Polyovular Follicles Research Articles

Polyovular Follicles in Mouse Ovaries Exposed Neonatally to Diethylstilbestrol in Vivo and in Vitro1

In 35-day-old C57BL/Tw female mice given daily injections of 1 microgram diethylstilbestrol (DES) for 5 days from the day of birth, a significantly higher incidence of polyovular follicles (PF) were found in the ovaries than in those of age-matched control mice. Ovaries of prepubertal mice treated neonatally with oil or DES (DES mice) showed an enhancement of ovulation and luteinization following a combined treatment with eCG and hCG. Tubal ova in DES mice treated with eCG plus hCG were surrounded by many granulosa cells. Incidence of PF in control mice was not changed by eCG plus hCG treatment. In contrast, PF incidence in DES mice was reduced by prepubertal injections of eCG plus hCG. A high incidence of PF was also found in newborn mouse ovaries transplanted for 30 days into ovariectomized adult hosts given DES injections, but not in ovaries transplanted into intact or ovariectomized DES-untreated hosts. When neonatal ovaries were cultivated in a serum-free medium containing DES for 5 days and then transplanted into ovariectomized hosts, PF were formed in the grafts, but not in DES-unexposed grafts. Oocytes from PF in DES mice were found to have a smaller capacity for fertilization when examined in vitro. The present study also demonstrated that neonatal ovaries exposed to estrogen in vivo or in vitro (which produces PF in prepubertal hosts) are capable of responding to gonadotropins given later, resulting in a reduction of PF incidence, and that exogenous estrogen acts directly on neonatal ovaries to induce PF.

The effects of an aromatase inhibitor and a 5 alpha-reductase inhibitor upon the occurrence of polyovular follicles, persistent anovulation, and permanent vaginal stratification in mice treated neonatally with testosterone.

Female C57BL/Tw mice were given 5 daily injection of 20 micrograms testosterone (T), 100 micrograms 4-hydroxy-4-androstene-3, 17-dione (4-HA), 100 micrograms 6-methylene-4-pregnene-3, 20-dione (6-MP), 4-HA + 6-MP, T + 4-HA, T + 6-MP, and T + 4-HA + 6-MP starting on the day of birth. The animals were ovariectomized at 30 days or 90 days of age and were killed at 150 days. The incidence of polyovular follicles (PF) at 30 days of age was significantly increased by neonatal treatment with T. By contrast, the PF incidence was significantly reduced by injections of 4-HA given simultaneously with T. Neonatally T- or T + 6-MP-treated 90-day-old mice had ovaries containing follicles and hypertrophied interstitial cells but no corpora lutea. By contrast, T + 4-HA (64%)- and T + 4-HA + 6-MP (82%)-treated mice had ovaries with corpora lutea. In the T + 4-HA + 6-MP (82%)-treated mice had ovaries with corpora lutea. In the T + 4-HA + 6-MP-treated, 150-day-old, ovariectomized mice, the number of mice showing vaginal epithelial stratification was significantly decreased as compared with T-treated mice. There were no significant differences in the number of layers, thickness, and mitotic rate of vaginal epithelium of T-treated mice compared with mice treated with T + 4-HA, T + 6-MP, or T + 4-HA + 6-MP. The present results indicate that development of PF and persistent anovulation are due to the direct action of estrogen (E) derived from T upon neonatal ovarian follicles and the neonatal hypothalamo-hypophysial system, and that T itself can induce ovary-independent vaginal changes, although 5 alpha-reduced androgen and estrogen derived from T seem to be more effective in this regard.

Polyovular follicles associated with human in vitro fertilization

Polyovular follicles were found in 61 (24%) of 251 laparoscopies performed for in vitro fertilization. Of 898 follicles that contained at least one oocyte, 76 (8%) were polyovular. When the oocytes from polyovular follicles were assessed by morphologic criteria, it was found that 46 of the follicles contained oocytes that were discordant in maturity. Thus, oocytes can develop at different rates even though they are exposed to the same follicular fluid. It is possible that the microenvironment provided by the cellular investments of oocytes may correlate more precisely with oocyte maturity.

Oocyte size and intrafollicular position in polyovular follicles in rabbits.

