Universiẗat, Diss., 2004--München.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, Committee on Developmental Biology, March 2001. / Includes bibliographical references. Also available on the Internet.

Th.--Méd.--Nancy 1, 1984. N°: 288.

No description available.

In two experiments, immature female Sprague-Dawley rats treated with superovulatory doses of pregnant mare serum gonadotropin (PMSG) were used to study the effects of antiandrogen, hydroxyflutamide, on steroid production, particularly the biologically active androgens, testosterone, 5α-dihydrotestosterone, and androstenedione. In the first experiment, the animals were given either 5 mg hydroxyflutamide or vehicle alone at 30 and 36 h following 40 IU PMSG. Compared to the vehicle group, hydroxyflutamide treatment significantly reduced the percentage of degenerate oocytes recovered from oviducts (p<0.05). Serum levels of aromatizable androgens, testosterone and androstenedione, and their aromatized product, estradiol-17ß significantly decreased (p<0.05) in hydroxyflutamide-treated group; however, the serum concentrations of nonaromatizable androgen, 5α-dihydrotestosterone, was not statistically different between the two groups. In the second experiment, ovaries stimulated with 4 or 40 IU PMSG were obtained 48 h later and cultured in the presence and absence of hydroxyflutamide (10⁻⁵M) and/or testosterone (10⁻⁷ M) to study [4⁻¹⁴C] pregnenolone metabolism to major steroids. In 40 IU stimulated ovaries, hydroxyflutamide significantly decreased the metabolism of pregnenolone to progesterone (p<0.01) and androstenedione (p<0.01) while the production of estradiol-17ß increased significantly (p<0.05); however, pregnenolone conversions to testosterone and 5α-dihydrotestosterone were not statistically different between the untreated and hydroxyflutamide-treated cultures. Testosterone completely reversed the hydroxyflutamide-induced alteration of pregnenolone metabolism. In contrast, there was no difference in the pregnenolone conversion patterns between the untreated and hydroxyflutamide or hydroxyflutamide plus testosterone groups in the culture of ovaries stimulated with 4 IU PMSG. Present results confirm previous reports that antiandrogen, hydroxyflutamide, decreases the percentage of abnormal oocytes recovered from superovulating rats, and indicates that this hydroxyflutamide effect may be partly mediated by altered ovarian steroidogenesis, specifically the reduced hypersecretion of aromatizable androgens, testosterone and androstenedione, and/or estradiol-17ß. / Medicine, Faculty of / Obstetrics and Gynaecology, Department of / Graduate

Studies to monitor bovine ovarian function with regard to follicular growth and turnover, and corpus luteum (CL) growth and function, were carried out during three different reproductive states: the postpartum anestrus period, early pregnancy and during the artificial control of the estrous cycle with the synthetic progestin norgestomet. Ovarian function was monitored using a combination of ultrasound imaging and progesterone (P₄) profiling. Growth of large antral follicles (> 10mm) was found to commence very early in the postpartum period and ovulation occurred as early as the first week postpartum. Short first postpartum estrous cycles (< 18 days) were observed in a minority of the animals studied (4/10) and the occurance of a short first cycle was not associated with an early ovulation following parturition. Growth of large antral follicles occurred in a wave-like pattern during the postpartum estrous cycles with most cycles being composed of two waves of growth, the second wave resulting in the growth of the ovulatory follicle. A wave-like pattern of growth of large dominant follicles was also seen through the first 60 days of pregnancy. There was no difference between pregnant and non pregnant cows in the size of the dominant follicle found on day 20. In addition no effect of the CL could be found on the side on which the dominant follicle was found, it was as likely to be on the ipsilateral ovary to the CL as on the contra lateral. The gonadotrophin ihibitor norgestomet did not effect follicular dynamics in the presence of the CL, however in the absence of a CL the dominant follicle present was maintained for the duration of the norgestomet treatment and then went on to ovulate upon norgestomet removal. In addition there was no new growth of antral follicles in the absence of a CL. Norgestomet did not effect the temporal relationship between the onset of standing estrus, the LH surge and ovulation. The results of the three studies suggest that a wavelike pattern of growth of large antral follicles is a characteristic of the bovine ovary regardless of the reproductive state. / Land and Food Systems, Faculty of / Graduate

