No description available.

published_or_final_version / abstract / Obstetrics and Gynaecology / Master / Master of Philosophy

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No description available.

No description available.

Two experiments were conducted to determine whether in ewes uterine concentrations of estrogen and progesterone receptors are affected by the presence of a conceptus or by the hormonal milieu associated with extremes in photoperiod to which ewes are exposed. In Exp.1, nine mature ewes were unilaterally ovariectomized by removing an ovary bearing the corpus luteum (CL). The ipsilateral uterine horn was ligated at the external bifurcation and a portion of the anterior ipsilateral uterine horn was removed and assayed for endometrial nuclear and cytosolic concentrations of estrogen receptor (ER) and progesterone receptor (PR) by exchange assays. After a recovery estrous cycle, ewes were bred to a fertile ram. On day 18 of gestation a 10 ml jugular blood sample was collected for measurement of serum concentrations of estradiol -17β (E₂) and progesterone by radioimmunoassay. Ewes were relaparotomized on day 18 and the remaining uterine tissue was removed. Endometrium from both the pregnant and nonpregnant uterine horn was assayed for nuclear and cytosolic ER and PR concentrations. Nuclear and cytosolic ER concentrations on day 10 of the cycle were greater than in endometrium of gravid and nongravid uterine horns on day 18 of gestation (p<.01). Endometrial nuclear PR levels were also greater on day 10 of the cycle than in the pregnant (p<.05) and nonpregnant horn (p<.01) on day 18 of gestation. There were no differences in nuclear and cytosolic ER and PR concentrations between the pregnant and nonpregnant uterine horn on day 18. Serum levels of E₂ and progesterone on day 18 of gestation were 16.56 ± 2.43 pg/ml and 1.74 ± 0.57 ng/ml, respectively. These data suggest that duration of exposure of the uterus to progesterone and(or) the presence of the conceptus causes a reduction in uterine concentrations of ER and PR. Further, an effect of the conceptus, if any, is exerted via a systemic route. In Exp. 2, ten mature ewes were bilaterally ovariectomized in early October. During the onset of the winter solstice (late December), a 10 ml blood sample was collected from five ewes for analysis of serum levels of E₂ and progesterone. Ewes were then laparotomized and approximately one-third to one-half of a uterine horn was removed and assayed for endometrial nuclear and cytosolic ER. The contralateral horn was ligated at the external bifurcation and 10 μg of E₂ in 3 ml of physiological saline was injected into the uterine lumen of the ligated horn. After 48 h, a jugular blood sample was collected for steroid analysis and a section of the E₂ treated horn was removed and assayed for endometrial cytosolic and nuclear ER. This procedure was repeated on the remaining five ewes during the height of the summer solstice (late June). Endometrial nuclear and cytosolic concentrations of ER prior to and after exogenous E₂ stimulation were similar during the winter and summer solstice (p>.05). However, treatment with E₂ increased endometrial nuclear and cytosolic concentrations of ER compared with those of the nonstimulated uterine horn during the winter and summer solstice (p<.05 for each). Serum levels of E₂ prior to luminal treatment of ewes with E₂ during the winter and summer solstice did not differ (16.55 ± 4.05 vs 16.00 ± 3.0 pg/ml, respectively, p>.05). Serum levels of E₂ 48 h after administration of E₂ did not differ among ewes at the winter and summer solstice (18.75 ± 2.4 vs 18.65 ± 1.65 pg/ml, respectively, p>.05). Serum levels of progesterone were basal (<0.10 ng/ml) and did not differ in ewes prior to and after E₂ treatment at the winter and summer solstice (p>.05). These data indicate that physiological factors and(or) hormones such as prolactin and melatonin secreted in response to extremes in photoperiod do not appear to influence uterine concentrations of ER in ovariectomized ewes. / Graduation date: 1991

