Effects of long-acting release octreotide on glucose homeostasis in acromegaly patients after trans-sphenoidal surgery.

The present study was aimed to investigate glucose homeostasis and insulin secretion in acromegalic patients during octreotide-long acting release (LAR) therapy and designed as an observational prospective study. 18 acromegalic patients who had undergone trans-sphenoidal surgery with active disease were included. All patients were treated with octreotide-LAR injection for 1 year. These patients received oral glucose tolerance test (OGTT) before, 21 days after, and 1 year after octreotide-LAR treatment. Primary outcomes were changes in glucose levels and insulin secretion during an OGTT. We also determined the differences between subjects with normalized and uncontrolled IGF-1 levels. Of the 18 patients treated with octreotide-LAR for 1 year, 89% achieved fasting GH levels <2.5 µg/l, 85% reached the nadir GH concentration <1 µg/l, and 61% achieved normal age- and sex-matched IGF-1 values. 21 days after one dose of octreotide-LAR injection, insulin response during OGTT significantly decreased, and the Matsuda index increased significantly. One year after octreotide-LAR therapy, most parameters of glucose homeostasis returned to baseline levels. However, insulin response during OGTT at 30 and 60 min, and the insulinogenic index were still significantly decreased. Compared with the IGF-1-normalized group, the IGF-1 uncontrolled group had the same fasting GH and nadir GH levels and a higher insulin AUC and total insulin secretion. During octreotide-LAR treatment, the early-phase insulin response to OGTT is reduced and plasma glucose levels remained normal in most patients. The IGF-1 uncontrolled group had the same fasting GH and nadir GH levels during OGTT, but had better glucose homeostasis.

Identification of two novel missense mutations in the KAL1 gene in Han Chinese subjects with Kallmann Syndrome.

OBJECTIVES: To identify mutations in the KAL1, the KAL2, and PROKR2/PROK2 genes and to characterize phenotypic features in 5 Chinese subjects with Kallmann Syndrome (KS) and 6 subjects with normosmic hypogonadotrophic hypogonadism (NHH) in Taiwan. DESIGN AND PATIENTS: Five unrelated males (age range 22-52 yr) with clinical manifestations of KS and 6 unrelated males (age range 24-47 yr) with NHH were analyzed. In addition, 5 relatives of KS subjects were also evaluated. Genomic DNA extraction, PCR, and DNA sequence analyses were performed using standard procedures. RESULTS: The 1st patient had a single missense mutation in his copy of the KAL1 gene, a T→G transversion in codon 134 that results in replacement of cysteine by gly cine. The 2nd affected subject had a single missense mutation in the KAL1 gene, a T→C transition in codon 163 that results in replacement of cysteine by arginine. The 3rd case was hemizygous for a nonsense mutation in codon 424 of exon 9 (c.CGA→TGA) of the KAL1 gene. This mutation predicts a markedly truncated protein. Two of the mutations (p.C134G and p.C163R) we identified in the KAL1 gene are novel. CONCLUSIONS: We identified 3 mutations, including 2 novel mutations, in the KAL1 gene in patients with KS in Taiwan. These data extend the variety of KAL1 gene mutations in KS and further define the role of the KAL1 protein in olfactory bulb development.

Improvement of glycaemia control in subjects with type 2 diabetes by self-monitoring of blood glucose: comparison of two management programs adjusting bedtime insulin dosage.

