A Survey of the Current Methods Used in the UK to Assess Pituitary Function

A national survey of the current methods used by specialists to evaluate pituitary function in the UK was performed by postal questionnaire. Seventy-three respondents, of whom 89% were consultants and 80% clinical endocrinologists, returned the questionnaire. Fifty per cent routinely used the insulin stress test (IST) to evaluate the hypothalamo-pituitary-adrenal (HPA) axis, while 50% routinely used tetracosactrin stimulation, there being little overlap between the two groups. This represents a significant change in clinical practice since the last survey in 1988. In those who used ACTH stimulation there was almost an equal split into those who administered the tetracosactrin intramuscularly (45%) or intravenously (47%). Furthermore, either the peak or 60 min Cortisol value was used by 71% when interpreting the result of the test, despite the fact that in previous studies only the 30 min Cortisol value has been shown to correlate with the IST result. The IST remains the most frequently used method to assess growth hormone reserve in adult subjects. The thyrotrophin-releasing-hormone and gonadotrophin-releasing-hormone tests are still used routinely by approximately a quarter of clinicians. These results provide data that could be used to develop guide-lines for the use of tests to investigate pituitary function.

A cross-sectional study of the prevalence of cardiac valvular abnormalities in hyperprolactinemic patients treated with ergot-derived dopamine agonists

CONTEXT

Concern exists in the literature that the long-term use of ergot-derived dopamine agonist drugs for the treatment of hyperprolactinemia may be associated with clinically significant valvular heart disease.

OBJECTIVE

The aim of the study was to determine the prevalence of valvular heart abnormalities in patients taking dopamine agonists as treatment for lactotrope pituitary tumors and to explore any associations with the cumulative dose of drug used.

DESIGN

A cross-sectional echocardiographic study was performed in a large group of patients who were receiving dopamine agonist therapy for hyperprolactinemia. Studies were performed in accordance with the British Society of Echocardiography minimum dataset for a standard adult transthoracic echocardiogram. Poisson regression was used to calculate relative risks according to quartiles of dopamine agonist cumulative dose using the lowest cumulative dose quartile as the reference group.

SETTING

Twenty-eight centers of secondary/tertiary endocrine care across the United Kingdom participated in the study.

RESULTS

Data from 747 patients (251 males; median age, 42 y; interquartile range [IQR], 34-52 y) were collected. A total of 601 patients had taken cabergoline alone; 36 had been treated with bromocriptine alone; and 110 had received both drugs at some stage. The median cumulative dose for cabergoline was 152 mg (IQR, 50-348 mg), and for bromocriptine it was 7815 mg (IQR, 1764-20 477 mg). A total of 28 cases of moderate valvular stenosis or regurgitation were observed in 24 (3.2%) patients. No associations were observed between cumulative doses of dopamine agonist used and the age-corrected prevalence of any valvular abnormality.

CONCLUSION

This large UK cross-sectional study does not support a clinically concerning association between the use of dopamine agonists for the treatment of hyperprolactinemia and cardiac valvulopathy.

Pituitary apoplexy: retrospective review of 30 patients—is surgical intervention always necessary?

The objective of this article is to review clinical outcomes in patients presenting with pituitary apoplexy and compare the results of conservative and surgical management. It took the form of a retrospective review of 30 patients (23M, 7F; age range: 17-86 years) with pituitary apoplexy diagnosed between 1988 and 2004. Presenting features included headache in 27 patients, 'collapse' in three and vomiting in 14. Complete blindness occurred in four patients, monocular blindness in two, decreased visual acuity in 12, visual field loss in 10 and ophthalmoplegia in 15. Only five had no initial visual deficit. CT was the initial mode of imaging in 22 patients: three such scans were initially reported as 'normal' and a further 10 as pituitary tumour only, with no haemorrhage. Ten patients proceeded to early pituitary surgery and 20 were managed conservatively. There was one death 24 days after admission in a patient with multiple co-morbidities. Of the six patients with blindness, three (two conservatively treated) regained partial vision. Of the remaining 19 patients with visual deficits, 10 (two surgically treated) recovered fully and eight (four surgically treated) partly so. At latest follow-up the following pituitary hormone deficiencies were identified: ACTH 19; TSH 20; testosterone 18; ADH (diabetes insipidus) eight. Later recurrence of a pituitary adenoma was observed in seven cases (including six of the 10 surgically treated patients). There was no evidence that those patients managed surgically had a better outcome. Early neurosurgical intervention may not be required in most patients presenting with pituitary apoplexy.