In this thesis I investigated the possibility that the kinin system could be involved in the process of ovulation. This study was divided into four parts, these are outlined be 1ow. (1) To determine whether and when the kinin system is activated in relation to ovulation, plasma kininogen levels were estimated in female rats, guinea pigs, and humans at different stages of their estrus or menstrual cycles. Non-ovulating females (women using oral contraceptives,, or post-menopausal women) and male guinea pigs served as controls. The ovulating females of all three species showed a marked decline in kininogen levels shortly before ovulation, suggesting that the kinin system was activated at this time. The fall was absent in the non-ovulating controls, with the exception of women using oral contraceptives. In the latter subjects the fall occurred at a similar time in the 'cycle', and was of a similar magnitude as the fall in normal women. These results showed that the fall is a preovulatory change and raised the possibility that a mechanism more fundamental than the events obstructed by the oral contraceptives could be at least partially responsible for the decline. (2) After establishing the timing of the fall in plasma kininogen levels, an attempt was made to locate the enzymes responsible for the change. The kinin-forming enzymes of the two locations most likely to be involved in kinin release during ovulation, that is, the plasma and the ovary were examined. The evidence indicated that kinin-forming enzymes were present in both locations and suggested that their concentrations increased as ovulation neared. (3) In order to examine the possibility that an ovulatory stimulus can activate the kinin system, female rats were treated with an ovulatory dose of luteinizing hormone (LH) or estradiol -17β one day before the anticipated time of ovulation and kininogen level declines. Estimation of plasma kininogen levels revealed marked declines in the LH-treated animals, estradiol-17β had no observable effect. This evidence suggested that LH, but not estradiol-17β could be responsible, at least in part, for the decreased kininogen values just before ovulation. (4) Lastly, to establish the ability of a kinin to initiate some of the more important events of the ovulatory process, the effects of bradykinin on ovarian smooth muscle contractility and ovarian follicular blood vessel permeability in the rat were examined. Bradykinin stimulated ovarian contractility in in vitro preparations to a significantly greater degree in ovaries isolated during the ovulatory period than at any other stage of the cycle. Also, the degree of movement of the dye Trypan Blue from the general circulation throughout ovarian follicular tissue over a ten minute exposure period was significantly greater in tissue from animals treated with bradykinin than those that were not. This suggests that bradykinin can increase ovarian follicular blood vessel permeability in the rat. Both of these bradykinin-induced effects were reduced, but not eliminated by indomethacin, suggesting that prostaglandins may be involved. Results from this study indicate that the kinin system is activated during the preovulatory period, possibly at the level of the ovary, that LH may be partially responsible for this activation, and that kinins may play a role in triggering increases in ovarian contractility and blood vessel permeability both directly and possibly via the release of prostaglandins. More definite proof awaits the development of a satisfactory kinin antagonist. / Science, Faculty of / Zoology, Department of / Graduate

The purpose of the studies reported in this thesis was to provide further evidence in support of the hypothesis that ovulation-inducing factor (OIF) is a component of seminal plasma which is conserved amongst mammals. Based on studies conducted in vivo, the results indicate that males ejaculate a substance during copulation which is responsible for the ovulatory and luteotrophic effect in female camelids. In our lab we have developed an <i>in vivo</i> llama bioassay to study the presence and biological effects of OIF in seminal plasma from different species.<p> The objective of the first experiment within the first study was to determine if llama seminal plasma would stimulate ovulation in prepubertal mice. Mice were treated with a single 0.1 mL intraperitoneal dose of 1) phosphate-buffered saline (negative control), 2) 5 µg gonadotropin-releasing hormone (GnRH), 3) 5 IU of human chorionic gonadotropin (hCG) or 4) llama seminal plasma. Results indicate that prepubertal mice treated with GnRH, hCG or llama seminal plasma stimulated similar proportions of mice to ovulate, which were all higher than the proportion of mice that ovulated after saline treatment. The number of oocytes observed under a stereomicroscope was also higher in all treatment groups than in mice treated with saline. However, the number of oocytes observed was lower in mice treated with seminal plasma than those treated with GnRH, both of which were similar to the number of oocytes observed in hCG treated mice.<p> In a second part of this study the corollary that OIF is present in the seminal plasma of horses and pigs was examined. Seminal plasma from horses or pigs was administered intramuscularly to female llamas and ovulation was monitored using transrectal ultrasonography. Llamas were treated with an intramuscular dose of 1) phosphate buffered saline (negative control), 2) llama seminal plasma (positive control), 3) equine seminal plasma or 4) porcine seminal plasma. Ovulations were detected in llamas treated with seminal plasma while none were observed in saline-treated llamas. The proportion of llamas that ovulated when treated with equine seminal plasma was higher than llamas treated with saline. The proportion of llamas that ovulated after porcine seminal plasma tended to differ from negative control groups, but did not reach statistical significance. The proportion of llamas that ovulated after equine or porcine seminal plasma treatment was lower than animals treated with llama seminal plasma which indicates that either OIF is not present in equal concentration among mammals, or that OIF is not structurally the same across mammals.<p> The second study was carried out to test the hypothesis that OIF stimulates LH secretion at the level of the anterior pituitary gland. The second objective was to determine if the degree of LH release was related to the dose of OIF treatment. Anterior pituitary cells (2 x 10^6 cells/ well) from either llamas (reflex ovulator) or cattle (spontaneous ovulator) were incubated for 2 hours with either media containing no treatment (control), GnRH or OIF. In all experiments, GnRH and OIF stimulated more LH secretion than control groups. An effect of dose was evident in the llama pituitary cell culture where mean LH concentrations were greater in wells treated with a higher dose of OIF in comparison to wells treated with a lower dose, both of which were higher than in wells with no treatment. Although OIF stimulated LH release in bovine cell cultures, an apparent dose response was not detected. Results indicate that the preovulatory LH surge observed after OIF treatment in camelids may be the result of OIF directly stimulating LH release from gonadotrope cells within the anterior pituitary gland. In conclusion these results illustrate that the presence and the response to OIF is conserved among species that share no relation or common reproductive strategy.