Hormone Disorders

Hormones play a crucial role in the etiology and consequences of obesity. Insulin, glucocorticoids, glucagon, androgens, thyroid hormones, and growth hormone affect the energy homeostasis in the body, and in some cases, impairment in their normal functions and activities can cause obesity. Several neuroendocrine diseases are believed to have a possible association with the development of obesity. Because hormones play such a crucial role in obesity, accurate measurement of these proteins with hormone assays is essential in obesity treatment. Hormone assays can help establish possible endocrine pathogenesis of obesity, and can reveal hormonal impairment due to obesity itself.

The hormones function in different ways as modulators of energy balance in human body. For example, insulin can affect the volume of fat cells by reducing food intake; glucocorticoids and glucagon can control fat storage through their effects on energy intakes; and androgens, thyroid, and growth hormones modulate the fat storage in the body via their effects on energy expenditure. All these show that in evaluation of a patient with obesity, hormone disturbances must be evaluated by hormone assays.

In such an evaluation, some disorders such as hypothalamic obesity, Cushing's syndrome, hypothyroidism, and polycystic ovary syndrome should be considered. In other words, in pathogenesis of obesity, hormonal factors should be noted and therapeutic strategies must include treatment of endocrine disorders as well. For example, studies suggest that growth hormone therapy can decrease the amount of stored body fat.

The rare syndrome of hypothalamic obesity is due to damage to some regions in human hypothalamus or the amygdala. In these parts of the brain, some regions process the information related to metabolic status of the body. Obesity is a presentation of damage to these regions caused by impairment in hypothalamus hormonal activity.

Obesity is an important clinical presentation in Cushing's syndrome too and in hypothyroidism, the decreased metabolic activity can lead to obesity and fat storage in the body.

In polycystic ovary syndrome (PCOS), obesity is a clinical feature in more than 50 percent of the patients. Some other neuroendocrine diseases related to obesity are hypogonadism, growth hormone deficiency, and pseudohypoparathyroidism.

All the described disorders are due to disturbances in hormone production and activities and the evaluation of endocrine system by hormone assays is crucial in finding the pathogenesis of obesity in any patient. Obesity itself can cause endocrine disorders such as insulin resistance with hyperinsulinemia. In this disorder, disturbance of glucose removal due to [Page 366]obesity and elevated insulin resistance cause hyperinsulinemia. In a patient with obesity, hormone assays can reveal the harmful effects of obesity on the hormonal activities as well.