitine in semen subsequent to an intravenous injection of carnitine is expected. Intravenous injections of carnitine (L-isomer and DL-isomers) caused a significant (P <0.05) elevation (more than 10-fold) in blood carnitine. However, carnitine injection failed to increase net secretion of carnitine into the ejaculate and blood elimination half-life was 2.3 hours. Mean concentrations of carnitine in the electroejaculate (3.0 nmoles/ml) were significantly lower than in the ejaculate following natural mating (180 nmoles/ml). Vasectomy decreased net carnitine per ejaculate to about 1/5 the prevasectomy value, when ejaculate was collected following natural mating. However, vasectomy did not affect carnitine concentrations in semen collected by electroejaculation. Twenty-one percent of the carnitine in semen originated in the accessory glands and 79% in the epididymides. Carnitine in the electroejaculate was originated almost exclusively in the accessory glands. It was concluded that the diagnostic value of carnitine in semen is limited. Some considerations are: secretion of carnitine is not organ specific, there are large individual variations, there is a negative effect of electroejaculation, and a carnitine loading dose technique is not feasible. However, there is a diagnostic potential in using carnitine assay to detect epididymides occlusion, but only when ejaculate is collected by an artificial vagina.

Changes in the proportion of type I and type III collagen in the developing and retained bovine placentome

The proportions of Type I and Type III collagen were evaluated from gestational, postpartum-retained, and released bovine placental membranes. Placentomes were excised at 90, 150, 210, and 270 days of gestation (n = 32) and from postpartum-retained (2 and 12 h, n = 8) and released (2 h, n = 4) membranes. Placentome components were processed for collagen, hydroxyproline, protein, and dry weight determination. Collagen extracts were separated by SDS-PAGE. Densitometry was used to establish the proportions of collagen alpha chains (Type I = 2 alpha 1 + 1 alpha 2; Type III = 3 alpha 1). No difference in the proportion of maternal caruncular Type I and Type III collagen was found. The proportion of Type I fetal cotyledonary collagen was lowest (p less than 0.05) at Day 90 of gestation but did not differ between Days 150, 210, 270, or between retained and released fetal membranes. The proportion of Type III fetal cotyledonary collagen was greatest (p less than 0.05) at Day 90. Retained fetal cotyledons had a greater (p less than 0.05) proportion of Type III collagen than did released fetal cotyledons. Therefore, although hydroxyproline content was not different between retained and released fetal membranes, the retained bovine fetal cotyledon was characterized by disproportionate amounts of Type III collagen as compared to the fetal cotyledon that was not retained.

Uterokinetic activity of fenprostalene (a prostaglandin F2α analog) in vivo and in vitro in the bovine

The luteolytic potency of fenprostalene (a PGF2alpha analog) is about 20-times that of naturally produced PGF2alpha. The objective of this research was to investigate the uterokinetic effects of fenprostalene at a luteolytic dosage (1.0 mg) in the cyclic and early postpartum cow, and in the isolated uterine horn. Uterine motility measurements were conducted on two consecutive days in each cow. Experimental protocol on Day 1 was: spontaneous motility was recorded for 1 h; fenprostalene was injected (1.0 mg i.m.), after which motility was recorded for 2 h; fenprostalene was injected (1.0 mg i.v.) and motility was recorded for 30 min; and oxytocin was injected (40 U i.v.), followed by a 30-min recording period. On Day 2, the treatment sequence was reversed: spontaneous motility was recorded for 1 h; oxytocin was injected (100 U i.m.), after which motility was recorded for 2 h; fenprostalene was injected (1.0 mg i.v.) and motility recorded for 30 min; and oxytocin was injected (40 U i.v.), followed by a 30-min recording period. In the in vitro experiment, different dosages of fenprostalene (5.9, 11.8, 17.6, and 29.4 ng/ml bath solutions) and oxytocin (0.06, 0.12, 0.18, and 0.60 mU/ml bath solutions) were tested in pairs for 1 h. The treatment was then repeated. In a different group, fenprostalene (5.9 ng/ml bath solution) and oxytocin (0.06 mU/ml bath solution) treatments were alternated. Fenprostalene (at luteolytic dosage) was not uterokinetic in either the cyclic or postpartum cow. However, fenprostalene and oxytocin had a significant uterokinetic effect (five- to six-fold pretreatment value) on the isolated uterine horn preparation at all dosages studied. Peak motility occurred between 10 to 15 min, followed by a gradual decrease to 40% at 60 min. When the treatments were repeated at 60 min, oxytocin but not fenprostalene caused a minute, transient contraction. However, fenprostalene-desensitized (by exposure to fenprostalene) uteri reacted significantly to oxytocin, and vice versa.

