Schilddrüsen-Hormon-Resistenz: unterschiedlicher klinischer Ausprägungsgrad bei fünf Patienten

Ziel: Erhöhte freie Schilddrüsenhormon-Konzentrationen bei nicht sup-primiertem TSH sind das biochemische Kennzeichen der Schilddrüsenhormon-Resistenz (RTH = Resistance to Thyroid Hormones). Bei der RTH liegt ein Rezeptordefekt in der ß-Untereinheit des Schilddrüsen-Hormon-Rezeptors vor. In der vorliegenden Arbeit wird über den unterschiedlichen klinischen und biochemischen Verlauf von fünf Patienten mit RTH berichtet. Methoden: Im Verlauf der letzten Jahre wurde der klinische Verlauf sowie die schilddrüsenspezifischen Parameter von fünf Patienten mit RTH untersucht. Ebenfalls erfolgte eine sonografische Untersuchung der Schilddrüse sowie die Bestimmung des Technetium-Uptakes unter Normal- und unter Suppressionsbedingungen. Die individuellen Exons des Schilddrüsen-Hormonrezeptor-ß-Gens wurden aus der Leukocyten-DNA mittels PCR amplifiziert und sequenziert. Ergebnisse: Bei allen Patienten zeigte sich eine Punktmutation in der T3-bindenden Domäne des Schilddrüsenhormonrezeptors. Bei zwei unserer Patienten handelt es sich um Spontanmutationen; bei drei der Patienten ist die RTH familiär bedingt. Drei von fünf Patienten hatten sich vor Diagnosestellung ein bzw. mehrmals einer Schilddrüsenoperation oder einer Radiojodtherapie wegen einer Struma bzw. wegen einer »therapierefraktären« Hyperthyreose unterzogen. Eine Patientin entwickelte zusätzlich eine Hyperthyreose vom Typ M. Basedow und mußte sich einer dritten Schilddrüsenoperation unterziehen. Beim sechs Jahre jüngeren Bruder besteht neben der RTH noch eine Hashimoto Thyreoiditis. Schlußfolgerung: Bei Patienten mit erhöhten freien Schilddrüsenhormonparametern und inadäquat erhöhten bzw. normalem TSH muß immer eine RTH in Erwägung gezogen werden. Der klinische Ausprägungsgrad der RTH ist äußerst variabel. Auch sollten bei Patienten mit RTH Schilddrüsenantikörperbestimmungen durchgeführt werden, um das Auftreten einer autoimmunen Schilddrüsenerkrankung nicht zu übersehen.

Unique alterations of thyroid function parameters after i.v. administration of alkylating drugs (cyclophosphamide and ifosfamide)

Alkylating drugs (cyclophosphamide and ifosfamide) have been in clinical use for the treatment of malignant diseases in the past. They are most useful anticancer agents and cyclophosphamide is also widely used for its immunosuppressive properties. However the effect of alkylating drugs on thyroid hormone parameters have not been evaluated so far. Three groups of patients were prospectively evaluated: Group I: 15 patients with Wegener's granulomatosis and 4 patients with severe scleritis received a single dose cyclophosphamide (15 mg/kg bw/day) and 250 mg prednisone i.v. Group II: 9 patients with malignant lymphomas were treated according to the IMVP 16-protocol. Patients received daily ifosfamide 1000 mg/m2 from day 0 to 4 and vepesid from day 0 to 2. Patients did not receive corticosteroids additionally. Group III: 6 patients with a relapse of malignant lymphomas received ifosfamide 1.500 mg/m2/day from day 0 to 4 i.v. and dexamethasone 40 mg/m2 as well as ara-c and etoposid. All patients received mesna to prevent hemorrhagic cystitis and odansetran or metoclopramide as antiemetic drugs. Alkylating drugs were given as a one hour infusion. Thyroid hormone parameters were determined before and on day 1, 2, 3, 4 after drug administration. We observed a significant increase in T4 and fT4 concentrations and a concomitant fall in TSH in either group one day after the administration of alkylating drugs. The effect was most pronounced in group III: T4 increased from 113 +/- 8 nmol/L to 175 +/- 8 (normal: 58-154) and fT4 from 14.0 +/- 0.8 to 24.8 +/- 2.5 pmol/L (normal 10-25). TSH dropped from 1.27 +/- 0.16 to 0.33 +/- 0.07 mU/L (normal 0.3-4). All changes were significant: p < 0.001. Two of the six patients displayed biochemical hyperthyroidism. Also reverse T3 increased significantly. Two days after drug administration a gradual normalization occurred. However, T3, Tg, TBG, Transthyretin and albumin levels did not change throughout the study period. One patient with coexisting hypothyroidism, who received his last thyroxine substitution therapy one day before the administration of cyclophosphamide (as in group I), also demonstrated an increase in T4, fT4 and rT3 and a fall in TSH concentrations. I.v. administrations of cyclophosphamide and ifosfamide induce a transient increase in T4 and fT4 concentrations and a concomitant fall of TSH in the presence of normal Tg, T3 and thyroid binding protein concentrations. These data suggest, that the changes are not due to a release of thyroid hormones from the thyroid itself, but is likewise related to a release of thyroxine from cellular pools such as the liver.

Influence of various modes of androgen substitution on serum lipids and lipoproteins in hypogonadal men

We investigated whether the androgen type or application mode or testosterone (T) serum levels influence serum lipids and lipoprotein levels differentially in 55 hypogonadal men randomly assigned to the following treatment groups: mesterolone 100 mg orally daily ([MES] n = 12), testosterone undecanoate 160 mg orally daily ([TU] n = 13), testosterone enanthate 250 mg intramuscularly every 21 days ([TE] n = 15), or a single subcutaneous implantation of crystalline T 1,200 mg ([TPEL] n = 15). The dosages were based on standard treatment regimens. Previous androgen substitution was suspended for at least 3 months. Only metabolically healthy men with serum T less than 3.6 nmol/L and total cholesterol (TC) and triglyceride (TG) less than 200 mg/dL were included. After a screening period of 2 weeks, the study medication was taken from days 0 to 189, with follow-up visits on days 246 and 300. Before substitution, all men were clearly hypogonadal, with mean serum T less than 3 nmol/L in all groups. Androgen substitution led to no significant increase of serum T in the MES group, subnormal T in the TU group (5.7 +/- 0.3 nmol/L), normal T in the TE group (13.5 +/- 0.7 nmol/L), and high-normal T in the TPEL group (23.2 +/- 1.1 nmol/L). 5 alpha-Dihydrotestosterone significantly increased in all treatment groups compared with baseline. Compared with presubstitution levels, a significant increase of TC was observed in all treatment groups (TU, 14.4% +/- 3.0%; MES, 18.8% +/- 2.5%; TE, 20.4% +/- 3.0%; TPEL, 20.2% +/- 2.6%). Low-density lipoprotein cholesterol (LDL-C) also increased significantly by 34.3% +/- 5.5% (TU), 46.4% +/- 4.1% (MES), 65.2% +/- 5.7% (TE), and 47.5% +/- 4.3% (TPEL). High-density lipoprotein cholesterol (HDL-C) showed a significant decrease by -30.9% +/- 2.8% (TU), -34.9% +/- 2.5% (MES), -35.7% +/- 2.6% (TE), and -32.5% +/- 3.5% (TPEL). Serum TG significantly increased by 37.3% +/- 11.3% (TU), 46.4% +/- 10.3% (MES), 29.4% +/- 6.5% (TE), and 22.9% +/- 6.7% (TPEL). TU caused a smaller increase of TC than TE and TPEL, whereas the parenteral treatment modes showed a lower increase of TG. There was no correlation between serum T and lipid concentrations. Despite the return of serum T to pretreatment levels, serum lipid and lipoprotein levels did not return to baseline during follow-up evaluation. In summary, androgen substitution in hypogonadal men increases TC, LDL-C, and TG and decreases HDL-C independently of the androgen type and application made and the serum androgen levels achieved. Due to the extended washout period for previous androgen medication and the exclusion of men with preexisting hyperlipidemia, this investigation demonstrates more clearly than previous studies the impact of androgen effects on serum lipids and lipoproteins. It is concluded that preexisting low serum androgens induce a "male-type" serum lipid profile, and increasing serum androgens further within the male normal range does not exert any additional effects. The threshold appears to be above the normal female androgen serum levels and far below the lower limit of normal serum T levels in adult men. These findings may have considerable implications for the use of androgens as a male contraceptive and for androgen therapy in elderly men.

Thyroid antibodies in children of mothers with auto-immune thyroid disease

In a cross-sectional study, 29 children aged between 1 month and 15.3 years (average age 6.8 years) born to mothers with Graves disease or Hashimoto thyroiditis were examined clinically, biochemically, and by sonography of the thyroid gland. At the time of examination all children were clinically euthyroid. Tests of thyroid peroxidase antibody, thyroglobulin antibody, TSH receptor antibody and free thyroxine (fT4) gave normal results. In 3 children subclinical hypothyroidism with elevated TSH and normal fT4 concentrations were found; one of these children had a minor decrease of total thyroxine. Three children with otherwise normal test results had marginally elevated triiodothyronine concentrations. Increased antibody titres were present in 8 out of 29 children. TSH function-blocking antibodies were elevated in 8 cases. In addition, cytotoxic antibodies were found in one of the children. The distribution pattern of antibodies was different in each child and unrelated to the type of maternal thyroid disease.