Home administration of lanreotide Autogel by patients with acromegaly, or their partners, is safe and effective

OBJECTIVE

The introduction of ready-to-use lanreotide Autogel has presented the possibility of patients receiving their acromegaly treatment at home. The objective of this study was to assess the ability of patients (or their partners) to administer repeat, unsupervised, injections of lanreotide Autogel without compromising efficacy or safety.

DESIGN

Multicentre (10 UK regional endocrine centres), open-label, nonrandomised, controlled study. Patients elected either to receive/administer unsupervised home injections after injection technique training (Test group) or continued to receive injections from a healthcare professional (Control group). Patients received monthly injections of lanreotide Autogel at their established dose. Effects were monitored for up to 40 weeks.

PATIENTS

Thirty patients (15 per treatment group) with acromegaly treated with a stable dose of lanreotide Autogel (60, 90 or 120 mg) for > or = 4 months before screening. Measurements The main outcome measure was the proportion of patients/partners who successfully administered injections throughout the study.

RESULTS

All Test group patients/partners qualified to administer injections. Fourteen of 15 patients fulfilled all criteria for successful administration of unsupervised injections (95% confidence interval, 70%-99%). Fourteen of 15 Test and 14/15 Control patients maintained growth hormone and IGF-1 control. Local injection tolerability was good for both treatment groups, and safety profiles were similar. All Test group patients continued with unsupervised injections after the study.

CONCLUSIONS

Patients with acromegaly or their partners were able to administer lanreotide Autogel injections with no detrimental effect on efficacy and safety; therefore, unsupervised home injections are a viable alternative to healthcare professional injections for suitably motivated patients.

Pituitary incidentalomas

The optimal strategy for hormonal screening of a patient with any incidentally discovered pituitary mass is unknown. The authors' review of the endocrinologic literature supports the view that such patients are at slightly increased risk for morbidity and mortality. This risk implies a benefit of early diagnosis for at least for some of the disorders, suggesting the importance of case finding. Nevertheless, the data in Table 1 illustrate that clinically diagnosed hormone-secreting pituitary tumors are far less common than incidentalomas. Clinically, one cannot accurately determine the approximately 0.5% of patients with incidentaloma who are at increased risk among the vast majority who are not. Given the limitations of diagnostic tests, effective hormonal screening requires a sufficiently high pretest probability to limit the number of false-positive results. This condition is met to varying degrees in the patient with a small incidentally discovered pituitary mass but no signs or symptoms of hormone excess. Even the more common lesions, such as prolactinoma, are relatively rare. [table: see text] Subjecting patients to unnecessary testing and treatment is associated with risk. In addition to its initial cost, testing may result in further expense and harm as false-positive results are pursued, producing the "cascade effect" described by Mold and Stein as a "chain of events (which) tends to proceed with increasing momentum, so that the further it progresses the more difficult it is to stop." The extensive evaluations performed for some patients with incidentally discovered masses may reflect the unwillingness of many physicians to accept uncertainty, even in the case of an extremely unlikely diagnosis. This unwillingness may be driven, in part, by fear of potential malpractice liability, the failure to appreciate the influence of prevalence data on the interpretation of diagnostic testing, or other factors. The major justification for further evaluation of these patients is not so much to avoid morbidity and mortality for the rare patient who truly is at increased risk but to reassure patients in whom further testing is negative and the physician. Physicians must take care not to create inappropriate anxiety in patients by overemphasizing the importance of an incidental finding unless it is associated with a realistic clinical risk. The authors' recommendations are based on currently available information to minimize the untoward effects of the cascade. As evidence accumulates, these recommendations may need to be revised. The benefit of the diagnosis of an adrenal or pituitary disorder must be considered in the context of the patient's overall condition. Additional studies are needed to analyze the clinical utility of hormonal screening for these common radiologic findings. Data from these studies can be used to identify critical gaps in knowledge and to adopt the epidemiologic methods of evaluation of evidence that have been applied to preventive measures. One must be careful to recognize lead-time bias, in which survival can appear to be lengthened when screening simply advances the time of diagnosis, lengthening the period of time between diagnosis and death without any true prolongation of life; and length bias, which refers to the tendency of screening to detect a disproportionate number of cases of slowly progressive disease and to miss aggressive cases that, by virtue of rapid progression, are present in the population only briefly. Physicians must avoid the pitfalls of overestimation of disease prevalence and of the benefits of therapy resulting from advances in diagnostic imaging. Clinical judgment based on the best available evidence should be complemented and not replaced by laboratory data.

