bluuebunny/crossref_metadata_2025 huggingface dataset:
The cellular and molecular basis of the ectopic ACTH syndrome
Authors: White A. , Clark A. J. L.
Published: March 2008

In recent years the techniques of molecular and cellular biology have made it possible to begin to dissect the origins and behaviour of the ACTH‐secreting tumour cell. It is becoming apparent that these tumours represent undifferentiated neuroendocrine cells, and it may be that their peptide‐secreting properties may have no more sinister oncological significance. However, an autocrine role for β‐endorphin may confer a selective growth advantage on the POMC‐expressing cell. It is still not clear why glucocorticoids fail to inhibit the POMC gene in these extra‐pituitary tumours despite the presence of glucocorticoid receptors. This may not be resolved until the mechanism for inhibition of POMC by glucocorticoids in the normal pituitary is understood, although it is tempting to speculate that a mutation in the glucocorticoid receptor or a tissue specific interaction is responsible for the resistance of POMC observed in the ectopic ACTH syndrome.

In studying the peptides secreted by the extra‐pituitary tumours responsible for the ectopic ACTH syndrome it would appear that direct measurement of ACTH precursors and comparison with the circulating concentrations of ACTH can give valuable information on the percentage of tumours which do not effectively process the ACTH precursors. However, far more data have to be collected on patients with occult tumours in order to identify whether this type of processing is tissue specific. Nevertheless, these studies provide useful insights into the mechanisms of intracellular signalling and regulation in such tumours which may identify unique pharmacological tools to inhibit ACTH secretion or more importantly tumour growth.
Melatonin stimulates growth hormone secretion through pathways other than the growth hormone‐releasing hormone
Authors: Valcavi Roberto , Zini Michele , Maestroni Georges J. , Conti Ario , Portioli Italo
Published: March 2008

OBJECTIVE There is evidence that melatonin plays a role in the regulation of GH secretion. The aim of this study was to investigate the neuroendocrine mechanisms by which melatonin modulates GH secretion. Thus we assessed the effect of oral melatonin on the GH responses to GHRH administration and compared the effects of melatonin with those of pyridostigmine, a cholinergic agonist drug which is likely to suppress hypothalamic somatostatin release.

DESIGN The study consisted of four protocols carried out during the afternoon hours. Study 1: oral melatonin (10 mg) or placebo were administered 60 minutes prior to GHRH (100 μg i.v. bolus). Study 2: GHRH (100 μg i.v. bolus) or placebo were administered at 0 minutes; oral melatonin or placebo were given at 60 minutes and were followed by a second GHRH stimulus (100 μg i.v. bolus) at 120 minutes. Study 3: placebo; oral melatonin (10 mg); oral pyridostigmine (120 mg); melatonin (10 mg) plus pyridostigmine (120 mg) were administered on separate occasions. Study 4: placebo; oral melatonin (10 mg); oral pyridostigmine (120 mg); melatonin (10 mg) plus pyridostigmine (120 mg) were administered on separate occasions 60 minutes prior to a submaximal dose (3 μg i.v. bolus) of GHRH.

SUBJECTS Four groups of eight normal male subjects, ages 22–35 years, were randomly assigned to each protocol.

MEASUREMENTS Growth hormone was measured by RIA at 15‐minute intervals.

RESULTS Oral melatonin administration had a weak stimulatory effect on GH basal levels. Prior melatonin administration approximately doubled the GH release induced by supramaximal (100 μg) or submaximal (3 μg) doses of GHRH. Melatonin administration restored the GH response to a second GHRH challenge, given 120 minutes after a first GHRH i.v. bolus. The GH releasing effects of pyridostigmine, either alone or followed by GHRH, were greater than those of melatonin. However, the simultaneous administration of melatonin and pyridostigmine was not followed by any further enhancement of GH release, either in the absence or in the presence of exogenous GHRH.

CONCLUSIONS Our data indicate that oral administration of melatonin to normal human males increases basal GH release and GH responsiveness to GHRH through the same pathways as pyridostigmine. Therefore it is likely that melatonin plays this facilitatory role at the hypothalamic level by inhibiting endogenous somatostatin release, although with a lower potency than pyridostigmine. The physiological role of melatonin in GH neuroregulation remains to be established.
Urinary growth hormone excretion in the assessment off children with disorders of growth
Authors: Skinner A. M. , Clayton P. E. , Price D. A. , Addison G. M. , Soo A.
Published: March 2008

OBJECTIVE We wished to evaluate the use of urinary GH measurements when compared to conventional GH provocation tests in the assessment of short children.

DESIGN Children presenting for the first time to a regional growth clinic were assessed clinically by one observer. Investigations comprising standard GH provocation tests and measurement of urinary GH were undertaken to exclude GH deficiency.

PATIENTS Fifty‐eight children aged 58‐16 years were enrolled. Ten were diagnosed on clinical assessment as GH deficient, 43 had delayed growth and/or familial short stature, and five had idiopathic short stature; the 48 children in the last two groups were defined as short normal.

MEASUREMENTS GH secretion was evaluated by two standard provocation tests and by the measurement of GH in five overnight urine collections. A normal peak GH concentration was defined as <16 μ/l. The values for urinary GH excretion were compared to normal ranges (2 standard deviations from the mean), established in healthy schoolchildren of normal stature.

RESULTS All children considered GH deficient on clinical grounds had low peak GH concentrations on provocation tests, while 8/10 had low values of urinary GH excretion. All short normal children with normal peak GH concentrations (n= 36) on provocation tests and 11/12 children with low peak GH concentrations had urinary GH excretion within the normal range. There was therefore a significant difference in the classification of‘normal’GH secretion in the two tests. If the clinical diagnosis was used as the standard by which GH tests were Judged, the predictive value of a positive urinary GH test in the diagnosis of GH deficiency was 89% compared with 45% for GH provocation tests.