Morphometric analysis of collagen in gestational and retained bovine placentomes

Bovine placentome collagen was quantified (P<0.01) at four gestational stages (90, 150, 210 and 270 d, n = 8 d ), at 2 h post partum without (n = 4) and at 2 and 12 h post partum with (n = 8) experimentally-induced placental retention. Placentome sections were fixed and stained for collagen. Fetal cotyledonary (FC) collagen volume fraction (V(V)) increased over days of gestation studied (V(V)=0.03+/-0.01, 0.06+/-0.01, 0.13+/-0.01 and 0.19+/-0.01). Fetal cotyledonary hydroxyproline (3.15+/-0.41, 4.55+/-0.41 and 7.04+/-0.41 mg/g) and FC protein (432.0+/-17.1, 479.9+/-17.1, 585.4+/-17.1 mg/g) increased over Days 90, 150 and 210 and were similar on Days 210 and 270. Fetal cotyledonary collagen V(V) and hydroxyproline did not differ between Day 270, retained and nonretained cotyledons. Protein concentration was higher in 2 h (578.1+/-18.5 mg/g) and 12 h (526.0+/-18.5 mg/g) retained versus nonretained (400.4+/-36.2 mg/g) cotyledons. Maternal caruncular (MC) collagen V(V) and protein concentration were higher on Days 90 and 150 than on Days 210 and 270. Maternal caruncular hydroxyproline was similar from Day 90 to 210 and increased from Day 210 to 270. Maternal caruncular collagen V(V), hydroxyproline and protein concentrations were similar on Day 270 and in 2 h and 12 h retained membrane caruncles. Gestational increases in placentome collagen occurred from FC sources. No difference in FC or MC collagen V(V) existed between Day 270, retained and nonretained placentomes.

Desensitization of rabbit myometrium to oxytocin and prostaglandin F2 alpha

The desensitizing effects of oxytocin (OT) and prostaglandin F2 alpha (PGF2 alpha) were investigated in the uteri of rabbits. Uterine motility was measured in anesthetized rabbits infused intravenously with either PGF2 alpha (50 micrograms/min) or OT (100 mU/min) alternately. The treatment sequence was saline (30 min), first drug (OT or PGF2 alpha, 90 min), second drug (OT if PGF2 alpha was first drug and vice versa, 90 min), and first drug (repeated) 60 min. Both OT and PGF2 alpha infusions increased motility approximately 200% within 5-10 min. Thereafter, motility decreased linearly to base-line value. Fifty percent desensitization was completed at 35-45 min and 100% at 90 min. A tenfold increase in the infusion rate caused no further increase in motility. However, OT infusion into a PGF2 alpha desensitized uterus (and vice versa) elicited an immediate uterokinetic response. Oxygen consumption and glucose oxidation rate of uterine slices measured at different stages (preinfusion, maximal motility, and desensitized) of uterine motility showed no difference (P greater than 0.05) between the two experimental treatments. It was concluded that either OT or PGF2 alpha infusions specifically desensitized the uterus.

