The Role Of Androgens In Osteoblast Development And Bone Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$64,631.00
Summary
Male hormones are essential for the growth and maintenance of bone in men, but exactly how and when they act on the bone forming cells is unclear. We aim to find out what happens when the target for male hormones (receptor) is removed in the bone forming cells at different stages of their development. This project will increase our understanding of how male hormones regulate bone formation and may assist in the design of new therapies for osteoporosis.
The Effect Of PKC Epsilon On The Insulin Receptor And Whole Body Glucose Homeostasis.
Funder
National Health and Medical Research Council
Funding Amount
$82,261.00
Summary
Increased fat availability is strongly associated with insulin resistance and type 2 diabetes. Data from this lab has shown animals lacking a particular enzyme (Protein Kinase C epsilon) are able to compensate for this insulin resistance and maintain normal blood glucose levels by elevating insulin availability, with a major site of action being the liver. This project therefore aims to examine the action of PKC epsilon on insulin clearance by the liver.
Investigation Of Transgenic Mouse Models Of Type 2 Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$412,200.00
Summary
Type 2 diabetes is a common condition characterised by high blood glucose, that afflicts 700,000 Australians. It causes blindness, kidney failure and an increased risk of heart attack and stroke. despite intensive study over many years, the reasons for the elevated blood glucose in this condition are not fully understood. Several abnormalities can contribute to the high glucose and different researchers have proposed different defects as the initial cause. It has proven difficult to unravel the ....Type 2 diabetes is a common condition characterised by high blood glucose, that afflicts 700,000 Australians. It causes blindness, kidney failure and an increased risk of heart attack and stroke. despite intensive study over many years, the reasons for the elevated blood glucose in this condition are not fully understood. Several abnormalities can contribute to the high glucose and different researchers have proposed different defects as the initial cause. It has proven difficult to unravel the sequence of events in the evolution of the syndrome because high glucose can cause insulin resistance and a defect in insulin secretion, both of which can lead to high blood glucose. One approach to study the consequences of specific defects is to genetically engineer them. The aims of this project are to: 1. make a mouse with reduced ability to store glucose in muscle. 2. test the metabolic consequences of a defect in the manufacture of glycogen (starch) in muscle. 3. study the effects of combining a defect in glucose storage with one that results in an oversupply of glucose. 4. study the effects on a mouse with a genetic predisposition for failure of beta cells (insulin making cells) of a defect in muscle glucose storage and over production of glucose. A successful completion of this grant will greatly enhance our understanding of how blood glucose is increased in Type 2 diabetes.Read moreRead less
The Role Fructose-1,6-bisphosphatase On The Regulation Of Hepatic Gluconeogenesis
Funder
National Health and Medical Research Council
Funding Amount
$212,485.00
Summary
Type 2 or adult onset diabetes is a disease characterised by high blood sugar that causes damage to the kidneys, eyes and to the circulation and many patients die from heart attack or stroke. There is an increase in the prevalence of diabetes in Australia and a substantial portion of the health budget is utilised by caring for people with diabetes. Determining what exactly causes the increase in blood sugar levels is critical in the treatment of the disease. It is known that the sugar produced a ....Type 2 or adult onset diabetes is a disease characterised by high blood sugar that causes damage to the kidneys, eyes and to the circulation and many patients die from heart attack or stroke. There is an increase in the prevalence of diabetes in Australia and a substantial portion of the health budget is utilised by caring for people with diabetes. Determining what exactly causes the increase in blood sugar levels is critical in the treatment of the disease. It is known that the sugar produced and released by the liver is an important contributor to the high blood sugar levels found in patients with diabetes. The main biochemical pathway responsible for this is called gluconeogenesis, a complex arrangement of enzymes, which convert amino acids and fat into sugar. Although it is known that this pathway is overactive in patients with diabetes, the exact reason for this is not clearly understood. The aim of this proposal is to produce a transgenic mouse that has an increase in liver sugar production as a result of an increase in gluconeogenesis, and to study its effects on blood sugar levels. Furthermore, studies will be performed to understand the regulation of this pathway by infusing the transgenic mice with insulin, the hormone that inhibits gluconeogenesis. The mechanism of action of insulin will be determined by the measurement of key enzymes that regulate gluconeogenesis. The significance of this grant is to identify possible sites for the development of new drugs or gene therapy that will lead to a decrease in the production of sugar by the liver. This will lead to better control of blood sugar levels and slow down or even prevent the onset of diabetes complications.Read moreRead less
Mechanisms Of Insulin Resistance And Diabetes Susceptibility
Funder
National Health and Medical Research Council
Funding Amount
$633,783.00
Summary
The two main forms of diabetes - types 1 (T1D) and 2 (T2D) - pose a major problem. It is difficult to identify what causes diabetes. Recently, people at risk of T1D were found to have insulin resistance, a condition thought typical only of T2D. Excitingly, we discovered that the best T1D animal model also shows insulin resistance, and we used it to map important genes. We will now identify these genes. This will help us understand the disease process and to develop better treatments for it.
