Follicular activity and ovulation regulated by exogenous progestagen and PMSG in anestrous ewes

Follicular dynamics and ovulation were compared in 3 groups of anestrous ewes: those treated with medroxyprogesterone acetate (MAP) sponges for 12 d, then with 750 IU PMSG at the time of sponge removal (P4 + PMSG, n = 6), or PMSG alone (n = 6) and untreated controls (n = 6). Waves of follicular activity were observed in all the animals. In the P4 + PMSG treatment group, MAP priming permitted more ovulatory follicles (P < 0.001) to be recruited without changing follicle growth rate; MAP priming also delayed the time of ovulation (P < 0.001) and the time of the LH surge (P < 0.01), which allowed for an increase in the size of ovulatory follicles (P < 0.05). Ovulation also resulted in normal luteal function after P4 + PMSG (P < 0.01) but not after PMSG alone, since premature luteal regression occurred in 80% of the cases and was related to the presence of follicles > 4 mm when P4 levels were < 1 ng/mL on the day following ovulation. The results showed that MAP priming increased the ovulation rate by increasing the number of follicles that responded to PMSG.     

Follicular development and ovulation in Macaca fascicularis,Saimiri sciureus and Galago senegalensis

A technique utilizing laparoscopy to determine the precise time of ovulation in three species is described. Determination is based on morphological changes that occur 24 to 36 hours before ovulation. This technique, coupled with mating sessions of short-duration, has been used to produce precisely defined pregnancies; the implications of this technique in reproduction research and teratology are discussed. A comparison of ovulation times in Macaca fascicularis indicates that ovulation normally occurs on day 13 of animals having a cycle length from 25 to 28 days. In animals with a cycle length from 31 to 34 days, ovulation occurred on day 14.8. Evidence presented does not substantiate previous claims for alternation between ovaries in consecutive cycles.     

Follicular growth and ovulation in postpartum beef cows following calf removal and GnRH treatment

This study investigated the effects of calf removal (CR) and gonadotrophin releasing hormone (GnRH) administration on the duration of the postpartum anoestrous period in suckled beef cows. Experiment 1 involved 20 multiparous suckled cows that were assigned to each of two treatments on Day 61 postpartum: (i) unlimited access to their calves (C; n=10) and (ii) calf removal for a period of 96 h (CR96, n=10). Experiment 2 involved 24 multiparous cows that were assigned to each of two treatments on Day 63 postpartum: (i) CR96 (n=12); and (ii) CR96 plus 250 microg of GnRH administered on the day before calf return (CR96+GnRH, n=12). Experiment 3 was a 3x2 factorial experiment, involving 48 multiparous cows assigned to the experiment on Day 58 postpartum. The factors were C, CR96 and calf removal for 144 h (CR144), and 0 or 250 microg GnRH administered on the day prior calf return. In Experiment 1, the number of cows that ovulated within 12 days of calf removal was higher (P<0.05) in CR96 group (3/9) compared to the C group (0/10). In Experiment 2, all 12 cows in the CR96+GnRH group ovulated. In contrast only 4/12 cows in the CR96 group ovulated in response to calf removal. The diameter of the ovulatory follicle tended (P=0.06) to be smaller in CR96+GnRH cows (9.8 +/- 0.3 mm) than in CR96 cows (11.3 +/- 0.9 mm). The maximum diameter attained by the corpus luteum (CL) also tended (P=0.08) to be smaller for cows in the CR96+GnRH than for cows in the CR96 group (12.1 +/- 2.4 mm versus 16.7 +/- 7.5 mm, respectively). Plasma progesterone concentrations 12 days after calf removal tended (P=0.06) to be lower in CR96+GnRH cows than in CR96 cows (0.66 +/- 0.1 ng/ml versus 2.00 +/- 1.1 ng/ml, respectively). Few cows in the CR96+GnRH group regained normal cyclical activity and the interval from onset of calf removal to conception was longer (P<0.05) compared to cows in the CR group (52.2 +/- 5.7 days versus 20.0 +/- 6.6 days). In Experiment 3, 5/8 cows on the CR144 group and all 8 cows in the CR144+GnRH group ovulated. However, the interval from CR to conception was similar for all treatments. Temporary (96-144 h) calf removal, particularly in combination with GnRH treatment, can induce a high proportion of beef cows to ovulate, but the restoration of oestrous cycles may not be achieved.     