Healthy follicles with 2-24 oocytes were observed in adult rabbit ovaries during all phases of folliculogenesis from primary to preovulatory follicles. Most follicles contained 2-3 oocytes which developed according to their topographical situation in the follicle. The central oocyte in a normal topographical situation has an almost normal growth and development up to metaphase II and cumulus expansion. The peripheral oocytes grow more slowly: most do not attain the normal size or resume meiosis and remain surrounded by ordinary granulosa cells. When the number of oocytes is higher than 3, the peripheral oocytes develop even more slowly, as do the central ones. It demonstrates the necessity for the oocyte to occupy a certain position inside the follicle and to reach a size which allows resumption of meiosis; the cumulus responds only to oocytes of normal size and position. We suggest that, despite the relative frequency of binovular follicles, fertilization of two oocytes originating from one follicle is unlikely.

A quantitative cytological study of polyovular follicles in mammalian ovaries with particular reference to the domestic bitch (Canis familiaris).

The incidence of polyovular types in the growing follicle population was estimated using quantitative cytology. Of 15 species studied, polyovular follicles were recorded in the following species and in ascending order of abundance: rabbits, rhesus monkeys, humans, cats, dogs. The incidence in bitches was 14% in animals aged 1-2 years but only 5% at 7-11 years old. The frequency of the various types of polyovular preantral follicle varied inversely with the numbers of oocytes per follicle and the probability of finding a follicle with more than 5 oocytes was remote. In young ovaries the frequency was constant in the early stages of growth but decreased in the largest preantral stage. The pattern in ageing ovaries was, by contrast, one of declining frequency such that few if any polyovular types completed development. The ovary of the ageing bitch was also characterized by a higher incidence of degenerating follicles and a much smaller pool of primordial stages. Polyovular follicles were larger than uniovular types at comparable stages which were defined by the number of granulosa cell layers. Their oocytes were smaller but the overall ooplasmic mass was increased with a corresponding increase in the mass of granulosa cells.

Polyovular follicles in the ovary of immature mice exposed prenatally to diethylstilbestrol.

Polyovular follicles (PF) occur in the ovary of 30-day-old offspring of ICR/JCL mice given 4 daily subcutaneous injections of 20-2,000 micrograms diethylstilbestrol (DES)/day from days 15 to 18 of gestation. PF containing 2-9 oocytes per follicle in the prenatally DES-exposed mice are increased 33- to 112-fold as compared to controls. In 5- to 25-day-old offspring of mothers given injections of 2,000 micrograms DES/day, PF are observed 17-65 times more frequent than in controls.

Frequent occurrence of polyovular follicles in ovaries of mice exposed neonatally to diethylstibestrol

The occurrence of polyovular follicles (PF) was examined at 10-34 days of age in the ovaries of BALB/cCrgl female mice given five daily injections of 0.1 microgram diethylstilbestrol (DES), 2 micrograms DES, 100 micrograms progesterone (P), 137 micrograms 17 alpha-hydroxyprogesterone caproate (HPC), 20 micrograms testosterone (T), 20 micrograms 5 alpha-dihydrotestosterone (5 alpha-DHT), or oil vehicle alone starting on the day of birth, and of C57BL/Tw females given five neonatal injections of 1 microgram DES, 20 micrograms 17 beta-estradiol (E2), 50 micrograms 5 alpha-DHT, 50 micrograms 5 beta-DHT, or the vehicle alone. Ovaries of 30-day-old C57BL mice given five daily injections of 1 microgram DES starting at 3-25 days of age were also examined. PF incidence (% of PF per ovary) and PF frequency (% of mice with PF) were significantly greater in BALB/c mice receiving injections of DES, P, HPC, and T than in the controls. In DES-treated mice at 34 days, PF incidence (2-13 oocytes/follicle) was 120-340 times higher than in the controls. BALB/c mice treated with T, P, and HPC showed PF incidence (two to four oocytes/follicle) three- to six-fold higher than in the controls. In 30-day-old C57BL mice treated with T, E2, and DES, PF incidence also increased by two- to 50-fold. 5 alpha-DHT and 5 beta-DHT failed to increase PF incidence. PF incidence was significantly increased only when neonatal DES treatment was begun on days 0 to 3, but was reduced when started at days 10-25.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Occurrence of polyovular follicles in ovaries of mice treated neonatally with diethylstilbestrol.