AIM: Self-monitoring of blood glucose (SMBG) is important for patients treated with insulin to detect asymptomatic hypoglycaemia and to guide patients towards reaching blood glucose goal. This study compared two management programs for adjusting bedtime insulin dose: program 1 (performed by study subjects) vs. program 2 (performed by study subjects and reminded by investigators). METHODS: This is a prospective, open-level, 28-week randomized trial in poorly controlled type 2 diabetic subjects. One hundred subjects treated with oral antidiabetic drugs plus bedtime insulin with glycated haemoglobin A(1C) (A1C) >8.0% were screened and received a structure education package in a 4-week run-in period. Seventy-eight subjects were randomized to two treatment programs (adjust insulin dose by themselves with or without investigators' reminder) and reviewed by the investigators at a 4-week interval clinical visit. RESULTS: The mean SMBG decreased significantly in both groups, with a greater decrease observed in program 2 vs. program 1 (from 198.7 +/- 43.1 to 122.6 +/- 21.9 mg/dl vs. from 194.0 +/- 42.7 to 151.6 +/- 37.7 mg/dl, p < 0.001). Bedtime insulin dose increased in both groups with a greater increase in program 2 (from 14.4 +/- 8.7 to 27.4 +/- 12.8 IU vs. from 14.3 +/- 8.3 to 18.4 +/- 6.2 IU, p < 0.001). There was a significant reduction in A1C from 9.54 +/- 1.67% to 7.76 +/- 1.27%, with a greater decrease (p < 0.001) in program 2 (2.17%) than in program 1 (1.40%). There were more subjects in the program 2 group achieving the treating targets: mean SMBG < or =120 mg/dl (46.9 vs. 17.9%) and A1C < or =7.0% (54.5 vs. 32.2%). There was no significant difference in the incidence of hypoglycaemia and body weight changes. CONCLUSIONS: Systematically titrating bedtime insulin dose added to oral therapy, especially combined with health care reminders, can safely improve glycaemic control in type 2 diabetes with poor glycaemic control. This regimen may facilitate safe and effective insulin therapy in routine medical practice and improve achievement of recommended standards of diabetes care.

Contribution of genetic factors to neonatal transient hypothyroidism.

BACKGROUND: The causes of neonatal transient hypothyroidism (NTH) remain incompletely understood. Whether it is influenced by genetic background is rarely discussed and remains unproven. A defect in thyroid peroxidase is a common cause of dyshormonogenesis of the thyroid gland in Taiwanese, with a novel mutation (2268insT) present in nearly 90% of alleles studied. OBJECTIVE: To determine if the presence of this common mutation is associated with NTH in Taiwan. METHODS: A mismatched primer was designed and used for this specific 2268insT mutation to screen 1000 normal babies and 260 babies with confirmed NTH. RESULTS: The carrier rate for 2268insT in normal babies (1/200) was significantly lower than in babies with NTH (1/13; p<0.0001). CONCLUSIONS: The results strongly suggest that the presence of this thyroid peroxidase mutation contributes to the development of NTH. Likely pathogenetic explanations include the effect of the stress of extrauterine adaptation during labour on an immature pituitary-thyroid axis in genetically predisposed individuals, combined with environmental triggers such as iodine deficiency, perinatal iodine exposure, and/or goitrogen contamination.

Activity of the stimulatory guanine nucleotide-binding protein is reduced in erythrocytes from patients with pseudohypoparathyroidism and pseudopseudohypoparathyroidism: biochemical, endocrine, and genetic analysis of Albright's hereditary osteodystrophy in six kindreds.

Multiple hormone resistance in many patients with pseudohypoparathyroidism (PHP) type Ia and Albright's hereditary osteodystrophy (AHO) is associated with deficient activity of the stimulatory guanine nucleotide-binding protein (Gs) of adenylate cyclase. To study further the relationship of deficient Gs activity to hormone resistance, we evaluated endocrine function and measured Gs activity of erythrocyte membranes from AHO patients with clinical hormone resistance (PHP type Ia) and from family members with AHO alone (pseudopseudohypoparathyroidism). The results of erythrocyte membrane Gs determinations were compared to those of unaffected relatives and normal subjects. Patients with pseudopseudohypoparathyroidism (pseudoPHP) had reductions in erythrocyte membrane Gs activity comparable to those in patients with PHP type Ia [43.4 +/- 11.9% (+/- SD) for PHP type Ia vs. 47.8 +/- 9.5% for pseudoPHP]. However, in contradistinction to patients with PHP type Ia, individuals with pseudoPHP did not have obvious endocrine dysfunction. Although deficient Gs activity appears to play an important role in the pathogenesis of these disorders, it is possible that Gs deficiency must be combined with other factors that limit cAMP production to cause clinically overt endocrine disease.