Absence of uterokinetic effects of prostaglandin F2α on oxytocin-reactive uterus in the mare

In most cyclic females, prostaglandin F(2 alpha) (PGF(2 alpha)) triggers a uterine motility response resembling that of oxytocin (OT). To determine if PGF(2 alpha) is a uterokinetic substance in the cycling mare, uterine motility was measured by intrauterine balloon technique in 12 conscious, normally cyclic mares. After 60 min of saline infusion, continuous intravenous (i.v.) infusion with OT (1 i.u./min) was followed by PGF(2 alpha) (200 microg/min) for 60 min each. The experiment was repeated 3 wk later except with PGF(2 alpha) preceding OT. A second group of mares was administered OT (60 i.u.) either i.v., intramuscularly (i.m.), or intrauterinely (i.u.). Plasma samples were studied for progesterone concentration. Control uterine motility for the first group of mares was (mean +/- SEM) 545.83 +/- 45.10 mm(2). Significant (P<0.05) elevation in uterine motility was recorded for OT (1118.60 +/- 70.56 mm(2)) regardless if PGF(2 alpha) preceded OT infusion or vice-versa. No significant difference (P>0.05) was seen in motility after PGF(2 alpha) (423.33 +/- 31.12 mm(2)) infusion. The uterokinetic effect of OT was greatest when OT was administered i.v. (1696.50 +/- 195.46 mm(2)) followed by i.m. (819.82 +/- 39.96 mm(2)), and it was least effective when administered i.u. (607.83 +/- 21.56 mm(2)) as compared to control uterine motility (279.78 +/- 22.33 mm(2)). Skin electrical resistance values rose from 0 to 2000 ohms with PGF(2 alpha) infusion (but not with OT), indicating that PGF(2 alpha) was bioactive. It was concluded that PGF(2 alpha) was not a uterokinetic substance in the cyclic mare.

Effect of electroejaculation on progesterone and cortisol excretion in bovine semen

Artificial vagina (AV) and electroejaculation (EE) are the 2 methods used to obtain semen from bulls. The purpose in the present study was to evaluate these 2 methods of collection when 2 markers, cortisol and progesterone, were injected IV. During period 1 (control measurement), semen was obtained by EE at 0, 20, 60, 120, and 180 minutes. In period 2, bulls were injected (3 days later) with a mixture of cortisol (113 mg) and progesterone (100 mg), and then samples were obtained by EE. In period 3, cortisol and progesterone were injected (3 weeks later), and samples were obtained by AV. Seminal plasma concentrations of cortisol and progesterone were maximal at 20 minutes in EE and AV collections. Seminal plasma concentrations of progesterone and cortisol were roughly 50% less in EE than in AV collection. However, the total excretion of progesterone and cortisol per collection was similar in both techniques. Excretion of cortisol was 14 to 33 times greater than that of progesterone. It was concluded that concentrations of markers in the EE were significantly less than those in AV collection. For this reason, total excretion and concentration of marker in semen should be accounted for when conducting excretion studies.

Passage of exogenous L-thyroxine and triiodothyronine into bovine ejaculate

The metabolic effects of thyroxine (T4) and triiodothyronine (T3) on spermatozoa metabolism and male anatomy have been demonstrated. The metabolic effects of T3 and T4 could affect the physiologic characteristics of the spermatozoa. There are little data on the passage of T4 and T3 into the ejaculate from blood. The passage of exogenous T4 and T3 from the blood into semen was measured after T4 (45 mg) or T3 (37.5 mg) was injected IV into 8 bulls. Blood and electroejaculate were obtained simultaneously at 20, 40, 60, 120, and 180 minutes and 24 hours after bulls were injected to determine T3 and T4 concentrations compared with base-line values. Blood T3 and T4 concentrations were increased (P less than 0.05) at 20 minutes after bulls were injected (1.1 +/- 0.25 to 598 +/- 76.3 ng/ml and from 66 +/- 5 to 1,318 +/- 105 ng/ml, respectively). Seminal concentrations of T4 were unchanged until 120 minutes after bulls were injected, when they increased (P less than 0.05) from less than 1.2 ng/ml to 4.7 +/- 1.9 ng/ml. However, seminal concentrations of T3 were increased (P less than 0.05) from less than 0.1 ng/ml to 0.5 +/- 0.2 ng/ml at 20 minutes and to 12.5 +/- 2.9 ng/ml at 120 minutes after bulls were injected. It was concluded that exogenous thyroid hormones passed into the ejaculate from blood, with T3 passing faster than T4.

