The effect of chronically administered cannabis extract on the female genital tract of mice and rats.

Daily administration of cannabis extract (mice: 1 mg/day, rats: 5 mg/day for a period of 64 days) results in a cessation of ovarian cyclic activity as judged by vaginal smear and the absence of corpora-lutea in the ovaries of treated rats and mice. Distinct effects are produced upon uterine tissue. Uterine glands were regressed and the stromal edema was conspicuous. Cannabis extract resulted in a decreased uterine RNA, glycogen, and sialic acid concentration. It also brings about a significant depletion in the level of adrenal ascorbic acid.     

Anti-steroidogenic activity of floral extract of Thespesia populnea Corr. in mouse ovary

Anti-steroidogenic activity of various extracts of T. populnea was screened in female albino mice. The weight of the uterus and ovaries were reduced significantly and the cholesterol and ascorbic acid content in ovaries were significantly elevated due to the treatment with extract of T. populnea. The significant inhibition of delta 5, 3 beta hydroxy steroid dehydrogenase and glucose-6-phosphate dehydrogenase, the two key enzymes involved in ovarian steroidogenesis were also observed in mouse ovaries after 15 days of treatment.     

Separation of the complexes formed between the regulatory and catalytic subunits of cyclic adenosine monophosphate-dependent protein kinase and topoisomerase I activity in preovulatory follicle-enriched immature rat ovaries

Our previous studies have shown that the regulatory subunits of the type II form of cAMP-dependent protein kinase (RII) present in soluble extract of immature rat ovaries elute from diethylaminoethyl-cellulose as three separate peaks of activity, based on their association with the catalytic subunit (C) of this enzyme, as R2IIC2, an apparent R2IIC, and R2II. Based upon the existence of ovarian RII in three different subunit arrangements, the large amount of C subunit-free R2II in this tissue, and a previous report which indicated that RII exhibited intrinsic topoisomerase I activity, we determined whether DNA topoisomerase I activity was associated with any of these molecular complexes of the ovarian RII subunits. Cyclic AMP-binding activities in soluble extracts of preovulatory follicle-enriched immature rat ovaries were separated by diethylaminoethyl-cellulose chromatography and sucrose density gradient centrifugation. Topoisomerase I activity cosedimented with the apparent R2IIC and R2II obtained from sucrose gradients but was not detected in fractions containing R2IIC2. Upon cAMP affinity purification of the RII derived from fractions containing R2IIC2, R2IIC, and R2II, respectively, no topoisomerase I activity could be detected in any fraction. Phosphorylation of the affinity purified RIIs by the C subunit of beef heart cAMP-dependent protein kinase did not alter this result. These data indicate that none of the RII subunits in soluble extracts of preovulatory follicle-enriched ovaries exhibit intrinsic topoisomerase I activity.     

Inhibitory action of melatonin on a pineal antigonadotropin.

An acidic extract of bovine pineal glands, partially purified by gel chromatography, yielded two distinct fractions which inhibited compensatory ovarian hypertrophy in mice. When the fractions were tested for antigonadotropic properties in the presence of melatonin only one fraction was found to be effective. Melatonin by itself and no stimulatory effect on COH, suggesting that melatonin blocked the antigonadotropic activity of the one fraction.     

Biochemical status of ovaries after induction of superovulation on different days of estrus cycle in mice

To investigate the role of ovarian status and to find out a suitable hormonal dose for induction of superovulation and its effect on biochemical status of the ovaries, the mice were injected with PMSG in doses of 5, 7.5, and 10 IU on different days of the estrous cycle i.e. proestrus, estrus, metestrus and diestrus followed by hCG injection 48 hr later. All these treatments increased the mean ovarian weight and ovulation rate when compared with that of control animals. Maximum response was observed by treatment with 7.5 IU PMSG on the day of estrus. This treatment resulted in a non-significant decrease in total proteins but a significant increase in the lipid concentrations while no change in cholesterol content of the ovaries of superovulated mice. The activity of acid phosphatase and lactate dehydrogenase significantly increased and alanine aminotranseferase significantly decreased in the ovaries of mice after superovulatory treatment when compared with that of control animals. This reveals that treatment with PMSG and hCG results in metabolic alterations in the ovaries which may perhaps be inducing biosynthetic deficiencies in oocytes as indicated by increased prenatal mortality in superovulated pregnant mice when compared with that of controls in the present studies.     

