scholarly journals Oestrous Frequency and Incidence of Pregnancy in Mice Housed Singly and in Groups at 4, 21, and 33°C

1972 ◽  
Vol 25 (4) ◽  
pp. 801 ◽  
Author(s):  
Pamela R Pennycuik
Keyword(s):  
Oestrous Cycle ◽  
Cycle Frequency ◽  
Tactile Contact ◽  
The Difference

Oestrous cycle frequency was measured in mice housed singly, in mice housed in groups, and in grouped females in olfactory and tactile contact with a male. The animals were kept at 4,21, or 33�0. When the mice were housed singly, all groups had between 2�2 and 3�5 cycles in the 16 days period of observation. The small differences between the groups were not significant. Grouping (15 mice per cage) caused a significant reduction in oestrous frequency at all three temperatures, but the differences between the temperature groups were not significant. Introduction of a caged male into the group of females had no effect on oestrous frequency at 4 and 21 �0. At 33�0 frequency increased and the difference between the temperature groups became significant. When the males were released into the cages of grouped females the incidence of pregnancy in the group at 33�0 was seven times greater than that at 4 or 21 �0.

Miniature ponies: 1. Follicular, luteal and endometrial dynamics during the oestrous cycle

2008 ◽  
Vol 20 (3) ◽  
pp. 376 ◽  
Author(s):  
E. L. Gastal ◽  
A. P. Neves ◽  
R. C. Mattos ◽  
B. P. L. Petrucci ◽  
M. O. Gastal ◽  
...  
Keyword(s):  
Comparative Studies ◽  
Potential Model ◽  
Oestrous Cycle ◽  
Maximum Diameter ◽  
Preovulatory Follicle ◽  
The Difference ◽  
Follicular Dynamics

Follicular dynamics were studied during 12 interovulatory intervals (IOIs) and 36 preovulatory periods in Miniature mares. The percentage of IOIs with the following follicle events was: ovulatory wave with only one follicle ≥10 mm (55%), diameter deviation similar to previous reports in larger mares (25%) and minor waves emerging before or after the ovulatory wave (55%). Follicle data were compared among Miniature ponies, large ponies and Breton horses (n = 12 IOIs per breed). The IOI was longer (P < 0.001) in Miniature ponies (23.3 ± 0.9 days) and in large ponies (23.9 ± 0.5 days) than in Breton horses (20.3 ± 0.7 days). The Miniature ponies had fewer (P < 0.0001) growing follicles ≥10 mm per ovulatory wave (1.5 ± 0.3) and more (P < 0.0004) ovulatory waves (6/11) with only one follicle ≥10 mm than large ponies (9.8 ± 0.8 and 0/12) and horses (5.8 ± 0.9 and 0/12). Maximum diameter of the preovulatory follicle was smaller (P < 0.003) in the Miniature ponies (38.3 ± 0.7 mm) than in the horses (44.5 ± 1.4 mm), but the difference between breeds was slight (6%) compared with the difference in bodyweight (65%). Considering the small number of follicles per ovulatory wave, Miniature mares are a potential model for comparative studies in folliculogenesis within and among species.

Light intensity and the oestrous cycle in albino and normally pigmented mice

1993 ◽  
Vol 27 (4) ◽  
pp. 385-390 ◽  
Author(s):  
Harry Donnelly ◽  
Palle Saibaba
Keyword(s):  
Light Intensity ◽  
Laboratory Animal ◽  
Oestrous Cycle ◽  
Lower Intensity ◽  
Albino Mice ◽  
The Difference

The effects of light intensity (15-20 lux & 220-290 lux) on the oestrous cycle of albino and normally pigmented mice were examined. The oestrous cycle of both types of mice was shorter at the lower intensity but the difference was significant only with the black mice. The proportion of albino mice from which embryos were recovered was significantly smaller than the proportion of black mice at 15-20 lux but not at 220-290 lux. No significant differences due to strain or light intensity were found in the number of embryos recovered. We conclude that pigmented mice respond in the same way as albino mice to changes in light intensity within the range normally found in laboratory animal accommodation. That is, increased light intensity prolongs the oestrous cycle and the period of vaginal cornification.

