LEPTIN

Leptin and its role in human glucose and lipid metabolism

Table of content

Introduction1

Strucutre2

Adipose tissues3

Discussion3

Discovery3

How Leptin works4

Adiposity signal5

Deficiency of Leptin5

Leptin and its role in human glucose and lipid metabolism6

Literature review7

Leptin and Diabetes9

Conclusion9

Appendix14

Leptin and Its Role in Human Glucose and Lipid Metabolism

Introduction

With the recent advances in medical research a number of new hormones have identified. The discovery of hormone Leptin also known as the “obesity hormone” has revolutionized the understanding of weight regulation and obesity, also leading to the first evidence of the tissues of adipose as an active endocrine organ. Leptin is a 16 kDa protein hormone that plays a very important role in expenditure of energy and energy intake counting the metabolism and appetite. The Ob (Lep) gene (Lep for Leptin and Ob for obese) has been identified on chromosome number 7 in humans. The endocrine era is now incorporated with the pathophysiology of obesity. The levels of Leptin are proportional directly to the amount of fat in humans. Leptin is responsible to selectively promote the fat metabolism and it also increases the expenditure of energy. It also takes part to control the weight of the body by regulating the intake of food and expenditure of energy by various mechanisms including the fat metabolism modulation and glucose (Bluher &Mantzoros, 2009,pp. 89).

In modern era, the mode of action of Leptin is studied extensively but many aspects of Leptin are still remaining unclear. However, it is known to modulate functions of immune system, neuroendocrine, angiogenic and reproductive along with maintaining the energy homeostasis. In understanding of metabolic homeostasis and energy balance the discovery of adipokine has provided immense advances. Adipokine is a versatile fat cell secreted polypeptide that is related to the family of cytokine based on its structure. Cytokines are the minute protein molecules that are cell signalling which are secreted by the cells of the immune and nervous system.

Exogenous therapy experimentation of leptin therapy has proved ineffective in triggering directly the weight loss in human beings. The fat individuals usually build up desensitization of Leptin like type 2 diabetes patients, who are insulin resistant. Therefore it is considered that the direct metabolic impact of exogenous leptin may not stimulate the loss of weight in individuals. The leptin effects are wide spread due to highly regulated critical nature of action. There has been a monumental growth in the area of research of Leptin not only for the weight of the body homeostasis but also for the neurological, gastrointestinal, immunological and reproductive functioning. After years of research on Lipid metabolism, science discovered the role of cytokine secretion, haematopoiesis, glucose metabolism, angiogenesis, cardiovascular pathology, function of immune and reproduction.

Strucutre

Leptin found mainly in the white adipose tissue is basically a 167 amino acid protein comprising of 4 alpha helices with an up-up-down-down topology. It mostly resembles in structure to the cytokines of the InterLeukin-6 family and granulocyte colony-stimulating factor (G-CSF).While studying the binding sites for the leptin hormone in order to develop a suitable antagonist, mapping of binding sites of leptin were done in accordance to ...