Morphological evaluation of microvascular networks and angiogenic factors in the selective growth of oocytes and follicles in the ovaries of mouse fetuses and newborns

In the mammalian ovary, there is a striking difference in the distribution of blood vessels to individual follicles, suggesting that a microvascular network affects the selective growth of oocytes and follicles. In the present study the role of microvascular networks and angiogenic factors on the selective growth of oocytes and follicles was evaluated histologically in fetuses and newborns of ICR strain mice. Apparent selective growth of oocytes and follicles was observed in the ovaries of 1 day old newborns and, at this time, microvascular networks were recognized electronmicroscopically around the follicle that had completed the formation of its follicular structure and contained oocytes more than about 20 μm in diameter. In 3 day old newborns, oocytes more than 30 μm in diameter were detected where blood capillaries were well vascularized. Immunoreactivity to epidermal growth factor (EGF) and a strongly negative charged (colloidal iron-positive) substance (glycosaminoglycans; GAG), which have angiogenic activity, were detected in the ovaries of 3 day or older newborns and were identified more often around growing follicles containing oocytes more than 30 (GAG) and 40 (EGF) μm in diameter. Ovaries removed from 20 day old fetuses and cultured for 4 and 6 days in vitro showed a different distribution of growing follicles. A proportion of oocytes 20.0–24.9 μm in diameter increased during 4 and 6 days of incubation. However, the majority of oocytes did not grow further. These findings indicate that microvascular networks and angiogenic factors are deeply involved in selective oocyte growth beyond approximately 20–30 μm in diameter in mouse ovaries.     

Vascular endothelial growth factor stimulates organ-specific host matrix metalloproteinase-9 expression and ovarian cancer invasion

Vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP) regulate each other, contributing to tumor progression. We have previously reported that MMP9 induces the release of tumor VEGF, promoting ascites formation in human ovarian carcinoma xenografts. The aim of this study was to investigate whether tumor-derived VEGF regulated the expression of gelatinase by the stroma, influencing the invasive properties of ovarian tumors. Tumor variants derived from 1A9 human ovarian carcinoma, stably expressing VEGF(121) in the sense (1A9-VS-1) and antisense orientations (1A9-VAS-3), were used. In vivo, zymographic analysis of tumors from 1A9-VS-1 implanted in the peritoneal cavity of nude mice showed higher levels of gelatinases, particularly murine MMP9, indicating that VEGF stimulates host expression of the matrix-degrading enzyme. Murine MMP9 expression was also high in the ovaries of mice bearing 1A9-VS-1 tumors. The effect on host MMP9 activity was organ-specific. The levels of host pro-MMP9 in ovaries correlated with the plasma levels of tumor VEGF and with the selective invasion of the ovaries. Induction of host MMP9 expression in tumors and ovaries was independent of the site of tumor growth as it was seen in mice carrying both intraperitoneal and subcutaneous tumors. The anti-VEGF antibody bevacizumab (Avastin) inhibited MMP9 expression and tumor invasion in the ovaries of mice bearing 1A9-VS-1 tumors. These findings point to a complex cross-talk between VEGF and MMPs in the progression of ovarian tumor and suggest the possibility of using VEGF inhibitors to affect MMP-dependent tumor invasion.     

Proteolytic inactivation of luteinizing hormone-releasing hormone (LHRH) by the whole rat ovary in vitro

Using 3H-labeled luteinizing hormone-releasing hormone (LHRH) at low concentrations, the in vitro proteolytic inactivation of the peptide hormone by whole rat ovaries was studied and compared with that by the soluble and particulate rat ovarian fraction. Whole rat ovaries were found to express the three proteolytic activities that were, according to their properties, also observed in rat ovarian homogenates: (1) soluble intracellular activity which was released into the medium, (2) released activity of membrane-bound origin, and (3) firmly membrane-bound activity. It is suggested that in vivo LHRH is largely inactivated extracellularly at least by enzymes that are located in the plasma membrane although the membrane-bound activity comprises only about 1% of the whole LHRH-inactivating capacity of the ovary.     