Follicular development, ovulation, fertilization and fetal development in tenrecs (Tenrec ecaudatus)

Reproduction in female tenrecs was studied on Praslin Island (4 degrees 20'S, 55 degrees 45'E) in the Seychelles from November 1977 to September 1980. Dissection and histological examination of reproductive tracts revealed that each ovary is encapsulated in a bursa. Polyovular follicles were abundant and contained up to 5 oocytes. The occurrence of more implanted fetuses than corpora lutea (CL) indicated successful polyovuly in 25% of pregnancies. No antrum was observed during follicular growth at oestrus, and follicles were relatively small at maturation, reaching a maximum diameter of 570 microns. Ovulation involves a gentle extrusion of the granulosa and ovum into the periovarian space. Spermatozoa were abundant in the female reproductive tract including the periovarian space at oestrus. Spermatozoa penetrated the loosely-packed theca of mature follicles and were present in CL, indicating that intrafollicular fertilization may occur. The relatively small CL formed by eversion, reaching a maximum size after implantation. Fusion of up to four CL occurred in the ovaries of 41% of pregnant females. Polyovulation in the tenrec was confirmed by the occurrence of 10.4 +/- 0.5 (mean +/- s.e.m.) CL and 9.7 +/- 0.5 (mean +/- s.e.m.) implantations. Resorption occurred in 74% of 19 dissectable pregnancies, occurring in both uterine horns in 26% of pregnancies. Coefficients of variation in weights of fetuses in each litter were 10.0-26.8%, with the largest value corresponding to 273% variation in fetus weights. Litter size in the Seychelles tenrecs was smaller than in the same species in Madagascar (17.1 +/- 1.9 implantations) where the tenrec is native.     

Follicular and FSH dynamics in ewes with a history of high and low ovulation rates

Daily transrectal ultrasound scanning and twice-daily blood sampling were used to monitor the temporal relationships between FSH concentrations and follicle development during complete interovulatory intervals for ewes in which the ovulation rate in each of the 2 previous years was high or low (> or = 3 and < or = 2 ovulations, respectively). Follicles that reached > or = 5 mm were used to define a follicular wave and were tracked retrospectively to 3 mm (emergence). The hypothesis that FSH surges (identified with a computer program) and follicular waves (retrospectively determined based on ultrasound scanning) are temporally associated was supported in both groups by the emergence of an anovulatory or ovulatory follicular wave near the peak of an FSH surge. Further support for the hypothesis was a significant increase in FSH concentrations before and a significant decrease after follicular-wave emergence in both groups independent of the identification of FSH surges. Ewes with a history of high ovulation rates had smaller follicles (anovulatory and ovulatory) and more ovulations, but the 2 groups were similar in the number of ovulatory follicular waves and associated FSH surges, number and characteristics of the FSH surges, and mean FSH concentrations per interovulatory interval. Surges of FSH were periodic (every 3 or 4 d) regardless of the ovulation-rate group or follicle response. In ewes with a low ovulation rate, the nonovulatory FSH surges were most frequently associated with emergence of detected anovulatory follicular waves. In ewes with a high ovulation rate, more FSH surges were not associated with a detected follicular wave, as defined, presumably because the largest follicle did not reach 5 mm. The results indicated that the factors resulting in a high ovulation rate were not exerted through circulatory patterns or concentrations of FSH but involved a shorter growth phase and smaller maximal diameter of follicles.     

