Efficacy of a prostaglandin analogue in reproduction in the anestrous mare

A prostaglandin F analogue was studied in anestrous mares: a dose-response study; a study in mares presumed pregnant; and a field evaluation of effective doses in breeding establishments. A dose of 2.0mg given by single subcutaneous injection to mares with initial plasma progesterone levels greater than 1.0ng/ml, caused luteolysis on the basis of decline in plasma progesterone concentrations. Follicle maturation leading to ovulation, accompanied by estrus, was observed, and fertility at mating either by natural service or artificial insemination was satisfactory. A dose of 1.0mg was generally effective for luteolysis, but pregnancy rates were lower than after 2.0mg. A proportion of mares which had less than 1.0mg of plasma progesterone at the time of injection ovulated and became pregnant.     

Induction of luteolysis in the mare with a prostaglandin analogue

Five mares were administered 0.5 to 2.0 mg of a prostaglandin analogue, RS 9390 (Syntex), during nine estrous cycles in February and March. Luteolysis as measured by peripheral plasma progesterone occurred in four cycles, transitory luteolysis following 0.5 mg RS 9390 in two cycles, while functional corpora lutea were not present in three cycles. In 8 out of 9 of these cycles the mares returned to estrus 1.5 to 5 days following treatment. It appears that RS 9390 can be used as a regulator of cycle length in mares.     

Luteolytic potencin in a novel prostaglandin analogue

Estrus induction in cycling sows with exogenous prostaglandin is hindered by the extended refractory period and resistance of swine to the luteolytic action of PG's. The luteolytic potency of a novel PGF_2α analogue, Schering ZK 71677, was assessed at four different dosages in chronically cannulated cycling swine. Dosages totalling 1, 1.5, 3 and 10 mg of ZK 71677 were split into two injections given intramuscularly on day 13 of the estrous cycle. Onset of behavioural estrus and serum levels of progesterone and PGF metabolite were monitored. The three lowest doses did not advance estrus but did cause a transitory decline in serum progesterone concentration on day 13. The 10 mg level advanced estrus in three of four sows although the overall mean cycle length did not differ from pretreatment cycles (18.5 ± 1.3 vs 21.3 ± 0.6 days). Progesterone values droppd steadily in all four sows in the 10 mg treatment group. No level of ZK 71677 affected serum levels of PGF metabolite. The highest level tested of PGF_2α analogue ZK 71677 elicited an uninterrupted decline in serum progesterone concentrations but was inconsistent in its ability to promote early onset of behavioural estrus in swine.     

Equine lymphocyte antigens and reproduction in the Standardbred mare

Equine lymphocyte antigen (ELA) gene frequencies were estimated for pacing and trotting Standardbred mares residing on a breeding farm in central Ohio. The ELA gene frequencies for Ohio Standardbreds did not differ significantly from the ELA gene frequencies of Kentucky Standardbreds, determined by Bailey (1983). No significant differences were found in the distribution of ELA class I antigens in horses with lower overall fertility or a history of abortion on the investigated breeding farm. Likewise, no significant association was observed when the ELA types of both the mare and the stallion to which she was mated were compared with the reproductive efficiency of the mare.     

Equine lymphocyte antigens and reproduction in the Standardbred mare

Summary. Equine lymphocyte antigen (ELA) gene frequencies were estimated for pacing and trotting Standardbred mares residing on a breeding farm in central Ohio. The ELA gene frequencies for Ohio Standardbreds did not differ significantly from the ELA gene frequencies of Kentucky Standardbreds, determined by Bailey (1983). No significant differences were found in the distribution of ELA class I antigens in horses with lower overall fertility or a history of abortion on the investigated breeding farm. Likewise, no significant association was observed when the ELA types of both the mare and the stallion to which she was mated were compared with the reproductive efficiency of the mare.     

Uterine luminal prostaglandin F in cycling mares

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

Luteolysis and cycle synchronization with a new prostaglandin analog for artificial insemination in the mare

Over a period of three years, 165 cyclic or anestrous Hanoverian mares received 177 treatments with 2, 3 or 4 mg of a novel luteolytic prostaglandin analog, K 11941. Heat and ovulations, indicating luteolysis, were observed after an average of 3.98 and 7.62 days, respectively, in 88.04% of 142 treated cyclic, postpartum and anestrous mares, and mares after an early loss of the conceptus. All doses tested were effective in inducing luteolysis as confirmed by determination of progesterone blood levels in samples collected daily, in 70 of 80 mares studied (87.5%). Attempts to achieve control of the cycle by various methods revealed that with K 11941 given once or twice, alone or in combination with hCG and/or an GnRH analog (Hoe 766), one can effectively concentrate estrus periods and follicular growth patterns, but can neither synchronize nor concentrate ovulations. Since most of the mares treated were confirmed problem mares, the pregnancy rate of 40.0% from first insemination at drug induced estrus, was regarded as satisfactory when compared to a pregnancy rate of 43.8% obtained with natural breeding in the same population. No drug related clinical signs of side-effects were observed.     