CONCLUSION The use of urinary growth hormone measurements leads to the classification of more children with disorders of growth having adequate GH secretion than that derived from GH provocation tests.
In‐vitro response of erythroid progenitors from children with thalassaemia major to human growth hormone and insulin‐like growth factor I
Authors: Merchav Shoshana , Graif Zvi , Skottner Anna
Published: March 2008

OBJECTIVE Most short‐statured children with β‐thalassaemia major have markedly reduced levels of circulating insulin‐like growth factor I (IGF‐I). Both human growth hormone (hGH) and IGF‐I enhance the in‐vitro growth of erythroid progenitors, with hGH exerting its effects via paracrine production of IGF‐I. The aim of this study was to characterize further the hGH‐IGF‐l axis abnormalities in thalassaemia major by evaluating the erythroid potentiating effects of both peptides in cultures of thalassaemic and control erythroid progenitors.

DESIGN Ten short‐statured thalassaemic children and nine age‐matched healthy donors were evaluated for the in‐vitro response of their peripheral blood erythroid progenitors to stimulation with hGH and IGF‐I.

MEASUREMENTS The frequency of erythroid progenitors in serum‐free cultures of thalassaemic and control peripheral blood mononuclear cells was enumerated following 14 days of incubation in the presence of hGH or IGF‐I.

RESULTS Biosynthetic hGH induced a similar dose‐dependent magnitude of colony enhancement in cultures of erythroid progenitors from thalassaemic children, as compared to controls. Significant enhancement of colony growth was detected at 42 μ/I hGH, with a maximal effect detected at 83 μ/I of this hormone (173 ± 8 vs 153 ± 9% of baseline erythroid progenitors in patients versus controls, respectively). Enhancement of both thalassaemic and control erythroid precursors by hGH was completely abrogated by monoclonal antibodies (αIR‐3) directed against the IGF‐I membrane receptor, thereby confirming the normal capacity of thalassaemic accessory cells to produce IGF‐I in response to hGH. Biosynthetic IGF‐I also enhanced the growth of thalassaemic and control erythroid precursors to 172±17 and 159±10% of baseline at 100 and 10 U/I, respectively.

CONCLUSIONS Our detection of a normal capacity of thalassaemic peripheral blood target cells to response to hGH and IGF‐I suggests that these patients do not suffer from a specific defect in receptor and/or post‐receptor mechanism(s) involving the response of these cells to both peptides. The normal responsiveness of thalassaemic target cells to hGH and IGF‐I suggests that both peptides may be useful in the treatment of growth retardation in thalassaemia.
A case of antibody formation against octreotide visualized with 111In‐octreotide scintigraphy
Authors: Kwekkeboom D. J. , Assies J. , Holland L. J. , Reubi J. C. , Lamberts S. W. J. , Krenning E. P.
Published: March 2008

A case of antibody formation in a patient with carcinoid syndrome is described. The patient was treated with octreotide in dosages up to 1 5 mg/day. Serum samples were analysed for the presence of octreotide antibodies before and after 20 months of octreotide treatment. In‐vivo 111ln‐octreotide scintigraphy was performed before and during therapy, and after antibodies had developed.

Before treatment, no serum antibodies against octreotide were detected. After 20 months of treatment, they were detectable up to a 1:115 serum dilution. The serum binding of 125I‐Tyr3‐octreotide was blocked by adding excess unlabelled Tyr3‐octreotide, indicating the presence of specific octreotide antibodies. Before treatment, a normal distribution of radioactivity in the spleen and kidneys, irregular uptake in the liver due to metastases, and a hot spot in the lower abdomen were found during 111ln‐octreotide scintigraphy. After antibodies had developed, increased radioactivity over the heart and high background radioactivity in the abdomen with only faint visualization of the spleen, liver, and kidneys were found, indicating a prolonged presence of 111ln‐octreotide in the blood resulting from its being bound to antibodies. Increased radioactivity was also seen at the injection sites of the drug in the upper legs. In‐vitro incubation of biopsy tissue from this site with 125l‐Tyr3‐octreotide revealed diffuse guanosine triphosphate (GTP) independent specific binding, indicating non‐G‐protein linked binding of labelled octreotide.

This report describes the characteristic abnormalities during in‐vivo 111ln‐octreotide scintigraphy in a patient with octreotide antibodies. These consisted of high back ground radioactivity due to prolonged circulation of antibody coupled 111ln‐octreotide together with visualization of the injection sites, which most probably results from local accumulation of antibodies.
Reversibility of hypogonadotrophic hypogonadism associated with genetic haemochromatosis
Authors: Cundy Tim , Butler Joan , Bomford Adrian , Williams Roger
Published: March 2008

OBJECTIVE Recent reports have suggested that hypogonadotrophic hypogonadism in men with genetic haemochromatosis can be reversed by aggressive venesection therapy. We have studied prospectively men with this complication of haemochromatosis in order to document the frequency and completeness of recovery from hypogonadism.

PATIENTS AND DESIGN Six men with symptomatic hypogonadotrophic hypogonadism and genetic haemochromatosis were studied before beginning venesection therapy and again after depletion of body iron stores.

MEASUREMENT Symptoms of hypogonadism, serum gonadotrophins and serum total and free testosterone concentrations.

RESULTS Five men aged 47–66 showed no symptomatic improvement and no change in serum gonadotrophin or testosterone concentrations. The symptoms of one man, aged 33, resolved completely after venesection and this was accompanied by increases in serum LH and FSH. Serum total and free testosterone concentrations increased fourfold, but remained subnormal.

CONCLUSION Only one partial recovery from hypogonadotrophic hypogonadism was seen and this was in the youngest subject. In reviewing the other documented cases of reversal it would appear that the age at diagnosis is critical and there are no proven cases of reversal of hypogonadotrophic hypogonadism in men over the age of 40 at the start of venesection therapy.
Expression of thyrotrophin receptor gene in thyroid carcinoma is associated with a good prognosis
Authors: Shi Yufei , Zou Minjing , Farid Nadir R.
Published: March 2008

OBJECTIVE The clinical course of thyroid carcinoma is very variable. It is well known that thyroid carcinomas of similar histology can behave differently in terms of local invasion and distant metastases: there is no reliable way to predict the disease course with confidence. In the present study we compared the TSH receptor and c‐myc mRNA levels in different stages of thyroid carcinomas to identify whether they are useful markers for thyroid tumour biological behaviour and prognosis.