A novel mutation in the calcium-sensing receptor gene in a Chinese subject with persistent hypercalcemia and hypocalciuria.

Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant disorder characterized by high penetrance of relatively benign, lifelong persistent hypercalcemia and hypocalciuria. By contrast, neonatal severe hyperparathyroidism represents a life-threatening form of hypercalcemia that can cause the early newborn mortality if immediate intervention is not undertaken. Both disorders are due to inactivation mutation of the human calcium-sensing receptor (CaSR) gene on chromosome 3q21-24. Up to now, more than 30 mutations in the CaSR gene associated with FHH have been described. In this study, we analyzed one 79-yr-old male with hypocalciuric hypercalcemia without siblings or children to compare with an additional group of 50 normal Chinese subjects in Taiwan. DNA sequence analysis of the CaSR gene was performed. The result showed that the proband had a heterozygous nonsense mutation in exon 7 of the CaSR gene at codon 648 (CGA-->TGA/Arg-->Ter). This mutation, located in the COOH-terminal of the first intracellular loop of the CaSR, predicts a markedly truncated protein. We have identified a novel R648X mutation in the CaSR gene in one patient with FHH in Taiwan

Fibrinolytic activity in Chinese patients with diabetes or hyperlipidemia in comparison with healthy controls.

Plasma tissue-type plasminogen activator (tPA), plasminogen activator inhibitor (PAI) and euglobulin lysis time (ELT) were determined before and after the venous occlusion test (VOT) in 3 groups of patients with mean age about 60 years: 29 diabetic patients (D group), 8 hyperlipidemic patients (H group) and 19 healthy controls (C group). In the D and H groups, the mean of morning tPA was significantly higher than that of the C group, but the means of PAI were not significantly different among the 3 groups. ELT was significantly shortened and tPA was markedly increased after the VOT in all 3 groups whereas PAI had not significantly changed. In conclusion, high tPA activity and good fibrinolytic response without significant change of PAI activity were found in the diabetic and hyperlipidemic patients, and no definite impairment of the fibrinolytic activity could be found in the Chinese patients with diabetes and hyperlipidemia. This might be one of the reasons why the Chinese has low incidence of thromboembolic diseases.

Insulin-like growth factor-I receptor increases in aortic endothelial cells from diabetic rats.

Endothelial cells are likely to play an important role in the development of diabetic vascular diseases, since they are exposed directly to the abnormal circulating metabolites of diabetes and may be easily damaged early in the natural course of vascular complications. In this study, aortic endothelial cells were cultured from diabetic BB rats. Their binding and internalization of insulin-like growth factor-I (IGF-I) were measured. IGF-I binding was higher in cells of diabetic rats than of control rats at both 37 degrees C (4.5% +/- 1.6% v 2.74% +/- 0.9% per mg protein, P < .05) and 4 degrees C (20.6% +/- 5.6% v 13.7% +/- 4.6% per mg protein, P < .01). Internalization of IGF-I also increased (1.62% +/- 0.2% v 0.74% +/- 0.15% of total count at 37 degrees C after 60 minutes, P < .05). Cross-linking studies showed that in cells from diabetic rats, the major band of 140 kd corresponding to the alpha-subunit of the IGF-I receptor increased in density by 50% compared with those from control rats. The IGF-I-stimulated tyrosine kinase activity (TKA) of partially purified receptor from cells of diabetic rats, measured using poly-glu-tyr as substrate, was normal. Since the biological effects of IGF-I are initiated by its binding to the IGF-I receptor, which is able to transduce mitogenic and metabolic signals, our results support the hypothesis that the IGF-I receptor is involved in the development of diabetic vascular complications.

Evidence for a delayed, integral, and proportional phase of glucocorticoid feedback on ACTH secretion in normal human volunteers.