Prolongation and cessation of estrous cycles in aging C57BL/6J mice are differentially regulated events

The relative contributions of ovarian failure and hypothalamic-pituitary dysfunction to the prolongation and cessation of estrous cycles were assessed by measuring the ability of acutely ovariectomized (OVX) middle-aged (12 mo) mice to cycle after receiving grafts (under the renal capsule) of ovaries from young (2 mo) mice. The potentially disruptive effect of the acyclic state on the cycling response to grafted, young ovaries was avoided restricting grafting to middle-aged hosts that were still cycling. The effect of chronic exposure to ovarian secretions before the cessation of cyclicity on age-related hypothalamic-pituitary dysfunction was also assessed. The cycling ability of long-term OVX middle-aged mice (i.e., OVX at 3 mo) bearing grafts of young ovaries was compared to that of age-matched acutely OVX controls. Grafted young ovaries extended the cycling lifespan of acutely OVX middle-aged hosts by 60%. The length of this extended cycling lifespan, however, was only 80% of that achieved by young hosts bearing grafts of young ovaries. Young ovaries in middle-aged mice markedly lowered the incidence of long cycles (greater than 5 days), shifting the modal cycle length to 5 days. However, young ovaries in middle-aged mice failed to increase the incidence of 4-day cycles, the modal cycle of young controls. Middle-aged ovaries grafted into young hosts lengthened their cycles and shortened their cycling lifespan to middle-aged values. Long-term ovariectomy failed to increase the cycling lifespan of middle-aged hosts bearing grafts of young ovaries beyond that achieved in acutely OVX mice. Long-term ovariectomy did shorten the modal cycle length of middle-aged mice to 4 days, although the duration of 4-day cycling was only one-third (2 mo) that of young controls. These results indicate that the relative contributions of ovarian and neuroendocrine factors to three major events of reproductive aging vary with each event. Whereas the hypothalamic-pituitary unit appears to play an important role in the initial shift from 4- to 5-day cycles, the aging ovary plays the major role in the subsequent shift to longer cycles and in the ultimate cessation of cyclicity. Although chronic exposure to ovarian secretions during the period of cyclicity does not play a major role in the cessation of cyclicity, it appears to contribute to the hypothalamic-pituitary changes responsible for the initial shift from 4- to 5-day cycles.     

Binding of human chorionic gonadotropin by rat ovarian slices: dependence on the functional state of the ovary (38571).

Ovarian receptors specific for hCG-LH can be induced by PMSG-ovine LH priming. The marked increase in binding activity was accompanied by a rise in ovarian progesterone concentration and preceded by ovarian weight increase. The high binding activity of heavily luteinized ovaries was followed by a decline to prepriming levels during luteolysis. The ovarian progesterone content was decreased simultaneously and no change in ovarian weight was evident. The data demonstrate that ovarian hCG binding activity undergoes variation which depends on the functional state of ovaries.     

Steroid synthesis in ovarian homogenates from immature mice treated with diethylstilboestrol in neonatal life

Female mice of the NMRI strain were treated with the synthetic oestrogen diethylstilboestrol (DES) for the first 5 days after birth. Pools of ovaries were removed from groups of 6-, 12-, 21-, 28- and 56-day-old females. An homogenate of an ovarian pool was incubated for 1 h in the presence of [3H]pregnenolone. Synthesized steroids were extracted and separated in a two-dimensional thin-layer chromatography system. Homogeneity of tentative steroids was verified with recrystallization to constant specific activity. Synthesis of [3H]progesterone and [3H]testosterone was demonstrated at 6 days, [3H]androstenedione at 12 days, [3H]17 alpha-hydroxyprogesterone at 21 days, and [3H]oestradiol-17 beta at 28 days. Up to 28 days (21 days for progesterone), the synthetic activity was lower in homogenates of DES-exposed ovaries than in control homogenates. After 28 days, values for recovered [3H]progesterone, [3H]androstenedione and [3H]oestradiol-17 beta were higher in DES homogenates than in control homogenates while the reverse was true for [3H]17 alpha-hydroxyprogesterone and [3H]testosterone. The results are compatible with an early and direct DES inhibitory effect on ovarian steroidogenesis and, later in immature life, a DES-induced disruption of the normal FSH-LH stimulation of ovarian development.     

Effect of cadmium chloride on the ovulation and structure of ovary in the inbred KP and CBA mice strains

A single dose of cadmium chloride (2.2 mumol/100 g of body weight) brought about in the sensitive KP strain alterations of the ovarian structure and disturbances in the ovarian cycle manifested by a prolongation of diestrus. Following cadmium administration and increase in the amount of atretic follicles, especially those showing stages 1I and 2II of degeneration, was observed in the ovaries of KP mice. The corpora lutea contained numerous degenerated cells and were infiltrated by abundant connective tissue cells. The used dose of cadmium chloride showed no influences upon progesterone level. The absence of changes in the ovarian morphology and in the duration of the oestrus cycle in CBA females suggest that this strain is resistant to cadmium chloride.     