Follicular and uterine prostaglandin levels in relation to uterine contraction and the first ovulation of a sequence in the hen

Changes in the concentration of progesterone, estrone, estradiol, prostaglandins (PG) E2, 6-keto F1 alpha and 13,14-dihydro-15-keto F2 alpha (PGFM) were measured in peripheral plasma, and in venous effluent from the shell gland and the largest (F1) and the second largest (F2) preovulatory follicles. Tissue concentrations in the F1, F2 and the most recently ruptured follicle and the shell gland also were determined. Changes in these criteria were compared to changes in uterine contraction before the first ovulation of a sequence. Significant increases of PGF2 alpha and PGFM in the peripheral plasma were observed when the frequency of uterine contraction reached a maximum, about 1 h before ovulation. Relative to peripheral plasma, the concentrations in F1 plasma of progesterone, PGF2 alpha and PGFM were increased 20-fold, 150-fold and 15-fold, respectively, at the time of the maximum frequency of uterine contraction. The highest tissue concentrations of PGs were also observed in the F1 follicle. These results suggest that the largest preovulatory follicle is the major source of PG synthesis and release. These PGs may stimulate uterine contraction and may also play a role in follicular rupture and release of the ovum.     

Follicular growth, ovulation and embryo recovery in dairy cows given FSH at the beginning or middle of the estrous cycle

Variability in the superovulation response is an important problem for the embryo transfer industry. The objective of this study was to determine whether FSH treatment at the beginning of the cycle would improve the ovulation rate and embryo yield in dairy cows. Twenty-eight postpartum cyclic dairy cows were allocated at random to 4 treatment groups (A, B, C and D). Group A cows (n = 10) received FSH (35 mg) at a decreasing dose, starting on Day 9 (Day 0 = day of estrus) for 5 days followed by PGF(2alpha) (35 mg) on Day 12. Cows assigned to Groups B, C and D (n = 6 cows each, respectively) were given 35 mg FSH at a decreasing dose from Days 2 to 6 followed by PGF(2alpha) on Day 7. Group C and D cows received PRID inserts from Day 3 to Day 7. Cows in Group D additionally received 1000 IU hCG 60 hours after PGF(2alpha) treatment. Ovaries were scanned daily using a real time ultrasound scanner from the beginning of FSH treatment until embryo recovery, to monitor follicular development, ovulation and the number of unovulated follicles. Embryos were recovered from the uterus by a nonsurgical flushing technique 7 days after breeding. There were no differences (P>0.01) in the number of follicles > 10 mm at 48 hours after PGF(2alpha) treatment among the 4 groups. The mean numbers of follicles were 10.6 +/- 1.2, 9.3 +/- 1.3, 12.2 +/- 1.3 and 15.0 +/- 2.9 for Groups A, B, C and D, respectively. A significantly (P<0.001) higher number of ovulations was observed and a larger number of embryos was recovered in Group A than in the other groups. The results of this study indicate that superovulation with FSH at the beginning of the cycle causes sufficient follicular development but results in very low ovulation and embryo recovery rates.     

Follicular wave emergence, luteal function and synchrony of ovulation following GnRH or estradiol benzoate in a CIDR-treated, lactating Holstein cows

