The concentration of estradiol-17 beta in bovine semen

This study was conducted to evaluate the influence of age, breed, epididymectomy and semen processing on the concentration of estradiol-17 beta (E2) in bovine semen. Semen was collected either by electroejaculation or with an artificial vagina. Neat semen samples were stored at -20 C until analysis. Processed, frozen semen and an egg yolk-citrate semen extender were obtained from a commercial semen processing firm and stored in liquid nitrogen at -196 C. The concentration of E2 in semen was determined by radioimmunoassay. Semen from mature (greater than 24 mo), fertile Brahman (n = 19), Brangus (n = 16), Charolais (n = 29), Holstein (n = 15) and Santa Gertrudis (n = 25) bulls was analyzed for E2 concentration, and no difference (P greater than .10) between breeds was found. There was no difference (P greater than .10) in seminal E2 concentration between mature, fertile bulls (n = 104) and epididymectomized bulls (n = 22). In semen collected from prepuberal (12 to 16 mo, n = 21), peripuberal (17 to 20 mo, n = 17) and mature (greater than 24 mo, n = 19), Brahman bulls, the mature bulls had a lower (P less than .01) semen E2 concentration than peripuberal and prepuberal bulls. There were no differences (P greater than .10) in seminal E2 concentration among peripuberal Angus (n = 8), Hereford (n = 8) and Brahman (n = 17) bulls.(ABSTRACT TRUNCATED AT 250 WORDS)     

Skeletal muscle protein metabolism and serum growth hormone, insulin, and cortisol concentrations in growing steers implanted with estradiol-17 beta, trenbolone acetate, or estradiol-17 beta plus trenbolone acetate.

Skeletal muscle protein degradation, measured by urinary N tau-methylhistidine excretion, and circulating concentrations of growth hormone (GH), insulin (INS), and cortisol (CT) were monitored in steers before and after implantation with estradiol-17 beta (E2; 24 mg) and trenbolone acetate (TBA; 300 mg). Yearling crossbred steers (n = 43) were randomly assigned to four treatment groups in a 2 x 2 factorial arrangement: nonimplanted controls (C); TBA; E2; and TBA plus E2 (TBA+E2). A subgroup (Block 1) of 16 steers was bled on d -12, 31, and 72 after implanting. Deposition of skeletal muscle protein was markedly increased (P less than .001) by E2 and TBA+E2 treatment. This response occurred mainly within the first 40 d after implantation and declined (P less than .001) in concert with decreasing (P less than .01) concentration of serum E2. Anabolic steroid treatment did not affect the rate of skeletal muscle protein breakdown. There was no apparent relationship between reduced serum CT concentration (linear effect; P less than .01) in TBA-treated steers and skeletal muscle protein degradation rate. Blood concentration and pulse activity of INS were not affected by anabolic steroid administration. Both TBA- and TBA+E2-implanted steers displayed a linear decrease (P less than .05) in serum GH concentration over time, which was similar to C. Lowered mean GH concentration resulted from a reduction (TBA main effect; P less than .05) in pulse amplitude of GH. Unlike TBA, TBA+E2, and C, only E2 maintained serum GH concentrations over time. Although increased muscle protein deposition was evident in TBA+E2-treated steers, an obvious causal relationship between this response and circulating GH, INS, and CT was not revealed. These results do not support the concept that combined androgenic agent and estrogen administration effectively reduce bovine muscle protein degradation by static modulation of circulating endogenous anabolic and antianabolic hormones.     

Effects of estradiol 17 beta implants on hematologic values and the chemiluminescence response of neutrophils of steers.

The effects of subcutaneous administration of a commercially available estradiol 17 beta implant on hematologic values and the chemiluminescence response of neutrophils were evaluated in 14 steers. Chemiluminescence and hematologic values were measured in treated (n = 8) and nontreated (n = 6) steers on days -14, -7, and -1 prior to implantation. Estradiol 17B was implanted into the treated group of steers on day 0, and blood samples were obtained from all steers on days 1, 2, 3, 4, 8, 15, 22, 29, 36, 43, and 50. The concentration of estrogen in serum was significantly (P = 0.0120) higher following implantation. Chemiluminescence and hematologic indices were not significantly affected by either implant status or serum concentrations of estrogen. The results of this study suggested that the use of implants containing estradiol 17 beta for promotion of weight gain in steers will not result in alterations of hematologic values or the neutrophil respiratory burst.     