Parturition control in sows with a prostaglandin analogue (alfaprostol)

The objective of this study was to determine the dose of alfaprostol (18, 19, 20-trinor-17-cyclohexyl-13, 14 didehydro-PGF(2)alpha-methylester) and the day of administration most effective in inducing sows to farrow during normal working hours (0700 to 1700). One-hundred forty multiparous crossbred sows, taken from a herd whose mean gestation length was 114.3 days, were assigned to one of five treatment groups: 1) control vehicle-propylene glycol, 2) 0.5 mg alfaprostol (AP). 3) 1 mg AP, 4) 2 mg AP and 5) 3 mg AP. Sows received an intramuscular injection of AP between 0800 and 0830 on either day 111, 112 or 113 of gestation. Parameters studied included interval from injection to birth of first pig, farrowing interval, total number of pigs born, number born alive, average birth weight, percent stillborn, interval from weaning to next estrus and number born alive next litter. The mean intervals from injection to the birth of the first pig were 55.2 +/- 7.1; 41.1 +/- 5.1; 29.6 +/- 4.0; 24.3 +/- 1.1; 24.8 +/- 0.9 h for groups 1, 2, 3, 4 and 5, respectively (P<0.05). The percentage of sows that farrowed during normal working hours (23 to 33 h after injection) for groups 1, 2, 3, 4 and 5 were 15, 53, 60, 77 and 70%, respectively. Average birth weights (kg) for treatment groups 1, 2, 3, 4 and 5 were 1.54 +/- 0.05; 1.65 +/- 0.05; 1.59 +/- 0.05; 1.54 +/- 0.05 and 1.42 +/- 0.05, respectively (P<0.05). Mean differences in total number of pigs born and number born alive were also statistically significant (P<0.05) but stillbirth rate was not different (P>0.05) among treatment groups. These results indicate that a single injection of 1, 2 or 3 mg of alfaprostol will successfully induce parturition the following day in a majority of the treated sows.     

Effect of periovulatory prostaglandin F2alpha on pregnancy rates and luteal function in the mare.

The objective of this study was to determine whether periovulatory treatments with PGF2alpha affects the development of the CL, and whether the treatment was detrimental to the establishment of pregnancy. Reproductively sound mares were assigned randomly to one of the following treatment groups during consecutive estrus cycles: 1. 3,000 IU hCG within 24 hours before artificial insemination and 500 microg cloprostenol (PGF2alpha analogue) on Days 0, 1, and 2 after ovulation (n=8), 2. 2 mL sterile water injection within 24 hours before artificial insemination and 500 microg cloprostenol on Days 0, 1, and 2 after ovulation (n=8); 3. 3,000 IU hCG within 24 hours before artificial insemination and 500 microg cloprostenol on Day 2 after ovulation (n=8); or 4. 3,000 IU hCG within 24 hours before artificial insemination and 2 mL of sterile water on Days 0, 1, and 2 after ovulation (controls; n=8). Blood samples were collected from the jugular vein on Days 0, 1, 2, 5, 8, 11, and 14 after ovulation. Plasma progesterone concentrations were determined by the use of a solid phase 125I radioimmunoassay. All mares were examined for pregnancy by the use of transrectal ultrasonography at 14 days after ovulation. Mares in Group 1 and 2 had lower plasma progesterone concentrations at Day 2 and 5, compared to mares in the control group (P < 0.001). No difference was detected between group 1 and 2. Plasma progesterone concentrations in group 3 were similar to the control group until the day of treatment, but decreased after treatment and were significantly lower than the control group at Day 5 (P < 0.001). Plasma progesterone concentrations increased in all treatment groups after Day 5, and were comparable among all groups at Day 14 after ovulation. Cloprostenol treatment had a significant effect on pregnancy rates (P < 0.01). The pregnancy rate was 12.5% in Group 1, 25% in Group 2, 38% in Group 3, and 62.5% in Group 4. It was concluded that periovulatory treatment with PGF2alpha has a detrimental effect on early luteal function and pregnancy.     

Nucleotide and prostaglandin cycling in canine cyclic hematopoiesis

Bone marrow cells were collected from normal dogs, normal dogs made neutropenic with cyclophosphamide, and 11 dogs affected with cyclic hematopoiesis (CH) on 3 consecutive days of separate 12- to 14-day cycles. The mononuclear marrow cells from both groups of control dogs and from the CH dogs on each of 12-cycle days were cultured for 2.5 hr in serum-free media. The amounts of prostaglandins (PGF2 alpha and PGE) and cyclic GMP (cGMP) measured in the media were found to vary with the cycle in the CH dog. PGF2 alpha was highest as the dogs recovered from the neutropenia and lowest 4 days before the onset of the next neutropenic episode. Cyclic GMP was lowest 4-5 days before the onset of neutropenia, then dramatically increased as the neutropenic period approached. Cyclic GMP was highest when PGF2 alpha was lowest. Normal dogs, made neutropenic with a single dose of cyclophosphamide, had elevations of PGF2 alpha but not PGE or cGMP during the recovery period of active granulopoiesis.     