Management of pituitary incidentalomas. A survey of British and American endocrinologists

The results of a survey of endocrinologists concerning their approaches to the evaluation of a patient with an incidentally discovered pituitary mass are presented in this article. The practices of British and American endocrinologists are compared. The wide variation in diagnostic approaches to the practice of ordering tests in the United Kingdom and the United States highlights the need for research and debate regarding the most appropriate management of patients with such findings.

A defect in the regional deposition of adipose tissue (partial lipodystrophy) is encoded by a gene at chromosome 1q

Partial lipodystrophy (PLD), also known as "Dunnigan-Kobberling syndrome," is transmitted as a highly penetrant autosomal dominant disorder that is characterized by a dramatic absence of adipose tissue in the limbs and trunk, more evident in females than in males. In contrast, fat is retained on the face, in retro-orbital space, and at periserous sites. Associated metabolic abnormalities, including insulin resistance, hyperinsulinemia, and dyslipidemia, are referred to as "metabolic syndrome X" (Reaven 1988). Despite the intense interest in the genetic determinants underlying fat deposition, the genes involved in the lipodystrophic syndromes have not been identified. We ascertained two multigeneration families, with a combined total of 18 individuals with PLD, and performed a genomewide search. We obtained conclusive evidence for linkage of the PLD locus to microsatellite markers on chromosome 1q21 (D1S498, maximum LOD score 6.89 at recombination fraction .00), with no evidence of heterogeneity. Haplotype and multipoint analysis support the location of the PLD locus within a 21.2-cM chromosomal region that is flanked by the markers D1S2881 and D1S484. These data represent an important step in the effort to isolate and characterize the PLD gene. The identification of the gene will have important implications for the understanding of both developmental and metabolic aspects of the adipocyte and may prove useful as a single-gene model for the common metabolic disorder known as "syndrome X."

Correcting impotence in the male dialysis patient: experience with testosterone replacement and vacuum tumescence therapy

Sexual dysfunction remains a common and often distressing problem in the male dialysis population. Traditionally its management has consisted of correction of anemia, optimization of dialysis, removal of implicated medication, and finally depot injections of a testosterone ester. At a dedicated renal impotence clinic, we studied the effectiveness of testosterone replacement in men with biochemically proven hypogonadism and then vacuum tumescence therapy in those with continued erectile dysfunction. Depot testosterone was given to 27 patients (aged 52.4+/-2.5 years; duration of dialysis, 2.00+/-0.40 years; and duration of sexual dysfunction, 2.92+/-0.49 years): sexual function was fully restored in only three (11.1%), and two gradually lost the response over 18 months. Nineteen patients (70.3%) had partial responses, varying from an increased sense of well-being alone to restored sexual function apart from an impairment of the duration of penile erection. Five patients (18.5%) had no response, and testosterone was contraindicated in another four. Four of the treated patients (14.8%) reported fluid retention. Vacuum tumescence devices were then offered to 32 patients who remained impotent but declined by six. Twenty-six patients (aged 49.6+/-2.2 years; duration of dialysis, 2.50+/-0.58 years; and duration of sexual dysfunction, 3.26+/-0.56 years) used the devices, with 19 (73.1%) having full correction of their erectile dysfunction; six also continued with depot testosterone to maintain their libido. Penile discomfort was described by five patients (19.2%) whose potency was not restored. A further five predialysis patients have used the devices, and all had correction of their erectile dysfunction. The correction of biochemical hypogonadism in the male dialysis population with testosterone rarely restores sexual function to normal, whereas vacuum tumescence therapy corrects penile erection dysfunction in most patients.

