The Radio-Sensitivity of Oocytes at Different Stages of Maturation

Journal Article · Tue Jul 16 04:00:00 EDT 1963 · Proceedings of the Royal Society B: Biological Sciences

DOI:https://doi.org/10.1098/rspb.1963.0038· OSTI ID:4674336

Mandl, A. M.

The viability of the zygote after fertile mating was used as an index to assess the radiosensitivity of oocytes in Graafian follicles at different times before expected ovulation, and at known stages of the maturation process. Radiosensitivity increases as the interval between irradiation and expected ovulation decreases; the increase is progressive as the oocyte passes from the late dictyate (diplotene) phase through the successive stages of maturation, at least up to congression of chromosomes at first metaphase. It is estimated that radiosensitivity increases by about ten times between the earliest and the latest developmental stages studied, on the day of pro-oestrus. Oocytes in medium- sized'' follicles (irradiated 5 to 35 days before fertilization) are highly radioresistant. The estimated LD/sub 50/ for oocytes at this stage is about three times higher than that for pre-ovulatory oocytes some 14 to 15 hr before expected ovulation. The total difference between the radiosensitivity of oocytes in medium-sized or growing follicles, and that of oocytes at first metaphase, is of the order of x30. X-irradiation is followed by superovulation and a decrease in the mean size of the corpora lutea of pregnancy. In general, the number of corpora lutea is inversely correlated with their mean size. The degree of superovulation is partially dependent on (a) the dose of x-rays and (b) the developmental stage of the oocytes at the time of irradiation. The radiosensitivity of the fertilized ovum, 8 to 12 hr after ovulation, is lower than that of pre-ovulatory oocytes which have reached or passed first metaphase. Subsequently, the sensitivity of the zygote decreases with advancing age. (auth)

• Research Organization: Univ. of Birmingham, Eng.
• Sponsoring Organization: USDOE
• NSA Number: NSA-17-031913
• OSTI ID: 4674336
• Journal Information: Proceedings of the Royal Society B: Biological Sciences, Journal Name: Proceedings of the Royal Society B: Biological Sciences Journal Issue: 970 Vol. 158; ISSN 0962-8452
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

AGE
ANIMAL CELLS
BIOLOGY AND MEDICINE
CHROMOSOMES
CORPORA LUTEA
CYTOLOGY
GONADS
LETHAL DOSE
MITOSIS
OOCYTES
OVARIES
PHYSIOLOGY
PREGNANCY
RADIATION DOSES
RADIOSENSITIVITY
REPRODUCTION
SEX
TESTING
VARIATIONS
VOLUME
X RADIATION