Apoptosis in granulose cells induced by intrafollicular peptide

Ovarian follicular fluid peptide (OFFP) purified from sheep ovaries has been earlier shown to induce degeneration of ovarian follicles in mice. In the present study, whether the effect of OFFP on granulosa cells was similar to apoptosis was studied using three parameters. Immature mice injected with pregnant mare serum gonadotropin on day 0 were administered with 10 or 20 μg of OFFP on day 1 and autopsied on day 2. The granulosa cells were collected from the ovarian follicles. The presence of apoptotic bodies were observed by staining the cells with acridine orange. DNA profiles of DAPI-stained cells analysed by flow cytometry also revealed apoptotic response to OFFP. Furthermore, agarose gel electrophoresis of low molecular weight DNA fraction extracted from the cells of OFFP-treated animals confirmed ladder formation and induction of apoptosis and not necrosis in granulosa cells. In conclusion, all the three parameters indicated apoptotic changes in granulosa cells of ovarian follicles in .mice treated with OFFP. The effect of OFFP seems to be exerted directly on the granulosa cells showing its autocrine role in the process of follicular atresia. This is discussed in the light of other intra/extra ovarian factors.     

Hepatic lipase deficiency attenuates mouse ovarian progesterone production leading to decreased ovulation and reduced litter size

The lipolytic enzyme hepatic lipase (HL) may facilitate mobilization of cholesterol substrate for ovarian steroidogenesis. We investigated whether HL was necessary for optimum reproduction in the female mouse by analyzing breeding performance and ovarian responses to gonadotropins in HL-/- mice. HL-/- female mice bred with HL-/- males had the same pregnancy success rate and pup survival rate as did wild-type (WT) mice but had significantly smaller litters, producing 1.7 fewer pups per litter. Mice were primed with eCG/hCG, and at 6 h post-hCG the HL-/- mice had smaller ovaries than did the WT mice. HL deficiency specifically affected ovarian weight; adrenal gland weights did not differ between WT and HL-/- mice. HL-/- mice weighed more than age-matched WT mice. Between the two mouse genotypes, uterine weights were the same, indicating that estrogen production was equivalent. However, the HL-/- ovaries produced significantly less progesterone than did the WT ovaries within 6 h of hCG stimulation. HL-/- ovaries had the same number of large antral follicles as did the WT ovaries but had fewer hemorrhagic sites, which represent ovulations, fewer corpora lutea, and more oocytes trapped in corpora lutea. We suggest that reduced progesterone synthesis following hCG stimulation attenuated the final maturation of preovulatory follicles, resulting in smaller ovaries. Furthermore, reduced progesterone production limited the expression of proteolytic enzymes needed for tissue remodeling, resulting in fewer ovulations with a corresponding increase in trapped or unovulated oocytes and providing a possible explanation for the smaller litter size observed in spontaneously ovulating HL-/- mice.     

Tachykinins in the normal and gonadotropin-stimulated ovary of the mouse

In this investigation, substance P (SP) and neurokinin A (NKA) concentrations have been determined in the ovary of control prepubertal mice, and prepubertal mice injected with pregnant mare serum (PMS) gonadotropin, an equine gonadotropin with predominant FSH action, or with PMS followed by human chorionic gonadotropin (hCG), which produces heavily luteinized ovaries after the stimulation with PMS. Control animals were injected with saline. The ovaries of animals treated with gonadotropins were heavier than the control ovaries, the combination of PMS plus hCG produced significantly heavier ovaries than PMS alone. The concentrations of SP and NKA in the ovaries of the animals treated with PMS or PMS/hCG were significantly lower than in control ovaries. No significant differences in ovarian tachykinin concentrations were observed between PMS and PMS/hCG-treated animals. The total ovarian content of SP was lower in PMS-injected animals as compared with the controls. The total ovarian content of NKA was not significantly different in the three groups of animals studied. These results show that ovaries stimulated with gonadotropins have lower concentrations of tachykinins than normal ovaries at the same age. It is therefore evident that gonadotropins can affect tachykinin stores in the ovaries of mice.     