CONCLUSION

Children of mothers with auto-immune thyroid disease often have thyroid antibodies without signs of thyroid disease. Whether antibody-positive children have an increased risk of developing thyroid disorders later in life must be examined in a longitudinal study.

Is there a methimazole dose effect on remission rate in Graves' disease? Results from a long-term prospective study. The European Multicentre Trial Group of the Treatment of Hyperthyroidism with Antithyroid Drugs

OBJECTIVE

The optimal antithyroid drug regimen for Graves' disease remains a matter of controversy. The European Multicentre Trial Group has investigated the effects of methimazole drug dose on the long-term outcome of Graves' disease.

DESIGN

Extended follow-up of patients from a prospective multicentre trial, designed to study methimazole dose effects on the outcome of Graves' disease. We have reported previously that the relapse rates did not differ after a medication-free observation period of 12 months; the relapse rates were 37% and 38%, respectively. In this paper, we describe the outcome in these patients after a mean observation period of 4.3 +/- 1.3 years and have looked for potential predictors of this outcome.

PATIENTS

Three hundred and thirteen patients with Graves' disease were randomized to treatment with a constant dose of 10 or 40 mg of methimazole for 1 year, with levothyroxine supplementation as required.

MEASUREMENTS

At the time of inclusion into the trial: thyroid size, T4, T3, TSH-binding inhibiting immunoglobulins, urinary iodide excretion, thyroid uptake, Crook's therapeutic index of hyperthyroidism (a measure of clinical disease severity). At the time of follow-up examination: TSH, T4, T3, thyroid size, thyroid ultrasound, THS-binding inhibiting immunoglobulins.

RESULTS

The overall relapse rate was 58%. There was no difference in relapse rates between patients treated with either 10 or 40 mg of methimazole (58.3 vs. 57.8%). Five patients had become spontaneously hypothyroid, without obvious relationship to antithyroid drug dose. Patients who relapsed and patients who remained in remission did not differ with respect to: age, goitre size, ophthalmopathy, median iodine excretion, serum T4 or serum T3, Crook's therapeutic index and thyroid uptake at the time of study entry. Thus, none of these variables was potentially suitable for predicting outcome. This finding was confirmed by Cox's proportional hazard regression. Thyroid volume, measured by ultrasound, did not differ between patients in remission and patients with relapse. There was no difference in the course of endocrine eye signs, in the requirement for steroid and radiotherapy for eye signs, or in thyroid echostructure between patients in the 10 and in the 40 mg group, nor was serum TSH different in patients who had remained in remission (0.8 +/- 0.6 mU/l in the 10 mg group, 1.0 +/- 0.8 mU/l in the 40 mg group).

CONCLUSIONS

The dose of methimazole in Graves' disease therapy can safely be kept to the minimal required dose. This will provide the same chance of remission as higher doses, and provide the best balance of risk and benefit.

Effect of small doses of iodine on thyroid function in patients with Hashimoto's thyroiditis residing in an area of mild iodine deficiency

OBJECTIVE

Several studies have suggested that iodine may influence thyroid hormone status, and perhaps antibody production, in patients with autoimmune thyroid disease. To date, studies have been carried out using large amounts of iodine. Therefore, we evaluated the effect of small doses of iodine on thyroid function and thyroid antibody levels in euthyroid patients with Hashimoto's thyroiditis who were living in an area of mild dietary iodine deficiency.

METHODS

Forty patients who tested positive for anti-thyroid (TPO) antibodies or with a moderate to severe hypoechogenic pattern on ultrasound received 250 microg potassium iodide daily for 4 months (range 2-13 months). An additional 43 patients positive for TPO antibodies or with hypoechogenicity on ultrasound served as a control group. All patients were TBII negative.

RESULTS

Seven patients in the iodine-treated group developed subclinical hypothyroidism and one patient became hypothyroid. Three of the seven who were subclinically hypothyroid became euthyroid again when iodine treatment was stopped. One patient developed hyperthyroidism with a concomitant increase in TBII titre to 17 U/l, but after iodine withdrawal this patient became euthyroid again. Only one patient in the control group developed subclinical hypothyroidism during the same time period. All nine patients who developed thyroid dysfunction had reduced echogenicity on ultrasound. Four of the eight patients who developed subclinical hypothyroidism had TSH concentrations greater than 3 mU/l. In 32 patients in the iodine-treated group and 42 in the control group, no significant changes in thyroid function, antibody titres or thyroid volume were observed.

CONCLUSIONS

Small amounts of supplementary iodine (250 microg) cause slight but significant changes in thyroid hormone function in predisposed individuals.

Efficacy and safety of iodine in the postpartum period in an area of mild iodine deficiency

BACKGROUND

Iodine deficiency (even moderate) plays a major role in pregnancy associated goiter development, which is only party reversible after pregnancy. The prevalence of post partum thyroiditis is reported to be slightly lower in areas of iodine deficiency. Thus iodine supplementation may be effective in decreasing pregnancy associated increase in thyroid volume, but enhances the risk of increasing the prevalence of thyroid dysfunction in the post partum period. Therefore, we evaluated the effect of iodine supplementation (with two different doses: 50 microg and 250 microg) on the prevalence of post partum thyroiditis and the decrease in thyroid volume up to 8 months post partum in an area of mild iodine deficiency.

PATIENTS AND METHODS

Thyroid volume of 56 women was evaluated 5 days and 3 months after delivery (study I). In an intervention study (Study II) 70 women were randomized to receive 50 or 250 microg of potassium iodide for a period of 8 months post partum beginning five days after delivery. Thyroid volume, the echogenecity of the thyroid gland, thyroid hormone parameters (T4, T3, fT4, TSH) and thyroid antibodies (TPO and Tg-Ab) were measured 5 days, 3 and 8 months after delivery.

RESULTS

A total number of 11 women developed postpartum thyroid dysfunction: 4 women developed manifest thyroid dysfunction (3 hyperthyroidism and 1 hypothyroidism) 3 months post partum. The remaining seven had subclinical hypo- or hyperthyroidism. All changes were clinically mild and transient as evidenced by normalization of thyroid hormone parameters on reexamination at 8 months. Among the eleven, 6 women in the 50 microg iodine group and 5 women of the 250 microg iodine group developed thyroid dysfunction, suggesting that the iodine dose did not affect post partum thyroiditis. The administration of only 50 microg iodine was associated with a significant fall of thyroid size already 3 months after delivery (25.4 +/- 1.5 ml (mean +/- sem) to 18.2 +/- 1.25 p <0.001). The application of 250 microg iodine was equally effective. 8 months post partum a slight but further decrease could be demonstrated. On the other hand, in study I no significant reduction in thyroid volume was observed in women receiving no supplementary iodine (thyroid volume at delivery 29 +/- 2.2 ml; at 3 months 27.5 +/- 3.0 ml.

CONCLUSION

The administration of supplementary iodine (up to 250 microg) to an unselected population, residing in an area of mild iodine deficiency, in the post partum period is save as indicated by a prevalence of 5.7% manifest thyroid dysfunction. These changes are clinically mild and transient. Even the amount of 50 microg of iodine supplementation seems to by very efficient in reducing pregnancy associated increments in thyroid volume.

Sequential changes of biochemical bone parameters after kidney transplantation

BACKGROUND

Persistent hyperparathyroidism after renal transplantation (Rtx) has been reported in several studies. However these studies evaluated biochemical bone parameters either only during a short time period (up to 6 months) or for a longer time period, but with long intervals in between. Therefore, we prospectively evaluated biochemical bone parameters of kidney-transplant recipients at short intervals for 2 years after surgery.

METHODS

Biochemical bone parameters were prospectively investigated in 129 patients 2, 3, 5, 8, 12, 18 and 24 months after Rtx. All patients received prednisone and cyclosporin A as immunosuppressive therapy, and 75 patients also received azathioprine. None of the patients was treated with calcium, phosphorus, or vitamin D preparations.

RESULTS

Serum creatinine levels decreased from 166.8 +/- 5.4 mumol/l to 140.0 +/- 4.9 two years after Rtx; (data are expressed as mean +/- s.e.m.). Serum phosphorus levels increased slightly from 0.9 +/- 0.022 mmol/l to 0.98 +/- 0.025 (12 m), but remained within the lower normal range. We observed a rise in total and albumin adjusted calcium concentrations 3 months after Rtx. 52% of all patients had serum calcium levels above 2.62 mmol/l (upper normal limit in our laboratory) 3 months after renal transplantation with a gradual decrease thereafter. There was no correlation of calcium and PTH levels. We observed a significant rise in biochemical bone parameters from 2 to 5 months after renal transplantation (P < 0.001): alkaline phosphatase (AP) increased from 164.3 +/- 9.4 to 236 +/- 12.7 U/l (normal 50-180), bone specific alkaline phosphatase (BAP) rose from 17.7 +/- 1.36 to 23.2 +/- 1.7 ng/ml (normal:4-20) and osteocalcin (OC) increased from 20.2 +/- 1.5 to 26.7 +/- 1.9 ng/ml (normal 4-12). AP and BAP levels values normalized 12 months after renal transplantation, whereas OC was still above normal throughout the study period. Patients were subdivided into two groups: those with good and those with impaired graft functions. Patients with good graft function had stable serum creatinine levels (< or = 132 mumol/l or < or = 1.5 mg/dl) well below the mean serum creatinine concentration during the study period. The significant changes in AP, BAP, and OC occurred irrespective of renal function. However, patients with impaired graft function (n = 65) had significantly higher PTH-levels (70 pg/ml higher) than patients with good graft function (n = 64), P < 0.01. PTH was positively correlated with serum creatinine (r = 0.81, P < 0.001). Moreover, patients with low 25 (OH) vitamin D levels (n = 63) had significantly higher PTH concentrations (between 40 and 80 pg/ml, P < 0.01) throughout the study period compared to patients (n = 66) with a sufficient 25(OH)D supply irrespective of graft function. There was a negative correlation of 25 (OH)D levels and PTH; (r = -0.49, P < 0.001). 1,25(OH)2D3 (evaluated in 24 patients) levels increased from 46.5 +/- 6.6 to 76.9 +/- 7.6 pg/ml (normal:35-90) at 12 months.