Relationship between endogenous estradiol-17 beta and estrous behavior in heifers

Thirty-five Holstein heifers were used to examine the relationship between endogenous estradiol-17 beta and estrous traits. During a non-superovulation period (NSP), estrous cycles were synchronized and during the periovulatory stage blood samples were collected every 6 h for 120 h for subsequent determination of estradiol-17 beta and progesterone. In addition, continuous observation for estrous behavior was performed for 98 h. A gonadotropin-induced superovulation period (SP) was begun 12 d after estrus was detected during NSP. Heifers were injected with FSH twice daily for 4 d and single injections of prostaglandin were given on d 14 and 15. Beginning at d 14, blood samples were collected every 6 h for 120 h for subsequent determination of estradiol-17 beta and progesterone. Continuous observation for estrous behavior was performed for 98 h. Peak estradiol-17 beta was greater during SP than during NSP (49.0 +/- 3.1 vs 12.9 +/- 3.0 pg/ml serum). Thirty-three and 31 of the 35 heifers were in estrus during NSP and SP, respectively; duration of estrus was 2.3 h longer during SP than during NSP. However, number of behavioral interactions during estrus did not differ between NSP and SP. In conclusion, estrous traits were similar, whereas peak estradiol-17 beta concentrations were markedly different between NSP and SP.     

Uterine involution in mares treated with progesterone and estradiol-17 beta

Bacteriology, histology, and scanning electron microscopy were used to evaluate uterine involution in 27 mares treated with daily injections of 150 mg of progesterone and 10 mg of estradiol-17 beta, commencing within 18 hours of parturition. These findings were compared with those for 24 untreated mares at postpartum day 10 or 11. The treatment resulted in significantly (P less than 0.05) greater uterine gland proliferation. Gland density was significantly (P less than 0.05) greater in mares treated for 6 to 10 days than in those treated 2 to 5 days. The proportion of ciliated cells to secretory cells lining the endometrial surface was significantly (P less than 0.05) greater in mares during delayed foal estrus than in those at postpartum days 10 to 11. The proportion of ciliated to secretory cells increased with increasing duration of treatment. It was concluded that treatment with progesterone and estradiol-17 beta allowed additional time for uterine involution in the early postpartum period.     

Factors affecting in-transit shrink and liver abscesses in fed steers

Live weight loss (shrink) and liver conditions (abscesses) were determined on 3,570 crossbred steers of predominantly British breeding over a 5-yr period. Starting in November 1979, steers were placed on feed at bimonthly intervals and provided one of three housing treatments: no shelter, access to overhead shelter or confinement. All steers were implanted with Synovex during the first 3 yr and Compudose the last 2 yr and fed a diet consisting of high-moisture corn grain, which provided 85% of the energy, and corn silage, along with a protein, vitamin and mineral supplement. Cattle were processed into beef after a feeding period of approximately 160 d. Year affected shrink (P less than .001), and month on feed and housing type tended to alter shrink. Cattle marketed during summer and fall and those outside without overhead shelter tended to shrink more. Year, month on feed and housing type affected liver condition (P less than .01). Cattle started on feed in November and January and cattle housed in confinement or outside without overhead shelter had higher incidences of liver abscesses and slower average daily gains (P less than .01). Daily gains for steers with normal and abnormal livers were not different (P greater than .19) for any month started on feed or housing treatment. These results indicate that under the conditions of this study a 2 or 3% weight loss should be expected during the marketing of finished steers and a 16% incidence of liver abscesses should be anticipated, with some modification of the latter due to time of year and housing. The presence of liver abscesses at the time of processing steers into beef did not reduce feedlot performance.     

Peripartum changes in plasma estrone sulfate and estradiol-17beta profiles associated with and without the retention of fetal membranes in holstein-friesian cattle