Cabergoline treatment of acromegaly: a preliminary dose finding study

OBJECTIVES

Studies of the dopamine agonist cabergoline in the treatment of hyperprolactinaemia have shown it to be a potent, long-acting and well-tolerated. The older dopamine agonist, bromocriptine, has traditionally had a place in the medical management of acromegaly, but poor patient tolerance of the high doses required, the need for multiple daily administration and incomplete biochemical responses have limited its role. We therefore sought to investigate the effect of cabergoline on growth hormone (GH) secretion in acromegaly and to define the most appropriate dose for suppression of GH DESIGN AND MEASUREMENTS: Patients with active acromegaly (defined as most recent random GH > 5 mU/l) were identified from the departmental clinical information system. After informed consent was obtained, basal GH levels were estimated during a 5 point day curve at least 2 months after withdrawal of any existing medical therapy for acromegaly. The cabergoline dose was escalated on a monthly basis for 4 months with a repeat 5 point GH day curve at the highest dose, and 0900 and 0930 GH estimations at the intermediate dose increment stages. Serum IGF-1 and prolactin were estimated on each occasion. Biochemical remission was defined as serum GH < 5 mU/l.

PATIENTS

Eleven acromegalics were investigated. Previous treatment included surgery (7), radiotherapy (5) and bromocriptine (5). Three patients had not received any previous treatment. All had random GH persistently > 5 mU/l prior to the study.

RESULTS

Ten patients completed the study. Of these, 7 showed a fall in the GH to < or = 33% and IGF-1 to < or = 67% of the basal value but only 2 achieved biochemical remission. All subjects showed maximum GH response at a dose of 0.5 mg daily of cabergoline. Four patients were unable to tolerate the maximum dose of 1 mg daily (nausea in one and nonspecific symptoms in three). The patient excluded from the analysis discontinued cabergoline and underwent surgery after 1 month because of worsening visual field defects.

CONCLUSIONS

Cabergoline may be a useful adjunct to the currently available treatment for acromegaly, but rarely achieves the goal of mean GH < 5 mU/l. The maximum suppression of GH is achieved within the dose range 1 mg twice weekly to 0.5 mg daily.

Erythropoietin and sexual dysfunction

BACKGROUND

Erythropoietin (rHuEpo) therapy has been shown to improve sexual function in the male dialysis population, with several studies suggesting a direct effect upon endocrine function, as well as correction of anaemia. Nevertheless many male dialysis patients receiving rHuEpo continue to complain of sexual dysfunction.

METHODS

At a dedicated renal impotence clinic, 65 male dialysis patients were screened for endocrine disturbances. Baseline serum sex hormones were compared between those receiving and not receiving rHuEpo, using either the two-sample t test or the Mann-Whitney U test, after assessing for normality. Results from four patients were excluded on account of either medications (antiemetic phenothiazines), hepatic dysfunction, or carcinomatosis.

RESULTS

Twenty-five patients (41.0%) were receiving rHuEpo, the recipients and non-recipients being well matched for haemoglobin (10.19 +/- 0.29 vs 10.55 +/- 0.25 g/dl, n.s.), age (51.1 +/- 1.9 vs 53.6 +/- 2.1 years, n.s.) and duration of sexual dysfunction (median, 3.0 vs 3.0 years, n.s.). The rHuEpo recipients had a higher median creatinine (1090 vs 972 micromol/l, P < 0.02), but similar nutritional status to the non-recipients (albumin 41.0 vs 39.0 g/l, n.s.). The total duration of rHuEpo therapy was 0.85 +/- 0.14 years. Prolactin levels were similar in both the rHuEpo recipients and non-recipients (440 vs 541 mu/l, n.s.), as were LH (11.0 vs 10.5 iu/l, n.s.) and FSH (8.0 vs 6.5 iu/l, n.s.). However, there were significant elevations of testosterone (19.8 +/- 1.3 vs 16.1 +/- 1.1 nmol/l, P < 0.05) and sex hormone binding globulin (SHBG) (40.5 vs 26.0 nmol/l, P < 0.01), with a trend toward elevated oestradiol (304 vs 248 pmol/l, P = 0.095) in the rHuEpo-treated group. Forty-eight subjects (78.7%) received peritoneal dialysis (PD), with the 19 rHuEpo recipients (39.6%) demonstrating increased serum testosterone (21.0 +/- 1.5 vs 16.6 +/- 1.3 nmol/l, P < 0.05), SHBG (40.5 vs 26.5 nmol/l, P < 0.01), LH (15.0 vs 10.0 iu/l, P < 0.01) and FSH (12.0 vs 5.3 iu/l, P < 0.05). These differences were not demonstrated in the 13 haemodialysis (HD) subjects.