CONCLUSION

Hypercalcaemia is a common phenomenon in the early period after kidney transplantation and occurs in the presence of low normal phosphorus levels. It is most probably related to improved PTH action and 1-hydroxylation of vitamin D. The rise in biochemical bone parameters between 3 and 5 months occurs irrespective of graft function and normalization is only achieved 1 year after transplantation. PTH is constantly elevated for up to 2 years after kidney transplantation and is most probably related (a) to impaired graft function and (b) to suboptimal 25 OH vitamin D supply.

[Thyroid hormone resistance: variable clinical manifestations in five patients]

AIM

The syndrome of thyroid hormone resistance (RTH) is characterised by elevated circulating thyroid hormones, unsuppressed TSH levels and peripheral refractoriness to hormone action. Patients with RTH may be clinically hyperthyroid if the pituitary gland is more insensitive than other tissues to thyroid hormones. More often, patients have peripheral tissue resistance as well and are euthyroid. RTH is related to point mutations in the T3-binding domain of the beta-receptor gene. We report the variable clinical and biochemical features of five patients with RTH.

METHODS

Five patients with RTH were clinically and biochemically evaluated: thyroid tests were done at baseline, after TRH stimulation and after T3-suppression test. Thyroid ultrasound was performed as well. Individual exons of the thyroid hormone receptor beta gene were amplified from leucocyte DNA in these patients using the polymerase chain reaction (PCR).

RESULTS

Sequence analysis identified a single point mutation at a certain nucleotide position. This corresponds to aminoacids substitutions at one position in the predicted aminoacid sequence. RTH was familial in three individuals and sporadic in two. Three of the patients underwent thyroid surgery or radioiodine treatment because of recurrent goiter and/or "refractory hyperthyroidism". Moreover, one of our patients with RTH developed also hyperthyroidism due to Graves disease and underwent thyroid surgery for the third time. Her brother, besides RTH, demonstrated strongly positive TPO-antibodies and a hypoechogenic pattern on ultrasound. So the diagnosis of Hashimoto's thyroiditis was made.

CONCLUSIONS

RTH has to be considered in all patients with inappropriate TSH secretion. The clinical manifestation of patients with RTH is heterogenous. Thyroid antibody measurements should be performed regularly in order to detect the development of coexisting autoimmune thyroid disease.

Testosterone substitution normalizes elevated serum leptin levels in hypogonadal men

The ob gene product leptin (OB) is a feedback signal from the adipocyte to the hypothalamus and is involved in regulation of food intake and energy expenditure in rodents. A major determinant of serum OB levels is fat mass. Several studies suggest that men have lower OB levels than women even after adjustment for percent body fat. We, therefore, investigated the influence of testosterone (T) substitution in hypogonadal men on serum OB levels. Hypogonadal men with T levels of 3.6 nmol/L or less and off substitution therapy for at least 3 months were assigned to two treatment groups: testosterone enanthate (TE; 250 mg, i.m., every 21 days; n = 10) or a single s.c. implantation of 1200 mg crystalline T (TPEL; n = 12). Blood samples for determination of T, 5 alpha-dihydrotestosterone (DHT), sex hormone-binding globulin, and 17 beta-estradiol were obtained before therapy and then every 21 days until day 189 and at follow-up visits on days 246 and 300. Serum OB levels were assessed on days 0, 42, 84, 126, 168, and 300. OB levels were referred to a normal range for men based on the analysis of OB levels in 393 adult men. Substitution with T led to a large rise in T and DHT in both groups compared to baseline values (average T, days 21-189: TE, 14.33 +/- 2.63 nmol/L; TPEL, 24.98 +/- 1.64; average DHT, days 21-189: TE, 4.20 +/- 0.57 nmol/L; TPEL, 5.11 +/- 0.56; P < or = 0.05). Concomitantly, 17 beta-estradiol increased in both groups, and sex hormone-binding globulin levels were significantly decreased. At baseline, serum OB levels in hypogonadal men were 3-fold elevated compared to those in normal men (12.39 +/- 2.93 micrograms/L vs. 4.28 +/- 0.52; P < 0.01) and not different between groups (TE, 13.7 +/- 5.6; TPEL, 11.3 +/- 2.9 micrograms/L). This elevation was retained after adjustment for body mass index in the normal control group [TE, 1.45 +/- 0.51 SD score (P < 0.0001); TPEL, 0.98 +/- 0.35 SD score (P < 0.0008)]. During T substitution serum OB was completely normalized (trough levels: TE, 4.6 +/- 1.0 micrograms/L; TPEL 4.3 +/- 0.9 micrograms/L). In multiple regression analysis, the androgen (T plus DHT)/estrogen ratio was the only significant determinant of OB levels (r = -0.32; P < 0.01). At baseline, OB levels did not correlate with body mass index, but during substitution, the correlation was considerably improved. We conclude that hypogonadal men exhibit elevated OB levels that are normalized by substitution with T. The only determinant of OB levels was the androgen/estrogen ratio, indicating a major influence of sex steroids on OB production. The interaction of T and OB might be part of a hypothalamic-pituitary-gonadal-adipose tissue axis that is involved in body weight maintenance and reproductive function.

Effects of various modes of androgen substitution therapy on erythropoiesis

In order to investigate differential effects of androgens on erythropoiesis, 55 men with clincally and biochemical confirmed hypogonadism were randomly assigned to 4 groups receiving different forms of androgen substitution: Mesterolone (MES) 100 mg/d, testosterone undecanoate (TU) 160 mg/d, testosterone enanthate (TE) 250 mg i.m./21 days or 1200 mg crystalline testosterone (TPEL) subcutaneously implanted at study begin. Previous testosterone medication had been suspended at least 3 months prior to study begin. Testosterone (T), dihydrotestosterone (DHT), hemoglobin (HB) and hematocrit (HC) were assessed before, during and after substitution of androgens. MES did not increase serum T and TU raised average T levels during substitution to 5.7 +/- 0.3 nmol/l, thereby doubling baseline concentrations. TE resulted in a 6fold increase of baseline T yielding 13.5 +/- 0.7 nmol/l and TPEL increased serum T 8.5fold to 23.2 +/- 1.1 nmol/l. Average DHT levels during substitution were 4.3 +/- 0.2 (MES), 3.3 +/- 0.2 (TU), 4.0 +/- 0.4 (TE) and 5.5 +/- 0.4 (TPEL) nmol/l. The groups receiving TPEL, TU or TE showed a significant rise of HB and HC compared to baseline, whereas in the MES group these parameters did not change significantly. MES increased HB by 5.6 +/- 1.8 g/l, TU by 12.7 +/- 2.8 g/l, TE by 21.1 +/- 2.6 g/l and TPEL by 21.7 +/- 4.0 g/l. HC was raised by 1.8 +/- 0. 4% in the MES group, 3.9 +/- 1.1% in the TU group and 6.4 +/- 0.9% and 6.5 +/- 1.6% in the TE and TPEL groups, respectively. Except for 1 subject in the TPEL group, the HB and HC stayed within the normal limits. We conclude that, T, but not DHT, stimulates erythropoiesis in a dose dependent manner. T levels within the low normal range for men are required for maximal stimulation of erythropoiesis.

Significant changes in thyroid hormone parameters after a four week recreation period at the North Sea without alterations of iodine intake

Many studies have been carried out evaluating thyroid hormone parameters in patients suffering from various illnessess. However data on thyroid function after a recreation period are missing. Therefore we evaluated thyroid hormone parameters in 178 patients (mostly suffering from chronic obstructive lung disease) undergoing a four week recreation period in a health spa on the island Borkum at the North Sea. We observed a subtle, but significant increase in basal TSH concentrations from 1.20 mU/l (median) to 1.50 mU/l; (p<0. 001) and a fall in T4 values from 97.5 +/- 17.7 nmol/l (mean +/- SD) to 90.3 +/- 17.0 (p<0.001) and T3 from 2.21 +/- 0.33 nmol/l to 2.09 +/- 0.33 (p<0.001). However no increase in iodine intake occurred during the four weeks: median iodine excretion 61 microg iodine/g creatinine at the beginning vs 65 microg iodine/g creatinine at the end.

