1/396. Implications of compound heterozygous insulin receptor mutations in congenital muscle fibre type disproportion myopathy for the receptor kinase activation. We studied insulin receptor kinase activation in two brothers with congenital muscle fibre type disproportion myopathy and compound heterozygous mutations of the insulin receptor gene, their parents, and their unaffected brother. In the father who has a heterozygote Arg1174-->Gln mutation, in situ activation of the receptor kinase in skeletal muscle was reduced about 70%. Selection of only those receptors that bound to anti-phosphotyrosine antibody showed that these receptors had normal kinase activity and that the reduction in overall kinase activity was due to the inability of about 70% of the receptors to become insulin-dependently activated. The mother carries a point mutation at the last base pair in exon 17 which, due to abnormal alternative splicing, could lead to normally transcribed receptor or truncated receptor lacking the kinase region. Kinase activation was normal in the mother's skeletal muscle, suggesting that virtually no truncated receptor was expressed. Receptor kinase activity was, however, reduced by 95 and 91% in the compound heterozygous brothers. This suggests that the mother's mutated allele contributes little to the generation of functional receptor protein and that the receptors in the mother's skeletal muscle are transcribed almost exclusively from the non-mutated allele. The mutation in exon 17 could lead to reduced transcription or rapid degradation of a predominantly transcribed truncated gene product or both. ( info) |
2/396. pregnancy after treatment with the insulin-sensitizing agent troglitazone in an obese woman with the hyperandrogenic, insulin-resistant acanthosis nigricans syndrome. OBJECTIVE: To report a case of unassisted pregnancy after 5 months of troglitazone treatment in a severely hyperandrogenic, insulin-resistant woman with acanthosis nigricans (hair-AN) previously managed with depot leuprolide acetate (LA) plus oral contraceptive and dexamethasone therapy. DESIGN: Case report. SETTING: Private infertility clinic. PATIENT(S): A 28-year-old African-American woman with excessive obesity (body mass index = 42 kg/m2) and hair-AN syndrome. INTERVENTION(S): Androgen suppression with depot LA plus oral contraceptive and dexamethasone therapy, troglitazone treatment resulting in normalization of fasting insulin and testosterone, spontaneous menses, and an unassisted pregnancy. MAIN OUTCOME MEASURE(S): luteinizing hormone and testosterone concentrations, fasting insulin and glucose levels, insulin-glucose ratios, hCG levels, and ultrasound examinations. RESULT(S): Spontaneous menses followed by an intrauterine pregnancy after 5 months of treatment with troglitazone, an insulin-sensitizing agent, in a woman with severe hair-AN syndrome whose hyperandrogenism previously could be normalized only with depot LA plus oral contraceptive therapy and dexamethasone. CONCLUSION(S): Troglitazone treatment resulted in attenuation of both hyperinsulinemia and hyperandrogenism in an obese woman with hair-AN and resulted in resumption of menses and a spontaneous pregnancy. ( info) |
3/396. Insulin-mediated pseudoacromegaly in a patient with severe insulin resistance: association of defective insulin-stimulated glucose transport with impaired phosphatidylinositol 3-kinase activity in fibroblasts. The purpose of this study was to clinically and biochemically describe an insulin resistant patient with insulin-mediated pseudoacromegaly and in addition, to examine the molecular cause responsible for the defective insulin-stimulated glucose transport in cultured fibroblasts derived from the patient. The patient was a 64 year old female with severe insulin resistant diabetes mellitus, requiring up to 200 U insulin per day, associated with typical acromegaloid characteristics including increased hand and foot size, macroglossia and development of coarse facial features. Pituitary magnetic resonance imaging as well as multiple GH and IGF-1 measurements were normal. In cultured fibroblasts derived from the patient, (i) insulin-stimulated glucose transport, (ii) the subcellular distribution of GLUT1 glucose transporters, (iii) insulin-stimulated IRS-1-immunoprecipitable phosphatidylinositol (PI) 3-kinase activity, as well as (iv) protein expression of the small GTP-binding protein Rab4 was determined. The results indicate, that insulin's ability to stimulate glucose transport is defective in the patients fibroblasts although the GLUT1 content in the plasma membrane was increased by 34% when compared to control cells. Furthermore, the IRS-1 dependent activation of PI 3-kinase was reduced by 39.6% after incubation with 10 nM insulin for 5 min. Interestingly, immunodetection of the small GTP-binding protein Rab4, which is believed to be involved in the regulation of glucose transporter vesicle targeting to the plasma membrane, revealed a marked reduction of the expression of Rab4 protein in a total membrane fraction by 57.4%. In conclusion, in fibroblasts of a patient with clinical and biochemical evidence of pseudoacromegaly, the defective insulin-stimulated glucose transport was associated with impaired insulin-stimulated PI 3-kinase activity, which may contribute to the severe insulin resistant state of this patient. ( info) |
| We report on a 27-year-old man with acanthosis nigricans (AN) associated with severe obesity, insulin resistance and hypothyroidism. A very low-calorie diet treatment decreased his weight and then ameliorated the insulin-resistant state. These effects were followed by remarkable improvement of the AN prior to the correction of the hypothyroidism. This confirms that AN may be mainly attributed to insulin resistance rather than hypothyroidism per se. ( info) |