DESIGN Thyroid tumour specimens were used as the source of RNA. The TSH receptor and c‐myc mRNA levels were detected by Northern blot analysis and quantitated by laser densitometry.

PATIENTS Thyroid tissues were obtained from five patients with multinodular goitres, 22 with differentiated and three with anaplastic carcinomas.

MEASUREMENTS Total cellular RNA was extracted from thyroid tissue specimens and blotted onto nylon membranes. Northern blot analysis was used to detect TSH receptor and c‐myc mRNA. The mRNA levels were then quantitated by laser densitometry and compared with each disease stage.

RESULTS TSH receptor mRNA levels were significantly lower in carcinomas as compared to benign tumours. With advancing disease stage, the neoplastic tissues generally showed a progressive decline in TSH receptor mRNA levels. Interestingly, in two specimens from patients with distant metastases, TSH receptor mRNA levels were not significantly reduced and were comparable to those in benign tumours. Both patients are still alive, one of them 18 years after operation, indicating that tumour histology is dissociated from its biological behaviour, c‐myc mRNA levels were increased but not significantly so in stage 1–3 carcinomas. However, in stage 4 carcinomas c‐myc expression was significantly increased. Thus c‐myc overex‐pression is associated with poor prognosis. Although there is a negative correlation between TSH receptor and c‐myc mRNA levels, the correlation was not significant. CONCLUSIONS These results indicate that decreased TSH receptor and increased c‐myc gene expression levels are associated with thyroid cell de‐differentiation. They are useful markers for thyroid tumour de‐differentiation and disease prognosis.
The effect of treatment with levothyroxine or iodine on thyroid size and thyroid growth stimulating immunoglobulins in endemic goitre patients
Authors: Wilders‐Truschnig M. M. , Warnkroß H. , Leb G. , Langstegert W. , Eber O. , Tiran A. , Dobnig H. , Passath A. , Lanzer G. , Drexhage H. A.
Published: March 2008

OBJECTIVE We assessed the effect of levothyroxine or iodine on thyroid size and on thyroid growth stimulating immunoglobulins in endemic goitre patients.

DESIGN Levothyroxine or iodine was given orally in an open randomized prospective study (100 and 200 μ g respectively).

PATIENTS Thirty‐seven euthyroid patients with diffuse iodine deficiency goitres and thyroid growth stimulating immunoglobulins were studied.

MEASUREMENTS Thyroid size, thyroid growth stimulating immunoglobulins (mitosis arrest assay), basal TSH, free T3, free T4, thyroid anti‐microsomal antibodies, anti‐thyroglobulin antibodies, anti‐TSH receptor antibodies and urinary iodine excretion were measured.

RESULTS Thyroid size decreased significantly in both groups, in the levothyroxine group more than in the iodine treated group. Thyroid growth stimulating immunoglobulins levels also decreased significantly in both groups. Between groups there was no statistically significant difference. A statistically significant correlation between thyroid growth stimulating immunoglobulins reduction profiles and goitre size reduction could not be established. TSH levels became suppressed in the levothyroxine group while the T4 values rose; in the iodine treated group TSH levels stayed constant as did T4. None of the patients developed thyroid microsomal or thyroglobulin auto‐antibodies and/or hyperthyroidism during the treatment.

CONCLUSIONS Levothyroxine as well as iodine was effective in reducing thyroid size as well as thyroid growth stimulating immunoglobulins levels in endemic goitre patients. Since in both groups TSH levels were not related to thyroid size reduction, other factors than TSH suppression must be responsible for the observed thyroid size reduction. Iodine itself by virtue of its antiproliferative action on thyrocytes may have had a direct action on the goitre reduction during iodine treatment; however, the levothyroxine dose, containing less iodine, had a similar effect. A complicated picture hence emerges with regard to factors involved in the shrinkage of iodine deficiency goitre during thyroxine or iodine therapy. These findings indicate that TSH and thyroid growth promoting immunoglobulins are not the only influences on the size of endemic goitres, although it cannot be excluded that these two factors contribute to influence the pathogenetic process.
Metabolic clearance rate of biosynthetic growth hormone after endogenous growth hormone suppression with a somatostatin analogue in chronic renal failure patients and control subjects
Authors: Garcia‐Mayor Ricardo V. G. , Perez Angel J. , Gandara Argimiro , Andrade Amalia , Mallo Federico , Casanueva Felipe F.
Published: March 2008

OBJECTIVE Several disturbances in the regulation of growth hormone secretion have been reported in chronic renal failure. The general assumption is that an altered hormonal clearance is at the basis of such GH alterations. Nevertheless, details of GH elimination kinetics in uraemia are not available. To clarify the role played by the kidney in its catabolism, GH elimination kinetics were studied in uraemic and control subjects after suppression of endogenous secretion of GH.

DESIGN In all subjects an analogue of somatostatin (octreotide 100 μ g i.v.) was administered as a bolus before GH (– 60 minutes). Sixty minutes later (0 min) biosynthetic GH (0 5 IU = 200 μ g) was administered intravenously as a bolus.

PATIENTS Six chronic renal failure patients before dialysis and six matched normal volunteers.

MEASUREMENTS Plasma GH levels were measured by an immunoradiometric assay.