published_or_final_version / abstract / Medicine / Master / Master of Philosophy

Both estradiol and progeterone are proposed autocrine or paracrine regulators of ovarian function in primate species. However, specific receptors for these steroids have not been localized to individual compartments of the primate ovary. Using immunocytochemical techniques, estradiol receptors were detected in the germinal epithelium, but not other structures, of ovaries obtained from rhesus or cynomolgus monkeys during the follicular and luteal phases of the menstrual cycle. In contrast, progesterone receptors were present in stromal and interstitial tissue, the thecal layers of healthy and atretic follicles, as well as the functional corpus luteum. These results are consistent with the concept of a receptor-mediated role for progesterone, but not estrogen, within the predominant gametogenic and endocrine structures, e.g., the follicle and corpus luteum, of the primate ovary. The recent discovery of distinct cell types in the corpus luteum of domestic ungulates has revised concepts on the control of luteal function in these species. Studies were designed to test the hypothesis that the primate corpus luteum consists of cell subpopulations that differ in physical characteristics, function and regulation. Cells enzymatically-dispersed from the monkey corpus luteum at mid-luteal phase of the menstrual cycle differed in size (diameter) and the presence of the steroidogenic enzyme, 3β-hydroxysteroid dehydrogenase (3β-HSD). Analysis of dispersed cells for forward and 90° light scatter properties by flow cytometry revealed two distinct continua (Cα and Cβ). These continua were isolated using the sorting capabilities of the flow cytometer. Cα contained single cells of ≤ 15 μm and cell clusters; the cells were typically 3β-HSD-negative nonsteroidogenic. Cβ consisted of single cells that increased in size up to 40 μm and were 3β-HSD-positive. Cβ was divided into two regions (R₁ and R₃) and the cells isolated. R₁ cells were ≤ 15 μm whereas R₃ cells were ≥ 20 μm. Basal progesterone and estrogen production by R₃ cells was greater than that produced by R₁ cells (as determined by radioimmunoassay of the incubation media). Relative stimulation of progesterone production by hCG, cAMP or PGE₂ was not different between R₁ and R₃ luteal cells. These results support the hypothesis that the primate corpus luteum consists of distinct cell subpopulations which differ in size and steroidogenic capacity. However, the cell types which secrete progesterone are typically responsive to gonadotropin and PGE₂, possibly via a cAMP-mediated pathway.

Thirty six cases of human endometrium (9 normals, 9 adenomatous hyperplasias and 18 cancers) were established as finite monolayer tissue cultures. All were evaluated for the presence of estrogen binding sites (EBS) by an indirect immunofluorescent (IF) technique. Positive EBS were identified in 33% of normals, 67% of hyperplasias and 62% of cancers. Serial subpassage EBS evaluation was performed in fourteen cases. In was observed that the stability of EBS positivity in vitro was related to type of endometrium rather than culture longevity (2 of 2 normals, 2 of 4 hyperplasias and 1 of 8 cancers remained positive throughout the period of study). Twelve of the cancers were studied for estrogen receptor by cytosol assay and 11 (91.6%) correlated with the IF marker method. Thirty-eight cases of breast cancer were studied for EBS by a direct cytochemical and immunofluorescent technique. Evaluation by the direct method proved to be consistent and easy in performance. Morphologic positivity was 60% with the indirect method and 94.7% with the direct method. Correlation with the chemical cytosol was 77% with the indirect method and 86.8% with the direct method. These results confirm and compare favorably with other reported studies of morphologic methods. It was suggested that attention should be directed to cellular localization of receptors as a possible means for predicting endocrine responsiveness of neoplasms. Cancers from tissues presumed to be target-variants for estrogen stimulation were investigated with the direct cytochemical technique to determine if EBS were present. Forty-eight randomly selected tumors from multiple organ systems were assessed for EBS. Appropriate control tests were used to determine specificity. A total of 23 of the 48 cases were interpreted as positive for EBS. These sites were localized to cytoplasmic, nuclear and nucleolar cellular compartments. Estrogen and progesterone receptors in patients with breast carcinoma are of value in the selection of patients for hormonal adjuvant therapy. Whether this will prove to be true for EBS in a variety of neoplasms is currently unknown and is worthy of investigation.

The gonadal steroids, testosterone and estradiol, are known to be important modulators of neuronal functions and behaviors in most vertebrate species. These steroid hormones also elicit changes in neuropeptide synthesis and secretion, alter specific neurohormone receptor levels, and alter neuronal morphology and electrophysiology. Many of the actions of androgens and estrogen are mediated by specific intracellular receptors found in certain regions of the brain. But where are these neuronal targets for androgens and estrogen found? The research in this thesis investigates the neuroanatomical distribution of androgen and estrogen receptors in the brain of a urodele amphibian, the roughskin newt, Taricha granulosa. Using immunocytochemistry with antibodies against these receptors, the distribution of both androgen and estrogen receptor-immunoreactive cells is described in the brain of this species. This study found brain regions that contain immunoreactive androgen receptors that have not previously been reported in poikilothermic vertebrates using other techniques. In addition, the distribution of estrogen receptor-immunoreactive cells in most brain areas, and the distribution of androgen receptor-immunoreactive cells in several brain areas, were found to be similar in this amphibian to those described in studies that employed in vivo autoradiographic techniques in other vertebrate species. This study suggests that the neuroanatomical distribution of gonadal steroid receptors is a relatively conserved trait in vertebrates. The widespread distribution of these receptors in the brain probably reflects the multiple functions that androgens and estrogen are known to have in the brain. / Graduation date: 1995