ÉTUDE COMPARATIVE DES EFFETS SEXUELS DES ANDROGÉNES NATURELS

1963 ◽  
Vol 43 (1) ◽  
pp. 27-46 ◽  
Author(s):  
C. J. Meyer ◽  
Ch. Krähenbühl ◽  
P. A. Desaulles
Keyword(s):  
Oestrous Cycle ◽  
The Other ◽  
Ventral Prostate ◽  
Male Rat ◽  
Naturally Occurring ◽  
Marked Activity ◽  
The Difference ◽  
Hydroxy Progesterone ◽  
Androgenic Effect ◽  
Very High

ABSTRACT A study was made of the activities exerted by the following naturally occurring androgens on the male sexual receptors of the capon and of the castrated male rat, and also of their inhibitory action on the oestrous cycle and gonadotrophic functions in the rat: testosterone, androsterone, androstenedione, adrenosterone, 11β-hydroxy-androstenedione, dehydroepiandrosterone, 17α-hydroxy-progesterone, and progesterone. When the effects of these androgens were investigated on a large number of receptors, the results revealed the differences in the spectrum of activity of each of the substances. Thus, for example, adrenosterone has an androgenic effect in castrated rats which is much greater than in the capon (corresponding to 50% and 5% respectively, of the activity of testosterone), whereas the difference in the androgenic effect exerted on the two species is much less marked in the case of androsterone and androstenedione. 17α-hydroxy-progesterone, on the other hand, displays marked activity on the capon's comb after local inunction, but has only a slight effect on the sexual adnexa of castrated rats. Of all the androgenic receptors investigated only the ventral prostate responds to treatment with progesterone. Of all the compounds included in this study, only 11β-hydroxy-androstenedione has an anabolic/androgenic ratio greater than testosterone, whereas with all the other compounds the ratio is less. Although the degree of inhibition exerted on the oestrous cycle is in all instances equivalent to less than 1/10 of that of testosterone, the anti-gonadotrophic activity as evidenced by experiments on parabiotic animals shows considerable variations from one steroid to the other. It is very high for androsterone and androstenedione (60% of that of testosterone), diminishes in the case of adrenosterone (20% of that of testosterone), and is even weaker in the case of 11β-hydroxy-androstenedione, dehydroepiandrosterone, 17α-hydroxy-progesterone, and progesterone, which has only 10% the activity of testosterone. The correlations between the different types of action and their possible implications are discussed.

76 Clock MUTANT MICE HAVING A DIMINISHED CIRCADIAN CLOCK SHOW ABNORMAL IMPLANTATION

2017 ◽  
Vol 29 (1) ◽  
pp. 145
Author(s):  
T. Amano
Keyword(s):  
Circadian Clock ◽  
Blastocyst Stage ◽  
Oestrous Cycle ◽  
Late Gestation ◽  
Maternal Genotype ◽  
Body Weights ◽  
Implantation Sites ◽  
The Difference ◽  
Reproductive Characters ◽  
Possible Cause