Steroidogenic capacity of residual ovarian tissue in 4-vinylcyclohexene diepoxide-treated mice

Menopause is an important public health issue because of its association with a number of disorders. Androgens produced by residual ovarian tissue after menopause could impact the development of these disorders. It has been unclear, however, whether the postmenopausal ovary retains steroidogenic capacity. Thus, an ovary-intact mouse model for menopause that uses the occupational chemical 4-vinylcyclohexene diepoxide (VCD) was used to characterize the expression of steroidogenic genes in residual ovarian tissue of follicle-depleted mice. Female B6C3F1 mice (age, 28 days) were dosed daily for 20 days with either vehicle or VCD (160 mg kg(-1) day(-1)) to induce ovarian failure. Ovaries were collected on Day 181 and analyzed for mRNA and protein. Acyclic aged mice were used as controls for natural ovarian senescence. Relative to cycling controls, expression of mRNA encoding steroidogenic acute regulatory protein (Star); cholesterol side-chain cleavage (Cyp11a1); 3beta-hydroxysteroid dehydrogenase (Hsd3b); 17alpha-hydroxylase (Cyp17a1); scavenger receptor class B, type 1 (Scarb1); low-density lipoprotein receptor (Ldlr); and luteinizing hormone receptor (Lhcgr) was enriched in VCD-treated ovaries. In acyclic aged ovaries, mRNA expression for only Cyp17a1 and Lhcgr was greater than that in controls. Compared to cycling controls, ovaries from VCD-treated and aged mice had similar levels of HSD3B, CYP17A1, and LHCGR protein. The pattern of protein immunofluorescence staining for HSD3B in follicle-depleted (VCD-treated) ovaries was homogeneous, whereas that for CYP17A1 was only seen in residual interstitial cells. Circulating levels of FSH and LH were increased, and androstenedione levels were detectable following follicle depletion in VCD-treated mice. These findings support the idea that residual ovarian tissue in VCD-treated mice retains androgenic capacity.     

Immunocytochemical studies of relaxin in ovaries of pregnant and cycling mice

Immunocytochemical staining for relaxin in ovarian sections of pregnant mice from day 11 through day 18 of gestation revealed that only corpora lutea (CL) of pregnancy are stained. Evaluation of serial sections of ovaries from a day 16 pregnant mouse revealed that the only luteal structures present are CL of pregnancy. The number of CL present in each ovary equaled the number of implantation sites in each related horn (7 on the right side and 8 on the left side). These large CL varied in shape, being round in some profiles to very elongate in others. All CL were immunochemically stained for relaxin using the peroxidase-antiperoxidase method of L. Sternberger (Immunocytochemistry, 2nd ed. Wiley, New York, 1979). The intensity of the strain varied from cell to cell within each CL. Small luteal structures that were observed to be immunochemically stained for relaxin were demonstrated to represent the periphery of CL of pregnancy. No luteinized follicles were observed and interstitial cells and follicles were not immunochemically stained in any of the day 16 serial ovarian sections or in any of the ovarian sections from pregnant mice on the other days of gestation studied. CL of previous cycles were not observed to be present in the ovaries at days 15, 16, or 18 of gestation. However on day 14 and before, CL of previous cycles were observed and they did not exhibit any relaxin immunostaining. Immunocytochemical studies using the biotin-avidin system revealed that no relaxin immunostaining could be demonstrated in the ovaries of cycling mice at any stage of the estrous cycle. In conclusion, this study revealed that the only ovarian structures demonstrating relaxin immunocytochemical staining in the mouse were CL of pregnancy.     

Endogenous oocyte antigens are required for rapid induction and progression of autoimmune ovarian disease following day-3 thymectomy

Female (C57BL/6xA/J)F(1) mice undergoing thymectomy on day 3 after birth (d3tx) developed autoimmune ovarian disease (AOD) and autoimmune disease of the lacrimal gland. As both were prevented by normal adult CD25(+) T cells, regulatory T cell depletion is responsible for d3tx diseases. AOD began as oophoritis at 3 wk. By 4 wk, AOD progressed to ovarian atrophy with autoantibody response against multiple oocyte Ag of early ontogeny. The requirement for immunogenic endogenous ovarian Ag was investigated in d3tx female mice, d3tx male mice, and d3tx neonatally ovariectomized (OX) females. At 8 wk, all mice had comparable lacrimalitis but only those with endogenous ovaries developed AOD in ovarian grafts. The duration of Ag exposure required to initiate AOD was evaluated in d3tx mice OX at 2, 3, or 4 wk and engrafted with an ovary at 4, 5, or 6 wk, respectively. The mice OX at 2 wk did not have oophoritis whereas approximately 80% of mice OX at 3 or 4 wk had maximal AOD, thus Ag stimulus for 2.5 wk following d3tx is sufficient. AOD progression requires additional endogenous Ag stimulation from the ovarian graft. In mice OX at 3 wk, ovaries engrafted at 5 wk had more severe oophoritis than ovaries engrafted at 6 or 12 wk; moreover, only mice engrafted at 5 wk developed ovarian atrophy and oocyte autoantibodies. Similar results were obtained in mice OX at 4 wk. Thus endogenous tissue Ag are critical in autoimmune disease induction and progression that occur spontaneously upon regulatory T cell depletion.     