Occurrence of polyovular follicles in ovaries of mice treated neonatally with diethylstilbestrol.

Enzyme studies on TPPase-reactive cytoplasmic structures observed in early meiotic prophase I of the hamster oocyte.

Ovaries of immature and adult hamsters were incubated in medium containing thiamine pyrophosphate (TPP) to determine the age at which TPPase-reactive cytoplasmic structures first appear in the germ cells, and at what age the structures cease to be present. The structures were found only in oocytes from animals 8-15 days of age. They occur in predictyate germ cells in polyovular follicles and in very early dictyate oocytes in unilaminar follicles. The TPPase-reactive structures were never observed in atretic oocytes, in unilaminar follicles of adult animals, nor in multilaminar follicles of animals at any age. Ovaries of 8-12-day-old animals and adults were then incubated in media in which one of the following substrates was substituted for TPP: uridine diphosphate (UDP), inosine diphosphate (IDP), and adenosine monophosphate (AMP). Half of the samples in each experiment were incubated in medium containing the inhibitor L-p-bromotetramisole. beta-Glycerophosphate was used in control incubations, or the substrate was omitted entirely. The cytoplasmic structures were found to be reactive after incubation in UDP-containing media, but not after incubation in media containing AMP. With IDP as substrate, reactions were atypical and confined to peripheral regions of the cytoplasm. Other sites of enzyme activity after incubation with the various substrates (cell membranes, zona pellucida, endoplasmic reticulum and Golgi apparatus) are also described and discussed.

Ultrasonically induced morphological damage to mouse ovaries

Mouse ovaries were exposed in in vivo to 1 MHz continuous wave ultrasonic energy at spatial peak intensities ranging from 5 to 100 W/cm 2 for times varying from 300 to 15 s depending on the intensity. Following exposure the ovaries were surgically removed at times ranging from immediately (within 60 s) to 7 days and prepared histologically for light microscopic analysis. The observed tissue alterations varied from severe, at the higher intensities to subtle, at the lower intensities. Lesions were manifested by pyknosis of cells, vacuolization of cells and tissue, eosinophilic cytoplasm, and general cellular disruption. Subtle alterations showed large numbers of polyovular follicles and increases in the amount of PAS positive material in the interstitial tissue. Various ovarian structures showed differing sensitivities to the insult with luteinized structures being preferentially altered.

Desmosomes: their occurrence between adjacent primary oocytes in polyovular follicles in the rabbit.

In polyovular, primordial follicles in the rabbit, desmosomes are found between apposing oocyte surfaces. Morphologically these desmosomes correspond closely to those described in epithelia of vertebrates. The desmosomes alternate with other junctions which are probably gap junctions.

Binovular Follicles in the Adult Human Ovary

The human ovary may contain binovular or polyovular follicles at birth, but they are unusual later in life. Binbovular follicles were found in bilateral ovarian biopsies from a patient with primary amenorrhea who had been treated with exogenous gonadotropins. The fine structural morphology of these follicles has shown that both oocytes were in the resting meiotic prophase, that their respective vitelline bodies faced each other across the intervening plasma membranes, and that the adjacent oocytes made mutual contacts similar to those found between granulosa cells and oocytes. From the appearance of the multivesicular bodies in nearby stromal fibroblasts it is suggested that these follicles had formed by fusion of two adjacent primordial follicles by a mechanism similar to the depolymerization of the ground substance in the apex of the Graafian follicle that leads to ovulation.

Anomalous patterns of mammalian oocyte maturation and fertilization.

This report illustrates some of the errors that may occur during in vivo and in vitro maturation and fertilization of mammalian ova, considers the possible mechanisms accounting for their occurrence, and discusses their functional consequences. Included in the description are anomalies of oocyte and follicular development, i.e., multinucleated oocytes, polyovular follicles, and aberrations of zona pellucida formation. Also considered are deviations from the normal process of oocyte maturation such as chromosomal anomalies, development of abnormal nuclear structures (subnuclei), inhibition of polar body formation and abberations of polar body structure. Anomalies of the process of fertilization such as polyspermia, sperm penetration into polar bodies, and development of multinucleated blastomers in two-cell embryos are also described.