Effect of plasma concentrations of ovarian steroids on their passage into uterine lumen in rabbits

Significant increment of blood-borne ovarian steroids are found in the uterine lumen 1 h after mating. Is the transfer of ovarian steroids into the uterus determined by the peripheral blood concentrations of the ovarian steroids? To answer this question, rabbits, ovariectomized 24 h earlier, were infused over a 1-h period with either estradiol (E2; 0.7 and 7.0 micrograms/h), progesterone (P4; 74 and 740 micrograms/h), or testosterone (T; 0.45 and 4.5 micrograms/h). E2, P4, and T were determined in the tissue and flushings of the uterus and tissue and flushings of the esophagus and plasma. A different group of rabbits was infused with E2 (0.7 micrograms), P4 (74 micrograms), and T (0.45 microgram/h) combined. The increase in plasma steroid concentration after infusion of either E2, P4, or T was reflected in an elevation of these steroids in the uterine lumen, albeit not in the same ratios as found in plasma. The simultaneous infusion of E2, P4, and T blocked completely the passage of T and decreased (P less than 0.05) the passage of E2 into the lumen of the uterus. Treatments did not affect the steroid concentration in the wall of the uterus. It was concluded that the content of E2, P4, or T in the uterine flushing increased when E2, P4, or T was infused individually. However, when these steroids were infused together, there was selective inhibition of the transfer process.

Stages of hyperadrenocorticism: response of hyperadrenocorticoid dogs to the combined dexamethasone suppression/ACTH stimulation test

A study was designed to evaluate the response of blood cortisol content in dogs tentatively diagnosed as having hyperadrenocorticism by using the combined dexamethasone suppression/ACTH stimulation test procedure. Four groups of abnormal responses were identified in 54 dogs. In group I (14.8% of the dogs with abnormal responses), the only abnormality was partial suppression with dexamethasone (clinically normal dogs suppressed to less than 10 ng/ml). In group II (29.6%), 2 abnormalities were found: partial suppression with dexamethasone and hyperreactivity to the ACTH stimulation test. In group III (typical pituitary-dependent hypercortisolism, 48.1%), 3 abnormalities were found: base-line hypercortisolemia, partial suppression with dexamethasone, and hyperreactivity to the ACTH stimulation test. In group IV (7.4%), 2 abnormalities were found: base-line hypercortisolemia and partial suppression with dexamethasone. Base-line blood cortisol content was normal in 44.4% of the adrenopathic dogs. A normal response to ACTH stimulation was seen in 25.9% of the dogs, and 74.1% of the dogs hyperreacted to the ACTH stimulation test. All of the adrenopathic dogs were found to suppress partially with dexamethasone. Failure to suppress the adrenal gland completely (less than 10 ng/ml) with dexamethasone was the most consistent finding in adrenopathic dogs when using the combined dexamethasone suppression/ACTH stimulation test procedure. It was concluded that the test procedure is feasible, flexible, and convenient for clinical situations. Also, these results suggested that there may be several stages in the negative feedback failure associated with hyperadrenocorticism in dogs.