RESULTS In both groups, the GH elimination curve fitted a bi‐exponential model. The calculated plasma volume and GH concentration at 0 minutes were similar in both groups, while uraemic patients presented a reduced distribution volume. In all parameters measuring GH elimination, chronic renal failure patients showed an impaired clearance. In fact, the area under the curve (mU/l/150 min) was 912.8 ± 170.6 for controls and 3524.8 ± 642.8 for chronic renal failure patients (P < 0.005). The GH half‐life was 13.8 ± 1.6 and 26.4 ± 2.9 minutes for control and uraemic subjects respectively (P<0.05), and the metabolic clearance rate MCR (ml/min/m2) was 265.3 ± 50.6 for controls and 79.9 ± 16.4 for uraemic patients (P< 0.05). The GH mean residence time (minutes) (MRT) calculated was 12.0 ± 0.5 for controls and 31.8 ± 4.6 for chronic renal failure patients (P<0.05).

CONCLUSIONS Contrary to previous estimates, GH elimination kinetics follows a bi‐exponential model and in normal subjects the GH half‐life of the second phase is 13.8 ± 1.6 minutes. Uraemic patients have impaired clearance of GH, suggesting that the kidney plays a role in GH disposal. However, the degree of impairment does not fully explain the alterations in GH secretion previously described in chronic renal failure.
Hyperactivity of the hypothalamo‐pituitary‐adrenal axis in obesity: a study of ACTH, AVP, β‐lipotrophin and Cortisol responses to insulin‐induced hypoglycaemia
Authors: Weaver J. U. , Kopelman P. G. , McLoughlin L. , Forslingt M. L. , Grossman A.
Published: March 2008

OBJECTIVE The purpose of this study was to determine whether alterations in the hypothalamo‐pituitary‐adrenal axis and arginine vasopressin secretion, which have been associated with animal obesity, also occur in man.

DESIGN Cross‐sectional analysis of extremely obese women and normal weight controls.

PATIENTS Thirty‐three obese premenopausal, non‐diabetic women (mean age 31 years, mean body mass index (BMI) 41), and 15 normal weight controls (mean age 24 years, mean BMI 22).

MEASUREMENTS AND RESULTS Arginine vasopressin (AVP), ACTH, β‐lipotrophin and Cortisol responses to insulin‐induced hypoglycaemia (0 2 units Actrapid/kg body weight for obese; 0.15 unit/kg for controls) were measured. The obese women were further characterized by anthropometric measurements (weight, body mass index, fat distribution) and indices of insulin secretion/ resistance: fasting insulin, insulin secretion during 75‐g oral glucose tolerance test area under curve, insulin‐stimulated gucose disposal and an index of insulin resistance. No significant differences were found in the basal levels of ACTH, AVP, β‐lipotrophin or Cortisol. An augmented peak β‐LPH (n = 16, P<0 02, the difference of the mean 3 65,95% confidence interval 1 33–10) and ACTH (n=16, P= 0 05, the difference of the mean 2 12, 95% CI 1–0–4 5) response were found in obese as compared with normal weight controls. Both ACTH and AVP areas under the curve were similar in both groups studied. There was additionally a direct positive association between the integrated ACTH response (area under the curve) and the weight of the obese subjects (P<0 05, r2= 0 265). The Cortisol response was negatively correlated with insulin‐stimulated glucose disposal (P<001, r2= 0 23), but not with other indices of insulin secretion/resistance (fasting insulin, oral glucose tolerance test area under the curve, index of insulin resistance) or fat distribution.

Comparable responses to hypoglycaemia were seen for AVP and Cortisol. There was no correlation between the ACTH, AVP or Cortisol responses.

CONCLUSION Obesity is associated with increased activity of the hypothalamo‐pituitary‐adrenal axis as supported by augmented ACTH and β‐lipotrophin secretion in response to insulin‐induced hypoglycaemia and the positive association between the ACTH response and the body weight of obese women studied.
Pharmacokinetic properties of the tocolytic agent [Mpa1d‐Tyr(Et)2, Thr4, Orn8]‐oxytocin (antocin) in healthy volunteers
Authors: Lundin S. , Broeders A. , Melin P.
Published: March 2008

OBJECTIVE The aim of this study was to study the pharmacokinetics of antocin, the tocolytic oxytocin antagonist [Mpa1d‐Tyr2(Et), Thr4, Orn8]‐oxytocin.

DESIGN Antocin was injected intravenously as a bolus dose (5 μmol). Blood samples were taken at intervals for 240 minutes. In addition, the binding of 125I‐Tyr10‐antocin to blood constituents was determined and compared with 125I‐AVP and 125I‐[Mpa‐1d‐Arg8]‐vasopressin (desmopressin).

SUBJECTS Eight healthy, non‐smoking adults, three male and five female.

MEASUREMENTS Antocin was measured using a specific radioimmunoassay after prior extraction of the plasma. Plasma binding was estimated using polyethyleneglycol precipitation.

RESULTS The rate of plasma disappearance of antocin was best fitted by a biexponential curve. The clearance of antocin was 23.5 ± 7–6 I/h, the volume of distribution was 13.1 ± 3.8 I and the biological half‐life was 39.0 ± 4.1 minutes, A greater proportion of 125l‐Tyr,10‐antocin bound to plasma proteins (33.5%) and red blood cells (13%) than did 125I‐AVP, 125l‐desmopressin and unlabelled desmopressin.

CONCLUSIONS The half‐life was longer and the clearance of antocin was less than that found in a previous study when a non‐specific antiserum was used. This is most likely because of the extended blood sampling time period which revealed the biphasic decay pattern. The higher plasma clearance of antocin compared to oxytocin and desmopressin may be explained by its increased binding to blood constituents rather than by differences in enzymatic degradation of the molecules.
Pituitary adenomas with high and low basal inositol phospholipid turnover; the stimulatory effect of kinins and an association with interleukin‐6 secretion
Authors: Jones T. H. , Kennedy R. L. , Justice S. K. , Price A.
Published: March 2008

OBJECTIVE We examined basal inositol phospholipid turnover and the response to the kinin, kallidin, in human pituitary adenomas and determined whether or not there was an association between these parameters and interleukin (IL‐6) secretion status by the tumours.