The circadian clock involves co-operative transcription of circadian genes including Clock and regulates circadian rhythms in mammals such as the rhythm of sleep and wakefulness. In reproductive physiologies in mammals, there are several time-dependent events such as progression of the oestrous cycle and embryonic development, and we therefore checked the reproductive characters of mice homozygous for Clock delta-19 mutation (CL) having a diminished circadian clock to elucidate the effect of the circadian clock on reproductive physiologies. Profiles of the oestrous cycle were the same in female (f) wild-type mice (WT) and fCL: oestrous cycles of both fWT and fCL consisted of the same 3 stages, proestrous, oestrous, and metestrous/diestrous stages, and the average lengths of each stage and one oestrous cycle were the same in 10 fWT and 14 fCL. We therefore compared outcomes from the 4 possible mating groups between WT and CL. Average numbers of newborn pups obtained from mating pairs of 14 male (m) WT × fWT, 10 mCL × fWT, 14 mWT × fCL, and 15 mCL × fCL were 13.4 ± 0.8, 12.6 ± 0.4, 12.3 ± 0.7, and 8.6 ± 1.5, respectively, and gradually decreased depending on the number of mutated Clock alleles in mothers and embryos. Since increases in body weights of the mothers during the gestation period were not different in the 4 mating groups and since there were no signs of spontaneous abortion from mid to late gestation, we reasoned that some embryos were lost before or at the time of implantation. Immediately before implantation (88 h after fertilization), neither the number of embryos collected from uteri nor the percentage of embryos that reached the pre-implantation stage (blastocyst stage) differed significantly among mating groups. In contrast, immediately after implantation (160 h after fertilization), the average numbers of implantation sites in mating pairs of 12 mWT × fWT, 11 mCL × fWT, 13 mWT × fCL, and 13 fCL × fCL were 13.0 ± 1.5, 13.1 ± 1.2, 11.7 ± 0.8, and 7.0 ± 1.3, respectively, and also gradually decreased with increase in the number of mutated Clock alleles in mothers and embryos. This decrease was accompanied by a significant lowering of the positions of implantation sites in uteri, a possible cause of the decrease of the number of newborns and implantation sites, and average percentages of embryos implanted in a lower part of the uterus were 48.8, 59.3, 69.7, and 77.7% in mWT × fWT, mCL × fWT, mWT × fCL, and mCL × fCL, respectively. The difference between the mCL × fWT and mWT × fWT groups was statistically significant (P < 0.05), and this difference was thought to be due to the difference in embryonic genotype, specifically between WT and heterozygous embryos. However, the distribution of implantation sites in the mWT × fCL group was significantly smaller than that in the mCL × fWT group (P < 0.05), presumably due to the difference in maternal genotype, specifically between WT and homozygous mutant dams. This study showed involvement of the circadian clock, possibly the maternal and embryonic circadian clock, in implantation among events that occur from fertilization to parturition.

Effect of stimulus duty cycle and cycle frequency on power output during fatigue in rat diaphragm muscle doing oscillatory work

1993 ◽  
Vol 71 (12) ◽  
pp. 910-916 ◽  
Author(s):  
E. D. Stevens ◽  
D. A. Syme
Keyword(s):  
Duty Cycle ◽  
Muscle Power ◽  
Diaphragm Muscle ◽  
Cycle Duration ◽  
Rat Diaphragm ◽  
Cycle Frequency ◽  
Length Changes ◽  
The Difference ◽  
Work Done ◽  
Measuring Force

Isolated rat diaphragm muscle was stimulated repetitively to induce fatigue, and the work done during each contraction was measured. Work per cycle was calculated by measuring force as the activated muscle was subjected to sinusoidal length changes (from 97 to 103% of L0, where L0 is rest length). Work was calculated from the loop formed when force was plotted against length. Work done was positive when the muscle was shortening and was negative when it was lengthening; net work was the difference. Work output was varied by changing the stimulus duty cycle (4, 8, or 16% of the total cycle duration) and cycle frequency (1, 2, or 4 Hz). The rate and extent of the decrease in power was influenced much more by changes in cycle frequency than by changes in duty cycle. Duty cycle and cycle frequency combinations that resulted in greater power in the prefatigue trials were associated with a more rapid rate of fatigue. However, net positive power at the end of the 15-min fatigue period was greater under these same conditions (i.e., high duty cycle and high cycle frequency). Fatigue in working diaphragm muscle depends more on cycle frequency than on duty cycle.Key words: skeletal muscle, muscle power, respiratory muscle, muscle lengthening.