To investigate the mechanisms responsible for glucocorticoid feedback on nonstress-induced ACTH secretion in normal subjects, 24 volunteer subjects (14 males and 10 females, 21 to 43 years) were divided into six groups in a randomized fashion and studied. Each subject received a single midnight dose of 30 mg/kg per body weight of metyrapone and then cortisol was administered according to different protocols in the next morning to provide extreme variations of the input signal. It was found that no obvious inhibition in plasma ACTH levels was shown during the first 15 min despite the fact that cortisol was given at rather larger doses and short time intervals. However, a significant suppression in plasma ACTH levels began to manifest approximately 30 min after cortisol administration in each study group and it became apparent that the degree of inhibition of ACTH level at 75 min correlated with the plasma cortisol concentrations at the same moment (r = 0.97, P less than 0.01) as well as with the dosage of cortisol during this time, whatever administered (r = 0.99, P less than 0.01). In summary, our data provided evidence for a delayed, proportional, and integral phase of glucocorticoid feedback on nonstress-induced ACTH secretion in normal human volunteers.

Modulatory effects of corticotropin-releasing factor on the delayed corticosteroid feedback in humans: implications of feedback sites.

We recently demonstrated the presence of a delayed phase of glucocorticoid feedback on nonstress-induced ACTH secretion in normal volunteers. In this study, we investigate the effects of corticotropin-releasing factor (CRF) on that delayed feedback pathway with an attempt to determine the sites on which glucocorticoid exerts its delayed feedback effects. Thirty normal subjects were subjected to study and each subject received a single midnight dosage of 30 mg/kg BW metyrapone before each test. The whole experiment was divided into two studies. In study I, we found that ovine CRF (oCRF) 1 microgram/kg BW alone as an IV bolus injection caused an increase in the plasma ACTH level, which persisted for at least 120 minutes. Continuous infusion of cortisol 25 mg/h alone for two hours produced a significant decrease in the plasma ACTH level; this fall of ACTH began 30 minutes after the onset of cortisol administration. When IV bolus injection of oCRF 1 microgram/kg BW and the continuous infusion of cortisol 25 mg/h for two hours were both given, the plasma ACTH level increased firstly and then decreased 60 minutes after the onset of cortisol administration, progressing thereafter to the end of the study. Study II showed in those who received the IV bolus injection of human CRF (hCRF) 100 micrograms and the continuous infusion of cortisol 25 mg/h for two hours, the plasma ACTH level increased firstly and began to decline 45 minutes after the onset of cortisol administration, progressing thereafter to the end of the test.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of creatine kinase isoforms by agarose gel electrophoresis in the diagnosis of myocardial infarction.

To evaluate a method to quantitate the isoforms of serum creatine kinase isoenzyme MM (CK-MM) by agarose gel electrophoresis, sera of normal subjects (n = 74) and patients with acute myocardial infarction (n = 21) and other diseases (n = 67) were studied. The within-assay imprecision (CV) for CK-MM1, -MM2, and -MM3 was 1.9%, 0.8%, and 2.2% at the activity of 79, 105, and 64 U/L (30 degrees C, CK-NAC), respectively; while the assay-to-assay imprecision was 4.8%, 3.2% and 3.9%, respectively. The method could detect 5 U/L or more of any CK-MM isoform and was linear with respect to CK activity at values less than 1100 U/L. Sera from healthy subjects (n = 74) contained mainly CK-MM1 (mean = 48.5%), with lesser amounts of CK-MM2 (mean = 30.6%) and CK-MM3 (mean = 20.8%). The central 95-percentile reference range for the ratio of MM3/MM1 was 0.12-1.34 with mean = 0.49. The sensitivity of CK-MM3/MM1 ratio greater than 1.3 in the diagnosis of acute myocardial infarction employing the first available sample was 90% at a specificity of 91%, compared with a sensitivity of 81% and specificity of 87% for the conventional CK-MB assay. At CK-MM3/MM1 ratio of 1.6 or more, the specificity increased to 96% while sensitivity remained unchanged at 90%. This procedure for the quantitation of serum CK-MM isoforms is convenient, practical and suitable for inclusion in the routine panel of cardiac tests.

Do smoking and diabetes change the hemostatic parameters?--a study in the Chinese people.