Uterotonic effect of prostaglandin F2 alpha and oxytocin on the postpartum cow

Uterine motility was measured in 6 mixed-breed beef cows 48 to 72 hours after parturition, using an intrauterine balloon technique. Baseline uterine motility was measured for 30 minutes after a stabilization period. After 25 mg of prostaglandin F2 alpha (PGF2 alpha) was given IM, motility was recorded for 2 to 4 hours. After PGF2 alpha injection, 200 IU of oxytocin was given IM and motility was recorded for 2 to 4 hours. Twenty-four hours later, oxytocin treatment was administered, and 2 to 4 hours later, PGF2 alpha was given. The tension-time index was calculated. When PGF2 alpha was given initially, it did not affect (P greater than 0.05) uterine motility. However, oxytocin after PGF2 alpha increased uterine motility an average of about 225% of that of base line 20 minutes after injection. When oxytocin was given before PGF2 alpha treatment, the average increment of uterine motility was 875% above base line 20 minutes after oxytocin injection. The injection of PGF2 alpha did not affect uterine motility significantly (P greater than 0.05), whether given before or after oxytocin treatment. There was a linear decrease in the uterotonic effect of oxytocin between 10 minutes and 2 hours. When oxytocin was injected first, the correlation coefficient for the time-response relationship was -0.98. When oxytocin was injected after PGF2 alpha, the correlation coefficient was -0.84. Seemingly, PGF2 alpha should not be used as a uterotonic agent in the postpartum cow; however, oxytocin was an effective uterotonic agent.

Retention of calcium in intestinal wall of the rabbit by treatment with a glucocorticoid

In this work, consideration was given to the possibility that increased retention of Ca in the intestinal wall may have resulted in the glucocorticoid-treated animal. Rabbits were treated with pharmacological doses of either dexamethasone, estrogen, or progesterone during 1 wk. Two milliliters of solution containing Ca (plus Mg, K, and Na) were infused into a double-ligated (4 cm apart) gut loop (jejunum). In addition, an adjacent loop was double ligated but received no infusion. Uterine horns were treated in the same way as the gut and were used as controls to test for organ specificity. After the organs were infused with the calcium solution, they were returned into the abdominal cavity for a 4-h period. Dexamethasone treatment was given to a different group of rabbits in which neither surgery was performed nor mineral solution was infused into the lumen of the intestine; in this experiment calcium concentrations were measured in the mucosa, submucosa, and serosa layer obtained from the duodenum, midjejunum, and distal jejunum. In rabbits subjected to surgery, the concentration of Ca in the whole wall of the intestine of the dexamethasone-treated rabbits (45.4 +/- 2.6 mM/kg dry tissue) was twice as large as in controls (22.6 +/- 3.2 mM/kg dry tissue) (P less than 0.05). Mg concentrations were moderately (17%) increased (P less than 0.05). In the group of rabbits receiving dexamethasone but not subjected to surgery, the concentration of Ca in the duodenum (mucosa, submucosa, and whole wall), midjejunum (whole wall), and distal jejunum (submucosa) was significantly (P less than 0.05) elevated as compared with controls. In these rabbits, the duodenum was the most affected segment of the intestine. The effect of dexamethasone was both organ and steroid specific but not mineral specific. This result suggests that one of the effects of the glucocorticoid (dexamethasone) treatment on the intestinal wall was to increase the retention of Ca.

Inhibition of gastric hydrochloric acid secretions in the rat given Ostertagia ostertagi (a gastric parasite of cattle) extract

The immersion of freshly collected Ostertagia ostertagi adults into saline solution (NaCl, 0.9%; pH 1.0) resulted in 100% mortality of worms within a 10-minute period. At pH 7.0, mortality was 58% after 270 minutes. At pH 2.2, which approximates the usual abomasal pH, 100% mortality resulted within 60 minutes. In the stomach of rats injected with an extract of O ostertagi (from the abomasum of cattle), there were decreased total secretion of hydrogen ions and volume of secretion (P less than 0.05) and increased mean pH of gastric secretion (P less than 0.05). These effects were similar to those found in stomach of rats treated with cimetidine. Results indicated that the pH of the abomasum was detrimental to parasitic survival and that hypochlorhydria found during ostertagiosis may be mediated partially by a chemical released from the parasite.