The aim of this study was to evaluate the changes in plasma concentrations of estrone sulfate (E(1)S) and estradiol-17beta (E(2)beta) during the peripartum period (from day 10 prepartum to day 1 postpartum) associated with and without retention of fetal membranes (RFM) in Holstein-Friesian cattle (n=42). Plasma samples were analyzed for E(1)S and E(2)beta by ELISA. All parturitions were spontaneous and normal. Of 38 cattle delivering singletons, 29 had no RFM (singleton-normal group) and nine had RFM for more than 12 h (singleton-RFM group). Four cows gave birth to twins, and each twin had its own fetal membrane (FM). Two twinning cows expelled both FMs normally within 12 h (twin-normal group). In the remaining 2 twinning cows (twin-RFM group), the FM was expelled normally for one twin (first), while the FM of the other (second) was retained. There were no significant differences in the E(1)S concentrations or their increments from the concentrations on the preceding day between the normal and RFM groups of singleton cows on any peripartum day. The mean plasma E(2)beta concentrations on each day from day 10 to day 3 prepartum were significantly lower (P<0.05) in the singleton-RFM group compared with the singleton-normal group; however, on days 2 and 1 prepartum, the increments in the E(2)beta concentrations from the concentrations on the preceding days were significantly higher (P<0.05) in the singleton-RFM group than in the singleton-normal group. Thus, the plasma E(1)S concentrations just before parturition may not be associated with RFM. In the cows with RFM, the lower plasma E(2)beta concentrations that were found prior to day 2 prepartum may have been associated with immature placentomes, and the rapid rise in plasma E(2) beta within 1 to 2 days prior to calving may have produced asynchrony of placental and/or fetal maturation in relation to calving, thus resulting in RFM.     

Concentration of IGF-I and estradiol-17beta in the blood plasma of pregnant cattle

Blood samples were collected from pregnant cows, heifers and also from non pregnant cows serving as controls. The determination of insulin-like-growth-factor-I (IGF-I) and estradiol-17 beta (E2) were performed immunologically. In the non pregnant cows E2 remained unchanged. IGF-I decreased around parturition and increased again commencing the 6th week of lactation. Compared to nonpregnant animals E2 but not IGF-I was slightly elevated during the first 10 weeks of pregnancy. During the 10th up to 20th week of pregnancy the mean values of IGF-I were increased as well as the ones of E2. During the late pregnancy the values of IGF-I in heifers are obviously more elevated as in lactating pregnant or non-pregnant cows; analogous high values were determined in pregnant cows only during the dry period. Before parturition even a negative correlation exists between IGF-I and E2. It is concluded that IGF-I is predominantly regulated by other factors.     

Effects of exogenous estradiol-17 beta on luteinizing hormone, progesterone, and estradiol-17 beta concentrations before and after prostaglandin F2 alpha-induced termination of pregnancy and pseudopregnancy in gilts.

This study evaluated the influence of exogenous estradiol-17 beta (E2) administration on LH concentrations and the number of animals returning to estrus after the termination of pregnancy or pseudopregnancy in gilts. Gilts were mated (pregnant; n = 11) on the 1st d of estrus or received 5 mg of estradiol valerate i.m. at d 11 to 15 after the onset of estrus (pseudopregnant; n = 9). Gilts were treated with prostaglandin F2 alpha (PGF2 alpha, 15 and 10 mg) at 12-h intervals on d 44 of pregnancy or pseudopregnancy. The day of abortion or luteolysis (progesterone less than .2 ng/mL) was considered d 0. Six pregnant and four pseudopregnant gilts received s.c. an E2 capsule (24 mg of E2) on d -20 and additional E2 capsules on d -13 and -6. The E2 capsules were removed on the day after PGF2 alpha administration. Blood samples were collected at 12-h intervals from d -21 to -3, at 6-h intervals from d -2 to 21 or the onset of estrus, and at 15-min intervals for 8 h on d -2, 1, 4, 7, 10, 14, and 18. After each 8-h sampling period, gilts were treated i.v. with GnRH at .5 micrograms/kg of BW and blood samples collected at 10-min intervals for 3 h. A greater (P less than .05) proportion of sham-treated gilts than of E2-treated gilts exhibited a preovulatory-like LH surge after abortion/luteolysis. It was evident that E2 supplementation before luteolysis reduced the ability of pregnant and pseudopregnant gilts to return to estrus.     