Plasma plasminogen activator inhibitor-1 (PAI) antigen, fibrinogen, antithrombin III (ATIII), protein C, beta-thromboglobulin (BTG), platelet count, fibrinogen degradation product (FDP) D-dimer, factors VII and XII, as well as cholesterol, triglyceride (TG) and glucose were determined in 163 subjects. First we compared the difference of these parameters between 50 diabetics (Group D, mean age 64.9 years) and 50 age-matched healthy controls (Group C, mean age 63.1 years). Nineteen of the diabetics and 19 of the healthy controls were smokers. Plasma glucose, cholesterol, TG and protein C were significantly higher in Group D than in Group C (p = 0.0010, 0.0308, 0.0083 and 0.0068, respectively), whereas ATIII and factor XII were significantly lower in Group D (p = 0.0213 and 0.0061). Secondly, we divided 113 healthy controls (Group C, including Group C plus 63 subjects at various ages) into smokers (mean age 56.7 years) and non-smokers (mean age 40.0 years) and compared the difference between them. Fibrinogen and glucose were higher in the smokers than in the non-smokers (p = 0.0139 and 0.0402, respectively). Other parameters were not different. In conclusion, our study did not find any important hypercoagulation state in the diabetics. Smoking can only increase fibrinogen and glucose without the change of other hemostatic parameters.

Relationship of plasminogen activator inhibitor-1 with plasma insulin, glucose, triglyceride and cholesterol in Chinese patients with diabetes.

Plasminogen activator inhibitor-1 (PAI) activity, plasma insulin, glucose, cholesterol and triglyceride (TG) concentrations were determined in 32 Chinese diabetic patients (mean age 61.4 yr) and 41 healthy controls (mean age 64.5 yr) to establish the relationships between these parameters. Insulin, glucose, cholesterol and triglyceride levels were significantly higher in the diabetics, whereas no significant difference of PAI activity was noted between groups. PAI activity was not affected by the increase of plasma insulin, cholesterol, TG or glucose. We have shown that PAI activity in Chinese diabetics was not affected by the common pathologic changes found in diabetes. This might be one of the reasons why fibrinolytic activity is not impaired in Chinese diabetics.

Hemostatic risk factors of coronary artery disease in the Chinese.

In order to find out the hemostatic risk factors of coronary artery disease in the Chinese, antithrombin III concentration, factor VII and fibrinogen assays, plasminogen activator inhibitor-1 antigen and platelet count were determined in 51 healthy controls (mean age 63.5 years, S.D. 10.3), 55 diabetics (mean age 66.0 years, S.D. 4.8) and 56 patients with arteriographically proved coronary artery disease (mean age 63.8 years, S.D. 8.7). Of the coronary artery disease group, 19 had single vessel disease, 21 had double vessel disease and 16 had triple vessel disease. Sixteen of this group also had a past history of myocardial infarction. There was no significant difference of the hemostasis parameters between diabetics and controls. Fibrinogen and factor VII, but not plasminogen activator inhibitor, were significantly higher in coronary artery disease patients than in controls (P = 0.0001, both) and in diabetics (P = 0.0001, both). No significant difference in the parameters was found in the coronary artery disease group, whether the patients had single vessel disease, double vessel disease, or triple vessel disease, or were with or without past myocardial infarction. In the myocardial infarction group, fibrinogen and factor VII were significantly higher than in the controls (P < 0.00005 and 0.0001, respectively) and in the diabetics (P = 0.0002 and 0.0004, respectively). We suggest that increased levels of fibrinogen and factor VII, but not plasminogen activator inhibitor, would be the hemostatic risk factors of coronary artery disease in the Chinese.

Fanconi syndrome: report of a case.

