Erythrocyte insulin-like growth factor-I receptor evaluation in normal subjects, acromegalics, and growth hormone-deficient and insulin-dependent diabetic children.

Insulin-like growth factor-I (IGF-I) receptors are characterized in several animal and human tissues. IGF-I receptor studies performed in erythrocytes to assess IGF-I receptor status at target-cell tissues are potentially useful for clinical studies, since tissue biopsies or cultures are not required. However, validation of results is challenged by some investigators on the basis of discrepancies described in comparative studies with other cell types, probably related to populations of different cell ages affecting binding to red blood cells (RBCs).

Computed tomography and ultrasonography of the adrenal glands in paracoccidioidomycosis. Comparison with cortisol and aldosterone responses to ACTH stimulation.

Fifteen patients with proven disseminated paracoccidioidomycosis (PCM) had computed tomography (CT) and ultrasonography (US) performed to evaluate the form, shape, density and size of their adrenal glands. Plasma and urinary cortisol were determined and adrenal reserve assessed by measuring the cortisol and aldosterone responses to synthetic ACTH. The adrenal CT showed unilateral lesions in two cases and bilateral in another four.

Insulin resistance in acromegaly: evaluation by studies of insulin binding to erythrocytes.

Insulin binding to erythrocytes (RBC) was evaluated in 10 acromegalic patients (6 females and 4 males) in comparison to 22 normal subjects (12 females and 10 males) in an attempt to study the insulin resistance of acromegaly. Basal glucose from all acromegalic patients were within the normal range but incremental glucose and insulin curves, respectively, on oGTT were significantly increased in the acromegalic patients suggesting an insulin resistant state. Basal growth hormone concentrations were elevated in all acromegalic patients, but no correlation was observed between insulin and GH levels.

Erythrocyte insulin receptor: normalization of binding data for the average cell age by the red cell creatine determination in obese, diabetic and acromegalic patients.

Insulin binding studies performed in erythrocytes (RBC) have been employed in clinical studies assessing the status of insulin receptors at target cell tissues. However, some authors challenged this assumption on the basis of some discrepancies described in comparative studies of other cell types, probably related to populations of different cell age affecting insulin binding to RBC. We evaluated insulin binding to RBC in normal males (n = 10), non-obese diabetic males (n = 13), normal females (n = 15), obese (n = 11) and acromegalic females (n = 5), before and after correction of insulin binding data for creatine concentration in the RBC as a procedure of correction for age, since a negative correlation was described between creatine content and RBC age which also correlates inversely with % insulin binding.

Effect of short- and long-term chlorpropamide therapy on oral glucose tolerance and erythrocyte insulin receptors in non-obese non-insulin dependent diabetes mellitus.

Erythrocyte (RBC) insulin receptors and the insulin response to glucose load (oGTT) were evaluated in ten male, non-obese, non-insulin dependent diabetic patients (NIDDM) before and after 14 and 90 days of 250 mg/day of chlorpropamide administration. In addition, as a control group, twelve healthy non-obese subjects were studied. Diabetic patients with fasting plasma glucose level higher than 14 mmol/l (group A), presented a significant improvement in the incremental glucose area only after 90 days of therapy.

Sequential studies of glucose tolerance and red blood cell insulin receptors in normal human pregnancy.

Insulin binding to erythrocytes was sequentially studied in 12 healthy pregnant women during the anabolic (11-22 wk) and the catabolic (31-38 wk) gestational phases. For comparison, we studied 12 nonpregnant subjects at mid-luteal and mid-follicular menstrual phases. Oral glucose tolerance tests were also performed during these studies.

Human erythrocyte insulin receptors in normal male and female subjects.

Human red blood cells (RBC) have been shown to have highly specific insulin receptors. We have studied the binding characteristics of insulin to these receptors in erythrocytes from normal male and female subjects on their usual diet and physical activity. There were no significant differences in insulin binding in erythrocytes from females between the two phases of the menstrual cycle.