Refractoriness of both uterus and mammary gland of the cow to prostaglandin F2 alpha administration:P clinical application

Uterine and mammary pressure changes were simultaneously measured in lactating nonpregnant cows injected (IV) with different doses (0.1 to 32.0 mg) of prostaglandin F2 alpha (PGF2 alpha). The total work of the uterus increased up to 250% of base-line value as the dose of PGF2 alpha was increased. But, a dose-response relationship was not seen in the uterus. Partial refractoriness was developed in the uterus, and total refractoriness was developed in the mammary gland. Further challenge with oxytocin (30 U) elicited significant responses in both the uterus and the mammary gland. Because of the development of refractoriness and side effects, PGF2 alpha is not recommended as a drug to be used when mechanical evacuation (free of endocrine effect) of the uterus or mammary gland (or both) is indicated.

Internal vomiting in the ruminant: effect of apomorphine on ruminal pH in sheep

Five sheep, with a rumen fistula inserted, were each injected (IV) with apomorphine (18 mg) and ruminal pH was measured every 5 minutes during a 1-hour period. During the base-line period (30 minutes) that preceded apomorphine injection, pH was constant in individual sheep and te group mean (+/- SD) was 7.1 +/- 0.35. After apomorphine was injected, group mean was 6.9, 6.0, 6.3, 6.3, 6.3, 6.4, 6.4, 6.5, 6.7, 6.9, 6.9, and 7.1 at 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 minutes, respectively. The pH reduction of ruminal content was recorded in 4 of the sheep. Maximal reduction occurred in the 10-minute period after apomorphine was injected. The pH returned to control value within 40 to 50 minutes after injection. Vomitus was not expelled through the mouth by any of the sheep. It was concluded that expulsion of acidic abomasal contents back into the preabomasal compartment (internal vomiting) was the cause of acidification of the rumen after apomorphine was injected.

Distribution of adrenergic receptors in the domestic fowl oviduct

The effect of epinephrine, phenoxybenzamine (alpha-receptor blocker), and propranolol (beta-receptor blocker) on the oviductal motility in an in vitro system was investigated in strips from infundibulum, magnum, isthmus, and uterus from laying hens. Epinephrine resulted in a significant (P less than .05) contraction of both infundibulum (+166.6%) and magnum (+70.3%) and relaxation of the uterus (-56.9%), while the response of the isthmus was inconsistent. Epinephrine induced contractions in propranolol blocked strips in all four oviductal segments studied (infundibulum, +138.1; magnum, +70.4; isthmus, +35.9; and uterus, +30.1%). Epinephrine, in phenoxybenzamine-blocked strips, resulted in relaxation of all segments (infundibulum, -27.5; magnum, -40.5; isthmus, -63.4; and uterus -53.6%). These results suggest that the activity of alpha-excitatory adrenergic receptors is greater in the anterior than in the posterior segment of the oviduct. conversely, greater activity of beta-inhibitory receptors seems to be present in the posterior than in the anterior segment of the oviduct.

Combined dexamethasone suppression and cosyntropin (synthetic ACTH) stimulation test in the dog: new approach to testing of adrenal gland function

A combined dexamethasone suppression and cosyntropin (synthetic ACTH) stimulation test was developed in the dog so that information concerning pituitary gland (hypophysis) and adrenal gland competence could be provided in a single trial, during a short time span. Treatment of dogs with dexamethasone (0.1 mg/kg, IM) resulted in total suppression (below assay sensitivity or < 10 ng/ml) of plasma hydrocortisone (cortisol) at postinjection hour (PIH) 2 in 100% of the dogs, whereas suppression was inconsistent at PIH 1. Cosyntropin (0.5 U/kg, IV) administration to normal or dexamethasone-suppressed dogs increased plasma hydrocortisone concentration 3.5 to 4.5 times base-line values at PIH 1, which was the time of maximal effect. The combined test concept for adrenal gland function is valid, convenient (three sample collections; 3-hour period), and allows testing of adrenal gland response to dexamethasone suppression and ACTH stimulation in a single trial. The following test procedure for dogs is recommended: (i) collect base-line plasma sample (0900 hours) followed by injection of dexamethasone (0.1 mg/kg, IM); (ii) collect second plasma sample 2 hours after dexamethasone (to evaluate suppression of plasma hydrocortisone concentration) followed by the injection of cosyntropin (0.5 U/kg, IV); and (iii) collect a third plasma sample 1 hour later to evaluate plasma hydrocortisone concentration after cosyntropin stimulation.

