J. A. H. Wass

SHORT AND LONG-TERM RESPONSES TO METYRAPONE IN THE MEDICAL MANAGEMENT OF 91 PATIENTS WITH CUSHING'S SYNDROME

Summary. objective To analyse the clinical and biochemical effects of metyrapone in the treatment of Cushings syndrome.

Long-term treatment of acromegaly with bromocriptine.

Seventy-three patients with active acromegaly were treated for three to 25 months with bromocriptine 10-60 mg/day. Seventy-one patients showed symptomatic and objective clinical improvement. This included reduction in excessive sweating, hand and foot size, and the number of headaches; improved facial appearance; and increased energy and libido. Abnormal visual fields became normal in two patients, one of whom had concomitant radiotherapy. Mean circulating growth hormone levels, obtained by averaging serial samples through the day, fell by more than 7 microng/l or became undetectable in 58 patients (79%) but did not reach normal values: only 15 patients had mean levels on treatment of 5 microng/l or less. Twenty-three patients were diabetic before treatment, and glucose tolerance became normal in 15 and improved in a further five. Provided the drug was started slowly side effects were minor when compared with the considerable clinical benefit obtained.

A single sleeping midnight cortisol has 100% sensitivity for the diagnosis of Cushing's syndrome

OBJECTIVE The diagnosis of Cushings syndrome remains a major challenge in clinical endocrinology. Various screening tests are commonly used to support a biochemical diagnosis in the context of clinical suspicion. The aim of this study was to compare the sensitivity in the diagnosis of Cushings syndrome of a single in‐patient sleeping midnight cortisol to a standard 48‐hour in‐patient low‐dose dexamethasone suppression test (LDDST) during the same admission.

Circadian variation of GH-independent IGF-binding protein in diabetes mellitus and its relationship to insulin. A new role for insulin?

Evidence is accumulating that a non‐GH dependent insulin‐like growth factor‐binding protein (IGF‐BP) is not only a carrier protein but also has an active role in the growth process.

An audit of the insulin tolerance test in adult subjects in an acute investigation unit over one year

OBJECTIVE We audited our practice of insulin tolerance testing (ITT) in terms of safety and technical success. We reviewed the results of those tests performed over a 12‐month period. By relating peak Cortisol response to 0900 h screening Cortisol level, we determined whether we could reduce the number of tests performed.

REDUCTION OF PITUITARY-TUMOUR SIZE IN PATIENTS WITH PROLACTINOMAS AND ACROMEGALY TREATED WITH BROMOCRIPTINE WITH OR WITHOUT RADIOTHERAPY

69 patients with prolactin-secreting or growth-hormone-secreting pituitary tumours were treated with bromocriptine with or without pituitary irradiation and followed up for 6 months to 6 1/2 years. Of 26 patients with prolactinomas, 11 had external pituitary irradiation in addition to bromocriptine. There was evidence of shrinkage of the pituitary tumour (either a reduction in fossa size or loss of visual-field defects) in 6 of these patients (23%), 3 of whom had been treated with bromocriptine alone. Of 43 acromegalic patients, 30 received external pituitary irradiation. 8 (19%) showed evidence of shrinkage of the pituitary tumour, including 2 who had received no radiotherapy. 1 patient treated with bromocriptine alone showed striking reduction in the size of his suprasellar extension, as assessed by serial computed-tomography scans over 11 months. At the same time his visual-field defects resolved and his deficient corticotrophin and thyrotrophin reserves returned to normal. Bromocriptine can reduce the size of both prolactin-secreting and growth-hormone-secreting pituitary tumours, and this is of potential importance in their management.

Hypertension is a major risk factor for aortic root dilatation in women with Turner's syndrome

Women with Turners syndrome (TS) have a threefold increase in mortality, primarily as a result of their cardiovascular complications. Recently, the risk of fatal aortic dissection has come to light as a major cause of mortality in women with TS. The aim of this study was to assess the prevalence of aortic root dilatation in a group of women with TS and to investigate the factors contributing to its development.

