Thesis (M.A.)--University of Wisconsin--Madison, 1984. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 95-103).

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.)--Boston University / The liver has been well established as being one of the most important organs involved in the metabolism of adrenocortical steroids. Liver perfusion, incubations with liver slices, homogenates and purified liver preparations all effect extensive changes on the steroid nucleus. In order to develop a step-wise scheme for the in vitro metabolism of a typical adrenocortical steroid and to localize enzyme systems effecting single metabolic transformations, 11-deoxycortisol was incubated with various rat liver homogenate fractions and the conversion products isolated and identified. The liver fractions were obtained by differential centrifugation of liver homogenates. This procedure afforded a 6000 x g supernatant, a 6000 x g residue (corresponding to mitochondria in sedimentation properties), a 78,000 x g residue (corresponding to microsoaes in sedimentation properties) and a 78.000 x g particulate free supernatant. Each tissue preparation was incubated with 11-deoxycortisol at 37° c. for two hours with flasks open to the atmosphere. A tissue to steroid ratio of approximately 1000:1, based on the initial weight of the liver, was employed [TRUNCATED].

18-hydroxycorticosterone, aldosterone and corticosterone were positively characterized in duck adrenal incubates. A compound resembling 11-dehydrocorticosterone was also present. The addition of 1 I.U. of ACTH/100 mg of adrenal tissue caused an increase in the production rate of all four steroids. The most dramatic effect however, was observed with respect to the synthesis of corticosterone. Aldosterone-4-¹⁴C and 18-hydroxycorticosterone-4-¹⁴C were isolated from the media of adrenal glands incubated in the presence of a tracer amount of corticosterone-4-¹⁴C. During the incubation the maximum specific activity recorded for aldosterone-4-¹⁴C was 66% of the specific activity of the precursor. This observation indicated that the primary pathway to aldosterone in the duck adrenal was probably via corticosterone. 18-hydroxycorticosterone may be an intermediate between corticosterone and aldosterone or may be a distinct end product of unknown biological activity. No difference in the biological half-life (T₁/2) of corticosterone was found between fresh-water maintained fresh-water loaded birds and birds maintained on fresh water or saline and loaded with saline. An increase in the apparent volume of distribution (A.V.D.) of corticosterone was found however in saline loaded ducks. This resulted in an increased secretory rate of corticosterone in those animals loaded with saline. In the saline maintained ducks an increased adrenal size was responsible for the enhanced corticosterone secretory rate. In those ducks maintained on fresh water and loaded with saline a weight specific increase in the corticosterone secretory rate was apparent. The implications of the increased corticosterone secretory rate are discussed in relation to the known dependence of nasal gland function in marine birds on a functional adrenal cortex. / Science, Faculty of / Zoology, Department of / Graduate

The purpose of this investigation was to determine whether or not the adrenocortical steroids influence the activity of the avian supra-orbital gland. In the intact saline loaded duck (Anas platyrhynchus), a diphasic excretory pattern was apparent, as an urinary diuresis was followed by activation of the supra-orbital glands. Variations in the circulating levels of adrenocortical steroids resulted in qualitative and quantitative changes in both phases of this response. Injection of exogenous, cortisol, cortexone and aldosterone caused an initial increase in the rate of nasal discharge and a consequent increase in the total output of Na⁺ and K⁺. Conditions of selective adrenocortical activity, i.e., subtotal adrenalectomy, severely impaired the extra-renal response while total adrenalectomy completely obliterated the response to an osmotic stimulus. The activity of the supra-orbital gland in the totally adrenalectomized duck was restored after treatment with cortisol. The renal phase in ducks treated with adrenocortical steroids was modified when compared to the control response. Administration of cortisol prior to saline loading resulted in a significantly lower total output of sodium although the volume of urine excreted did not differ from the control value. Treatment with aldosterone resulted in a significantly lower renal output of both Na⁺ and K⁺ as well as a decrease in urine volume. Cortexone and ACTH showed the control renal pattern of excretion. Unilateral adrenalectomy caused no apparent change in the renal excretory pattern whilst total adrenalectomy caused a significant increase in the total volume of urine excreted as well as on increase in the total output of Na⁺ and K⁺. Totally adrenalectomized birds maintained on cortisol reverted to a normal excretory pattern. The influence of adrenocortical steroids on the control of the avian supra-orbital gland is discussed. It can be said with certainty that adrenocortical steroids influence the activity of the supra-orbital gland of the Domestic Duck (Anas platyrhynchus). Furthermore, cortisol administered to the adrenalectomized animal reactivates the gland suggesting that a glucocorticoid is essential for its function. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

No description available.

Thesis (M.Sc. (Pharmacy)) - Rhodes University, 2007.

Context: The human foetal adrenal (HFA) is an integral component of the foeto-placental unit and important for the maintenance of pregnancy. Low kisspeptin levels during pregnancy are associated with miscarriage, and kisspeptin and its receptor are expressed in the HFA. However, the role of kisspeptin in foetal adrenal function remains unknown. Objective: The objective of this work was to determine the role of kisspeptin signaling in the developing HFA. Methods: Experiments using H295R adrenocortical cells and primary HFA cells as in vitro models of the foetal adrenal were conducted. The spatiotemporal expression of the kisspeptin receptor, Kiss1R in the HFA was examined. The production of dehydroepiandrosterone sulphate (DHEAS) from HFA cells after kisspeptin treatment, alone or in combination with adrenocorticotropic hormone or corticotropin-releasing hormone was compared. The association of plasma kisspeptin levels with HFA size was analysed in a longitudinal clinical study. Thirty-three healthy pregnant women were recruited at their 12-week routine antenatal ultrasound scan. Serial measurements of foetal adrenal volume (FAV) and maternal kisspeptin levels at four antenatal visits (∼20, 28, 34, and 38 weeks' gestation) were collected. Outcomes of pregnancy were recorded, including neonatal auxology and complications in the postnatal period. Neoantal adrenal remodeling was characterized by Results: Expression of Kiss1R was present in the HFA from 8 weeks after conception to term and was shown in the inner foetal zone. Kisspeptin significantly increased DHEAS production in H295R and second-trimester HFA cells. Serial measurements of kisspeptin confirmed a correlation with FAV growth in the second trimester, independent of sex or estimated foetal weight. Conclusions: Together, these studies demonstrate that kisspeptin plays a key role in the regulation of the HFA, and thus the foeto-placental unit, particularly in the second trimester of pregnancy.

No description available.