This study evaluated the effect of GnRH or estradiol benzoate (EB) on follicular wave emergence and progesterone concentrations, and following a second injection of GnRH, synchrony of ovulation, and pregnancy rates in a controlled internal drug release (CIDR)-based timed AI (TAI) protocol in lactating Holstein cows. Cows received a CIDR device without hormone (controls), with an injection of 100 microg GnRH or with an injection of 4 mg EB. Thereafter, all received PGF(2 alpha) at the time of CIDR removal on Day 7, GnRH on Day 9, and TAI 16 h later. Follicular wave emergence occurred within 7 days in 19/20 GnRH-treated, 14/20 EB-treated and 5/20 control cows (P < 0.05). The interval to wave emergence was the shorter and less variable (P < 0.01) in the GnRH group (2.9 +/- 0.2 days) than in the EB (4.7 +/- 0.5 days) or control (4.8 +/- 1.0 days) groups. Serum progesterone concentrations from Days 4 to 7 were higher (P < 0.01) in the GnRH-treated cows that ovulated than in those that did not ovulate, or in control and EB-treated cows. The diameters of dominant follicle on Day 7 differed among groups (P < 0.01), and the diameters of the preovulatory follicle on Day 9 were larger (P < 0.01) in the control and GnRH groups than in the EB group. The proportion of cows with synchronized ovulations did not differ among groups, but pregnancy rate to TAI was higher (P < 0.05) in the GnRH group (65%; 13/20) than in the control (30%; 6/20) or EB (35%; 7/20) groups. Results suggest that GnRH treatment of CIDR-treated lactating Holstein cows will result in synchronous follicular wave emergence, large preovulatory follicles and synchronous ovulation, resulting in an acceptable pregnancy rates to TAI.     

Follicular development, steroidogenesis and ovulation within ovaries exposed in vitro to hormone levels which mimic those of the rat estrous cycle

In order to more clearly define the hormonal factors responsible for follicular growth, ovulation and steroidogenesis, a perifusion culture system was developed. This culture system was capable of exposing the ovaries to hormonal levels which mimic the 4-day estrous cycle of the rat. Using this culture system, ovaries were exposed to the in vivo levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol-17 beta and progesterone to within the mean +/- one standard deviation of the values reported by Butcher et al. (1974a). During the 4-day culture period, the diameter of the follicles gradually increased in a manner similar to that of cycling rats. After 4 days in vitro, the ovaries ovulated 4.3 +/- 0.6 oocytes/ovary as assessed by the presence of ruptured-partially luteinized follicles. This in vitro ovulation rate was not significantly different from the in vivo ovulation rate of 5.0 +/- 0.8 oocytes/ovary (P greater than 0.05). The pattern of follicular growth within cultured ovaries was similar to that of the cycling rat, although the number of small follicles recruited to grow was reduced. The steroid secretory patterns also were slightly different in the cultured ovaries. These data indicate that physiological ovarian responses which are similar to those of cycling rats can be induced within cultured ovaries. With further utilization of this culture technique, the precise role of gonadotropins, ovarian steroids and other hormonal agents can be examined in order to define specific ovarian functions which are controlled by each hormonal agent.     

Follicular development and a single ovulation induced with pulsatile administration of Gn-RH in anovulatory women: studies of hormonal analysis and follicular sonometry

The method of pulsatile administration of gonadotropin-releasing hormone (Gn-RH) has been proven as a useful means for induction of ovulation in anovulatory women. In our series of clinical trials, 23 out of 29 anovulatory patients ovulated with pulsatile administration of Gn-RH. Seven patients who ovulated volunteered for the present study with daily hormonal analysis and follicular sonometory . Two patients have oligomenorrhea, 3 patients secondary amenorrhea-1st grade (the sole administration of gestagen required for withdrawal bleeding) and the remaining 2 patients secondary amenorrhea-2nd grade (the combined administration of estrogen and gestagen required for withdrawal bleeding). A diagnosis of hyperprolactinemia was made for one patient with secondary amenorrhea-1st grade. Pulsatile administration of Gn-RH was performed by the use of a self-administered infuser . The infuser was connected to an i.v. indwelling catheter via a specially designed blood backflow eliminater . Five micrograms or less of Gn-RH was given every 2 hr from 07:00 to 23:00 hr daily. Five patients received HCG during the preovulatory period. In one patient, a short term treatment of HMG was added to Gn-RH treatment. Follicular sonometry revealed the development of a single dominant follicle which reached between 20 and 28 mm (23.7 +/- 0.12 mm, mean +/- S.E.) in diameter at the preovulatory period. Disappearance of a dominant follicle was recognized in the early luteal phase. Characteristic increases in estradiol were recognized concomitantly with the development of a dominant follicle. Progesterone levels after ovulation were within the limits of its normal "luteal phase" rise. The present data suggest that pulsatile administration of low dose Gn-RH with nocturnal interruption of treatment is effective for normal progress of follicular development in various types of anovulatory patients, culminating in single ovulation. This paper includes the discussion on our method which may be responsible for a high success rate of ovulation induction.     