CORTICOTROPHIN RELEASING FACTOR: RESPONSES IN NORMAL SUBJECTS AND PATIENTS WITH DISORDERS OF THE HYPOTHALAMUS AND PITUITARY

Synthetic CRF‐41 has been given to 43 patients with hypothalamic, pituitary or adrenal diseases and contrasted with the responses in 20 normal subjects. In the normal subjects the mean increment in serum cortisol (± SE) was 276 ± 38 nmol/l; the increments showed a significant negative correlation with the basal serum cortisol levels (r= ‐0·56; P<0·02). The mean peak serum cortisol was 662 ± 34 nmol/1 and the mean peak corticosterone was 28·6 ± 3·8 nmol/1. There was a significant positive correlation between the peak serum corticosterone and cortisol concentrations (r= 0·84; P<0·0001). Dexamethasone pretreatment abolished the rise in cortisol in response to CRF‐41. The peak serum cortisol following CRF‐41 was not significantly different between the normal subjects and those patients with pituitary disease who had normal cortisol responses to insulin‐induced hypoglycaemia. However, in individual patients the peak cortisol levels induced by hypoglycaemia were greater than, but significantly correlated with, those induced by 100 μg of CRF‐41. Seven patients were ACTH deficient in response to hypoglycaemia, and of these six responded normally to CRF‐41. Only one of these patients had a lesion clearly originating in the hypothalamus; four had pituitary tumours with suprasellar extensions and the remaining patient had idiopathic GH and ACTH deficiency. Our data suggest that these patients have a functional defect of ACTH secretion due to the failure of CRF to reach the corticotroph. Of the four patients with pituitary‐dependent Cushings disease who were on no treatment at the time of testing, three showed an exaggerated and one a normal response to CRF‐41. These normal or enhanced responses of hypercortisolaemic patients with Cushings syndrome contrast with the complete inhibition of the responses to CRF‐41 in normal subjects given dexamethasone. In the treated patients with Cushings syndrome

Autoimmune thyroid syndrome in women with Turner's syndrome—the association with karyotype

OBJECTIVE Females with Turners syndrome (TS) are at an increased risk of developing autoimmune thyroid disease. Studies assessing the influence of karyotype on thyroid autoimmunity in adults with TS have yielded conflicting results but have been limited by small numbers. The aim of this study was to determine the frequency of thyroid autoimmunity in a large cohort of women with TS and to assess the influence of karyotype on the development of thyroid disease.

Development and Validation of a Specific Radioimmunoassay for Somatostatin in Human Plasma

Little is known about the factors controlling somatostatin secretion in man, and data are not available on the changes in circulating levels in various human physiological or pathophysiological states. This is mainly a consequence of the technical difficulties involved in measuring somatostatin in plasma. In the presence of plasma, binding of somatostatin tracer to antibody was consistently decreased by about 20%, and this could not be abolished by the addition of EDTA and aprotinin or by the use of specially prepared somatostatin-free plasma. Furthermore, in the presence of plasma, endogenous somatostatin does not dilute in parallel with synthetic cyclic somatostatin standard. We have, therefore, developed and validated a radioimmunoassay for somatostatin using prior extraction of the peptide onto leached silica glass. Tyrosine-11 somatostatin was iodinated using lactoperoxidase and purified on ODS silica. This method is superior to iodination using chloramine-T with CMC cellulose purification, and gives a highly purified preparation with a shelf-life of at least eight weeks. Using this tracer and a specific antiserum, the limit of sensitivity of the assay was 10 pg/ml, with an intra-assay coefficient of variation of 12% (n = 16) and inter-assay coefficient of variation of 15% (n = 10). Parallelism has been demonstrated between standard synthetic cyclic somatostatin and all extracted plasma samples. The mean recovery of exogenous somatostatin from plasma was 78%. The fasting level of immunoreactive somatostatin at 0900 hours in 40 normal subjects ranged from 17 to 81 pg/ml. Care is needed, however, when comparing these values with those obtained from other laboratories since standard preparations of somatostatin vary considerably in their immunopotency.