A 59-year-old female patient was admitted because of muscle weakness in all four limbs for a period of 5 days. She had been found to have Graves' disease 4 years ago previous to this, and had received a subtotal thyroidectomy 1 year later. Hypothyroidism supervened and she had been receiving levothyroxine replacement in recent years. She also had non-insulin-dependent diabetes, which was controlled with diet only. During the 5 days prior to admission, she developed muscle weakness which finally worsened to complete paralysis of all four limbs. Physical examination showed tenderness and weakness of the extremity muscles. Abnormal laboratory data included serum K, 1.6 mEq/L; P, 1.2 mg/dl; uric acid, 1.6 mg/dl; fasting glucose, 267 mg/dl; T3, 36.65 ng/dl; T4, 4.0 micrograms/dl; TSH, 5.35 mu u/ml; free T4, 0.57 ng/dl; and metabolic acidosis with pH, 7.298; PCO2, 27.0 mmHg; and HCO3, 12.8 mEq/L. An EKG showed a prominent U wave, and urinalysis revealed renal glucosuria and massive aminoaciduria. An oral sodium bicarbonate loading test showed an increasing loss of bicarbonate through the urine, while the plasma bicarbonate level was elevated. Clinical manifestations improved after the administration of sodium bicarbonate, potassium chloride and neutral phosphate.

Subclinical hypothyroidism is a risk factor for nephropathy and cardiovascular diseases in Type 2 diabetic patients.

AIMS: The purpose of this study was to determine the relationship between subclinical hypothyroidism and prevalence of retinopathy and nephropathy, incident cardiovascular disease, and mortality in Type 2 diabetic patients without taking thyroid medication. METHODS: Serum thyrotropin and free thyroxine concentrations were measured in 588 Type 2 diabetic subjects in Taipei Veterans General Hospital, Taiwan. In a cross-sectional study, we examined the prevalence of retinopathy and nephropathy. In a longitudinal study, we examined the risk of cardiovascular disease events, cardiovascular mortality and total mortality in the 4-year follow-up. RESULTS: In the cross-sectional analysis, subclinical hypothyroidism was associated with a greater prevalence of diabetic nephropathy (odds ratio, 3.15 [95% CI, 1.48-6.69]) and did not show a high prevalence of diabetic retinopathy (odds ratio, 1.15 [95% CI, 0.59-2.26]) compare to euthyroid diabetics. During the 44.0 +/- 7.4 months of follow-up, 51 participants had cardiovascular events. The risk of cardiovascular events was significantly increased in Type 2 diabetics with subclinical hypothyroidism after adjustment for age, sex, A1C, other standard cardiovascular risk factors and medication (hazard ratio, 2.93; 95% CI, 1.15-7.48; P = 0.024), but it became nonsignificant after additional adjustment for urinary albumin-to-creatinine ratio (hazard ratio, 2.06; 95% CI, 0.67-6.36; P = 0.211). The rates of cardiovascular-related and total mortality did not significantly differ by thyroid status. CONCLUSIONS: Type 2 diabetic patients with subclinical hypothyroidism are associated with an increased risk of nephropathy and cardiovascular events, but not with retinopathy. Our data suggest that the higher cardiovascular events in subclinical hypothyroidism with Type 2 diabetes may be mediated with nephropathy.

Two novel mutations in the MEN1 gene in subjects with multiple endocrine neoplasia-1.

Multiple endocrine neoplasia type 1 (MEN1) is characterized by parathyroid, enteropancreatic endocrine and pituitary adenomas as well as germline mutation of the MEN1 gene. We describe 2 families with MEN1 with novel mutations in the MEN1 gene. One family was of Turkish origin, and the index patient had primary hyperparathyroidism (PHPT) plus a prolactinoma; three relatives had PHPT only. The index patient in the second family was a 46-yr-old woman of Chinese origin living in Taiwan. This patient presented with a complaint of epigastric pain and watery diarrhea over the past 3 months, and had undergone subtotal parathyroidectomy and enucleation of pancreatic islet cell tumor about 10 yr before. There was also a prolactinoma. Sequence analysis of the MEN1 gene from leukocyte genomic DNA revealed heterozygous mutations in both probands. The Turkish patient and her affected relatives all had a heterozygous A to G transition at codon 557 (AAG-->GAG) of exon 10 of MEN1 that results in a replacement of lysine by glutamic acid. The Chinese index patient and one of her siblings had a heterozygous mutation at codon 418 of exon 9 (GAC-->TAT) that results in a substitution of aspartic acid by tyrosine. In conclusion, we have identified 2 novel missense mutations in the MEN1 gene.