Follicular dynamics and temporal relationships among body temperature, oestrus, the surge of luteinizing hormone and ovulation in Holstein heifers treated with norgestomet

The effects of chronic treatment with norgestomet on follicular dynamics, corpus luteum growth and function as well as the temporal relationships among body temperature, oestrous behaviour, the luteinizing hormone (LH) surge and ovulation following implant removal were studied in 16 Holstein heifers. Oestrous cycles of the heifers were initially synchronized using 2 injections of prostaglandin F-2 alpha (PGF-2 alpha) 12 days apart. The heifers were then implanted with a norgestomet ear implant for 9 days, beginning either at the middle of the synchronized cycle (dioestrus) or at the end of the synchronized cycle (pro-oestrus). Follicular dynamics, corpus luteum growth and regression, and plasma progesterone were not affected by norgestomet treatment at dioestrus. The dominant follicle present at the time of norgestomet implantation in the pro-oestrus group was maintained during the 9-day implant period of 6 of 8 heifers and ovulated after implant removal. Time from implant removal to onset of standing oestrus and time to LH peak following implant removal were highly correlated with the time of ovulation (r = 0.92 and 0.96, respectively). Onset of standing oestrus and the LH peak and the onset of standing oestrus and peak vaginal and rectal temperatures were also highly correlated (r = 0.96, 0.82 and 0.81, respectively). It is concluded that any decrease in pregnancy rates following treatment with norgestomet is not due to asynchrony among oestrus, the LH surge and ovulation.     

Follicular dynamics in Serrana goats

Twenty-two Serrana goats were studied through two successive estrous cycles in order to characterize their follicular dynamics during the breeding season. The ovaries of the goats were scanned daily by real-time ultrasonography and all follicles >or=3mm were measured and classified. The data were classified by the number of follicular waves per goat to test the hypothesis that temporal and morphological differences between the last follicular wave of an ovary, irrespective of ovulation, will affect the selection of the next ovulatory wave. The mean interovulatory interval was 20.7+/-1.0 days (mean+/-S.D.). Three to five waves per estrous cycle were observed and 61.3% (19/31) of cycles had four waves. In estrous cycles with four waves, the day of onset of the first, second, third and fourth wave was 1.4+/-1.0, 6.9+/-1.4, 11.6+/-1.8 and 16.8+/-1.6, respectively. No differences (P>0.05) were found between the day of onset of the first and second waves for estrous cycles with three, four or five waves. However, the day of onset of the third and fourth waves occurred later when the number of waves per estrous cycle increased (P<0.001). The duration of the interwave interval (time between the day of onset of two consecutive waves) was longer when the second wave was ovulatory. The length of the growth phase (2.4+/-0.9 days) and size (5.9+/-0.7 mm) of the dominant follicle in the second wave were lower (P<0.01) than for the first wave (3.3+/-1.2 days and 6.6+/-0.9 mm, respectively) and the fifth wave (4.1+/-1.2 days and 7.5+/-1.0mm, respectively). Within pairs of ovaries, the onset of the last wave occurred later (P<0.05) and was less variable in ovulatory ovaries (day 16.8+/-1.4, n=20) than in anovulatory ovaries (day 15.1+/-3.7, n=20). The length of the growing phase was longer (P<0.001) in the last waves of ovulatory ovaries (3.1+/-0.9 days) than in the last waves of anovulatory ovaries (1.7+/-0.8 days). These results support the hypothesis that the day of onset of the ovulatory wave is related to or, at least, conditioned by the luteolysis and the decrease in plasma progesterone. In summary, the estrous cycle of Serrana goats is characterized by sequential follicular wave growth with a great variability in their onset and duration, with the exception of the ovulatory wave. The temporal and morphological differences observed in the last wave of estrous cycle provide strong evidence for the role of progesterone in their regulation.     

