Abnormal Body Fat Distribution Research Articles

Abnormal body fat distribution detected by computed tomography in diabetic men.

Previous studies of body fat using tape measurement of body circumference and hand-held caliper skinfold measurements have suggested abnormal fat distribution in patients with diabetes mellitus. These methods, however, have high interobserver variability and cannot assess intra-abdominal fat independent of subcutaneous fat. We used computed tomography to evaluate body fat distribution in a group of 53 Japanese-American men of similar age and body mass index (weight divided by height squared). As determined by a 75-g oral glucose tolerance test, 29 subjects had type II diabetes and 24 were normal. Computed tomography cuts were obtained at three body levels to measure thorax, abdomen, and thigh subcutaneous fat area as well as intra-abdominal fat area. We found greater intra-abdominal fat in men with diabetes than in those without (123.74 vs. 95.54 cm2, P = 0.034) and a greater ratio of thorax to thigh subcutaneous fat (2.55 vs. 1.88, P = 0.016). These findings support the hypothesis that fat in different areas of the body differs metabolically. Computed tomography can be a useful tool for investigating whether abnormal body fat distribution is associated with the pathogenesis of abnormal glucose tolerance.

Transplantation of ACTH-secreting pituitary tumor cells in athymic nude mice.

Chronic excess of glucocorticoids results in Cushing's syndrome in humans. A common cause of excess cortisol secretion is the presence of an adrenocorticotropin secreting pituitary tumor which stimulates the adrenal cortex to produce excess glucocorticoids. ACTH-secreting AtT-20 mouse pituitary cells transplanted subcutaneously in oestrogenized athymic nude mice form tumors rapidly. Six weeks after receiving the tumor transplants, the mice weighed 45% more than normal mice due to the increase in body fat. The tumor-bearing mice exhibit the familial "buffalo hump" appeaance due to the abnormal distribution of body fat. The adrenal glands of the tumor-bearing animals are enlarged due to hypertrophy of the zona fasciculata. The foamy looking fasciculata cells in normal mice were converted to dense, eosinophilic cells in the tumor-bearing mice. Transplantation of normal pituitary glands to athymic nude mice with or without oestrogen treatment did not produce these morphological changes. The experimental model described here may be useful for future studies of Cushing's syndrome.

Surgery of the adrenals

The adrenals occupy an interesting field for surgical study both from the specific disorders of the gland itself and from the possibilities of improving bodily functions through alteration of hormonal balances in disease. The adrenal medulla elaborates two hormones, epinephrine and nor-epinephrine. Both hormones raise blood pressure, but epinephrine stimulates the pituitary-adrenal axis and decreases total peripheral resistance, whereas nor-epinephrine is vasoconstrictive through all vascular beds and does not affect pituitary adrenal relations. Pheochrome tumors of the adrenal medulla produce both hormones, are characterized by paroxysmal or sustained hypertension with hypermetabolism, and offer problems of hypertensive crises and adrenal cortical insufficiency in their surgical removal. The adrenal cortex elaborates several hormones related to salt and water metabolism, nitrogen metabolism, carbohydrate metabolism, adrenogenital functions and pituitary release of ACTH. Cushing's syndrome is the clinical picture of adrenal cortical tumors or hyperplasia, resulting in an increased production of corticoids. Virilism, feminism, or precocious sexual development may also result from adrenogenital hormones, an adrenogenital syndrome. Hypertension, abnormal body fat distribution and electrolyte disturbances are common in cortical tumors or hyperplasia. The newest diagnostic adjuncts in the evaluation of abnormal adrenal states include the use of adrenolytic drugs, presacral air injection and urinary hormonal analyses. Surgery of the adrenals requires attention to hypertensive crises during the operative procedure and avoidance of adrenal cortical insufficiency in the postoperative period. The adrenolytic drugs are useful in avoiding hypertensive crises. Cortisone, salt and DOCA in proper dosages can control postoperative adrenal cortical insufficiency and bilateral total adrenalectomy is now feasible with an operative mortality of 5 per cent. Bilateral total adrenalectomy has been utilized to alter the hormonal environment in patients with hopeless breast carcinoma. Preferably the patient should be over forty-five, must have no residual ovarian hormonal activity, should have differentiated carcinoma with a fairly long interval between radical mastectomy and appearance of metastases. It is palliative, not curative, and is successful in about 35 per cent of the cases. Extensive or total adrenalectomy has been utilized in the treatment of progressive malignant hypertension, with or without associated sympathectomy. Renal impairment is a contraindication to its use. It is again palliative in about 35 per cent of the cases, but does not cure the fundamental vascular disturbance in hypertension.