Insulin secretion and sensitivity in acromegaly.

To examine the effect of excess growth hormones on carbohydrate metabolism, we studied glucose-stimulated insulin secretion and glucose utilization in 6 patients with acromegaly and 6 age-, sex- and weight-matched normal subjects. The levels of plasma glucose and serum insulin were determined during fasting and every 30 min up to 180 min after 75 g of oral glucose loading. In addition, plasma glucose, serum insulin and serum C-peptide were measured during euglycemic glucose clamp with insulin infusion of 40 mU/m2,min-1. The acromegalic patients had significantly higher mean levels of fasting plasma glucose (p less than 0.05) and insulin (p less than 0.01). After glucose loading for 3 h, the acromegalic patients also had a higher incremental area under the curve of plasma glucose (p less than 0.05) and serum insulin (p less than 0.05). However, no significant difference in the fasting molar ratio of C-peptide/IRI was noted between these two groups. During euglycemic clamp studies, the steady-state serum insulin levels were identical between the two groups. The glucose disposal rate was lower in acromegalics than in normal subjects (p less than 0.01). The results demonstrated that glucose intolerance, hyperinsulinemia and insulin resistance are present in acromegalic patients.

Thyrotropin-and prolactin--secreting pituitary tumor dissociated hormonal response to bromocriptine.

A 41-year-old male with recurrent hyperthyroidism resulting from pituitary tumor was studied. Because of recurrent hyperthyroidism, he had been treated with propylthiouracil for four years and had been operated. At the time of high serum thyroid hormone (T4: 20 micrograms/dl; T3:502 ng/dl), there was also elevated basal serum TSH level (55 microU/ml) which could not be suppressed by exogenous thyroid hormone administration. In addition, the serum TSH showed blunt response to intravenous TRH infusion. An elevated serum prolactin level was also observed (111 ng/ml). After bromocriptine administration (2.5 mg daily), the suppressibility of serum TSH level was found better than that of prolactin level. The existence of a TSH- and PRL-secreting pituitary tumor in this patient exhibited a dissociated hormonal response to low doses of dopaminergic agents.

Rapid quantification of adenosine cyclic 3',5'-monophosphate by competitive enzyme-linked immunosorbent assay.

A reliable and rapid enzyme-linked immunosorbent assay (ELISA) for cyclic AMP determination is described. Succinyl cyclic AMP, coupled to human albumin, was injected into rabbit to elicit antibodies to cyclic nucleotide hapten. Succinyl cyclic nucleotide to human albumin as immunogen or the cyclic AMP to porcine thyroglobulin as coating antigen was conjugated by a carbodiimide coupling procedure. The latter conjugate, captured to microplate with coating buffer and blocked with 0.8% gelatin for 30 minutes, was bound to antibody in inverse proportion to free cyclic AMP in a sample or standard. Bound antibody was then quantified with horseradish peroxidase-labelled goat antirabbit immunoglobulin and ABTS (2, 2'-Azinobis (3-ethylbenzthiazolinesulfonic Acid). Our results showed that concentration of both standard and sample cyclic AMP could be measured as low as 2.5 fmol/well (0.05 pmol/ml). The intra- and inter-assay coefficients of variation for samples were 6.0-8.0% and 8.9-9.5%, respectively. In addition, there was no cross-reaction of the antisera with ADP, ATP, 5'-AMP or cyclic GMP. Short period of incubation at room temperature seems as good as long period of incubation at 4 degrees C. The biological study demonstrated a consistency between increase in platelet-cyclic AMP generation after prostaglandin E1 stimulation and its biological effects. Our approach to ELISA is validated by showing agreement in levels, obtained in parallel by ELISA and RIA, of cyclic AMP content in extracts of prostaglandin E1-stimulated platelet cells.