IN CONCLUSION

a recreation period at the North Sea is associated with subtle but significant changes in thyroid hormone parameters. However no increase in iodine intake occurs during the four week observation period.

Triiodothyronine (T3) reflects renal graft function after renal transplantation

OBJECTIVE

Abnormalities in thyroid function are observed in patients with end stage renal disease. However, there are no data available evaluating sequential changes of thyroid function after renal transplantation. Therefore, we have studied thyroid hormone function in the immediate post-operative period after renal transplantation in order to determine the relationship between improving renal function and changes in thyroid hormone economy.

DESIGN AND PATIENTS

Thyroid function was evaluated in 22 patients before and on days 1, 3, 7 and 15 after renal transplantation. All patients received prednisone and cyclosporin as immunosuppressive therapy. Twelve patients with normal renal function undergoing comparable surgical procedures served as a control group.

MEASUREMENTS

Serum creatinine and thyroid hormone parameters (total T4, total T3, free T4, free T3, thyroxin binding globulin (TBG), reverse T3, T3 sulphate and TSH) were measured.

RESULTS

According to post-operative kidney function after renal transplantation, patients could be subdivided into three groups: five patients had primary graft function (group I); seven patients had delayed graft function because of acute renal failure (group II); 10 patients had delayed graft function requiring high doses of prednisone and some also of OKT3 because of acute rejection (group III). There was a significant fall in T3 and T4 concentrations with a concomitant rise in reverse T3 in all patients up to 3 days after renal transplantation. However, only patients in group I reached pre-operative values on day 15 after renal transplantation (serum creatinine 167 +/- 52 microM), whereas patients in group II (creatinine 609 +/- 118 microM) and group III (creatinine 839 +/- 71 microM) continued to have T3 concentrations well in the hypothyroid range (group I, 1.68 +/- 0.28 nM) vs 0.87 +/- 0.09 nM in group II and 0.76 +/- 0.10 nM in group III; P < 0.01). Serum T4 concentrations were also low in group III (47.7 nM vs 100.2 nM in group I; P < 0.05) 15 days after renal transplantation. These changes were accompanied by a concomitant fall in T3/TBG ratio and in free T3. Elevated reverse T3 returned to normal values in all groups on the 15th day after renal transplantation. TSH fell significantly on the first post-operative day, but did not return to pre-operative values in renal transplantation patients. In the control group, TSH did not change during the study period. T3 sulphate, known to be elevated in chronic renal failure, remained above normal in all patients irrespective of graft function during this study period.

CONCLUSIONS

T3 concentrations reflect renal graft function after renal transplantation. T3 is below normal in patients with delayed graft function (acute renal failure or acute rejection). The post-operative period (up to 3 days after renal transplantation) is associated with a low T3 syndrome. TSH does not return to pre-operative values even in patients with primary graft function. This might be due to the administration of prednisone. T3-sulphate is elevated before and after renal transplantation irrespective of graft function.

Influence of coronary artery bypass surgery on thyroid hormone parameters

The postoperative period after cardiac surgery with cardiopulmonary bypass (CPB) is associated with a low T3 syndrome, i.e. low T3 and fT3 concentrations in the presence of normal T4 and TSH concentrations. So far, results from studies evaluating thyroid function during and after CPB are rather conflicting. We therefore evaluated prospectively thyroid function in 28 patients before, during and up to 3 days after coronary artery bypass surgery. We could demonstrate the most significant changes in thyroid hormone concentrations on day 1 after CPB (low T3 and fT3 concentrations, elevated rT3 concentrations in the presence of a significant fall of TSH). T3 fell from 1.93 to 0.6 nmol/1 and fT3 from 5.5 to 1.42 pmol/1. Those patients with low cardiac output syndrome after surgery had significantly lower T3 concentrations than patients without this complication. Moreover, those patients, who already had significant lower T3 values prior to CPB, also demonstrated low T3 concentrations on day 1 after CPB. Cortisol usually has a suppressive effect on TSH secretion. However, the effect of cortisol on TSH in patients undergoing CPB seems to be not that important: those patients with high endogenous cortisol concentrations on day 1 after CPB had similar TSH values to those patients with only slightly elevated cortisol concentrations. Also, the application of high doses of catecholamines seems to have only minor effects on TSH secretion, because those patients requiring high doses of dopamine over a prolonged time period had essentially the same TSH values after CPB. Patients who had been exposed preoperatively to high doses of iodine did not demonstrate significantly different thyroid hormone concentrations.

IN CONCLUSION

We could demonstrate that CPB induces a low T3 syndrome up to 3 days after surgery. Those patients with low T3 concentrations prior to surgery demonstrate postoperatively a more severe degree of nonthyroidal illness (NTI). Catecholamines and cortisol seem to have only minor effects on the TSH secretion after CPB. The influence of a previous iodine contamination is negligible.

Pharmacokinetics and pharmacodynamics of subcutaneous testosterone implants in hypogonadal men

OBJECTIVE

There are advantages and disadvantages with all of the presently available types of testosterone replacement for hypogonadal men. We performed this investigation to establish detailed data about the pharmacokinetics, pharmacodynamics, feasibility and side-effects of subcutaneously implanted testosterone (T) pellets.

DESIGN AND MEASUREMENT

In a single-dose, open-label, non-randomized study, 6 T-pellets, each containing 200 mg of fused crystalline T, were implanted in the subdermal fat tissue of the lower abdominal wall of 14 hypogonadal men. Blood samples for determination of T, LH, FSH, 5 alpha-dihydrotestosterone (DHT), sex hormone binding globulin (SHBG) and oestradiol (E2) were obtained at 0, 0.5, 1, 2, 4, 8, 12, 24, 36, 48 hours and on day 21 after implantation and then every 3 weeks until day 189, and on days 246 and 300 during follow-up. In another 36 hypogonadal men the feasibility and side-effects of T-pellets were evaluated.

PATIENTS

Fourteen patients participated in the detailed pharmacokinetic study and another 36 patients in the assessment of feasibility and side-effects. All patients (age range 18-61 years) suffered from primary or secondary hypogonadism (T < 3.6 nmol/l).

RESULTS

The pharmacokinetic study in 14 hypogonadal men revealed an initial short-lived burst release of T with a peak concentration of 49.0 +/- 3.7 nmol/l at 0.5 +/- 0.13 days which was followed by a stable plateau lasting until day 63 (day 2, 35.2 +/- 2.3; day 63, 34.8 +/- 2.6 nmol/l). Thereafter serum T gradually declined and was close to baseline concentrations on day 300. Apparent terminal elimination half-life (t1/2) was 70.8 +/- 10.7 days and apparent mean residence time 87.0 +/- 4.5 days. On average, serum T was below 10 nmol/l after 180 days. Absorption of T followed a zero-order release kinetic with an absorption half-time of 74.7 days (95% confidence interval: 71.1-78.5) and was almost complete by day 189 (95.9 +/- 0.84%). Serum DHT and E2 were significantly elevated from day 21 to day 105 and correlated significantly with T (DHT, r = 0.65, P < 0.0001, E2, r = 0.67, P < 0.0001). SHBG was significantly decreased from day 21 to day 168. In 6 men with primary hypogonadism T suppressed LH and FSH to the eugonadal range from day 21 to 126 and 42 to 105, respectively, with nadirs occurring at day 84 (LH) and day 63 (FSH). LH and FSH were highly inversely correlated with T (r = -0.47 and -0.57). The only side-effect observed during 112 implantations in the total group of 50 men were 6 local infections (5.4%) leading to extrusion of 5 pellets in 3 men. When given the choice, all patients except one preferred T-pellets to their previous T medication for permanent substitution therapy.

CONCLUSION

T-pellets are the androgen formulation with the longest biological action and strongest pharmacodynamic efficacy in terms of gonadotrophin suppression. The pharmacokinetic features are advantageous compared to other T preparations and the patient acceptance is high.

Differential presentation of cortical and trabecular peripheral bone mineral density in acromegaly

Growth hormone (GH) has been suggested as a therapeutic tool for the treatment of osteopenia. To assess the differential influence of growth hormone on cortical and trabecular bone, bone mineral densities (BMD) of the ultradistal radius were determined in 18 men and 19 women with clinically and biochemically confirmed acromegaly using peripheral computed tomography and a specialized scanner (Stratec XCT 900). The results were expressed in equivalents to hydroxyl-apatite (mg/ccm) and compared with the BMD of healthy controls (17 men, 34 women). Cortical bone mineral density was significantly higher in acromegalic women (295.2 +/- 18.4, X +/- SEM) and men (339.4 +/- 21.2) compared to healthy women (243.0 +/- 12.8) and men (272.2 +/- 15.9). In contrast, trabecular BMD did not differ between acromegalic patients (men: 161.0 +/- 16.1; women: 116.5 +/- 10.5) and controls (men: 158.0 +/- 12.2; women: 134.1 +/- 6.3). Acromegalic women showed a significant correlation between insulin-like growth factor (IGF-I) expression and cortical BMD, whereas in acromegalic men GH levels correlated significantly with cortical BMD. Greatly increased serum osteocalcin levels in both, acromegalic men (15.5 +/- 3.3 ng/ml) and women (12.9 +/- 1.8) compared to controls (men: 6.7 +/- 1.7; women: 7.7 +/- 1.0) indicates the activation of osteoblastic bone formation. This study revealed an increase in cortical BMD at the forearm; in acromegalic patients; though trabecular BMD did not differ from controls. The differential mineralization of cortical and trabecular bone in acromegaly may be indicative of the detrimental effect accompanying pituitary insufficiency can have on trabecular bone, despite substitution therapy, but could also be due to different reactivity of cortical and trabecular bone to GH and/or IGF I. The observable increase of bone mineral density in acromegaly suggests a potential use for GH in treating osteoporosis.

