Rosiglitazone as an option for patients with acromegaly: a case series

<p>Abstract</p> <p>Introduction</p> <p>In the patient with acromegaly, pituitary surgery is the therapeutic standard. Despite undergoing surgery, a significant number of patients with acromegaly continue to have uncontrolled growth hormone secretion. These patients require other treatments such as external irradiation and/or drug therapy.</p> <p>Case presentation</p> <p>We present the clinical and laboratory responses to six months of treatment with rosiglitazone in four cases. In all four cases, the patients had persistent growth hormone overproduction despite previous surgical treatment and other conventional therapy. Case 1 is a 57-year-old Caucasian woman, case 2 is a 51-year-old Hispanic man, case 3 is a 32-year-old Hispanic woman, and case 4 is a 36-year-old Hispanic man. In three of these patients, basal and nadir growth hormone and insulin-like growth factor 1 levels were significantly decreased (<it>P </it>< 0.05 and <it>P </it>< 0.01, respectively).</p> <p>Conclusion</p> <p>Rosiglitazone could be a treatment option in select patients with acromegaly.</p

Effect of insulin sensitivity on SHBG levels in premenopausal versus postmenopausal obese women.

This study was performed to evaluate the impact of insulin sensitivity on sex hormone-binding globulin (SHBG) and sex steroids in premenopausal and postmenopausal euthyroid obese women. A total of 227 women were eligible for this study. All were euthyroid, obese, and overweight; ages ranged from 25 to 69 years. Women were divided into premenopausal (n=151) and postmenopausal (n=76) groups. SHBG, sex steroids, thyrotropin, fasting and postprandial glucose, lipid profile, uric acid, serum insulin, and blood pressure were measured. No significant difference was found in mean SHBG levels between premenopausal and postmenopausal women. The investigators observed that during transition from premenopause to postmenopause, SHBG levels increased in insulin-sensitive women in the postmenopausal group; however, SHBG levels decreased in insulinresistant women. It was concluded that SHBG blood concentration factors are likely to change during transition from premenopause to postmenopause. The positive effect of estradiol on SHBG levels is probably stronger in premenopausal women than in postmenopausal women. It has been noted that after menopause, the impact of insulin resistance on SHBG level seems more important than the effect of estradiol

during weight loss in obese women

Objective: The aim of this study was to assess the impact of insulin sensitivity on the relationship between sex hormone-binding globulin (SHBG) and insulin levels during active weight loss in euthyroid obese women. Research Design and Methods: The study population comprised 80 premenopausal overweight and obese (BMI >= 27) women (mean age 41.44 +/- 10.03 years). Seventy patients were considered eligible for the study. Hypocaloric diets were given to all patients. Of 70 subjects who were initially willing to participate in the study, only 64 continued through to the last stage of the study. Measurements: Anthropometric parameters, metabolic markers and sex hormone status were measured at baseline and on completion of the 12-week study period. Results: Following the diet, significant decreases in insulin, homeostasis model assessment (HOMA) for insulin resistance and fasting glucose were noted. However, HOMA insulin secretion values did not change significantly. Interestingly, there was no significant correlation between SHBG and insulin levels at baseline. After weight loss, SHBG concentrations were significantly and negatively correlated with insulin levels. Therefore, it was concluded that, in severe insulin resistance, insulin does not inhibit the SHBG level. These findings could be important, but the authors have not found a similar relationship in the literature. Conclusion: The findings of this study provide some clues to the relationship between insulin and SHBG in insulin-resistant obese subjects. Insulin sensitivity or loss of fat tissue or leptin seem to be involved in the relationship between SHBG and insulin. Copyright (c) 2008 S. Karger AG, Basel

Relationship between insulin and sex hormone-binding globulin levels during weight loss in obese women.

OBJECTIVE: The aim of this study was to assess the impact of insulin sensitivity on the relationship between sex hormone-binding globulin (SHBG) and insulin levels during active weight loss in euthyroid obese women. RESEARCH DESIGN AND METHODS: The study population comprised 80 premenopausal overweight and obese (BMI > or =27) women (mean age 41.44 +/- 10.03 years). Seventy patients were considered eligible for the study. Hypocaloric diets were given to all patients. Of 70 subjects who were initially willing to participate in the study, only 64 continued through to the last stage of the study. MEASUREMENTS: Anthropometric parameters, metabolic markers and sex hormone status were measured at baseline and on completion of the 12-week study period. RESULTS: Following the diet, significant decreases in insulin, homeostasis model assessment (HOMA) for insulin resistance and fasting glucose were noted. However, HOMA insulin secretion values did not change significantly. Interestingly, there was no significant correlation between SHBG and insulin levels at baseline. After weight loss, SHBG concentrations were significantly and negatively correlated with insulin levels. Therefore, it was concluded that, in severe insulin resistance, insulin does not inhibit the SHBG level. These findings could be important, but the authors have not found a similar relationship in the literature. CONCLUSION: The findings of this study provide some clues to the relationship between insulin and SHBG in insulin-resistant obese subjects. Insulin sensitivity or loss of fat tissue or leptin seem to be involved in the relationship between SHBG and insulin

The PPAR-gamma activator rosiglitazone fails to lower plasma growth hormone and insulin-like growth factor-1 levels in patients with acromegaly.