Regulation Of Insulin Signalling And Glucose Homeostasis By Protein Tyrosine Phosphatases
Funder
National Health and Medical Research Council
Funding Amount
$542,462.00
Summary
A common feature of type 2 diabetes is high blood glucose due to peripheral insulin resistance. Protein tyrosine phosphatases (PTPs) that antagonise insulin signalling might be important targets for therapeutic intervention in type 2 diabetes; inhibition of specific PTPs may allow for enhanced IR signalling to alleviate insulin resistance. This proposal will examine the roles of PTPs and in particular TCPTP in insulin signalling and glucose homeostasis.
The Mechanisms Of The Anabolic Actions Of Androgens In Bone.
Funder
National Health and Medical Research Council
Funding Amount
$470,960.00
Summary
Androgens (male sex hormones) are one of the few agents that increase bone formation. Androgens act by binding to a specific protein, the androgen receptor (AR). To understand exactly how androgens increase bone formation, we will study mice in which the AR is inactivated only in bone forming cells at specific stages of their development. Understanding the way in which androgens act on bone to increase size and strength will be of great benefit in the design of new treatments for osteoporosis.
Osteoporosis is a major health burden resulting from bone fractures in older men and women due to progressive loss of bone and weakening of the skeleton. No current treatment effectively reverses this bone loss. Using genetic models in mice, we have identified a pathway, involving the nerve signal molecule NPY, that is capable of inducing large (200 - 300%) increases in bone very rapidly (within a few weeks), in the skeleton of adult mice. This proposal is aimed at characterising this new pathwa ....Osteoporosis is a major health burden resulting from bone fractures in older men and women due to progressive loss of bone and weakening of the skeleton. No current treatment effectively reverses this bone loss. Using genetic models in mice, we have identified a pathway, involving the nerve signal molecule NPY, that is capable of inducing large (200 - 300%) increases in bone very rapidly (within a few weeks), in the skeleton of adult mice. This proposal is aimed at characterising this new pathway to assess its potential to provide new treatments for human osteoporosis. This research is important because of the size, rapidity and inducibility of the effect. Moreover, since it originates in the brain, it represents a quite novel mechanism by which the skeleton is potentially maintained and repaired. The experiments contained in the initial sections of the proposal are designed to assess not only the ability of the NPY-pathway to protect against bone loss but also to examine the possibility of repair to a fragile skeleton. The bone loss models chosen for study represent postmenopausal and age-related osteoporosis, two prevalent and increasingly common conditions in the aging world population. The latter section of the proposal seeks to clarify the mechanism by which the increase in bone formation occurs within the bone. Understanding the working of this pathway will be vital in developing future treatment regimens. This proposal investigates a novel, powerful and rapid pathway for repairing weakened skeletons. The knowledge resulting from this proposal has the potential to provide an important contribution to skeletal health and thus aged health worldwide.Read moreRead less
Lipid Metabolism In The Aromatase Knock-out Mouse (ArKO)
Funder
National Health and Medical Research Council
Funding Amount
$408,055.00
Summary
Studies of humans with natural mutations in aromatase, the enzyme responsible for oestrogen biosynthesis, have revealed a number of unexpected roles for oestrogens in both males and females. These discoveries even challenge the definitions of oestrogens and androgens as we now know them. We have created a mouse model of oestrogen insufficiency by targetted disruption of the aromatase gene. These mice display a number of age dependent phenotypes including both male and female infertility, undermi ....Studies of humans with natural mutations in aromatase, the enzyme responsible for oestrogen biosynthesis, have revealed a number of unexpected roles for oestrogens in both males and females. These discoveries even challenge the definitions of oestrogens and androgens as we now know them. We have created a mouse model of oestrogen insufficiency by targetted disruption of the aromatase gene. These mice display a number of age dependent phenotypes including both male and female infertility, undermineralisation of the bones, intra-abdominal obesity, hypercholesterolaemia and insulin resistance. We are addressing the mechanisms of all of those phenotypes but in the present application we focus on the abnormalities in lipid metabolism. Thus we will seek to understand the increase in adiposity by examining the role of oestrogen in lipid synthesis, oxidation and breakdown in adipose tissue from intra-abdominal sites. We will also examine the role that oestrogen plays in cholesterol uptake, synthesis and catabolism by the liver as well as fatty acid synthesis and oxidation by the liver. These studies will be correlated with whole body parameters such as feeding behaviour, physical activity, energy expenditure, glucose and fat oxidation rates. We will also examine the effect of feeding a high cholesterol or a high fat diet on lipid metabolism in the oestrogen deficient animals, and we will determine the effect of oestradiol and isoflavone replacement on the phenotype. In this way we aim to reach a better understanding of the multiplicity of roles that oestrogens play in the regulation of lipid and cholesterol metabolism in both males and females. The results of such studies will be the development of better strategies to deal with pathologies resulting from disturbances in cholesterol and lipid metabolism.Read moreRead less