Response to methimazole in Graves' disease. The European Multicenter Study Group

OBJECTIVE

A variety of regimens continue to be used in the treatment of Graves' disease with antithyroid drugs. We have investigated the factors which determine the initial response to methimazole (time until euthyroidism is achieved) in Graves' disease.

PATIENTS

Five hundred and nine patients with Graves' disease in different European countries with normal and subnormal iodine supply. Patients were randomized to treatment with either 10 or 40 mg of methimazole per day for one year, with levothyroxine supplementation as required to maintain euthyroidism. Investigations were carried out before treatment and at 3 and 6 weeks and 3, 6, 9 and 12 months.

MEASUREMENTS

Response was assessed by serial measurements of serum thyroid hormones. TSH receptor antibodies, thyroid autoantibodies and urinary iodide excretion were measured centrally. Twenty-minute thyroid uptake was measured by standard techniques. Data were collected and analysed centrally. Standard techniques as well as a stepwise logistic regression model were used to examine the relations between methimazole dose, age, goitre size, presence of endocrine eye signs, thyroid hormone levels, urinary iodide excretion, thyroid uptake, index of disease severity (Crooks), presence of TSH receptor antibodies and duration of the hyperthyroid phase.

RESULTS

Within 3 weeks, 40.2% of patients responded to 10 mg of methimazole and 77.5% responded within 6 weeks. The corresponding figures for 40 mg of methimazole were 64.6 and 92.6%. Significant associations were found between duration of hyperthyroidism and the following variables: goitre size, urinary iodide excretion, methimazole dose, presence of TSH receptor antibodies (TBIAb), index of disease severity (Crooks) and pretreatment thyroid hormone levels. Response to methimazole was delayed in patients with large goitres, iodine excretion of > or = 100 micrograms/g creatinine, high pretreatment thyroid hormone levels, elevated levels of TBIAb and treatment with only 10 mg of methimazole. In the 10-mg group, 46% of patients were euthyroid within 3 weeks when urinary iodide was < 50 microgram/g of creatinine, and only 27% when iodide was above 100 micrograms/g. By stepwise logistic regression, the main factors for the response to methimazole were daily dose, pretreatment T3 levels, and goitre size.

CONCLUSION

Methimazole dose, pretreatment serum T3 levels, and goitre size are the main determinants of the therapeutic response to methimazole in Graves' disease, at least in areas comprising low, subnormal and normal iodine supply.

Effectiveness of prophylactic therapy on goiter recurrence in an area with low iodine intake--a sonographic follow-up study

There is no agreement as to whether or not drug treatment after surgery for nodular goiter is effective in preventing recurrence of goiter. Data about recurrences in areas of marginally low iodine intake (like Germany) vary widely. Therefore, we performed a retrospective study in 104 patients who had been treated surgically because of benign uninodular or multinodular goiter. The mean follow-up period was 6.4 years (minimal 1 year) with at least three examinations. Thyroid ultrasound with volumetric analysis was recorded in each patient. Thirty-two patients did not receive any prophylaxis, 50 patients were treated with L-thyroxine, 17 patients with a combination of L-thyroxine and iodine and 5 patients with iodine alone. Recurrence of goiter was documented in 28.0% of the untreated patients and in 8.9% of the patients on prophylaxis (P < 0.05). The mean increase of thyroid volume was 7.3 ml versus 3.1 ml in patients without versus with prophylactic drug treatment (not significant). No significant correlation was found between the increase of thyroid volume and age of the patients, follow-up time, or initial thyroid volume, respectively. These data clearly demonstrate the effectiveness of prophylactic drug therapy to prevent recurrence of goiter after thyroid surgery in an iodine-deficient area.

Low interleukin-2 receptor levels in serum of patients with insulin-dependent diabetes

Interleukin-2 receptors are released in the circulation in response to antigenic ro mitogenic stimulation of T-lymphocytes. Abnormal serum interleukin-2 receptor levels have been found in young children with type 1 diabetes and "prediabetes." We measured interleukin-2 receptor levels in 17 patients with newly diagnosed type 1 diabetes, 21 patients with long-standing type 1 diabetes, 19 patients with long-standing type 2 diabetes, 19 islet-cell antibody positive nondiabetic polyendocrine patients, 12 islet-cell antibody-positive first-degree relatives of patients with type 1 diabetes and compared the results to age- and sex-matched normal controls. We found significantly lower interleukin-2 receptor levels in patients with newly diagnosed and long-standing type 1 diabetes compared to normal controls (87 +/- 11 and 93 +/- 11 vs. 142 +/- 25 and 132 +/- 40 U/ml, P < 0.001 and P < 0.01). There were no significant differences in interleukin-2 receptor levels between prediabetic groups and normal controls or patients with long-standing type 1 or type 2 diabetes. There was no correlation between glycosylated hemoglobin, blood glucose levels, and interleukin-2 receptor in the groups with long-standing type 1 or type 2 diabetes. We conclude that patients with type 1 diabetes have low interleukin-2 receptor serum levels. This phenomenon is acquired close to disease onset and is unlikely to be an early markers of type 1 diabetes.

Treatment of prolactinoma patients with the new non-ergot dopamine agonist roxindol: first results

We studied the effects of the new non-ergot D2-dopamine agonist roxindol for the treatment of human prolactinomas. Roxindol is a non-ergot drug with additional 5-hydroxytryptamine type 1 A agonist and serotonin reuptake inhibitory activity. Ten patients with prolactin-secreting pituitary adenomas received roxindol three times daily at a dosage of 7.5-30 mg/day for at least 4 weeks according to a prospective protocol. All patients but one had received oral bromocriptine previously without normalization of prolactin levels. Serum prolactin profiles were analyzed once a week during the first month of therapy and at 4-week intervals thereafter. Mean baseline serum prolactin was suppressed from 23,000 +/- 13,600 mU/l (range 1500-141,000 mU/l; 20 mU/l = 1 microgram/l) by 37 +/- 11% after 1 week, by 49 +/- 9% after 4 weeks, and by 65 +/- 11% (n = 8) after 24 weeks of treatment. Serum prolactin was normalized in two patients. A tumor volume reduction of 20-25% was obtained in two subjects. Compared with previous treatment with oral bromocriptine the decrease in serum prolactin was comparable. In contrast, tolerance of roxindol was superior in five of seven patients with major side effects with bromocriptine, including three subjects who had discontinued bromocriptine because of adverse reactions. Four subjects spontaneously reported improvement of psychological and physical performance. One patient had a transient increase of serum transaminases. Thus, for the first time we could show a suppressive effect of roxindol on prolactin secretion in human prolactinomas. Due to its good tolerance roxindol may provide a useful alternative to bromocriptine.

The long-acting somatostatin analogue octreotide alleviates symptoms by reducing posttranslational conversion of prepro-glucagon to glucagon in a patient with malignant glucagonoma, but does not prevent tumor growth

A 52-year-old female with metastatic glucagonoma secreting glucagon and chromogranin A was treated with the somatostatin analogue octreotide for 2 years without any additional tumor-reducing interventions. Before therapy plasma glucagon was above 8 micrograms/l (normal < 0.2) and within 2 days 3 x 200 micrograms octreotide daily suppressed plasma glucagon to 2.2-2.5 micrograms/l. Concomitantly, chromogranin A dropped from 0.85 mg/l (normal < 0.1) to 0.2. After 3 weeks the preexisting disabling necrolytic migratory erythema had vanished completely, and weight loss was temporarily stopped. During therapy chromogranin A and plasma glucagon rose, exceeding pretreatment levels after 3 and 14 months, respectively. After 1 year the erythema recurred, responding only transiently to increasing doses of octreotide. The patient died after 2 years of therapy of tumor cachexy despite very high doses of octreotide (4 x 600 micrograms/day). Throughout treatment octreotide did not prevent tumor growth, as demonstrated by computed tomography and sonography. Determination of immunoreactive glucagon before and during octreotide therapy in fractions of plasma samples subjected to gel chromatography revealed a reduction in the ratio of glucagon to preproglucagon from 1.83 (before) to 0.56 (during therapy), indicating inhibition of posttranslational processing of preoproglucagon by octreotide, thereby reducing circulating bioactive glucagon. In summary, octreotide induced a remission of clinical symptoms by inhibiting posttranslational conversion of preproglucagon to glucagon but did not prevent tumor growth. Therefore, octreotide is a valuable therapy for rapid relief of clinical symptoms, thereby improving the possibilities for other tumor-reducing therapies.

