Thesis (M.S.)--University of Wisconsin--Madison, 1961. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 70-73).

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Bibliography: leaves 179-231. / xv, 234 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this thesis is to characterise the oophorectomised rat model for post menopausal bone loss by determining the effect of oophorectomy on calcium balance and the components of calcium balance in young and adult rats. The study utilises the metabolic calcium balance technique for this purpose. Many of the characteristics of the animal model are described particularly in terms of the effects of oophorectomy on bone histomorphometry and metabolic markers of bone turnover. The study characterises the changes in calcium balance and its components through the growth period. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physiology, 1996

Skeletal muscle proteins are the largest amino acid pool in animal body and are continuously degraded and resynthesized. Dozens of factors have been shown to influence the balance between synthesis and degradation and thereby regulate muscle growth and function. It is now know that one of the major regulatory bases of muscle metabolism is neuron-muscle interaction. A neurogenic factor, ciliary neurotrophic factor (CNTF), is proposed to exert myotrophic actions and could possible be a mediator of neuron-muscle interactions. The goal of this study was to investigate the effects of CNTF on muscle protein turnover in an in vitro system. CNTF was applied to differentiated cultured muscle cells (L8 cell line). Radiochemical labeled amino acids were added to the culture medium to determine the rate of incorporation or release by the cells as indexes of protein synthesis and protein degradation, respectively. Total protein was measured as an index of change in total protein accretion. Twelve hours of CNTF treatment increased myofibrillar protein synthesis by 10%. However, longer CNTF treatment (24 hours) reduced non-myofibrillar protein synthesis. CNTF (1 ng/ml) decreased protein degradation but higher doses (20 ng/ml) accelerated protein degradation. These changes in protein turnover resulted from changes in the myofibrillar protein fraction rather than from changes in turnover of the non-myofibrillar fraction. The change in protein synthesis and protein degradation resulted in an increase in total protein accretion of about 6%. Compared with the myotrophic studies on the effects of CNTF in vivo, the action of CNTF were relatively small. Reverse transcription polymerase chain reaction (RT-PCR) analysis showed that CNTF receptor alpha subunit (CNTFR��) mRNA expression is lower than which is expressed in muscle tissue. This could explain the reason why CNTF exerted smaller effects in vitro compared to those reported in vivo. Overall, CNTF exerts a small but statistically significant anabolic actions in cultured skeletal muscle and the actions were highly dose-dependent. The limited action of CNTF in vitro may be related to its low receptor density in the L8 cell (compared to in vivo). Because actions may be highly dose-dependent, a challenging series of studies are ahead for anyone wishing to identify the signal transduction mechanisms which account for CNTF's actions. / Graduation date: 1998

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Graduation date: 1992

Serine transhydroxymethylase (STHM), a pyridoxal 5'- phosphate requiring enzyme is indirectly involved in pyrimidine deoxynucleotide metabolism. A decrease in the activity of this enzyme could lead to altered deoxycytidine (dC) metabolism. This study was undertaken to determine if a vitamin B-6 deficiency affects dC metabolism. The effect of a vitamin B-6 deficiency on the activity of STHM in liver, thymus, spleen and bone marrow was examined. In addition, the effect of a vitamin B-6 deficiency on urinary excretion of dC was examined. The effect of a vitamin B-6 deficiency on the urinary excretion and tissue retention of ³H label from ip injected ³H-dC was monitored. Rats were assigned in groups of six to one of four treatment groups: ad libitum control (ALC), pair fed control (PFC), ad libitum deficient (ALD) or meal fed deficient (MFD). At the end of weeks 2 and 6, rats from each treatment group received an ip injection of ³H-dC. Urines were collected for 24 hours following the ip inhibited due to lack of cofactor, then dTMP levels would fall. In an attempt to increase the concentration of dTMP, enzymes active in the conversion of dC and dCMP to dUMP would be expected to increase. Thus, dC salvage pathways would increase and dC synthesis would decrease as metabolism shifts toward production of deoxythymidine triphosphate (dTTP). The result would be lower urinary dC excretion. The present study was undertaken to explore the relationship between vitamin B-6 and pyrimidine deoxynucleotide metabolism. There were four hypothesis tested: Vitamin B-6 deficient rats will excrete less urinary dC than either ad libitum or pair fed controls; vitamin B-6 deficient rats will excrete a lower percentage of labeled dC in urine than control rats; vitamin B-6 deficient rats will incorporate less labeled dC into DNA than control rats but may retain more label in tissues as dC metabolites; activity of STHM from tissues of vitamin B-6 deficient rats will be lower than that from the control rats. / Graduation date: 1990

Graduation date: 1994