CONCLUSIONS

Male dialysis patients complaining of sexual dysfunction after correction of anaemia with rHuEpo are characterized by higher levels of serum testosterone and SHBG, but not suppression of hyperprolactinaemia or hyperoestrogenism. Male PD subjects receiving rHuEpo also demonstrated increased LH and FSH.

An assessment of optimal hydrocortisone replacement therapy

OBJECTIVE

To assess the management of hydrocortisone replacement therapy in one institution, and derive recommendations for optimum starting and maintenance replacement therapy with hydrocortisone.

DESIGN

Retrospective survey of clinical management using a clinical information system and the patient case notes.

PATIENTS

Using the department's clinical information system, 210 patients were identified who had been treated with hydrocortisone. Case notes were reviewed and 130 patients were identified whose records contained the results of at least one valid hydrocortisone day curve. Data on 174 day curves performed on these patients (65 on twice daily and 109 on thrice daily hydrocortisone regimes) formed the basis of this analysis.

METHODS

Hydrocortisone day curves had been performed as part of routine clinical management: patients collected a 24 h urine for free cortisol on the day prior to the test and took their morning hydrocortisone at the normal time, at home, on wakening. During a day-case attendance serum cortisol was then measured at 0900 h, 1230 h (prior to any lunchtime dose) and 1730 h (prior to the evening dose). 'Optimal replacement' was arbitrarily defined as that dose which achieved a UFC and 09:00 h cortisol within the reference range for the normal population (to avoid over-replacement) combined with 1230 h and 1730 h cortisol above 50 nmol/l, and ideally above 100 nmol/l (to avoid under-replacement). Raw data from all hydrocortisone day curves was analysed in an Excel spreadsheet to determine the effect of different dose regimens on the percentage of patients achieving each and all of these 4 criteria, and on an overall 'quality score' (comprising 1 point for each of the 4 criteria attained).

RESULTS

Patients on twice daily hydrocortisone regimes achieved optimal replacement in 15% of cases compared to 60% on thrice daily regimes (P < 0.001 by chi 2); mean overall 'quality scores' for these regimens were 2.72 and 3.49 respectively (P < 0.001 by t-test). Of individual dose regimens with sufficient cases for valid comparison, a dose of 10 mg/5 mg/5 mg (rising/lunch/evening) achieved optimal replacement in 66% and mean 'quality score' of 3.62 (n = 53), compared to 50% and 3.32 for 10 mg/ 10 mg/5 mg (n = 28) and 10% and 2.48 for 20 mg/-/10 mg (n = 29).

CONCLUSIONS

The use of arbitrary, but logical, criteria to assess the quality of hydrocortisone replacement regimens indicates that optimal replacement is achieved with thrice daily hydrocortisone regimens, and that the traditional twice daily regime results in a 0900 h cortisol above normal in one-third, and late afternoon cortisol below 50 nmol/l in one-half of patients thus treated. An appropriate starting dose of hydrocortisone of 10 mg/5 mg/5 mg (rising/lunch/evening) is suggested, with subsequent individual adjustment based on simple hydrocortisone day curves.

Dunnigan-Kobberling syndrome: an autosomal dominant form of partial lipodystrophy

Dunnigan-Kobberling syndrome is a form of partial lipodystrophy characterized by sparing of the face. Despite descriptions of six families since 1974, details of total body adipose tissue distribution and studies of carbohydrate and fat metabolism are lacking. The mode of inheritance also remains unclear, with most authors favouring an X-linked dominant transmission lethal in the hemizygous male. We examined 23 members of a family, of whom at least eight had partial lipodystrophy. Auxological evaluation and cross-sectional imaging showed absence of subcutaneous fat, presence of adipose tissue inside the body cavities, and skeletal muscle hypertrophy. Biochemical evaluation identified insulin resistance but revealed inadequate suppression of non-esterified fatty acids. In this family, male-to-male transmission supports an autosomal dominant mode of inheritance for Dunnigan-Kobberling syndrome.