Antithyroid drug-induced agranulocytosis: clinical experience with ten patients treated at one institution and review of the literature

The frequency, predisposing factors and course of agranulocytosis (granulocytes < 250/microliter) secondary to antithyroid drugs were studied in a cohort of 1256 continuously treated outpatients with hyperthyroidism during the 15 year period from 1973 to 1987. Two cases of agranulocytosis were detected; the frequency was 0.18% (95%-confidence intervals, 0.0-0.44%). This prevalence appears to be lower than reported in previous studies (up to 1.8%). For other adverse drug reactions, there was a clear-cut relationship to initial thionamide dose and to the body mass index; most reactions occurred during the first weeks of treatment. In addition, eight patients referred for thionamide drug- induced agranulocytosis were studied, and the following results obtained: Methimazole dose in patients with agranulocytosis was almost twice as in other patients (63.3 +/- 19.7 vs 34.3 +/- 29.7 mg daily) suggesting that this complication was related to dose. The interval between start of antithyroid drug treatment and first symptoms of agranulocytosis was 33 days (median; range, 23-55 days); hence, prolonged treatment beyond this period would appear relatively safe. Withdrawal of the causative agent and treatment of infection led to recovery of leukocyte counts within 15 days (median; range, 5-31 days). Two fatal outcomes were seen in referred patients. In one severely hyperthyroid patient with methimazole-induced agranulocytosis, recombinant human granulocyte/macrophage colony stimulating factor induced clinical and hematologic recovery within a few days of administration. In conclusion, agranulocytosis is the most severe side effect of antithyroid drugs. According to our results and a literature review, it occurs almost exclusively during the first ten weeks of treatment and is probably related to the drug dose.(ABSTRACT TRUNCATED AT 250 WORDS)

[Immune activity and serum interleukin-2-receptor concentration in autoimmune thyroid diseases]

Serum interleukin-2 receptor (IL-2R) concentrations were compared in 55 patients with thyrotoxicosis (14 men, 41 women, mean age 43.5 +/- 17 years), 18 patients with Hashimoto's thyroiditis (5 men, 13 women, mean age 47 +/- 15 years) and 28 healthy subjects (12 men, 16 women, mean age 30 +/- 10 years). The patients with thyrotoxicosis were divided into three groups depending on the activity or stage of the disease: 17 patients with florid untreated hyperthyroidism, 23 euthyroid patients receiving treatment with antithyroid drugs and 15 patients with thyrotoxicosis in remission after completing one year's antithyroid treatment. The patients with untreated thyrotoxicosis had significantly higher IL-2R values than the euthyroid patients receiving treatment or those in remission (207 +/- 112 vs 139 +/- 66 and 91 +/- 26 U/ml, P < 0.05 and P < 0.01). The IL-2R values of patients with thyrotoxicosis in remission were, however, significantly lower than those of the 28 healthy subjects (126 +/- 34 U/l; P < 0.01) or the euthyroid patients receiving treatment (P < 0.05). The 18 patients with Hashimoto's thyroiditis had significantly lower serum IL-2R values (70 +/- 39 U/ml) than the healthy controls. These data show that the serum IL-2R level depends on the state of thyroid metabolism and on the activity phase of the thyrotoxicosis. The low serum levels of IL-2R in patients with Hashimoto's thyroiditis could signify a genetically determined decrease in IL-2R production or might be linked with the destruction of thyroid tissue by the chronic autoimmune process.

Factitious hyperthyroxinemia due to a monoclonal IgA in a case of multiple myeloma

A clinically euthyroid 53-year-old woman with an IgA-lambda-secreting multiple myeloma presented with increased serum concentrations of thyroid hormones. Laboratory studies revealed increased total thyroxine (T4) and triiodothyronine (T3) concentrations, a high-normal free T4 concentration, and a normal basal thyrotropin (TSH) concentration with a normal response to thyroliberin (TRH). Her serum concentration of IgA was 11,040 mg/L (normal range 900-4500 mg/L) and immunoelectrophoresis revealed it to be monoclonal. This monoclonal IgA bound both T4 and T3, as determined by serum immunoelectrophoresis and direct binding studies. Immunoelectrophoresis in the presence of [125I]T4 or [125I]T3 localized the radiolabeled iodothyronines to a band corresponding exactly to the precipitin arc of the monoclonal IgA. We performed direct binding studies with IgA purified by affinity chromatography with the lectin jacalin. Purified IgA (50 micrograms) bound both [125I]T4 (12.3%) and [125I]T3 (2.7%) specifically and in a dose-dependent manner. Scatchard analysis of competitive-binding data utilizing [125I]T4 and unlabeled T4 revealed a Kd of 2.2 x 10(-7) mol/L. The binding capacity for T4 was approximately 7 mumol/L. Thus, in this case of IgA-secreting myeloma, the monoclonal IgA acts as an additional thyroid hormone-binding protein in serum that interferes in the T4 and T3 RIAs. This is the first report of a monoclonal IgA producing an apparent euthyroid hyperthyroxinemia.

Factitious hyperthyroxinemia due to a monoclonal IgA in a case of multiple myeloma

A clinically euthyroid 53-year-old woman with an IgA-lambda-secreting multiple myeloma presented with increased serum concentrations of thyroid hormones. Laboratory studies revealed increased total thyroxine (T4) and triiodothyronine (T3) concentrations, a high-normal free T4 concentration, and a normal basal thyrotropin (TSH) concentration with a normal response to thyroliberin (TRH). Her serum concentration of IgA was 11,040 mg/L (normal range 900-4500 mg/L) and immunoelectrophoresis revealed it to be monoclonal. This monoclonal IgA bound both T4 and T3, as determined by serum immunoelectrophoresis and direct binding studies. Immunoelectrophoresis in the presence of [125I]T4 or [125I]T3 localized the radiolabeled iodothyronines to a band corresponding exactly to the precipitin arc of the monoclonal IgA. We performed direct binding studies with IgA purified by affinity chromatography with the lectin jacalin. Purified IgA (50 micrograms) bound both [125I]T4 (12.3%) and [125I]T3 (2.7%) specifically and in a dose-dependent manner. Scatchard analysis of competitive-binding data utilizing [125I]T4 and unlabeled T4 revealed a Kd of 2.2 x 10(-7) mol/L. The binding capacity for T4 was approximately 7 mumol/L. Thus, in this case of IgA-secreting myeloma, the monoclonal IgA acts as an additional thyroid hormone-binding protein in serum that interferes in the T4 and T3 RIAs. This is the first report of a monoclonal IgA producing an apparent euthyroid hyperthyroxinemia.

Long-term treatment of acromegalic patients with repeatable parenteral depot-bromocriptine

We studied the efficacy and tolerability of a repeatable long-acting parenteral depot-bromocriptine preparation (Parlodel LAR) in 14 acromegalic patients, 10 of whom had received oral bromocriptine therapy previously, 2 of them showing intolerance to oral bromocriptine. Patients received i.m. injections of 50-100 mg depot-bromocriptine at 4-week intervals for 3-24 months (median 6). Growth hormone profiles were assessed by four daily samples at 4-week intervals. Main daily growth hormone levels decreased from 52.1 +/- 12.3 micrograms/l (mean +/- SEM) to 19.4 +/- 4.7 micrograms/l on the day of injection. In 6 patients, growth hormone values were lowered by more than 50%, whereas IGF-I levels decreased only slightly and growth hormone values during the oral glucose tolerance test remained non-suppressible. Tumour sizes were not affected. Two women became pregnant and were delivered of healthy babies. Side-effects typical of bromocriptine occurred frequently on the days of injection and diminished in most patients after 2 months of therapy despite increasing dosage. Compared with previous oral bromocriptine therapy, 9 of 10 patients preferred the depot preparation, whereas the reduction of growth hormone levels was similar during both treatments. In conclusion, depot-bromocriptine should be considered for acromegalic patients intolerant to oral bromocriptine.

A prospective randomized trial of antithyroid drug dose in Graves' disease therapy. European Multicenter Study Group on Antithyroid Drug Treatment

Some studies have suggested that increasing the daily dose of anti-thyroid drugs might improve long-term remission rates of Graves' disease. Therefore, this question was addressed in a prospective multicenter trial involving 18 thyroid clinics in Europe, mostly in iodine-deficient or moderately iodine-sufficient regions. Five hundred and nine patients with Graves' hyperthyroidism were enrolled in a prospective randomized trial comparing the remission rates after treatment with methimazole (MMI) at two fixed dosages (10 vs. 40 mg) with levothyroxine supplementation. The treatment and follow-up periods lasted 12 months each. Sixty and seven-tenths percent of the recruited patients (total, 309; 153 in the 10 mg, 156 in the 40 mg group) were finally evaluated, and comparison of the two groups showed that they were well matched with respect to a wide range of variables, including parameters of thyroid function. With 10 mg MMI daily, 68.4% of the patients were euthyroid after 3 weeks, and 84.9% after 6 weeks, compared to 83.1% and 91.6%, respectively, with the use of 40 mg MMI daily. TSH receptor antibodies decreased similarly in the two groups, 25% of patients in the 10 mg group, and 30% in the 40 mg group still being TSH receptor antibodies positive after 12 months. One hundred and ninety six (63.4%) of the 309 patients achieved remission of Graves' disease. The two MMI doses were equally effective; 35.9% compared to 37.2% of patients treated with 10 and 40 mg MMI, respectively, had relapses. There was no difference in the length of the time interval between stopping treatment and recurrence between the two groups. However, the rate of adverse drug reactions increased from 39/251 (15.5%) in the 10 mg group to 67/258 (26.0%) in the 40 mg group (P < 0.01). Under conditions of iodine deficiency or borderline sufficient iodine supply, 40 mg MMI daily will render more patients with Graves' disease euthyroid within the first 6 weeks of treatment than 10 mg daily, but at the expense of an increased rate of adverse reactions. However, patients treated with 40 mg MMI daily for 1 yr have no higher chance of remission than patients treated with 10 mg. It does not appear justified at present to recommend MMI doses higher than required for the control of hyperthyroidism (with the goal of immunosuppression).