Induction of intestinal evacuation or vomition (or both) in the dog by prostaglandin F2alpha injection: clinical potential

Different groups of dogs were given prostaglandin F2alpha IM. The dosage range was between 0.022 and 0.555 mg/kg of body weight. Defecation, including contents from the cranial portion of the large intestine, occurred in 40% to 100% of the dogs within 3.16 to 12.5 minutes after injection depending on dosage administered. Defecation (83.3% of dogs), without vomition, occurred in dogs given a dosage of 0.111 mg/kg. Emesis (87.5% of dogs) and defecation (75.0% of dogs) were observed in dogs given a dosage of greater than or equal to 0.444 mg/kg. Emesis occurred in 1.6 to 2.6 minutes after defecation in dogs given more than 0.444 mg/kg. Latency for emesis response varied between 3.2 and 11.5 minutes. The effect of the drug lasted approximately 15 minutes, with most dogs showing a single episode of defecation or vomition (or both). Besides a marked increase in respiratory rate, side effects were minor. Seemingly, prostaglandin-F2alpha may become the preferred drug for the clinical inducement of vomition and defecation in dogs.

Mastitis-metritis-agalactia complex in sows: effect of the dosage of oxytocin on intramammary pressure in lactating healthy sows

The dose-response and time-response relationships between injected oxytocin and intramammary pressure were investigated in normal lactating sows. In less than 39 s after 20, 40, or 80 U of oxytocin was given (IM injection), there was a rapid initial increase in intramammary pressure (15 to 27 mm of Hg) which lasted 22 to 32 s. After this initial response, there were secondary oscillations in pressure which lasted approximately 40 minutes (20 U) and up to 60 minutes (40 or 80 U). Changes in intramammary pressure during each oscillation varied between 1 and 5 mm of Hg. Mean values for frequency and amplitude of oscillations and total work (area under the trace) were measured. Compared with response obtained after 20 U of oxytocin was given, responses obtained at the 40-U or 80-U dose level had an increased frequency (150.0% and 249.0%, respectively) and total work (36.6% and 104.4%, respectively), but not amplitude. Thus, there may be some clinical advantage in milk let-down effect when sows are given the larger doses of oxytocin (40 or 80 U). These results indicate that newborn pigs should be allowed to nurse at the same time in which oxytocin is injected.

Porcine mastitis-metritis-agalactia (MMA) syndrome: mammary gland responsiveness to oxytocin given to healthy sows during lactation

Mammary gland responsiveness to exogenous oxytocin during lactation was assessed by measuring changes in intramammary pressure of healthy sows given (IM injection) synthetic oxytocin (40 U). Response to oxytocin was measured once a week for the first 8 weeks of lactation. Recordings of pressure changes were expressed as mean area (cm2) under the trace at each 10-minute interval over 30 minutes after oxytocin had been given. During the 2nd week of lactation, there was a 55.3% increase (P less than 0.05) in responsiveness to oxytocin (25.1 +/- 4.2 cm2/10 minutes) as compared with the 1st week (13.9 +/- 2.2 cm2/10 minutes). Responsiveness decreased, however, from the 2nd to the 8th week. Since the incidence of mastitis-metritis-agalactia in sows is particularly high during the 1st week of lactation, low responsiveness of the mammary gland to oxytocin may be a contributing factor.