The use of the short tetracosactrin test for the investigation of suspected pituitary hypofunction

The short Synacthen (tetracosactrin) test (SST) is an established method of assessing adrenocortical reserve, and is increasingly replacing the insulin tolerance test (ITT) for the assessment of the hypothalamic-pituitary-adrenal (HPA) axis. However, there is no consensus on how the test is performed, and various time points and routes of administration are used. The present study was done, first, to determine whether there was any difference in cortisol responses when Synacthen was administered intramuscularly compared with intravenously and, secondly, to compare cortisol responses at 30 and 60 min. We found no significant difference between the two routes of administration. However, cortisol responses at 60 min were significantly higher than at 30 min (P < 0.05). Previous validations for the use of the SST in place of the ITT have used cortisol responses 30 min after Synacthen. We conclude that where the SST is used to assess the HPA axis, cortisol response at 30 min after intravenous Synacthen should be used.

Two macroprolactinomas presenting with neurological signs

Macroprolactinomas commonly cause pressure effects on immediate parasellar structures, in particular on the optic chiasm to cause visual field defects. Pressure on more distant brain structures is rarely reported. We describe two massive prolactinomas presenting with neurological signs, including signs of hemiparesis which, to our knowledge, has not been reported previously.

Imaging in endocrinology: use of a potential methodology for audit consensus development

OBJECTIVE

To explore areas of consensus in the use of imaging techniques in the investigation of endocrine disorders.

DESIGN

A postal questionnaire sent to members of the Endocrine Section of the Royal Society of Medicine following a meeting of the Section in January 1993 on Imaging in Endocrinology.

SUBJECTS

Fifty-two specialists completed the questionnaire which was sent in the first mailing after the meeting.

MEASUREMENTS

Consensus statements were defined as those in which greater than 75% of respondents either agreed or opposed the statement. Majority support or rejection was defined as greater than 50% in favour with less than 25% opposed or vice versa.

RESULTS

Many areas of consensus were defined particularly in the field of the use of imaging in the investigation of pituitary disease. The questionnaire highlighted difficulties in obtaining a consensus view on the imaging techniques which should be employed in the investigation of thyroid, parathyroid and pancreatic disorders.

CONCLUSION

The results are a useful guide to areas in which further discussion and/or research is required. This methodology could, and we believe should, be applied to other areas of endocrine practice. Such results provide an initial data base to develop national audit guide-lines on the use of imaging techniques in endocrine disorders.

Preliminary observations using endocrine markers of pituitary venous dilution during bilateral simultaneous inferior petrosal sinus catheterization in Cushing's syndrome: is combined CRF and TRH stimulation of value?

OBJECTIVE

We determined whether the measurement of hormones in pituitary blood permits correction for dilution by non-pituitary blood during bilateral simultaneous inferior petrosal sinus blood sampling in Cushing's syndrome.

DESIGN

Bilateral simultaneous inferior petrosal sinus blood sampling was performed after combined hCRF and TRH stimulation. Peak ACTH concentrations were corrected for the TSH and PRL inter-sinus ratio, assuming uniform secretion of both hormones into each inferior petrosal sinus.

PATIENTS

Eight patients with clinical and biochemical features of Cushing's syndrome.

MEASUREMENTS

Basal and stimulated ACTH, TSH and PRL concentrations were measured after bilateral simultaneous inferior petrosal sinus blood sampling and simultaneously from a peripheral forearm vein.

RESULTS

Basal central:peripheral ACTH ratio misdiagnosed four of eight patients as having non-pituitary disease. Peak uncorrected ACTH central:peripheral ratio erroneously suggested two of eight patients had non-pituitary disease. ACTH central:peripheral ratio corrected by TSH and PRL correctly predicted pituitary-dependent disease in all eight cases and provided correct lateralization data in four of five patients with a unilateral pituitary microadenoma.

CONCLUSION

This study suggests that measuring other hormones in pituitary blood after TRH stimulation can offer a simple and reliable method for correcting for dilution by non-pituitary blood during bilateral simultaneous inferior petrosal sinus blood sampling in Cushing's syndrome.