DESIGN Pituitary adenoma tissue was dispersed and cells were cultured in monolayer for 96 hours. The medium was then removed and assayed for IL‐6 and anterior pituitary hormones. The cells were labelled with 3H‐myoinositol for 24 hours and then incubated under basal conditions with kallidin and, in some cases, with TRH and GnRH for 60 minutes. Total inositol phosphate accumulation and pituitary hormone secretion were assessed.

PATIENTS Tissue was collected from 29 consecutive patients being treated surgically for pituitary adenomas.

MEASUREMENTS Total 3H‐inositol phosphates, growth hormone, prolactin, LH, FSH, TSH and immunoreactive IL‐6.

RESULTS Two groups of pituitary adenomas were identified, one with high and one with low basal inositol phospholipid turnover. Kallidin stimulated inositol phosphate accumulation in seven of the 29 adenomas studied. The kallidin‐responsive adenomas were associated with high basal phosphoinositide turnover. All seven kallidin‐responsive adenomas secreted IL‐6. The adenomas studied with high basal inositol phosphate production were also responsive to TRH and in two tumours to GnRH. Kallidin stimulated GH release in one GH‐secreting adenoma but had no effect on hormone secretion from any other tumour.

CONCLUSION Two groups of pituitary adenomas have been identified with high and low basal inositol phosphoinositide turnover. Phosphoinositide metabolism is readily stimulated by kallidin and TRH in adenomas with high but not low turnover. Kinin‐responsive adenomas secreted IL‐6 but IL‐6 secretor status does not preclude that they will respond to kallidin.
Discrimination between β‐endorphin and β‐lipotrophin in human plasma using two‐site immunoradiometric assays
Authors: Gibson S. , Crosby S. R. , White A.
Published: March 2008

OBJECTIVE We wished to discriminate between the opioid peptide β‐endorphin (β‐EP) and its non‐opioid precursor β‐lipotrophin (β‐LPH) in normal subjects and patients with ACTH‐related disorders.

DESIGN We produced monoclonal antibodies to β‐EP and β‐LPH for the development of two‐site immunoradiometric assays (IRMAs) which specifically quantitate β‐EP and β‐LPH.

PATIENTS Samples were obtained from patients with a range of ACTH‐related disorders and compared with 18 normal subjects. Peptide levels were also compared in six patients with Cushing's syndrome undergoing bilateral inferior petrosal sinus sampling with corticotrophin releasing hormone administration.

MEASUREMENTS In the β‐EP IRMA, antibody 6B2, specific for β‐EP 18–27, is radiolabeled and antibody 2E10, recognizing β‐EP 1–5, is coupled to Sephacryl S‐300 as solid phase. The IRMA is specific for β‐EP (β‐LPH cross‐reacts <0.02%), has a detection limit of 14 ± 0 7 pmol/l (n = 7) and has a within‐assay coefficient of variation of <10% between 4.9 and 1200 pmol/l. In the β‐LPH IRMA, antibody 6B2, which recognizes an epitope common to β‐LPH and β‐EP, is radiolabeled and paired with solid‐phase antibody 5C11 which recognizes β‐LPH 39–56. The binding site of this antibody ensures that β‐EP cannot be measured in the β‐LPH assay. The detection limit is 0.8 ± 0.1 pmol/l (n= 9) and the within‐assay coefficient of variation is <10% at concentrations 1.7–870 pmol/l.

RESULTS In normal subjects, β‐EP and β‐LPH levels were < 1.4–1.7 pmol/l (< 5–6 ng/l) and 2.5–6.7 pmol/l (29–77 ng/l) at 0930 h and < 1.4–1.7 pmol/l (<5–6 ng/l) and 1.9–4.5 pmol/l (22–49 ng/l) at 1600 h, respectively. In patients with ACTH‐related pathologies concentrations of β‐EP and β‐LPH paralleled those of ACTH. The ratio of β‐LPH: β‐EP in plasma varied between 3.2:1 and 38:1 in these patients demonstrating that β‐LPH is the major circulating peptide derived from the C‐terminal of pro‐opiomelanocortin in man. However, in two patients undergoing bilateral inferior petrosal sampling with corticotophin releasing hormone for diagnosis of Cushing's disease β‐EP concentrations increased rapidly during the first 5 minutes of the test, resulting in a sharp decrease in the β‐LPH: β‐EP ratio. These results suggest that β‐EP is preferentially released in response to acute corticotrophin releasing hormone stimulation.

CONCLUSIONS It is concluded that two‐site IRMAs for β‐EP and β‐LPH provide an easy approach to study the dynamic changes in processing of β‐LPH to β‐EP.
The determination of delta‐5‐androstenediol and its sulphate in serum and urine by gas chromatography‐mass spectrometry
Authors: Dikkeschei L. D. , Wolthers B. G. , Willemse P. H. B. , van der Pol H. , der Ruyter‐Buitenhuis A. W. , Nagel G. T.
Published: March 2008

OBJECTIVES We developed an assay for delta‐5‐andro‐stenediol (adiol) and delta‐5‐androstenediol‐3‐sulphate (adiol‐3S) in serum and adiol and total adiol sulphate (adiol‐S) in urine.

DESIGN An analytical procedure using HPLC and gas chromatography‐mass spectrometry was devised and tested for its reliability.

MEASUREMENTS After addition of deuterated androstenediol as internal standard, serum and urine samples were extracted. Steroid sulphates were hydrolysed. The extracts and hydrolysates were purified on HPLC, adiol was derivatized using heptafluorobutyric anhydride and finally quantified by gas chromatography‐mass spectrometry.

RESULTS The assay is accurate and reproducible. The coefficient of variation (CV) for the determination of adiol in serum samples is 4% (intra‐assay) and 9% (interassay) and for urine samples 3 and 8% respectively. The intra‐assay CV for the adiol‐3S analyses is 5% for serum and 2% for urine samples while the interassay CV values for adiol‐3S are 10% for serum and 7% for urine samples. The recovery of adiol and adiol‐3S from serum and urine samples is 97%.