Circulating reproductive hormones and hypothalamic oestradiol and progestin receptors in infertile Zucker rats

1989 ◽  
Vol 120 (2) ◽  
pp. 331-336 ◽  
Author(s):  
E. M. Whitaker ◽  
A. C. Robinson
Keyword(s):  
Preoptic Area ◽  
Plasma Concentrations ◽  
Underlying Mechanism ◽  
Reproductive Hormones ◽  
Oestrous Cycle ◽  
Zucker Rats ◽  
Medial Basal Hypothalamus ◽  
Progestin Receptors ◽  
Obese Rats ◽  
The Difference

ABSTRACT Plasma concentrations of LH, FSH, prolactin and progesterone were measured during the oestrous cycle in obese (fa/fa) and non obese (Fa/?) Zucker rats. In obese rats the mid-afternoon surge of LH during prooestrus was reduced compared with that in non-obese rats (P<0.05), and the maximum concentrations of FSH and prolactin declined more slowly during oestrus. Progesterone concentrations were higher during most of the oestrous cycle in obese rats. Oestradiol and progestin receptors were measured in the hypothalamus of female Zucker rats. Lower concentrations of oestradiol receptors were found in the preoptic area of obese rats (P<0.05). Concentrations of oestradiol receptors in the medial basal hypothalamus were also lower in obese rats, though the difference was not statistically significant. Concentrations of progestin receptors were similar in both phenotypes in the preoptic area and media basal hypothalamus. It seems likely that the abnormalities in reproductive hormones and oestradiol receptors contribute to the infertility of obese female Zucker rats. The underlying mechanism has still to be determined. Journal of Endocrinology (1989) 120, 331–336

197 The Effect of Gonadotropin-Releasing Hormone Agonist on Superovulation and Estrous Synchronization in Female Sprague Dawley Rat

2018 ◽  
Vol 30 (1) ◽  
pp. 239
Author(s):  
Y.-K. Jin ◽  
H.-S. Bae ◽  
J.-Y. Lee ◽  
S.-Y. Yum ◽  
K.-M. Kim ◽  
...  
Keyword(s):  
Gonadotropin Releasing Hormone ◽  
Oestrous Cycle ◽  
Control Group ◽  
Sprague Dawley ◽  
Releasing Hormone ◽  
Estrous Synchronization ◽  
Injection Group ◽  
Significant Difference ◽  
The Difference ◽  
Set Up

A large number of oocytes and adequate recipient conditions are required to produce genetically modified rats by embryo transfer. In this study, we investigated the effect of a synthetic gonadotropin-releasing hormone (GnRH) agonist, buserelin, on (1) superovulatory response in donor rats, and (2) oestrous cycle synchrony in recipient female Sprague Dawley rats at 8 weeks of age. First, for superovulation, donors were divided into 2 groups: control and buserelin injection group (42 μg mL−1). Superovulation was performed in both groups by injection of pregnant mare’s serum gonadotropin (PMSG, 150 IU) at Day −3 and human chorionic gonadotropin (hCG, 150 IU) at Day −1 (Day 0 = oocyte collection). In addition, the buserelin group was given 42 μg mL−1 buserelin on Day −4. Oviduct and ampulla were removed surgically to collect the oocytes. As results, more ovulations were detected in the 42 μg mL−1 buserelin group (6.18 ± 1.10 oocyte/rat, n = 240) than in the control group (5.06 ± 0.82 oocyte/rat; n = 124; t-test P = 0.038). Second, 2 groups were set up to investigate the effect of administration of buserelin on synchronizing the oestrus cycle of recipients. Because the oestrous cycle of the rat was 4 to 5 days, we examined the difference of vaginal impedance between the 2 groups on Day 4 after injection and checked whether there was a significant difference in the synchronization of the oestrous cycle. An impedance value >3.0 kΩ was considered as an indication for proestrus stage; therefore, we analysed the data >3.0 kΩ in both groups. In results, the incidence of proestrus was significantly increased in buserelin injection group (n = 128) than in the control group (n = 70). In addition, there was a significant difference in mean impedance in the 2 groups (buserelin injection group: 4.25 ± 3.79 kΩ; control group: 1.43 ± 1.20 kΩ; P < 0.005). In conclusion, administration of 42 μg mL−1 buserelin had a beneficial effect on oocyte ovulation and oestrous synchronization, and it will be usefully applied in the production of transgenic rats.

