Possible role of interferon-gamma in ovarian function

Paternal Exposure to Ribavirin: Pregnancy and Neonatal Outcome

We report seven cases of newborns conceived within 6 months from the end or during paternal ribavirin exposure.

The anovulation in female mice resulting from postnatal injections of estrogen is correlated with altered levels of CD8+ lymphocytes

PROBLEM

Injections of estradiol-17 beta (E2) are known to both induce anovulation and alter lymphocyte maturation in female mice. The current study examined whether the two events are related.

METHOD OF STUDY

Female (C3H/HeJ x 129J)F1 (C31) mice were injected with 20 micrograms of E2 from 0-3 days, or from 3-6 days, postpartum. At 8, 12, 20, 32, or 40 weeks of age, the animals were killed, T lymphocytes were characterized, and ovaries were histologically examined for the presence of corpora lutea.

RESULTS

Animals injected with E2 from 0-3 days postpartum had percentages of CD8+ thymocytes and CD8+ splenocytes that were always lower than in noninjected females, and the E2-injected animals never ovulated, even by 40 weeks of age. In contrast, animals injected with E2 from 3-6 days of age had percentages of CD8+ thymocytes and CD8+ splenocytes that, although initially lower than in control females, attained control values by 32 weeks of age. In addition, at 32 weeks of age a number of the 3-6-day E2-injected females ovulated, whereas at earlier ages none had. Further, injections of E2 had little effect on the percentages of CD4+ thymocytes and splenocytes in these animals.

CONCLUSIONS

The results suggest that E2-induced anovulation in C31 female mice is correlated with decreased levels of CD8+ lymphocytes, and an increased CD4+/CD8+ lymphocyte ratio.

Ovarian follicular growth, ovulation and atresia. Endocrine, paracrine and autocrine regulation

This chapter describes a finely tuned series of events that results in ovarian morphological changes including follicular growth, dominant follicle selection, oocyte development, ovulation, and corpus luteum formation. These changes are under the obligate control of the pituitary gonadotropins FSH and LH. The signaling mechanisms whereby the gonadotropins stimulate these changes in the ovary are now well described. The gonadotropin membrane receptors have been cloned and the cellular events proceeding from receptor binding to phosphorylation of protein gene regulators, such as CREB, have been elucidated. A whole series of intraovarian paracrine and autocrine regulators have been described as having the capability of "fine tuning" the effects of gonadotropins (see Tables I and II), and they are likely involved in dominant follicle selection and the demise of the corpus luteum. The roles of the individual paracrine regulators are, as of yet, not well known, but the IGF system offers an attractive paradigm for these intraovarian factors. Lastly, we have described the explosion of data on intracellular and intranuclear regulators. The challenge for us will be to understand the physiological significance of the seemingly unlimited number of regulatory possibilities. Much has been learned concerning the regulation of the morphological changes seen in the ovary, but much more remains to be elucidated.

Immunohistochemical localization of interferon-gamma in normal human ovary

There is increasing evidence that cytokines are important intraovarian non-steroidal regulators. The aim of the present study was to evaluate the presence in the human ovary of interferon (IFN)-gamma, a cytokine produced by T lymphocytes after mitogenic or antigenic stimulation. Very low levels of IFN-gamma (0.025-0.057 IU/ml) were found in follicular fluid of large spontaneously maturing follicles, in the ovarian vein (< 0.01-0.079 IU/ml) or peripheral blood (< 0.01-0.06 IU/ml). The avidin-biotin immunocytochemical technique, with appropriate monoclonal antibodies, was used to localize IFN-gamma-positive cells, human leukocyte antigen (HLA)-DR molecules, activated T cells, T helper/inducer cells and T cytotoxic/suppressor cells. IFN-gamma-positive cells were only detected in preovulatory follicles, associated with the follicular basal lamina, thecal vessels and interstitial tissue. In the same large follicles very few T helper/inducer cells were detected, but a high proportion of T lymphocytes expressed the CD8 phenotype in the theca, interstitial tissue and follicular cavity. No IFN-gamma-positive cells were observed in preantral and small antral follicles. The results indicate that the human ovary contains immunoreactive IFN-gamma, suggesting that the cytokine plays a paracrine role in human ovarian function.