CONCLUSIONS The developed assay meets the analytical demands needed for clinical applications.
Thyroxine suppressive therapy decreases bone mineral density in post‐menopausal women
Authors: Kung Annie W. C. , Lorentz Theodore , Tam Sidney C. F.
Published: March 2008

OBJECTIVE Hyperthyroidism is associated with increased bone turnover and decreased bone mass. This study aimed to evaluate the bone mineral density (BMD) of post‐menopausal women on long‐term thyroxine suppressive therapy.

DESIGN An age and sex‐matched cross‐sectional study.

PATIENTS Thirty‐four post‐menopausal women with carcinoma of thyroid, post total thyroidectomy nd M ablation, on L‐T4 for 12 2 ± 6–6 years (mean±SD). Controls were 34 age‐matched healthy Southern Chinese women.

MEASUREMENTS Total body and regional BMDs were determined by dual‐energy X‐ray absorptiometry. Bone turnover was assessed by biochemical markers.

RESULTS In the thyroxine treated group, total body mineral content was significantly lower than the controls (1652±356 vs 1994±270 g meaniSD,P<0 005). They also had lower BMDs in the lumbar spine, femoral neck, trochanter and Ward's triangle (0 75 ± 0 15 vs 0 92 ± 0 16 g/ cm2, P<0005; 0–62±0–12 vs 0–70±0–12 g/cm2,P<0–01; 0–55±0–14 vs 063±015 g/cm2, P<0.001; 055±014 vs 0–63 ±0–14 g/cm2, P < 0.005 respectively.) The thyroxine treated group also had higher serum alkaline phosphatase and osteocalcin levels as well as urinary hydroxypro‐line excretion, suggesting that they had high turnover bone loss. However, the Z‐scores of the various regional BMDs were correlated only with the serum osteocalcin level and showed no correlation with the serum thyroxine level or with the dosage or duration of thyroxine treatment. CONCLUSION Long‐term thyroxine suppressive therapy was associated with bone loss and preventive therapy may be indicated in these post‐menopausal women at risk of osteoporosis.
A long‐term follow‐up study of patients with non‐toxic diffuse goitre in Japan
Authors: Hara Takeshi , Tamai Hajime , Mukuta Toshio , Fukata Shuji , Kuma Kanji , Nakagawa Tetsuya
Published: March 2008

OBJECTIVE Although non‐toxic diffuse goitre is a common disorder, little is known of the clinical course of patients. We therefore decided to investigate the long‐term clinical outcome of patients with non‐toxic diffuse goitre.

DESIGN A retrospective study.

PATIENTS Of 850 patients with non‐toxic diffuse goitre who met our criteria and were seen in our thyroid clinic between 1977 and 1985, 108 who had been followed for from 5 to 14 years (mean 8 years) were entered in this study. All patients fulfilled our criteria having soft diffuse goitres, normal serum TSH and T4 concentrations, and undetectable antithyroglobulin and antithyroid microsomal antibodies.

MEASUREMENTS A family history of thyroid disease was obtained and the occurrence of Graves' ophthalmopathy was noted. Serum TSH and T4 concentrations, and antithyroglobulin and antithyroid microsomal antibodies were measured during the follow‐up period. Thyroidal radioactive iodine uptake (RAIU), serum free T4 and free T3 concentrations, and TSH binding inhibitory immunoglobulin (TBII) activities were determined in all patients who were subsequently found to have abnormal serum TSH or T4 concentrations or signs of Graves' ophthalmopathy.

RESULTS Thirty‐six of the 108 patients (33%) had a family history of autoimmune thyroid disease. Elevated serum T4 or free T4 concentrations and depressed serum TSH concentrations were found in six patients during the follow‐up period. Hyperthyroid Graves' disease was diagnosed in four of the six patients, subacute thyroiditis in one, and transient post‐partum thyrotoxicosis in one. Hypothyroidism was found in one patient who was diagnosed as having transient post‐partum hypothyroidism. Euthyroid Graves' disease was diagnosed in one patient. Furthermore, six of these eight patients had a family history of autoimmune thyroid disease in first‐degree relatives.

CONCLUSION During a prolonged follow‐up period of patients with non‐toxic diffuse goitre, Graves' disease was found in five of 108 patients (four hyperthyroid Graves' and one euthyroid Graves'), post‐partum thyroid dysfunction in two, and subacute thyroiditis in one. Six of these eight patients had a family history of autoimmune thyroid disease in first‐degree relatives. Long‐term follow‐up is necessary for patients with non‐toxic diffuse goitre, especially those who have a family history of autoimmune thyroid disease.
Leucine metabolism in patients with Cushing's syndrome before and after successful treatment
Authors: Bowes S. B. , Benn J. J. , Scobie I. N. , Umpleby A. M. , Lowy C. , Sönksen P. H.
Published: March 2008

OBJECTIVE Results from studies on the effect of glucocor‐ticosteroids on protein turnover in both rat and man have been conflicting. The aim of this study was to investigate the primary cause of muscle wasting in patients with Cushing's syndrome.

DESIGN Studies of whole body 1‐14C‐leucine turnover in patients with Cushing's syndrome before and after successful treatment, and in control subjects.

PATIENTS Eleven patients with Cushing's syndrome before and after (n= 5) treatment and 11 control subjects.

MEASUREMENTS Whole body 1‐14C‐leucine turnover to determine leucine metabolic clearance rate, leucine production rate, leucine oxidation rate and leucine incorporation into protein.