The effects of mutant p-alleles on the reproductive system in mice.

SUMMARYThep6H,p25H, andpbsalleles at the pink-eyed dilution locus in mice (Mus musculus) cause sterility in males and semi-fertility in females when homozygous, while thepd, pun, p, and + alleles do not reduce fertility. Pituitaries from sterile males had significantly lower proportions of gonadotropic cells than pituitaries from fertile males. Ovaries from semi-fertile females contained large numbers of developing follicles, but no corpora lutea or corpora hemorrhagica were found. The proportion of polyovular follicles in ovaries of semifertile females was abnormally high.Pituitary gonadotropins appear to be reduced in the sterile genotypes although the lesion cannot be localized. Possible relationships between these and other pleiotropic effects of mutantp-alleles are discussed.

Polyovular follicles in squirrel monkeys after prolonged diethylstilboestrol treatment.

Summary. Almost 30% of ovarian follicles contained more than one oocyte in squirrel monkeys with chronic implants of diethylstilboestrol. Polyovular follicles were relatively infrequent in control animals. This finding raises the possibility of neogenesis of oocytes in adult haplorhine primates.

Correlation of ovarian abnormalities in young golden hamsters with ovarian estrogens and progesterone.

AbstractA correlation between ovarian steroids and ovarian abnormalities is demonstrated. The decrease in levels of ovarian estrogen and progesterone is correlated, one week later, with an increase in polyovular follicles and then in multinucleate ova. The time sequence of the onset of ovarian abnormalities, as correlated with levels of estrogens and progesterone are an indication of the possibility of hormonal control of the ovarian abnormalities.

Correlation of ovarian abnormalities in young golden hamsters with blood estrogen content.

AbstractThe possibility that the incidence of polyovular follicles and multinucleate ova may depend upon hormonal balance, in the hamster, has been investigated with respect to circulating estrogens. Samples were drawn at weekly intervals from the third through the seventh week of age. An inverse correlation was found to exist. Total blood estrogen decreased from day 21 to day 35, then increased through day 49. Polyovular follicles are most numerous at day 35 while multinucleate ova are most numerous on day 42. Non‐polar estrogen decreased from day 21, achieving a low 28 day level which was maintained throughout the study period. More polar estrogens dropped to the thirty‐fifth day and rose by the forty‐ninth day. The limiting factor in the decrease of more active polar estrogens may be lack of conversion of non‐polar to polar estrogens or a tendency toward rapid degradation and loss of polar estrogens. The role of the fluctuating estrogen titres in the development of ovarian abnormalities is discussed.

Polynuclear ova and polyovular follicles in the ovaries of young guinea pigs

AbstractNOrmal and atypical follicular structures were classified and counted in the ovaries of guinea pigs 3 to 11 weeks of age. The per cent of primary and secondary follicles remain almost constant throughout the period of observation. Corpora lutea appeared at the fifth week and reached what appeared to be the mature level by the sixth week. The per cent of follicles having polynuclear ova reached an early peak at four weeks and decreased sharply at five weeks postpartum. The per cent of polyovular follicles increased to a low peak at nine weeks and decreased in frequency thereafter. The frequencies of atretic follicles with polynuclear ova and of quency thereafter. The frequencies of atretic follicles with polynuclear ova and of atretic polyovular follicles were significantly higher than that of atretic normal follicles. The results of this study were compared to simular observations on the Swiss mouse, Golden Hamster and Sprague‐Dawley rat. The data were discussed in relation to gonadotripic hormone levels.

The Origin and Fate of Polyovular Follicles in the Striped Skunk

Polyovular follicles develop from primary sex cords in the ovarian medulla of the juvenile striped skunk, Mephitis mephitis . These PF are homologous with the seminiferous tubules of the male. The PF degenerate during the first summer after birth in the young skunk. The ova may degenerate without degeneration of the follicular granulosa cells which remain as anovular medullary cords. When the entire follicle degenerates, a thecal interstitial gland forms and contributes to the mass of medullary interstitial tissue. PF may be induced to ovulate by injections of exogenous gonadotropins but it appears that in the untreated animal degeneration typically occurs rather than ovulation.