Direct ovarian - uterine transfer of progesterone increases embryo survival in gilts

2011 ◽  
Vol 23 (7) ◽  
pp. 921 ◽  
Author(s):  
R. Z. Athorn ◽  
P. Stott ◽  
E. G. Bouwman ◽  
R. Ashman ◽  
S. O'Leary ◽  
...  
Keyword(s):  
Uterine Horn ◽  
Oestrous Cycle ◽  
The Other ◽  
Embryo Survival ◽  
Unilateral Ovariectomy ◽  
Maintenance Requirement ◽  
Local Supply ◽  
The Difference ◽  
Circulating Levels ◽  
Post Implantation

This study employed a unilateral ovariectomy model to investigate the relevance of the local supply of progesterone (ovary) compared with the systemic supply of progesterone, in terms of embryo survival in the ipsilateral uterine horn as opposed to the contralateral uterine horn. Thirty gilts were unilaterally ovariectomised (ULO) during the luteal stage of their first oestrous cycle. Half of the ULO gilts were fed at 1.2 maintenance requirement (M), while the other half were fed at 2.4 M. Across ULO gilts 0.8 more embryos survived in the ipsilateral horn compared with the contralateral horn at Day 35 of gestation (P < 0.05). In ULO gilts on the 2.4 M feed level the difference (+1.3; P < 0.05) between the ipsi- and contralateral horn was more pronounced than on the 1.2 M feed level (+0.4; NS). The higher feed level reduced circulating levels of systemic progesterone on Day 5 of pregnancy but not embryo survival at Day 35. However, post-implantation embryo survival was lower on the low feed level. In conclusion, these data indicate that local progesterone supply from the ovaries to the uterus contributes to the probability of embryo survival.

Reproductive performance during early pregnancy in cattle with contrasting early pregnancy rates

2001 ◽  
Vol 26 (2) ◽  
pp. 283-288
Author(s):  
W.H McMillan ◽  
A J. Peterson ◽  
S.F. Cox ◽  
S.J. Pearson ◽  
M.J. Donnison
Keyword(s):  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Early Pregnancy ◽  
Reproductive Performance ◽  
Oestrous Cycle ◽  
Interferon Tau ◽  
Protein Levels ◽  
Reactive Protein ◽  
The Difference ◽  
Establishment Phase