Induction of parturition in the pig using a new prostaglandin analogue (K11941)

Eighty seven sows, taken from a herd whose mean gestation length was 116 days, were allotted at random on day 114 of gestation to one of five treatment groups as follows: (1) 175 mug prostaglandin analogue (closprostenol I.C.I. Ltd) (2) 1 mg K11941 (alfaprostol VETEM Ltd), (3) 2 mg K11941, (4) 3 mg K11941 (5) 2 ml saline (control). All prostaglandin analogues induced parturition significantly earlier than controls (P < 0.05), but there were no differences between any of the prostaglandin treatments in the interval to birth of the first piglet (P > 0.05). The mean intervals to parturition were 24.6, 22.3, 24.9, 30.7 and 53.0 hours for treatments 1, 2, 3, 4 and 5 respectively. Almost two-thirds of treated sows farrowed during the working period of the day following injection compared with a small proportion of control animals. Induction of parturition had no effect on birth weight, piglet survival to 3 weeks or on subsequent weaning to service interval in treated sows. Results show that this new analogue of prostaglandin (K11941) is effective in inducing farrowing in the sow.     

前列腺素E分子网络对哺乳动物生殖的调控

磷脂酶A2、环氧合酶以及前列腺素E合成酶是前列腺素E合成途径中顺序起作用的重要酶类,其中前列腺素E合成酶有两种不同的亚型,分别介导不同的前列腺素E合成反应。前列腺素E可与其受体特异性结合,并通过旁分泌和自分泌两种形式调节细胞反应,参与多种生理过程。近来研究发现,前列腺素E受体不仅存于质膜,而在核膜上也大量存在。前列腺素E核受体介导的信号转导途径与膜受体介导的信号途径不同,对于基因转录的调控机制也不同。本文综述并探讨了上述分子所组成的网络系统在哺乳动物生殖,尤其是雌性生殖过程中所发挥的重要作用。     

Absence of uterokinetic effects of prostaglandin F 2 alpha on oxytocin-reactive uterus in the mare

In most cyclic females, prostaglandin F(2alpha) (PGF(2alpha)) triggers a uterine motility response resembling that of oxytocin (OT). To determine if PGF(2alpha) 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(2alpha) (200 mug/min) for 60 min each. The experiment was repeated 3 wk later except with PGF(2alpha) preceeding 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(2alpha) preceded OT infusion or vice-versa. No significant difference (P>0.05) was seen in motility after PGF(2alpha) (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(2alpha) infusion (but not with OT), indicating that PGF(2alpha) was bioactive. It was concluded that PGF(2alpha) was not a uterokinetic substance in the cyclic mare.     

Efficacy of cycling training based on a power field test

The efficacy of an 8-minute field test to prescribe exercise intensity and assess changes in fitness was evaluated before and after 8 weeks of indoor cycling, and the results were confirmed by laboratory assessment. Changes in maximal steady-state power (MSSP), power at lactate threshold (PT(lact)), maximal power (Pmax), and maximal oxygen uptake (VO2max) were measured on 56 participants (20 women, 36 men; mean +/- SD. 46.5 +/- 10.0 years) who completed 1-hour, biweekly indoor stationary cycling classes on their own road bike outfitted with a Power Tap Pro power meter. The MSSP was defined as the average power during an 8-minute field test, which was administered at the beginning (pre) and end (post) of the training intervention. Individual training ranges were calculated from the pre-MSSP in accordance with Carmichael Training Systems. Laboratory assessments of PT(lact), Pmax, and VO2max were made on 24 of the participants the same weeks MSSP was evaluated. After training, MSSP increased 9.2% (195.4 +/- 56.6 vs. 213.8 +/- 57.2 W; p < 0.05), and PT(lact) increased 12.9% (178.3 +/- 47.1 vs. 201.5 +/- 47.6 W; p < 0.05). The MSSP was approximately 7.5 % higher than PT(lact). Pmax increased approximately 6.7% (315.2 +/- 65.1 to 336.5 +/- 65.9 W), and VO2max increased approximately 6.5% (46.2 +/- 10.7 to 49.1 +/- 10.5 ml x kg(-1) x min(-1)). The MSSP and PT(lact) were highly correlated (r = 0.98) as was MSSP and VO2max (r = 0.90). The results of this research indicated that (a) the field test is a valid measure of fitness and changes in fitness, (b) it provided data for the establishment of training ranges, and (c) a biweekly power-based training program can elicit significant changes in fitness.