Characterization of ovarian function in granulocyte-macrophage colony-stimulating factor-deficient mice

During the estrous cycle and early pregnancy, lymphohemopoietic cytokines and chemokines contribute to the regulation of ovarian function by orchestrating the recruitment and activation of leukocytes associated with the ovulatory follicle and corpus luteum. The purpose of this study was to investigate the physiological role of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the ovary, utilizing mice genetically deficient in GM-CSF. Our results show that the mean duration of the estrous cycle in GM-CSF-deficient (GM-/-) mice was extended by 1.5 days (mean +/- SE, 4.9 +/- 0.3 vs. 6.5 +/- 0.5 days for GM+/+ and GM-/- mice, respectively). Similar ovulation rates were observed in immature superovulated mice (31.8 +/- 7.7 vs. 28.9 +/- 6.4 oocytes per mouse) and adult naturally cycling mice (10.4 +/- 0.8 vs. 10.3 +/- 0.8 oocytes per mouse). Furthermore, comparable numbers of oocytes were released from GM+/+ and GM-/- ovaries in an in vitro perfusion model. However, ovaries in pregnant GM-/- mice were found to comprise fewer cells and synthesize less progesterone (141.6 +/- 10.3 vs. 116.5 +/- 6 nM plasma), although the duration of pseudopregnancy was unaltered by GM-CSF deficiency (11.0 +/- 0.2 vs. 11.0 +/- 0.5 days). Immunohistochemical staining of leukocytes in the ovary during the periovulatory period indicated that the size and composition of ovarian leukocyte populations were unaltered in the absence of GM-CSF. However, an effect of GM-CSF deficiency on the activation phenotype of ovarian leukocytes was indicated by a 57% increase in mean secretion of nitric oxide in in vitro-perfused GM-/- ovaries, and diminished major histocompability complex (MHC) class II (Ia) expression in ovarian macrophages and/or dendritic cells (30.5 +/- 7. 2% vs. 9.1 +/- 1.8% positive stain in GM+/+ and GM-/- ovaries, respectively). Furthermore, ovarian macrophages and neutrophils were diminished in number after parturition, with significantly decreased CD11b+ (Mac-1) staining in the stromal region of postpartum GM-/- ovaries (6.7 +/- 0.6 vs. 3.6 +/- 0.7% positive stain). In summary, GM-CSF does not appear to be essential for ovarian function but may play a role in fine-tuning the activation status and adhesive properties of ovarian myeloid leukocytes. Aberrant activation of these cells appears to compromise the luteinization process and the steroidogenic capacity of the corpus luteum during early pregnancy in GM-CSF-deficient mice.     

Efficacy of Ginkgo biloba on Vaginal Estrous and Ovarian Histological Alterations for Evaluating Anti‐Implantation and Abortifacient Potentials in Albino Female Mice

Ginkgo extract, EGb 761 is known as a vasoregulatory variable for the conventional reproduction therapy. EGb 761 was orally administered in 0 (control), 3.7, 7.4, and 14.8 mg/kg bw/day for 28 days (thereafter mated with normal fertile male), from day 1 to day 7 of pregnancy or from the 10th to 18th day of pregnancy, respectively. Vaginal smears were performed daily. On 20th day of pregnancy, the females were killed by cervical dislocation and their kidneys, liver, brain, placenta, spleen and ovaries were removed and weighed. The ovaries were prepared for histological examinations, and then ovarian follicles were counted. Maternal toxicity, estrous cycle, reproductive hormones, ovarian follicle counts, resorption index, implantation index, fetal viability and fetuses, and placenta mean weights were evaluated. There was a dose‐dependent ovarian toxic effect of EGb 761. Ovarian follicle counts, resorption index, implantation index, fetal viability were significantly reduced in 14.8 mg/kg bw/day dose. Treatment with 14.8 mg/kg bw/day EGb 761 induced disruption of estrous cycle and caused maternal toxicity, in addition to fetal toxicity. Therefore, the data obtained indicate that Ginkgo biloba extract at 14.8 mg/kg bw/day dose level exhibit toxic effect on reproductive cyclicity and could have anti‐implantation and abotifacient properties in female mice.