Control of prolactin-secreting macroadenomas with parenteral, long-acting bromocriptine in 30 patients treated for up to 3 years

OBJECTIVE

We investigated the effect of intramuscular injections of long-acting bromocriptine in patients with macroadenomas.

STUDY DESIGN AND PATIENTS

Thirty patients with PRL-secreting pituitary macroadenomas were treated with repeated 4-weekly intramuscular injections of 50 or 100 mg of a long-acting, repeatable bromocriptine formulation for six to 37 injections, amounting to a total of 473 injections. Twenty patients received parenteral bromocriptine as primary therapy, ten had persisting hyperprolactinemia after previous therapies including pituitary surgery (n = 7), oral bromocriptine (7), and pituitary irradiation (2).

MEASUREMENTS

A PRL day profile was obtained and the patients' clinical status and history were documented, at intervals. Detailed clinical, laboratory, and radiological (pituitary nuclear magnetic resonance or computed tomography scan) evaluations were performed at baseline, after 1 injection and every 6th injection thereafter.

RESULTS

In all patients PRL was suppressed from a mean +/- SEM pretreatment level of 32,620 +/- 8680 to 4480 +/- 1140 mU/I on the third day after the first injection. In 12 patients PRL levels normalized (< 400 mU/I) with the first to fourth injection, in three additional patients PRL levels normalized after 8-15 months. In 19 patients PRL was suppressed to less than 1000 mU/l. In three patients PRL did not decrease to less than 50% of pretreatment; in two of them on oral bromocriptine prior to this study there had been a comparable low efficacy. Of 28 patients with macroadenomas (median height 22 mm) tumour shrinkage was evident in 15 by nuclear magnetic resonance or computed tomography scan 28 days after the first injection, and in three additional patients after 6 months. There was further regression in seven cases after 12, 18 or 24 injections. Adenoma size (mean +/- SEM) decreased to 66 +/- 7% of the pretreatment value. The 40 adverse events noted in 20 of 30 patients during 24 hours after the first injection were similar to known side-effects of oral bromocriptine, nausea and postural hypotension being the most frequent. With repeated injections, on average 0.6 adverse events were noted per injection (mostly mild asthenia). There were no local adverse reactions at the injection site.

CONCLUSION

We conclude that long-acting repeatable bromocriptine in patients with macroprolactinomas offers a safe and efficacious primary treatment that ensures compliance and gives long-term control. Adverse reactions are comparable to oral bromocriptine but subside with repeated injections.

Long-term follow-up in patients with autonomous thyroid adenoma

A group of 375 untreated euthyroid patients with solitary autonomous adenoma of the thyroid were studied in a long-term follow-up (observation period 52.8 (mean)/46 (median), range 3-204 months). During the period of observation, 133 (34.2%) of all initially untreated patients underwent treatment (surgery, radioiodine, antithyroid medication) because of hyperthyroidism, mechanical problems, or at the patient's request. Sixty-seven patients developed hyperthyroidism resulting in a mean incidence of 4.1% per year. The incidence of hyperthyroidism increased during follow-up (3% in the first seven years, 10% in the following years). Age, sex, nodule size, initial scintigraphic appearance and the TRH test were of no individual prognostic value in predicting hyperthyroidism. Eleven of 14 patients with untreated hyperthyroidism became euthyroid without treatment during the time of follow-up. After iodine excess (by history or elevated iodine levels in urine, N = 45), 14 patients (31%) developed hyperthyroidism. In conclusion, we recommend a definitive treatment of autonomous adenoma at least in patients with advanced age, concomitant diseases and a higher probability of iodine exposure.

Basophilic leukocytes in hypothyroidism

Since in the literature basophilia is frequently related to myxedema, we evaluated basophilic leukocytes in patients with hypothyroidism, applying routine techniques used in clinical laboratories. The study included normal persons, untreated patients with hypothyroidism, and euthyroid subjects with hyperlipidemia. The number of circulating basophils was determined by differential counts of Pappenheim stained blood smears. No difference in relative and total basophil counts was detected in patients with hypothyroidism as compared to healthy controls (1.0% and 58.1 basophils/microliters vs. 0.8% and 50.8 basophils/microliters, respectively). The percentage of basophils in myxedema associated with hypercholesterolemia amounted to 1.0%, their absolute number to 57.6/microliters; in hypothyroid patients presenting normal serum cholesterol levels, the relative and absolute numbers of basophilic leukocytes was not statistically different (0.83% and 61.1 basophils/microliters, respectively). We conclude that in patients with hypothyroidism the number of basophils is not statistically different from the values of basophils in healthy controls. Furthermore, the number of peripheral blood basophils in hypothyroidism is not related to the serum cholesterol level.

Effect of small doses of iodine on thyroid function during caloric restriction in normal subjects

It is well recognized that starvation and malnutrition are associated with a low-T3 syndrome in man. A similar condition has been observed after intake of a low carbohydrate hypocaloric diet. However, little is known about the influence of iodine on these conditions. Therefore, we evaluated the effect of iodine supplementation on thyroid function before and after a short-term intake of a low carbohydrate diet in normal subjects residing in an iodine-deficient area. The study was performed in 16 young euthyroid, nonobese volunteers (11 males, 5 females). The subjects were placed on a low carbohydrate (800 kcal) diet for 4 days. Eight subjects received 500 micrograms iodine (oral) daily beginning 4 weeks before diet. The control group (n = 8) received no iodine. After iodine supplementation, iodine excretion increased from 52 to 405 micrograms iodine/g of creatinine. Total T4 showed a slight but significant increase (104.2 nmol/l vs. 115.8 micrograms/dl; p < 0.001); fT4 was unchanged. The intake of the hypocaloric low carbohydrate diet resulted in a striking decrease in both total and free T3 and an increase of rT3 irrespective of iodine supplementation. T4 and fT4 were not affected in either group. During diet, iodine administration resulted in a decrease of basal TSH from 2.3 to 1.2 mU/l (p < 0.05), delta TSH from 10.3 to 4.5 mU/l (p < 0.01) and delta T3 (T3 180 min after TRH) from 0.7 to 0.3 nmol/l (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic factors in medullary thyroid carcinoma: evaluation of 741 patients from the German Medullary Thyroid Carcinoma Register

A retrospective study of 741 patients with medullary thyroid carcinoma diagnosed between 1967 and 1991 was carried out by members of the German Medullary Thyroid Carcinoma Study Group to evaluate prognostic factors. A total of 559 patients (75%) were considered to have sporadic disease, and 182 (25%) had the familial type. The sex ratio (male to female) was 1:1.4 in sporadic disease patients, and the mean age at diagnosis was 45.9 years (range 5-81 years). For familial disease patients the sex ratio was 1:1.1, and the mean age at diagnosis was 33.4 (range 5-77 years). The follow-up time for 630 patients ranged from 1 month to 20.8 years (mean 13.0 years). The overall adjusted survival rate was 86.7% at 5 years and 64.2% at 10 years. In a univariate analysis the stage of disease at diagnosis, age, sex, and type of disease (sporadic, familial) were relevant prognostic factors, with a better prognosis for young female patients with familial disease and diagnosed at an early stage. In a multivariate proportional hazards analysis, the difference in the survival rate of patients with familial disease versus those with the sporadic form disappeared, while prognostic information provided by age and sex was still significant. The poorer prognosis of patients with sporadic medullary thyroid carcinoma may be related to the patients' older age at detection and more advanced tumor stage at diagnosis. There seems to be no difference in biological behavior between tumors of the sporadic and those of the familial type.