Investigation of Cushing's syndrome by inferior petrosal sinus sampling

Bilateral simultaneous inferior petrosal sinus sampling, in combination with CRH stimulation, is now able to confirm the diagnosis of pituitary-dependent Cushing's disease with near certainty. In expert hands, the procedure is straightforward and safe. As well as confirming the differential diagnosis, the test may aid surgical success, especially if no adenoma is apparent at transsphenoidal exploration. In this article, we review the technique and its interpretation and consider which patients should undergo the procedure.

Transsphenoidal resection in Cushing's disease: undetectable serum cortisol as the definition of successful treatment

OBJECTIVE

We tested the hypothesis that in Cushing's disease, ACTH secretion from the normal pituitary surrounding an ACTH-secreting adenoma is inhibited and hence removal of the entire adenoma should result in an undetectable serum cortisol in the immediate post-operative period.

DESIGN

A retrospective study of patients undergoing transsphenoidal selective adenomectomy, hemi-hypophysectomy or total hypophysectomy for Cushing's disease at St Bartholomew's Hospital between 1985 and 1990.

PATIENTS

Forty-eight consecutive patients (33 women, mean age 43, range 7-69 years) undergoing transsphenoidal hypophysectomy for Cushing's disease. Ten patients who underwent a second operation were re-evaluated; the patients were followed for a median time of 40 months after operation (range 15-70).

MEASUREMENTS

Post-operatively, serum cortisol was measured daily at 0900 h. Serum TSH, T4, prolactin, LH, FSH, testosterone or oestradiol plus plasma and urine osmolality were measured.

RESULTS

After initial surgery, post-operative serum cortisol was undetectable (< 50 nmol/l) in 20 out of 48 patients (42%) and < 300 nmol/l in 32 out of 48 patients (67%). Re-exploration of the pituitary fossa in 10 patients found undetectable cortisol levels in 25 (52%) and levels < 300 nmol/l in 39 (81%) patients. Cushing's syndrome has not recurred, clinically or biochemically, in any patient in whom the post-operative cortisol was < 50 nmol/l. Post-operatively, hypothyroidism was present in 40% of patients and hypogonadism in 53% of men and 30% of premenopausal women. Diabetes insipidus, persisting for at least six months, occurred in 46% of patients.

CONCLUSIONS

Cushing's disease has not recurred in any patient with an undetectable serum cortisol (< 50 nmol/l) post-operatively. Serum cortisol should be regarded as a tumour marker in Cushing's disease and the aim of transsphenoidal hypophysectomy for Cushing's disease should be to render the immediate post-operative serum cortisol undetectable.

A case of multiple endocrine neoplasia: hyperparathyroidism, insulinoma, GRF-oma, hypercalcitoninaemia and intractable peptic ulceration

A 42-year-old woman with a family history of multiple endocrine neoplasia type 1 (MEN 1) presented with symptomatic hypoglycaemia and peptic ulceration. Investigation revealed an insulinoma, hyperparathyroidism, hypercalcitoninaemia with a positive pentagastrin stimulation test, acromegaly due to a GRF-oma, hyperprolactinaemia and normal serum gastrin levels. Five pancreatic tumours were removed at laparotomy and immunostaining was positive for insulin, calcitonin, somatostatin and glucagon. Post-operatively she developed elevated serum gastrin levels and gross peptic ulceration, despite H2-blockers, and died of gastro-intestinal haemorrhage suggesting that removal of the somatostatinoma may have allowed increased gastrin secretion from a gastrinoma. This case emphasizes the importance of measuring a wide variety of tumour marker peptides in MEN 1 and suggests that caution is required in interpretation of the pentagastrin stimulation test in such cases. Patients with MEN 1 and known peptic ulceration may require perioperative omeprazole treatment even if serum gastrin levels are normal.

A retrospective audit of the combined pituitary function test, using the insulin stress test, TRH and GnRH in a district laboratory

OBJECTIVE

To assess the value of the combined insulin stress test (IST), thyrotrophin-releasing hormone (TRH) and gonadotrophin hormone-releasing hormone (GnRH) tests.

DESIGN

A retrospective audit of 232 such tests performed between 1980 and 1989 inclusive.

PATIENTS

One hundred and ninety-seven patients with known or suspected pituitary disease.

MEASUREMENTS

IST, TRH and GnRH responses were retrieved from laboratory records. Case notes were surveyed for clinical data and additional results.