High plasma estradiol-17beta levels in dogs with benign prostatic hyperplasia and azoospermia

The semen quality of 22 dogs (4 to 7 years old) with benign prostatic hyperplasia (BPH) was examined at the hospital of our university, and 4 of the 22 BPH dogs were diagnosed as azoospermic. The mean peripheral plasma estradiol-17beta (E2) level (17.3 pg/ml) of the 18 BPH dogs with spermatogenic function was higher than that of 5 normal male dogs and their mean T level (1.7 ng/ml) was lower. The mean E2 level (27.3 pg/ml) of the 4 BPH dogs with azoospermia was significantly higher than the value in the BPH dogs with spermatogenic function (P<0.01), and the mean T level (1.1 ng/ml) was significantly lower (P<0.05). Five normal male dogs were given 10 intramuscular injections of estradiol benzoate (E2B) 5 microg/kg, at 3-day intervals to investigate the relationship between high plasma E2 levels and the cause of the BPH and azoospermia. Their testes and prostates were measured and biopsied both before and 30 days after the start of E2B injections. At 30 days after the start of the E2B injections, the mean peripheral plasma T levels had decreased by half, and the mean testicular volume had decreased to 88% of original volume. The numbers of spermatocytes, spermatids, and spermatozoa in the seminiferous tubules of all of the dogs were significantly lower (P<0.05, 0.01). In addition, the mean prostatic volume increased to 130%, the mean height of the glandular epithelium decreased, and the glandular lumen became increased in diameter. These findings indicate that both BPH and serious spermatogenic dysfunction may be simultaneously induced by protracted high plasma E2 levels in dogs.     

Effects of season and estradiol-17 beta on luteinizing hormone release in ovariectomized sows.

This study examined the ability of estradiol-17 beta (E2) to suppress LH release in the sow during different months of the year. Six chronically ovariectomized sows were fitted with vena caval cannulas (d 0) and blood samples were collected at 6-h intervals for 6 d. Sows were treated s.c. with E2 capsules (24 mg of E2/275 kg of BW) at d 3. Additional blood samples were collected at 15-min intervals for 8 h on d 2 and 5. After each 8-h frequent sampling period, sows were treated i.v. with GnRH at .5 microgram/kg of BW, and blood samples were collected at 10-min intervals for 3 h. The protocol was repeated at monthly intervals for 13 mo. Luteinizing hormone concentrations were determined for all serum samples, and E2 concentrations were quantified in samples collected at 6-h intervals. Data were analyzed by split-block analyses of variance. Serum E2 concentrations increased (P less than .001) from 5.0 +/- .3 pg/ml before E2 treatment to 26.0 +/- .2 pg/ml after E2 treatment. The interval from GnRH administration to peak LH concentration was shorter (P less than .001) before E2 treatment than after E2 treatment (28.7 +/- 2.2 vs 71.0 +/- 2.2 min). It was evident that baseline LH, mean LH, pulse frequency, and pulse amplitude and LH release after GnRH administration failed to demonstrate seasonal changes. In summary, LH release was suppressed after treatment with E2 and was affected minimally by month of the year. In addition, E2 inhibitory effects of LH release included hypothalamic and anterior pituitary sites of action.     

Pfaffia paniculata-induced changes in plasma estradiol-17beta, progesterone and testosterone levels in mice

The present study undertook chemical analysis of components of Pfaffia paniculata roots. In addition, an animal experiment was conducted in which mice had ad libitum access to water enriched with powdered P. paniculata root for 30 days. Changes in plasma concentrations of estradiol-17beta and progesterone in female mice and of testosterone in male mice were ascertained. The results revealed that P. paniculata roots contain two types of phytosteroids, beta-sitosterol and stigmasterol, in addition to other compounds such as pfaffic acid, allantoin, saponins, beta-sitosteryl-beta-D-glucoside, and stigmasteryl-beta-D-glucoside. Regarding changes in plasma concentrations of hormones, levels of the sex hormones estradiol-17beta, progesterone and testosterone were clearly higher for mice that drank P. paniculata root-enriched water than for mice that drank plain water. Powdered P. paniculata root is easily dissolved in feed or water, and as no adverse reactions were seen in mice within 30 days of oral intake, consumption of P. paniculata for long periods of time appears safe.     