RESULTS Plasma leucine concentration (mean ± SEM 100 ± 6 μ mol/l), leucine metabolic clearance rate (9.97 ± 0.11 μ mol/min/kg), leucine turnover (0.98 ± 0.11 μ mol/min/kg) and leucine incorporation into protein (0.71 ± 0.09 μ mol/min/kg) were all significantly reduced in patients with Cushing's syndrome compared with control subjects (122 ± 6 μ mol/l, P < 0.05; 13.61 ± 1.27 μ mol/min/kg, P < 0.05; 1.65 ± 0.12 μ mol/min/kg, P < 0.05; 1.46 ± 0.10 μ mol/min/kg, P < 0.001, respectively). Leucine oxidation rate was similar in the patients with Cushing's syndrome and control subjects. When leucine metabolism was expressed in terms of lean body mass (LBM) in five patients with Cushing's syndrome and 11 control subjects, leucine MCR, leucine turnover and leucine oxidation were not significantly different in the two groups. However, leucine incorporation into protein was significantly reduced (P< 0.001) in the patients with Cushing's syndrome (1.07 ± 0.20 μ mol/min kg LBM) compared with control subjects (1.95 ± 0.11 μ mol/min/kg LBM).

CONCLUSION We conclude from these studies that the muscle wasting associated with Cushing's syndrome is primarily due to a reduction in protein synthesis.
Necrosis of a phaeochromocytoma associated with spontaneous remission of diabetes and hypertension
Authors: Zanin Lucia , Rossi GianPaolo , Poletti Alessandro , Piotto Andrea , Chiesura‐Corona Matteo , Pessina Achille C.
Published: March 2008

The diagnosis of phaeochromocytoma is sometimes difficult since its clinical presentation is quite variable. We report a 52‐year‐old woman who presented with acute diabetes mellitus and severe hypertension, which spontaneously disappeared. MIBG‐scintigraphy and urine and plasma catecholamines were normal. At surgery, a largely necrotic phaeochromocytoma was found. Pathological examination demonstrated extensive avascular necrosis, which had occurred spontaneously without any major symptoms.
Alternate‐day GnRH therapy for ovarian hypofunction induced by weight loss: treatment of six patients who remained amenorrhoeic after weight gain
Authors: Kotsuji Fumikazu , Kubo Makoto , Takeuchi Yuzuru , Tominaga Toshiro
Published: March 2008

objective Body weight loss has an adverse effect on the pituitary‐ovarian function, and no restoration of the function occurs in 20–30% of patients even after the recovery of body weight. In the present study, the efficacy of alternate‐day GnRH therapy was investigated in six patients whose pituitary‐ovarian function had not recovered at 15 months to 6 years after the recovery of body weight.

DESIGN Synthetic GnRH (100 μg) was injected intramuscularly on alternate days for a total of 12 doses. On the completion of GnRH administration the efficacy of clomi‐phene‐human chorionic gonadotrophin (hCG) therapy was evaluated. A GnRH loading test and evaluation of LH secretion patterns were also performed to investigate the changes in hypothalamic‐pituitary‐ovarian function secondary to GnRH treatment.

RESULTS All six patients ovulated in response to clomiphene‐hCG therapy after 1–3 courses of GnRH treatment. The ovulatory response to clomiphene‐hCG continued during follow‐up periods of 5 months to 5 years. The initial hormonal change induced by GnRH treatment was a rise in the basal serum FSH level and a return of the FSH response to GnRH loading. This was followed by an increase in serum LH and the return of LH response to GnRH loading. In all six patients, pulsatile LH secretion was absent before starting GnRH treatment. GnRH treatment produced LH pulses in five of the six patients, although the pulse frequency was less than that in normally cycling women. A further increase in the pulse frequency was observed during clomiphene therapy.

CONCLUSIONS Alternate‐day GnRH administration is effective in inducing responsiveness to clomiphene in patients with anovulation secondary to weight loss.
Effects of norethisterone on bone related biochemical variables and forearm bone mineral in post‐menopausal osteoporosis
Authors: Horowitz Michael , Wishart Judith M. , Need Allan G. , Morris Howard A. , Nordin B. E. Christopher
Published: March 2008

OBJECTIVE Progestogens may be a useful therapeutic alternative to oestrogen in the treatment of post‐menopausal osteoporosis. The purpose of this study was to determine the effects of norethisterone on forearm bone mineral content and bone related biochemical variables in patients with post‐menopausal osteoporosis.

DESIGN/PATIENTS The effects of treatment with norethisterone (5 mg/day) on bone related biochemical variables was determined in 44 women with post‐menopausal osteoporosis. The effects of norethisterone on forearm bone mineral content (FMC) were evaluated by serial measurements in 39 of these women.

MEASUREMENTS We measured forearm mineral content, forearm mineral density, forearm fat content and fat‐corrected forearm mineral density. Biochemical measurements included plasma calcium and plasma calcium fractions (ionized, protein bound, complexed and ultrafiltr‐able), alkaline phosphatase, bicarbonate, phosphate, albumin and globulins, serum parathyroid hormone, osteocalcin and 1,25‐dihydroxyvitamin D, radiocalcium (45Ca) absorption and fasting urinary calcium/creatinine, sodium/creatinine, phosphate/creatinine and hydroxypro‐line/creatinine molar ratios.

RESULTS After 4 months of treatment norethisterone produced a fall in plasma calcium (mean ± SEM from 2 40 ± 0 14 to 2 32 ± 0 13 mmol/l, P < 0 001), primarily in the non‐ionized calcium, due to a decrease in plasma bicarbonate (from 29 ± 0–28 to 27 ± 0–28 mmol/l, P < 0 001). There were decreases in urinary calcium/creatinine (from 0 41 ± 0 03 to 019 ± 0 02, P < 001) and sodium/creatinine (from 15 ± 11to10 ± 0 93, P< 0 001) molar ratios and a rise in the renal tubular maximum for calcium reabsorption (TmCa) (from 2 36 ± 0 041 to 2 55 ± 0 059 mmol/l of glomerular filtrate, P < 0 001). Plasma phosphate, urinary phosphate/creatinine and tubular maximum for phosphate reabsorption (TMP) all fell (P<001). Both the urinary hydroxyproline/creatinine (P < 0 001) and plasma alkaline phosphatase (P < 0 001) fell. Serum parathyroid hormone rose from 41 ±0 36 to 5‐5 ±0–51 pmol/l (P < 0 02) and radiocalcium absorption increased from 0 67 ±0 08 to 0 81 ±0 10 fx/h (P < 0 01). There was no change in serum 1,25‐dihydroxy vitamin D. After treatment with norethisterone for 4 months there was an increase in forearm bone mineral content (P<0 05) and a decrease in forearm fat content (P < 002). After two years treatment with norethisterone fat‐corrected forearm bone mineral content rose (mean change 17‐0 ± 5‐5 mg/cm, P < 0 01).