Adrenal gland function in the horse: effects of cosyntropin (synthetic) and corticotropin (natural) stimulation

The plasma concentration of hydrocortisone was determined in mares given either cosyntropin (100 IU, given IV) or corticotropin (200 IU, given IM). Plasma hydrocortisone concentrations of the mares treated with cosyntropin increased by 46%, 57% and 80% at 30, 60, and 120 minutes, respectively, when compared with base-line values; these values returned to base line at 240 minutes. In mares treated with corticotropin, mean plasma hydrocortisone concentrations increased by 42%, 143%, 101% and 155% at 30, 60, 120, and 240 minutes, respectively, when compared with base-line values. Differences in total leukocyte count, total eosinophil count, and plasma concentrations of electrolytes (calcium, sodium, magnesium, potassium) of cosyntropin- and corticotropin-treated mares, and these values in control animals were not significant. Results of the present study indicated that the horse responds to small dosages of cosyntropin (IV) in a prompt and reproducible manner as determined by plasma hydrocortisone values. Response to corticotropin was slow and less consistent. Thus, administration of cosyntropin to the horse, according to test results with paired samples collected (before administration and again at 2 hours after injection), was found to be a prompt and meaningful test of adrenal gland function.

Effect of luteinizing hormone on ovarian release of steroids: ovarian vein-sampling technique in conscious gilt

After ventral midline laparotomy was done, silastic tubing was inserted into the ovarian vein through a cranial branch of the uterine vein. The free end of the silastic tubing was exteriorized through a perforation of the dorsal wall of the vagina and then passed to the outside of the vulva. The free end of the tubing was sutured to the skin approximately 3 cm lateral to the ventral aspect of the vulva. In the ovarian vein of the sow, the plasma concentration of ovarian steroids was 1.5 to 4.0 times greater than that in peripheral blood, thus making possible the detection of changes not found in peripheral plasma samples. Blood samples were taken immediately after surgical placement of the sample collection tube for a 4-month period from unstressed gilts. Surgical stress seems to increase significantly the release of steroids into the ovarian vein. After the luteinizing hormone injection, progestin but not estrogen was consistently released into the ovarian vein.

Oestrogen content of semen and the effect of exogenous oestradiol-17beta on the oestrogen and androgen concentration in semen and blood plasma of bulls

The concentration (mean +/- S.E.M.) of oestrogen in semen (0-89 +/- 0-04 ng/ml) of bulls was 8-9-fold higher than in blood plasma (0-10 +/- 0-01 ng/ml) while the concentration of androgen in semen (1-15 +/- 0-26 ng/ml) was 2-7-fold lower than in blood plasma (3-21 +/- 0-47 ng/ml). This concentration of oestrogen in semen was not influenced by 0,1,3 or 5 false mounts or when ejaculations occurred at 2-min intervals. When 100 mg oestradiol-17beta were injected i.v. the oestrogen level in semen followed that in the plasma.

Sex steroids in follicular fluid and blood plasma during the estrous cycle of pigs

Concentrations of estrogen (E), progestin (P),and androgen (A) were determined in follicular fluid (FF), and concentrations of E and P were measured in peripheral plasma and perifollicular plasma during the estrous cycle in the pig. Also, concentrations of E, P,and A were determined in the utero-ovarian vein (U-OV) plasma every 2h during estrus period in pigs. It was observed that as follicles increased in size, the concentration of E, P, andA in the FF rises from 13,32 and 1 ng/ml at day 8 of the cycle to 180, 754, and 21 ng/ml at day 20 of the cycle, respectively. Approximately 12 h before ovulation there is a significant (P less than 0.01) drop of E, P, and A in the FF to 27, 120, and 0.77 ng/ml, respectivley. Concentrations of E and P in FF and peripheral plasma do not correlate during the second half of the estrous cycle. At day 20 of the cycle, E and P concentrations in the plasma were 20 pg/ml and 0.4 ng/ml, respectively. Concentration of P in the U-OV plasma started increasing 18 to 24 h after the onset of estrus, which is coincident with the drop of P concentration in the FF. As estrus progressed there was a linear drop of E concentration (r = 0.90) in the U-OV plasma. E and P concentrations in the FF were found to be about 1000 times greater than those in the peripheral blood and 5 times greater than in the blood obtained from the perifollicular capillary network at the end of the cycle.