Thi Leptin Case Study

Genetic research of obesity was partly successful in establishing obesity in model organisms – rodents where obesity occurs spontaneously together with other pathological aspects (insulin resistance, …). The main cause of monogenic obesity in these model organisms are common mutations always present in only one gene. Results of research on model organisms allowed us to understand biological mechanisms of calorie intake and regulation and maintenance of body weight. The most important insight into obesity was achieved in 1994 after discovery of ob gene encoding for leptin. In two years period, using screening method, candidate homologous genes, selected on genetic study basis on mice, another five genes were identified. Mutations on these genes were found to be the cause of autosomal recessive or dominant monogenic obesity. Products of these genes are leptin and its receptor, proopiomelanocortin (POMC) melanocortin receptor 4 (MC4R) and

Even despite electric shocks, they continued to eat until they became obese. When the researchers switched the obese rats’ diet to a healthy one, the rats refused to eat for almost two weeks. The rats that ate the fast food stopped responding to Leptin, a hormone that regulates hunger. As the rats became more obese, the amount of Leptin in their bodies indicated that the rats were on the brink of starvation; however, the rats continued to eat and become even more obese (Greviskes, 2013).

Over 60% of the people in the U.S are obese, obesity ranks second among preventable causes of death. What you eat is what you are. More and more people are becoming obese which is not healthy. People who suffer from obesity are going to face severe chronic illness or stress. A person who is obese is not necessarily overweight but has too much body fat. Many experts use BMI index for an accurate measurement for a body fat. BMI is calculated by a formula that includes a person’s height and weight. One important cause of insulin is obesity. Insulin is supposed to transport blood sugar into the cells of the muscle and fat. Since the year 1980 the obesity rate in the U.S. has changed. In 2000 the obesity rate was 30% percent but in 2013 it

In wild type mouse there is no effect on food intake, body weight and blood glucose though we give more leptin because here the leptin receptors are constant. But, in ob/ob mouse the food intake, body weight and blood glucose levels are decrease because the presence of leptin receptor. However, in the db/db mouse there is no effect due to the absence of the leptin

instrument of the advancement of obesity is not fully recognized and it is understood to be a

Consequently, the result of this negative trend caused obesity to be the second leading cause of preventable deaths with 18% of American adults dying each year (CDC, 2016). According to the National Institute of Diabetes and Digestive and Kidney Diseases “more than one-third (35.7%) of adults are considered obese. More than 1 in 20 (6.3%) have extreme obesity” (NIDDK, 2012).

The hormone Leptin containing a malfunction is one of the causes for Monogenic Obesity, among many others. Leptin is a hormone that helps regulate body fat and also helps in parts of the brain that controls hunger and tells the body when it’s full. When the Leptin hormone is shortened or absent the body doesn’t secrete fat, but rather stores it making a person become obese. In 1997, two Pakistani cousins were reported with extreme obesity, “Both children had undetectable levels of serum leptin and were found to be homozygous for a frameshift mutation in the LEP gene (ΔG133), which resulted in a truncated protein that was not secreted.” (endocrine.org) In other words, the children contained two types of the same gene whether it be dominant or recessive that were either inserted or deleted causing the levels of the Leptin hormone to be shortened. After the findings of the two Pakistani cousins, there have been five more cases reported with children that lack the leptin hormone, which are all of Pakistani descent, but not related to each other. There has only been one case reported that was found in an Algerian family of three siblings in which the leptin receptor was found abnormal were one was joined to the other allowing a mutated one to work causing there to be more Leptin hormones than there needed to

acute effects of leptin on synaptic plasticity in the arcuate nucleus of the hypothalamus. The arcuate nucleus is one of the key targets of circulating hormones such as leptin. At least two distinct populations of neurons with opposing actions on food intake residein the arcuate nucleus, " (p.63). Pinto's data is ultimately described as helpful but also created many more questions, probably more than it answered.

Although many individuals are uncertain about the increasing statistics associated with obesity, more than seventy percent of men and virtually sixty-two percent of women within the United States adult population are overweight or obese (Wilmore, Costill, & Kenney). Obesity refers to the condition of having an excessive amount of body fat. If an individual’s amount of body fat becomes too excessive, he/she is at a much greater risk of developing life-altering diseases such as heart failure, hypertension, type II diabetes, cancer, gallbladder disease, osteoarthritis, etc. (Wilmore, et al., 2008).

Obesity is defined as the excessive build-up of body fat that has major detrimental effects on an individual’s health (Caballero, 2007). The major cause of this excess accumulation of body fat is due to a positive energy balance i.e. when the input of energy into the body system exceeds the output of energy which in turn facilitates in weight gain (Caballero, 2007). Obesity is a major health issue in modern day society, firstly because it affects approximately 300 million people worldwide (Weight Management Centre and secondly, drastic alteration in the body’s fat intake also leads to the increasing prevalence of other major health conditions such as cardiovascular disease, stroke, non-insulin dependent diabetes and hypertension (WMC, 2010).

Obesity has been around for several thousands of years but hasn’t always been a serious epidemic. A higher amount of fat or stored energy used to mean a greater chance at surviving a famine, but those times are long gone in the industrialized world. As time has progressed, we’ve see an exponential growth in obesity rates despite our best efforts to slow it down. In order to contain and eventually decrease obesity rates, we would first need to know what fuels this powerful monster of the western culture. Has our problem been generated from an increase in inactivity, sugar consumption, fat consumption, other factors or a combination of them? A collection of studies have been observed to discover what the real main factor to obesity in

Obesity, the condition of being severely overweight, is a serious issue in the United States that is gradually beginning to affect more and more citizens. In recent years, the number of Americans suffering from this chronic disease has significantly increased. Researchers have found that nearly one third of the U.S. population is considered overweight and, on average, three hundred thousand individuals die yearly as a result of obesity (Hollands et al. 2). When one participates in little to no physical activity and their diet consists mostly of high fat foods, chances are they will gain weight. If someone becomes obese, they may develop serious health related issues that, in some cases,

Obesity has become the silent killer in American society. It is a risk factor for numerous chronic diseases including the four leading causes of death. Obesity can be linked to stroke, heart disease, cancer and diabetes, all serious health problems that can be fatal. Obesity is linked to 300,000 deaths annually in the industrial world (Flamholz, 2001). Often in society and in the medical community there exists a lack of understanding that obesity is in fact a disease and needs attention, otherwise the rates of many diseases will continue to climb.

It was merely a decade ago that the obesity epidemic was thought to only be a minor problem and had only alarmed a small number of endocrinologists interested by the size of the situation (James, 2008). However today, the problem of obesity is vast with more awareness of its presence by doctors and individuals alike. In fact, the Center for Disease Control and Prevention states, “More than one-third (34.9% or 78.6 million) of U.S. adults are obese (CDC, 2014)”. These numbers are outrageous and eye opening, leaving millions looking for a solution to this troubling epidemic. Obesity is not simply a cosmetic flaw as some might think, but is actually a very dangerous state of being for any individual to sustain long-term. Mentioned further in

Leptin is a hormone that inhibits hunger. It is produced by the fat tissues in the body. Currently, it is known that leptin increases heart rate if it is introduced to the body in high concentrations; however, if it is introduced to the body in low concentrations, it decreases heart rate (Lin 2015). Because leptin is one of the hormones in charge of when an individual chooses to eat a snack/meal, it is important the effects on an individual’s heart rate in the case that leptin is only ever present in high concentrations. If leptin is introduced into the body in high concentrations but at frequent time intervals (6 times a day), the null hypothesis is that the heart rate of the individual will increase consistently. The hypothesis is that given