BACKGROUND/AIM: Despite combined therapy consisting of surgery, external X-ray, and medical therapy, a significant number of acromegaly patients continue to have uncontrolled growth hormone (GH) secretion and active disease. These patients, particularly those with large or invasive tumors, require additional therapy to decrease their GH levels. Our aim was to investigate whether patients with documented GH-secreting pituitary adenomas leading to acromegaly would respond with attenuation of GH and insulin-like growth factor-1 (IGF-1) levels after treatment with a peroxisome proliferator-activated receptor gamma (PPAR-gamma) agonist. METHODS: We conducted prospective analyses in the Endocrinology Clinic of the Pamukkale University. Acromegaly patients who had active disease participated in two admissions: before and after 6 weeks of daily treatment with 8 mg of oral rosiglitazone. Four male and 3 female patients have completed the study. Basal and nadir GH levels during an oral glucose tolerance test were determined, and the IGF-1 and IGF-binding protein-3 levels were also measured both before and 6 weeks after the rosiglitazone treatment. RESULTS: Treatment with rosigitazone did not reduce basal and nadir GH levels during the oral glucose tolerance test and the IGF-1 levels in the patient population as a whole (p > 0.05). CONCLUSIONS: The PPAR-gamma activator rosiglitazone, used at maximum approved dosage, did not reduce plasma GH and IGF-1 levels in patients with acromegaly. Further studies with higher doses and longer duration of PPAR-gamma agonist administration would be required to determine its usefulness in the treatment in this group of patients

The use of lithium carbonate in the preparation for definitive therapy in hyperthyroid patients.

OBJECTIVE: The aim of this study was to elucidate the effectiveness of lithium carbonate prior to thyroidectomy or radioiodide therapy in patients with thyrotoxicosis. SUBJECTS AND METHODS: Lithium carbonate was used as preoperative preparation or radioiodide therapy in 5 patients with Graves' disease and in 1 patient with toxic multinodular goiter because of side effects of thionamide in 5 patients and ineffectiveness of antithyroid medication in the remaining patient. RESULTS: All 6 patients had a benign course following treatment without thyroid storm. No adverse effects or complications of lithium carbonate were observed. CONCLUSION: This report shows that lithium carbonate can be safely used preoperatively or prior to radioiodide therapy in circumstances where antithyroid medications are contraindicated and are ineffective in obtaining an euthyroid status

acromegaly

Background/ Aim: Despite combined therapy consisting of surgery, external X- ray, and medical therapy, a significant number of acromegaly patients continue to have uncontrolled growth hormone ( GH) secretion and active disease. These patients, particularly those with large or invasive tumors, require additional therapy to decrease their GH levels. Our aim was to investigate whether patients with documented GH- secreting pituitary adenomas leading to acromegaly would respond with attenuation of GH and insulin- like growth factor- 1 ( IGF- 1) levels after treatment with a peroxisome proliferator- activated receptor gamma ( PPAR- gamma) agonist. Methods: We conducted prospective analyses in the Endocrinology Clinic of the Pamukkale University. Acromegaly patients who had active disease participated in two admissions: before and after 6 weeks of daily treatment with 8 mg of oral rosiglitazone. Four male and 3 female patients have completed the study. Basal and nadir GH levels during an oral glucose tolerance test were determined, and the IGF-1 and IGF- binding protein- 3 levels were also measured both before and 6 weeks after the rosiglitazone treatment. Results: Treatment with rosigitazone did not reduce basal and nadir GH levels during the oral glucose tolerance test and the IGF- 1 levels in the patient population as a whole ( p 1 0.05). Conclusions: The PPAR- gamma activator rosiglitazone, used at maximum approved dosage, did not reduce plasma GH and IGF- 1 levels in patients with acromegaly. Further studies with higher doses and longer duration of PPAR- gamma agonist administration would be required to determine its usefulness in the treatment in this group of patients. Copyright (C) 2007 S. Karger AG, Basel

stimulating hormone

introduction: It is well recognized that there is a close relationship between TSH and PRL levels. The aim of this study was to evaluate the impact of insulin sensitivity on the association between TSH and PRL in euthyroid obese subjects.Material and Methods: Retrospective cross-sectional analysis was carried out on 165 euthyroid obese or overweight female patients. Prolactin, TSH, free thyroxine (FF4), free triiodothyronine (FF3), fasting plasma levels of insulin and glucose, postprandial levels of glucose, homeostasis model assessment (HOMA) for insulin resistance (HOMA-IR) and insulin secretion (HOMA-beta cell), body weight, height, body mass index (BMI) and waist circumference were assessed. Statistical tests used were unpaired Student's t-test adjusted by Bonferroni's method and Pearson correlations with Bonferroni corrections.Results: There was no significant difference in prolactin levels between insulin sensitive and resistant subjects. Compared to insulin sensitive subjects, TSH levels were higher in insulin resistant subjects but it was not statistically significant. We observed significant positive correlation between prolactin and TSH in insulin sensitive and normoglycemic subjects (r=0.273, p=0.039 and r=0.253, p=0.023, respectively) but this correlation was lost in insulin resistant subjects and subjects who had fasting glucose levels 100mg/dl (r=0.057, p=0.609 and r=0.090, p=0.404, respectively).Conclusions: The findings of this study provide some clues about the relationship between PRL and TSH in insulin sensitive obese subjects. The insulin sensitivity and carbohydrate homeostasis seem to be involved in relationship with PRL and TSH by the brain via serotoninergic and dopaminergic system