Increased serum neopterin levels in patients with Graves' disease

Neopterin (NPT) a marker of activation of the T-lymphocyte/monocyte axis has been measured in serum of 89 patients with autoimmune thyroid disease (72 patients with Graves' disease and 17 patients with autoimmune thyroiditis) and compared to a group of 24 normal controls and 24 patients with nontoxic goitre. There was a significant correlation between NPT levels and age in the patients with nontoxic goitre (r = 0.447, p < 0.001) but not in patients with autoimmune thyroid disease. Significantly higher NPT levels were found in all patients with Graves' disease (GD) compared to age and sex matched healthy controls, and patients with nontoxic goitre (5.7 +/- 2.4 vs 4.1 +/- 1.7, and 4.0 +/- 1.5, p < 0.01). However, there was no difference in NPT levels between each group of patients with GD when subdivided in: hyperthyroid newly diagnosed GD, treated GD, GD in remission and relapse. Patients with autoimmune thyroiditis did not have abnormal NPT levels compared to age and sex matched normal controls. Neopterin serum levels were not influenced by hyperthyroidism as no significant differences in NPT levels could be found in 24 patients with hyperthyroid Graves' disease and 13 patients with toxic goitre or toxic adenoma when compared to age and sex matched euthyroid patients with Graves' disease or normal controls. Moreover, there was no significant difference in mean NPT levels 1. before and after restoration of euthyroidism in 10 patients with hyperthyroid Graves' disease and 2. before and under T3 supplementation in 18 patients with Graves' disease in remission who underwent a T3 thyroid suppression test.(ABSTRACT TRUNCATED AT 250 WORDS)

Cervical pheochromocytoma: a rare localization and a difficult diagnosis

A 45-year-old hypertensive female with insulin-treated diabetes mellitus presented to our clinic with elevated urinary norepinephrine (NE) concentrations and a negative 131-metaiodobenzylguanidine (MIBG) scintigraphy, errouneously limited to the abdomen, for evaluation of a pheochromocytoma (Pheo). Despite antihypertensive medications blood pressure remained highly variable and frequently elevated. Further biochemical testing, including a glucagon provocation test and a clonidine-suppression test, revealed autonomous NE secretion. In order to avoid repeat MIBG-scintigraphy, other non invasive imaging techniques were performed, including real time sonography (7.5 MHz) of the neck which revealed a tumor. Fine needle aspiration of this tumor tissue demonstrated cells compatible with Pheo. Histology and immunohistochemistry of the excised tumor confirmed the diagnosis of Pheo. After surgical removal of the tumor, urinary and plasma NE levels normalized. Without any medication the blood pressure of the patient was now only slightly hypertensive. Only half of the daily insulin dose was needed to maintain the patient euglycemic.

Conservative and surgical management of incidentally discovered adrenal tumors (incidentalomas)

Of 50 patients with incidentalomas (INC), 18 were adrenalectomized and in 18 patients the INC was left in place. For 14 patients clinical data were insufficient for evaluation. Follow-up investigation of the 18 unoperated subjects 11-101 months (median 32.2) after the diagnosis had been made revealed unchanged size of the INC [initially 2.1 +/- 0.8 cm (mean +/- SD) at follow-up 2.0 +/- 1.0 cm]. Cushing's syndrome developed in one patient, which was not evident at the initial discovery of the INC 32 months before. "Pre-Cushing's Syndrome" was detected in 1 patient and confirmed in a second who had displayed a pathologically high dose dexamethasone suppression test 101 months before. In addition, 3 male patients with a hitherto unknown mild subclinical defect of 21-hydroxylase activity were identified. The remaining 12 patients had normal endocrine activity of their adrenals. Eighteen patients were adrenalectomized with an average tumor size of 3.96 +/- 1.88 cm. Histologically, 10 (52%) adenomas were observed, including 3 with signs of hypercortisolism. Adrenal hyperplasias were observed in 2 patients, metastasis in 1 patient. 31.5% of the INC which were removed were nonmalignant tumors of other than adrenal origin. We conclude that initially endocrinologically inactive adrenal tumors can eventually develop autonomous endocrine activity and therefore need to be reexamined at regular intervals. Conservative management with regular follow-up investigations is the preferable treatment for small incidentalomas when endocrine over-activity has been excluded and no indications of malignancy exist. Based on these observations and the literature a diagnostic and therapeutic strategy is presented.

[Familial panhypopituitarism]

Two Italian brothers showed identical subsequent loss of anterior pituitary function during the first decades of their life, developing panhypopituitarism. The investigations carried out indicate that in this family the etiology is hereditary in nature, being X-chromosomal recessive or autosomal recessive, with the defect located at the level of either the hypothalamus or the pituitary gland.

Control of prolactin secretion

1. Prolactin is a 21,500 Dalton single-chain polypeptide hormone but may occur in 50 kDa and 150 kDa molecular variants. 2. These large PRL variants may be secreted predominantly; this condition is termed "macroprolactinemia". It is characterized by high immunological and normal biological serum levels of prolactin, and lack of clinical symptoms of hyperprolactinemia. 3. The information on PRL is encoded on chromosome 6. Transcription can be enhanced and suppressed by a variety of hormonal factors. 4. PRL is secreted in a pulsatile fashion; it displays a circadian rhythm (with a maximum during sleep) and is stimulated by some amino acids. PRL also responds to mechanical stimulation of the breast. 5. PRL rises during pregnancy, and maintainance of hyperprolactinemia (and, thereby, physiological infertility) is dependent on the frequency and duration of breast feedings. 6. Hypothalamic regulation of prolactin mainly involves tonic inhibition via portal dopamine. The physiological importance of various stimulating factors present in the hypothalamus is still incompletely understood. In particular, there is still no place for TRH in PRL physiology. 7. PRL is released in response to stress; this response may be mediated by opioids. The low-estrogen, low-gonadotropin amenorrhea of endurance-training women is not mediated by prolactin, however. 8. Estrogens stimulate PRL gene transcription via at least two independent mechanisms. There are many clinical examples of this estrogen effect on prolactin serum levels, and also on the growth of prolactinomas. 9. Mild hyperprolactinemia remains an enigma which cannot satisfactorily be resolved by biochemical or radiological testing. The border between "normal" and "elevated" prolactin is ill-defined. The possibility of macroprolactinemia complicates this matter even further. 10. The number of drugs which suppress prolactin by acting on pituitary D2 receptors, and which are useful in the treatment of hyperprolactinemia, continues to increase. In the field of ergot alkaloids, parenteral application appears to be a logical solution to the problem of the high first-pass effect; in addition, this form of treatment is frequently better tolerated than the oral route. 11. Prolactinoma development is presently being studied employing molecular biological techniques; the question of whether tumorigenesis can be attributed to specific defects of gene regulation remains to be answered.

TSH secretion in Cushing's syndrome: relation to glucocorticoid excess, diabetes, goitre, and the 'sick euthyroid syndrome'

Thyrotrophin (TSH) secretion was studied in 63 patients with Cushing's syndrome (53 patients with pituitary dependent Cushing's disease, eight with adrenocortical tumours, and two with the ectopic ACTH syndrome). Prior to treatment, TSH response to 200 micrograms of TRH intravenously was significantly decreased compared to controls; TSH response was 'flat' (increment less than 2 mU/l) in 34 patients (54%). Patients with a flat response to TRH had significantly higher morning and midnight cortisol levels than patients with a TSH response of 2 mU/l and more; this was not due to differences in serum thyroid hormone levels. Basal TSH, TSH increment after TRH, and stimulated TSH value, but not serum triiodothyronine, were correlated with cortisol measurements (0800 h serum cortisol, midnight cortisol, and urinary free corticoid excretion). After exclusion of 40 patients with additional disease (severe systemic disease, diabetes mellitus, or goitre), cortisol-TSH correlations were even more pronounced (r = -0.73 for midnight cortisol and stimulated TSH levels), while in the patients with additional complications, these correlations were slight or absent. Successful treatment in 20 patients was associated with a rise in thyroid hormone levels and the TSH response to TRH. These results indicate that (1) the corticoid excess but not serum T3 is the principal factor regulating TSH secretion in Cushing's syndrome, (2) a totally flat response to TRH is rare, and (3) TSH suppression and lower than normal serum thyroid hormone levels are reversible after treatment. Since factors like severe systemic disease, diabetes mellitus and goitre also affect TSH secretion, they tend to obscure the statistically significant correlations between cortisol excess and TSH secretion.

A multihormonal response to corticotropin-releasing hormone in inferior petrosal sinus blood of patients with Cushing's disease

Bilateral, selective, and simultaneous catheterization of the inferior petrosal sinus is not only a valuable tool in the differential diagnosis of Cushing's syndrome, but may also provide new insights into paracrine interactions at the pituitary level. We have investigated whether CRH (1 microgram/kg BW) has any effect on the release of PRL, GH, TSH, or the alpha-subunit of hCG during this procedure. Sixteen patients under evaluation for Cushing's syndrome (Cushing's disease, n = 12; ectopic ACTH syndrome, n = 2; glucocorticoid resistance, n = 1; hormonally inactive adenoma, n = 1) were catheterized. Two of the patients with Cushing's disease received 4.0 mg naloxone iv 15 min before stimulation with CRH. Patients with Cushing's disease demonstrated a central/peripheral gradient and an intersinus gradient not only for ACTH, but also for PRL, alpha-subunit, GH, and TSH, provided that the latter two hormones were not completely suppressed by the glucocorticoid excess. Moreover, all hormones increased in response to CRH on the side with the highest ACTH concentration; PRL rose from 31.2 +/- 6.4 to 61.6 +/- 12.4 micrograms/L (P less than 0.01), and alpha-subunit from 2.6 +/- 0.6 to 6.4 +/- 1.7 micrograms/L, (P less than 0.01). Naloxone was unable to abolish the PRL or alpha-subunit increase in response to CRH. A multihormonal response to CRH in inferior petrosal sinus blood was also observed in the patient with glucocorticoid resistance and in the patient with the hormonally inactive tumor, but not in the patients with ectopic ACTH secretion. The multihormonal response to CRH could be explained by cosecretion of other hormones together with ACTH from corticotroph adenoma, by an effect of CRH on pituitary blood flow, or by a paracrine action of pituitary corticotrophs on adjacent normal pituitary cells. Our results do not support the concept that such a paracrine action is mediated by beta-endorphin. However, a higher dose of naloxone may be required to antagonize the action of pituitary beta-endorphin.