An obesity epidemic is evident in first world countries including Australia. Twenty seven percent of men aged 55-64 in this country are obese. Obesity results in increased mortality and morbidity from type 2 diabetes, cardiovascular disease, renal disease and endometrial cancer, among others. Given our flaccid lifestyles, it is imperative that the metabolic processes underlying obesity be fully understood, to allow development of suitable treatment modalities. This proposal seeks to establish an ....An obesity epidemic is evident in first world countries including Australia. Twenty seven percent of men aged 55-64 in this country are obese. Obesity results in increased mortality and morbidity from type 2 diabetes, cardiovascular disease, renal disease and endometrial cancer, among others. Given our flaccid lifestyles, it is imperative that the metabolic processes underlying obesity be fully understood, to allow development of suitable treatment modalities. This proposal seeks to establish an important new element in our understanding of the development of obesity, the transcription factor STAT5. With previous NHMRC support, we developed sophisticated genetically modified mice which lack defined signalling processes initiated by growth hormone, an anti-obesity agent. These studies showed a strong correlation between ability to activate STAT5 and resistance to obesity. There is fragmentary literature evidence to support our hypothesis, which could also explain some of leptins anti-obesity actions. Using mice which lack STAT5, we shall establish a role for STAT5 as an antiobesity agent. The actions of STAT5 are normally blocked by feedback inhibitors referred to as SOCS, discovered by Australians. We shall define which SOCS is the feedback regulator for obesity control, allowing us to develop specific anti-SOCS agents which will act as novel anti-obesity agents.Read moreRead less
Nutrient And Hormone Delivery To Muscle: Interactions Between Insulin And Exercise
Funder
National Health and Medical Research Council
Funding Amount
$304,375.00
Summary
Exercise is known to be beneficial in the treatment and prevention of Type 2 diabetes and in particular muscle insulin resistance. Also, exercise and insulin share similar acute actions on muscle. Firstly, muscle contraction has a well established action to increase glucose uptake, and secondly, both muscle contraction and insulin act to increase capillary recruitment. This latter phenomenon is thought to enhance nutrient delivery and waste product removal. There is evidence that the increase in ....Exercise is known to be beneficial in the treatment and prevention of Type 2 diabetes and in particular muscle insulin resistance. Also, exercise and insulin share similar acute actions on muscle. Firstly, muscle contraction has a well established action to increase glucose uptake, and secondly, both muscle contraction and insulin act to increase capillary recruitment. This latter phenomenon is thought to enhance nutrient delivery and waste product removal. There is evidence that the increase in capillary flow due to muscle contraction is accompanied by increases in total blood flow. For insulin action we now have preliminary data to indicate that capillary recruitment occurs within a 5-10 min application of a physiologic dose of insulin independent of a change in total blood flow suggesting a redistribution of flow. Muscle contraction also increases capillary recruitment and it raises the question of whether similar mechanisms underlie insulin- and muscle contraction-induced capillary recruitment or whether there are distinct and complementary pathways. In this project we plan to define the mechanisms responsible for contraction- and insulin-induced capillary recruitment in muscle. We hypothesize that similar mechanisms are operative, with both insulin and muscle contractions acting via NO-dependent mechanisms. Because of capillary reserve, and different initial steps of the signalling systems stimulated by insulin and exercise, capillary recruitment by combined contraction and insulin stimuli will be additive at both sub maximal and perhaps at maximal insulin pathway stimulation. Signalling mechanisms will be compared and the role of non-nutritive route as a flow reserve assessed.Read moreRead less