Relationships between LH and estradiol-17 beta after removal of luteal progesterone in the ewe

Three experiments were conducted to examine the relationship between systemic concentrations of luteinizing hormone (LH) and estradiol-17 beta (E2) after withdrawal of progesterone in cycling ewes. In Exp. 1, ewes were assigned randomly to one of three treatments: laparotomy (C), removal of the luteal ovary (ULO), or ULO plus anesthesia with sodium pentobarbital for 6 h beginning 4 h after surgery. Anesthesia was used in an attempt to block the expected increase in tonic secretion of LH. Patterns of LH and E2 in these three groups did not differ during the 24-h experimental period. In Exp. 2, a longer period of anesthesia was utilized. Forty-eight ewes were assigned at random to one of four treatments: C, ULO, lutectomy or an intrafollicular injection of prostaglandin F2 alpha (PGF2 alpha). One-half of the ewes in each group were anesthetized with sodium pentobarbital from initiation of treatment (0 h) until 10 h after surgery. Sodium pentobarbital did not suppress the increases in LH and E2 after progesterone withdrawal. The regression of concentrations of E2 on concentration of LH was not significant. In Exp. 3, ewes were infused with either saline or dopamine after receiving an im injection of PGF2 alpha. Tonic secretion of LH increased after 4 h in ewes infused with saline, but not in ewes infused with dopamine. Despite the suppression of LH, concentrations of E2 increased in dopamine-treated ewes as in control ewes. Therefore, the initial increase in E2 after a decline of progesterone in cycling ewes is independent of increases in LH.     

Factors affecting the retention of calcium by the chick

The addition of 5 or 10% tallow to a broiler diet containing 0.9% calcium reduced the retention of that element, although not sufficiently to cause a deficiency. Supplementation of the diets with vitamin D₃ above the minimum requirement level did not improve the retention of calcium in the added fat diets.     

Effect of estradiol-17 beta treatment of gilts on blood mononuclear cell functions in vitro.

Porcine blood mononuclear cells (BMC) were exposed to prepartum concentration of estrogen in gilts before acquisition (in vivo), and their subsequent reactivity (in vitro) was explored. In a cross-over experimental designed study, 6 ovariectomized gilts were injected once with 3.75 mg of estradiol-17 beta benzoate in arachidic oil or with arachidic oil only during 2 experiments. The ability of their BMC to proliferate in response to stimulation with phytohemagglutinin, concanavalin A, and pokeweed mitrogen was assayed in cultures of blood and in cultures of purified BMC. After 2 days of mitogen stimulation, activity of accessible interleukin 2 was quantified in supernatants obtained from cultures of purified BMC and supernatants of blood cultures stimulated with pokeweed mitogen. Also, production of immunoglobulins by purified BMC in response to polyclonal stimuli was measured. Three days after treatment with estradiol, the proliferative response was suppressed in blood cultures stimulated with concanavalin A (P less than 0.05) and phytohemagglutinin (P less than 0.07). Effects of estradiol treatment were not found in any of the assays performed with purified BMC. We, therefore, assumed that in vivo exposure to estradiol can affect the function of porcine BMC; however, this was only evident when the in vitro assays were performed on blood cultures.     

Dose-response shift in the ability of gilts to remain pregnant following exogenous estradiol-17 beta exposure

Sixty mated gilts were assigned to a 2 X 6 factorial arrangement (n = 5) of day of injection (d 9 and 10 vs 12 and 13; d 0 = first day of estrus) and dose of estradiol-17 beta (0, .125, .5, 2, 8 and 32 mg X gilt-1 X d-1). Gilts were subsequently slaughtered on d 30; pregnancy was verified and percent embryonic survival calculated. A 64-fold shift in the dose-response curve for percent embryonic survival illustrated that the adverse effects of exogenous estradiol-17 beta were less when administered on d 12 and 13 as compared with d 9 and 10 (day X dose, P less than .01). This experiment demonstrated that the uterine-embryonic environment of d 12 and 13 pregnant gilts was more tolerant of exogenous estrogen alterations than that of d 9 and 10 pregnant gilts.     

Therapeutic effect of aromatase inhibitor in two azoospermic dogs with high plasma estradiol-17beta levels

Two azoospermic dogs with high plasma estradiol-17 beta (E(2)) levels were subcutaneously injected with an aromatase inhibitor (AI), 4-androstene-4-ol-3,17-dione, 2 mg every other day for 4 weeks. Before the AI treatment the plasma E(2) levels of the two dogs (21 and 22 pg/ml, respectively) were higher than those of 2 normal dogs (8.1 and 12.3 pg/ml), and they fell to 11-17 pg/ml between 1 and 4 weeks after the start of AI treatment. The plasma testosterone levels after the start of AI treatment had increased to 2.1-3.1 ng/ml. A small number of sperm were detected in the semen of the two dogs between 3 and 6 weeks after the start of AI treatment. These results indicate that the testicular function of infertile dogs with high plasma E(2) levels can be temporarily improved by AI therapy.