CONCLUSIONS These results suggest that norethisterone prevents bone loss in post‐menopausal osteoporosis by decreasing bone turnover, has a vitamin‐D independent effect on intestinal calcium absorption, and increases serum parathyroid hormone levels.
Tissue resistance to 1,25‐dihydroxyvitamin D without a mutation of the vitamin D receptor gene
Authors: Hewison M. , Rut A. R. , Kristjansson K. , Walker R. E. , Dillon M. J. , Hughes M. R. , O'Riordan J. L. H.
Published: March 2008

OBJECTIVE Hereditary vitamin D resistant rickets (HVDRR) is characterized by severe rickets and is often accompanied by alopecia. Mutations in the gene encoding the vitamin D receptor have been found in this condition. In a patient with the characteristic phenotype we have investigated the functional defect and sequenced the gene to seek a mutation.

DESIGN Patient and control cell lines prepared from skin fibroblasts and peripheral blood lymphocytes were used to measure binding of 1,25(OH)2D3 and to isolate vitamin D receptor mRNA. VDR cDNA was sequenced and transfected into receptor defective cells.

PATIENT A child with alopecia diagnosed as having rickets due to resistance to 1,25(OH)2D3.

MEASUREMENTS Cytosolic binding and nuclear association of 1,25(OH)2D3 were determined in patient and control cells, and functional response to 1,25(OH)2D3 assessed by measurement of 24‐hydroxylase activity. VDR mRNA was prepared, reverse transcribed, and cDNA sequenced. VDR cDNA was also transfected into VDR‐deficient CV‐1 cells and functional response to 1,25(OH)2D3 assessed by co‐transfection with a chloramphenicol acetyltransferase (CAT) reporter plasmid.

RESULTS VDR from the patient were able to bind 1,25(OH)2D3 but showed no nuclear localization resulting in an absence of functional response to 1,25(OH)2D3. Sequencing revealed that the VDR coding region was normal. Expression studies of the patient's VDR showed functionally normal VDR as evidenced by normal trans‐activation in the presence of 1,25(OH)2D3.

CONCLUSION These data indicate a new cause of tissue resistance to 1,25(OH)2D3 which occurs in the absence of mutations in the coding region of VDR gene and which is characterized by defective nuclear localization of this receptor.
The effect of morphine and naloxone administration on maternal oxytocin concentration in late pregnancy
Authors: Lindow Stephen W. , van der Spuy Zephne M. , Hendricks M. Salie , Nugent Fiona A. , Dunne Timothy T.
Published: March 2008

OBJECTIVE Modification of the inhibitory control of oxytocin secretion by endogenous opiates in late pregnancy may be one of the factors involved in the onset of labour. The interrelationships between exogenously administered opioids and oxytocin may demonstrate activity of this control mechanism.

This study was undertaken to investigate the effect of an opiate and an opiate antagonist on maternal oxytocin levels in late pregnancy.

DESIGN Patients were randomized to receive either morphine (5 mg), naloxone (2.4 mg) or sterile water (1 ml) intravenously.

PATIENTS Thirty women with singleton pregnancies greater than 36 weeks gestation who were not in labour were studied.

MEASUREMENTS Blood for peripheral oxytocin levels was sampled every 2.5 minutes for 15 minutes before and 15 minutes after administration of the assigned substance. Oxytoxin was measured by radioimmunoassay. Peripheral β‐endorphin levels were measured at the beginning and end of the study.

RESULTS There was no significant change in the maternal oxytocin concentration after administration of either morphine, naloxone or sterile water compared to pretreatment levels. β‐Endorphin levels did not change significantly, either from the beginning to the end of the study, or between groups.

CONCLUSION In late pregnancy exogenous opiates and opiate antagonists have no effect on maternal peripheral oxytocin levels.
Hypercalcaemia due to parathyroid hormone‐related protein: long‐term circulating levels may not reflect tumour activity
Authors: Savage Mark W. , Fraser William D. , Bodmer Charles W. , Ginty Andrew F. , Gallagher James A. , Robinson John , Williams Gareth
Published: March 2008

Parathyroid hormone‐related protein is responsible for the hypercalcaemia caused by many tumours. Measurement of parathyroid hormone‐related protein is becoming more accessible with the introduction of commercial assays. We report a case of hypercalcaemia of malignancy secondary to parathyroid hormone‐related protein in a woman with renal carcinoma. The parathyroid hormone‐related protein was assayed using a new immuno‐radiometric assay. We demonstrated an initial fall in parathyroid hormone‐related protein and calcium levels after surgery and a rise in both before clinical relapse. However, the clinical relapse was itself associated with a fall in serum parathyroid hormone‐related protein, nephrogenous cAMP and calcium, suggesting that the tumour had stopped producing parathyroid hormone‐related protein or perhaps that post‐translational processing had occurred as the tumour advanced. The tumour was investigated for parathyroid hormone‐related protein mRNA content using reverse transcriptase polymerase chain reaction, both at diagnosis in surgically removed material, and using post‐mortem specimens. The level of parathyroid hormone‐related protein mRNA, while present, was much reduced in the recurrent tumour suggesting that active parathyroid hormone‐related protein production fell substantially as the tumour advanced. This case suggests that, although demonstration of parathyroid hormone‐related protein in hypercalcaemia is useful for diagnosis, tumoral secretion of this product may alter.