5/396. insulin resistance in patients with depression and its changes in the clinical course of depression: a report on three cases using the minimal model analysis. It has been reported that depression and diabetes mellitus often occur together, and insulin resistance has been observed in patients with depression. For further understanding of the relationship of depression to insulin resistance, three patients with depression were given the oral glucose tolerance test (OGTT) and the frequently sampled intravenous glucose tolerance test (FSIGT) with minimal model analysis before and after antidepressant treatment. Depressive patients showed decreased glucose tolerance, enhanced insulin secretion, and diminished insulin sensitively during OGTT and FSIGT. These abnormalities were resolved after their recovery from depression without changes in body weight or diet. ( info) |
6/396. Triglyceride-induced diabetes associated with familial lipoprotein lipase deficiency. Raised plasma triglycerides (TGs) and nonesterified fatty acid (NEFA) concentrations are thought to play a role in the pathogenesis of insulin-resistant diabetes. We report on two sisters with extreme hypertriglyceridemia and overt diabetes, in whom surgical normalization of TGs cured the diabetes. In all of the family members (parents, two affected sisters, ages 18 and 15 years, and an 11-year-old unaffected sister), we measured oral glucose tolerance, insulin sensitivity (by the euglycemic-hyperinsulinemic clamp technique), substrate oxidation (indirect calorimetry), endogenous glucose production (by the [6,6-2H2]glucose technique), and postheparin plasma lipoprotein lipase (LPL) activity. In addition, GC-clamped polymerase chain reaction-amplified dna from the promoter region and the 10 coding LPL gene exons were screened for nucleotide substitution. Two silent mutations were found in the father's exon 4 (Glu118 Glu) and in the mother's exon 8 (Thr361 Thr), while a nonsense mutation (Ser447 Ter) was detected in the mother's exon 9. Mutations in exons 4 and 8 were inherited by the two affected girls. At 1-2 years after the appearance of hyperchylomicronemia, both sisters developed hyperglycemia with severe insulin resistance. Because medical therapy (including high-dose insulin) failed to reduce plasma TGs or control glycemia, lipid malabsorption was surgically induced by a modified biliopancreatic diversion. Within 3 weeks of surgery, plasma TGs and NEFA and cholesterol levels were drastically lowered. Concurrently, fasting plasma glucose levels fell from 17 to 5 mmol/l (with no therapy), while insulin-stimulated glucose uptake, oxidation, and storage were all markedly improved. Throughout the observation period, plasma TG levels were closely correlated with both plasma glucose and insulin concentrations, as measured during the oral glucose tolerance test. These cases provide evidence that insulin-resistant diabetes can be caused by extremely high levels of TGs. ( info) |
| The presence of insulin receptor antibodies is a rare cause of insulin resistance. patients usually have a combination of hyperglycemia, insulin resistance, acanthosis nigricans, and autoimmune features. We report a patient with systemic lupus erythematosus and severe insulin resistance due to insulin receptor antibodies. The most striking aspect of the clinical presentation is the resistance to insulin therapy, with our patient unresponsive to doses of up to 154,075 units in a day. While on a low-dose glucocorticoid therapy, the patient had clinical improvement, and glucose levels subsequently became normal even without insulin and glucocorticoid. ( info) |
8/396. A case of acromegaly accompanied by adrenal preclinical Cushing's syndrome. We encountered a 58-year-old woman with acromegaly accompanied by a cortisol-secreting adrenal tumor without clinical features of hypercortisolism. The simultaneous occurrence of these two endocrinopathies in one individual is extremely rare. She was diagnosed as having diabetes mellitus 8 years ago. Afterwards, in spite of insulin therapy, her hyperglycemia could not be well controlled. Her acromegaly and preclinical Cushing's syndrome were histopathologically proven to be due to a pituitary adenoma and an adrenocortical adenoma, respectively. Successful treatment for these endocrinopathies resulted in greatly improved blood sugar control because of a reduction in insulin resistance. In this case of preclinical Cushing's syndrome, replacement therapy with glucocorticoid was able to be discontinued at only 8 weeks after adrenalectomy, so that the period of necessary replacement was much shorter than that for overt Cushing's syndrome. This is the first report describing insulin resistance before and after treatment in a case of acromegaly accompanied by adrenal preclinical Cushing's syndrome. ( info) |
9/396. Ovarian responses to hCG stimulation: insulin resistance/hyperinsulinaemia vs. insulin deficiency. polycystic ovary syndrome is a heterogeneous disorder characterized by signs and symptoms of hyperandrogenism and insulin resistance. We present the clinical and hormonal features in an adolescent girl who had distinct intervals of insulin deficiency and insulin resistance/hyperinsulinaemia. This case report confirms that insulin resistance/hyperinsulinaemia exacerbates ovarian hyperandrogenism. ( info) |
10/396. Clearance of acanthosis nigricans associated with the hair-AN syndrome after partial pancreatectomy: an 11-year follow-up. We describe a woman with the syndrome characterised by hyperandrogenism, insulin resistance and acanthosis nigricans (the hair-AN syndrome), and an associated insulinoma (islet B-cell tumour), whose signs and symptoms cleared after partial pancreatectomy. ( info) |