卵泡液蛋白质组学研究进展

蛋白质组的概念最初在1994年提出.蛋白质组学是以细胞内全部蛋白质的存在及其活动为研究对象,它极大地促进了我们对后基因组时代基因功能的理解.卵泡液作为卵母细胞生长和分化的培养基,直接或间接影响卵母细胞的生育力和发育潜能,其中的一些蛋白质可以作为卵母细胞成熟的标记.应用蛋白质组学方法可以筛选与卵母细胞成熟及一些与生殖疾病有关的标记蛋白.本文就卵泡液的蛋白质组学研究进展作简要综述.     

卵泡内环境对猪卵泡卵体外成熟和发育的影响

研究卵泡内环境对猪卵母细胞体外成熟、受精及受精卵体外发育的影响。主要结果如下：直径≥5mm、4－4.9mm、3－3.9mm和2－2.9mm的卵泡卵母细胞体外成熟率分别为90.5%、89.7%、85.4%和67.4%,体外受精后,卵母细胞的发育能力随卵泡直径的增大而增强,直径≥5mm和4－4.9mm卵泡卵的2－细胞、3－4－细胞发育率显著高于直径2－2.9mm的卵泡卵（P＜0.05或0.01）。体外成熟培养36h、42h和48h,直径2－2.9mm卵泡卵的体外成熟率,体外受精后的卵裂率差异不显著（P＞0.05）。在体外成熟培养液中添加5％或15％的不同直径卵泡的卵泡液,各组间卵母细胞的体外成熟率,受精卵的体外发育率均无显著差异,结果表明：卵泡大小对猪卵母细胞体外成熟、受精及受精卵体外发育有重要影响。     

Follicular recruitment in long-term hemicastrate rats

In the long-term hemicastrate rat, the total number of ova shed during estrus is the same as in the intact rat. To determine if the dynamics of follicular development are the same in the hemicastrate rat as in the intact control rat, the remaining ovary was removed from rats 20 to 30 days after hemiovariectomy. Complete serial sections of each ovary were prepared for histological examination. All follicles greater than or equal to 300 micrometers were counted, measured, and examined for signs of atresia. Long-term hemicastrate rats had a total complement of half as many healthy antral follicles compared to intact rats at estrus. At metestrus, there were half as many small and medium antral follicles in long-term hemicastrates as in controls. However, the total number of large antral follicles was the same in hemicastrate and intact rats. Thus, by metestrus, the appropriate number of follicles for ovulation appears to have been achieved in both animals, with all these large antral follicles located in the one remaining ovary of the hemicastrate rat, while they are distributed between both ovaries of the intact rat. Ovaries of the long-term hemicastrate rats contained far fewer attretic follicles than ovaries of intact rats. These findings suggest that the process of follicular recruitment differs greatly between intact and long-term hemicastrate rats. Atresia of small and medium antral follicles (300-400 micrometers in diameter) is apparently a necessary step in achieving the correct number of ovulatory follicles in the intact rat, yet the hemicastrate rat arrives at the correct number of ovulatory follicles without atresia.     

Follicular cell-derived thyroid cancer in children

Thyroid carcinoma is a rare disease in childhood. The only known causative factor is radiation exposure during childhood. Most cases can be cured by surgery and eventually radioiodine. The aim of initial treatment should be the total removal of neoplastic foci with a minimal morbidity. Some cancer-related deaths have been reported decades after initial treatment.