Mouse Ovarian Development Research Articles

Mouse ovary developmental RNA and protein markers from gene expression profiling

To identify genes involved in morphogenetic events during mouse ovary development, we started with microarray analyses of whole organ RNA. Transcripts for 60% of the 15,000 gene NIA panel were detected, and about 2000 were differentially expressed in nascent newborn compared to adult ovary. Highly differentially expressed transcripts included noncoding RNAs and newly detected genes involved in transcription regulation and signal transduction. The phased pattern of newborn mouse ovary differentiation allowed us to (1) extend information on activity and stage specificity of cell type-specific genes; and (2) generate a list of candidate genes involved in primordial follicle formation, including podocalyxin ( Podxl), PDGFR-β, and a follistatin-domain-encoding gene Flst1. Oocyte-specific transcripts included many (e.g., Deltex2, Bicd2, and Zfp37) enriched in growing oocytes, as well as a novel family of untranslated RNA's (RLTR10) that is selectively expressed in early stage follicles. The results indicate that global expression profiling of whole organ RNA provides sensitive first-line information about ovarian histogenesis for which no in vitro cell models are currently available.

Expression and regulation of gonadotropin‐re leasing hormone (GNRH) and its receptor MRNA transcripts during the mouse ovarian development

The present study examines the expression and regulation of gonadotropin‐releasing hormone (GnRH) and its receptor (GnRH‐R) mRNA levels during mouse ovarian development. A fully processed, mature GnRH mRNA together with intron‐containing primary transcripts was expressed in the immature mouse ovary as determined by Northern blot analysis and reverse transcription‐polymerase chain reaction (RT‐PCR). The size of ovarian GnRH mRNA was similar to that of hypothalamus, but its amount was much lower than that in the hypothalamus. Quantitative RT‐PCR procedure also revealed the expression of GnRH‐R mRNA in the ovary, but the estimated amount was a thous and‐fold lower than that in the pituitary gland. We also examined the regulation of ovarian GnRH and GnRH‐R mRNA levels during the follicular development induced by pregnant mare's serum gonadotropin (PMSG) and/or human chorionic gonadotropin (hCG). Ovarian luteinizing hormone receptor (LH‐R) mRNA was abruptly increased at 48 h after the PMSG administration and r...

Influences of prenatal and postnatal fraternity size on ovarian development in the mouse.

An experiment was conducted to test effects of prenatal and postnatal fraternity size (size of litter in which an individual develops prenatally or is reared postnatally) on ovarian development in mice. Fraternity size treatments were created by standardizing sizes of prenatal and postnatal fraternities in which mice were gestated and reared. Prenatal fraternity size was standardized by surgery on Day 9 of gestation to 6, 10, and 14 fetuses. Postnatal fraternity size was standardized by randomly assigning pups to litters of 5, 10, or 15 pups within 24 h of birth. Female pups were killed at either 3 or 20 wk of age and right ovaries were prepared for histology. Follicles were classified by size and morphology, and numbers of follicles in each class were tabulated. Interaction of postnatal fraternity size and age was observed for number of antral follicles (p less than 0.05). Mice reared in small postnatal fraternities had more antral follicles at weaning (3 wk) and fewer antral follicles at maturity (20 wk of age) than mice reared in large postnatal fraternities. No effect of either prenatal or postnatal fraternity size on other follicle populations was observed (p greater than 0.20). Numbers of Type 2 (primordial), Type 3a, and Type 3b follicles changed with age (p less than 0.01); numbers of primordial follicles declined with age, but numbers of Type 3a and 3b follicles increased. A hypothesis of a negative association between postnatal fraternity size and number of antral follicles at 3 wk of age was supported, but a hypothesis of a positive association between fraternity size and number of primordial follicles was not supported.

Proceedings: Ovarian development in mice treated neonatally with progesterone and its effects on fertility.

Administration of steroid hormones to rodents during the neonatal period results in an alteration of gonadal function and subsequent maturity. These results have been reported in rats and mice treated neonatally with oestrogens or androgens (Kinml, 1970, 1971; Peters & Sorensen, 1970; Eshkol, Lunefeld & Peters, 1970). In the present study, Swiss strain female mice were injected with a single dose of 1 mg progesterone at the age of 5 days and ovarian development was studied in the neonatal and the juvenile periods. The treated mice were also observed for vaginal opening and subsequent fertility. Histological studies revealed that the proliferation of the granulosa cells and antrum formation in the follicles of treated animals was affected, and the fertility of these mice was impaired. Although the oestrous cycles were normal, sexual maturity (based on the age at which the first vaginal plug was seen) was delayed. However, only 30% of the matings were fertile and fewer young were born than in the control group. These results indicate, that, like other steroids, progesterone play a significant role in the neonatal development of the mouse ovary and the subsequent fertility of the animal.

The development of mouse ovaries after low-dose irradiation at birth.

SummaryA single dose of 20 r of x-rays given to mice at birth influences the development of their ovaries considerably. The effect becomes evident a few hours after radiation, and the damage can be traced in the infantile and pre-pubertal ovaries and in the organs of young mature animals. The immediate damage seems to be due to the marked radiation sensitivity of oocytes in pachytene, i.e. the pre-stationary stage of meiotic prophase, in which many of the oocytes still are on the day of birth in the ‘Street’ mouse. Oocytes in pachytene disappear quickly after radiation, whereas oocytes already in the stationary phase of meiosis at the time of radiation seem more resistant to immediate damage. Although irradiated animals start to ovulate at about the same age as normal animals and produce morphologically normal ova soon after they reach maturity, histological analysis reveals already marked degeneration and destruction of parts of the ovary at that time.