AbstractCauses of variation amongst cattle within a herd in their ability to initiate and maintain pregnancy are largely unknown. An experimental animal resource has recently been established to understand the biology of early reproductive performance. This paper summarises the results achieved during the establishment phase and from several experiments aimed at determining the physiological basis of the difference between sub-herds of contrasting pregnancy rates on Day 60. Each of 155 contemporary yearling heifers received 2 in vitro-produced embryos on 6 separate occasions during a 26-month period. Sixty days after transfer, pregnancy and twinning rates were determined ultrasonically, pregnancies terminated and the process repeated. The interval between successive transfers was greater than 100 days. Heifers were ranked on their aggregate pregnancy rate performance after 6 rounds of transfer, and the highest (High) and lowest (Low) 25 were retained. Differences in reproductive performance during the establishment phase of the herd are reported. In addition, several subsequent experiments examined ovarian follicle turnover and progesterone levels during an oestrous cycle, early embryo development after either AI or embryo transfer, and protein, interferon tau and ubiquitin-cross-reactive protein levels in uterine luminal flushings.Pregnancy rates were 7-folder higher in the High sub-herd (76 vs. 11%), with much of this difference apparent by Day 25. The proportion of heifers observed in standing oestrus prior to embryo transfer and the interval from the end of synchronisation treatment to the onset of oestrus were similar in the sub-herds. Oestrous cycle length, ovarian follicular dynamics and progesterone profiles during the oestrous cycle were also similar. More conceptuses had elongated by Day 14 in the High sub-herd (67 vs. 14%, P<0.05), which also tended to have a higher pregnancy rate after artificial insemination (52 vs. 29, P<0.1). Total protein in flushings from the uterus was similar in the sub-herds on Day 14 and Day 17. Conceptuses in the High sub-herd were longer on Day 17 following embryo transfer (6.5 vs. 4.8, P<0.05). Interferon-tau levels were higher in the High sub-herd (25.9 vs. 16.1, P<0.01), although ubiquitin cross-reactive protein levels were also higher in the High sub-herd, but this difference just failed to reach significance. We conclude that: 1. Most of the difference in sub-herd pregnancy rate occurs within 3 weeks of ET; 2. Ovarian factors are unlikely to contribute to the difference; 3. Major differences occur after blastocyst hatching and probably depend upon a differing endometrial environment before Day 14; 4. Differences in the ability of the uterine milieu to stimulate the expression of interferon-tau may be responsible for the differences in pregnancy rate; 5. The two sub-herds are a unique experimental resource for understanding early pregnancy in cattle following either AI or ET.

Milk progesterone profiles during anoestrus through to pregnancy in Greek dairy goats (Capra prisca): the effect of melatonin treatment and male introduction

1993 ◽  
Vol 56 (3) ◽  
pp. 333-339 ◽  
Author(s):  
S. Belibasaki ◽  
D. Zygoyiannis ◽  
P. Davies ◽  
J. M. Doney
Keyword(s):  
Oestrous Cycle ◽  
Sexually Active ◽  
Progesterone Concentration ◽  
Dairy Goats ◽  
Melatonin Treatment ◽  
The Mean ◽  
The Difference ◽  
Mean Time ◽  
Mean Concentration ◽  
Stimulation Of

AbstractTwo groups of 10 lactating does were housed separately, in isolation from bucks. Does in one group (T) were implanted with melatonin; the second group (U) were not implanted. After 30 days, five implanted and five non-implanted bucks were introduced, singly, into both groups of females each day. Subsamples of milk were taken from the daily output of each doe on 3 days each week for progesterone analysis.Mean milk progesterone concentration during anoestrus varied significantly amongst individuals (P < 0·001), but the difference between T and U groups was not significant (1·51 and 1·93 (s.e.d. 0·52) μg/l, respectively). Elevated progesterone levels, indicative of a short oestrous cycle and commencing days 2 to 5 after male exposure, were observed in most does. Mean progesterone concentrations were 9·9 and 9·6 (s.e.d. 1·32) μg/l in T and U does respectively. Most does showed a second short cycle starting at 12 to 18 days, (mean concentration 8·4 and 10·6 (s.e.d. 1·64) ng/l, respectively). Untreated does then returned to anoestrus until mated at 63·1 (s.e. 0·94) days after male introduction. In contrast, T does either became pregnant or had a normal oestrous cycle, followed by a repeat cycle or pregnancy (mean onset 21·7 (s.e. 2·22) days after male introduction). The mean time of effective mating for group T does was 37·3 (s.e. 5·91) days, 26 days earlier than for U does (P < 0·001). Mean progesterone concentration in early pregnancy was 65·7 (s.e. 5·78) and 67·6 (s.e. 5·41) μg/l in T and U does, respectively. Males did not become sexually active until after the onset of luteal activity in the females, although treated males were earlier than untreated. There were no significant differences in lactation pattern associated with the progesterone profiles in the two groups.The introduction of males during late anoestrus initiates short luteal cycles. Only those does closest to onset of the breeding season, in this case induced by melatonin, continue to cycle normally and mating success may require early stimulation of sexual activity in males.

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