RESULTS

A basal serum cortisol level of less than 100 nmol/l (or less than 200 nmol/l in patients who had recently received glucocorticoid replacement therapy) accurately predicted a subnormal response to hypoglycaemia. All patients with a basal cortisol level of greater than 400 nmol/l, except those who had recently received steroids, showed a normal cortisol response. In retrospect, by consideration of such basal values, 55% of ISTs could have been avoided if the only aim was to assess cortisol reserve. A deficient growth hormone (GH) response to hypoglycaemia was, however, common in patients with a normal cortisol response. Two-thirds of patients with GH deficiency would have been missed if an IST had been avoided on the basis either of basal cortisol levels alone, or of cortisol responses to an alternative test which did not test GH reserve. There was poor agreement between the pituitary response to TRH and GnRH and basal levels of thyroxine and gonadotrophins respectively, suggesting that these releasing hormone tests are misleading.

CONCLUSIONS

The IST provides information regarding pituitary function not provided by other tests of the hypothalamic-pituitary-adrenal axis, so that the choice between the IST and alternative tests must depend on a critical assessment of what information is required. Routine TRH and GnRH testing appears to yield little information of practical clinical value.

Short and long-term responses to metyrapone in the medical management of 91 patients with Cushing's syndrome

OBJECTIVE

To analyse the clinical and biochemical effects of metyrapone in the treatment of Cushing's syndrome.

DESIGN

An evaluation of the standard clinical practice at one institution.

PATIENTS

Ninety-one patients with Cushing's syndrome: 57 pituitary-dependent Cushing's disease, 10 adrenocortical adenomas, six adrenocortical carcinomas and 18 ectopic ACTH syndrome.

MEASUREMENTS

The acute response to metyrapone was assessed by measuring cortisol, 11-desoxycortisol and ACTH at 0, 1, 2, 3, 4 hours after a test dose of 750 mg of metyrapone. The longer-term effect of metyrapone was judged by measuring serum cortisol at 0900, 1200, 1500, 1800, 2100 and sometimes 2400 h and calculating a mean.

RESULTS

A test dose of 750 mg of metyrapone decreased serum cortisol levels within 2 hours in all groups of patients and this effect was sustained at 4 hours. At the same time, serum 11-desoxycortisol levels increased in all patients, while plasma ACTH increased in patients with pituitary Cushing's disease and the ectopic ACTH-syndrome. Fifty-three patients with Cushing's disease were followed on short-term metyrapone therapy (1 to 16 weeks) before other more definitive therapy. Their mean cortisol levels (median 654 nmol/l, range 408-2240) dropped to the target range of less than 400 nmol/l in 40 patients (75%) on a median metyrapone dose of 2250 mg/day (range 750-6000). Metyrapone was given long term in 24 patients with Cushing's disease who had been given pituitary irradiation, for a median of 27 months (range 3-140) with adequate control of hypercortisolaemia in 20 (83%). In 10 patients with adrenocortical adenomas and six with adrenocortical carcinomas, metyrapone in a median dose of 1750 mg/day (range 750-6000) reduced their mean cortisol levels (median 847 nmol/l, range 408-2000) to less than 400 nmol/l in 13 patients (81%). In 18 patients with the ectopic ACTH-syndrome the 'mean cortisol levels', obtained from five or six samples on the test day (median 1023 nmol/l, range 823-6354) were reduced to less than 400 nmol/l in 13 patients (70%), on a median dose of 4000 mg/day (range 1000-6000). Reduction of cortisol levels was clearly associated with clinical and biochemical improvement. The medication was well tolerated. Transient hypoadrenalism and hirsutism were unusual but were the most common side-effects.

CONCLUSIONS

In our experience metyrapone remains a most useful agent for controlling cortisol levels in the management of Cushing's syndrome of all types.

Lack of modulation of the adrenocortical response to ACTH by an opioid peptide

Eight normal male subjects received 1 mg dexamethasone at 23.00 h and 0.5 mg on wakening followed by a physiological intravenous dose of synthetic ACTH1-24 250 ng, with and without the administration of a stable met-enkephalin analogue (guanyl-DAMME, 100 micrograms) 10 minutes prior to the ACTH. The opioid analogue caused no change in the peak, incremental, or incremental area under the curve responses of plasma cortisol to the ACTH. This study does not support a role for opioid peptides in the acute modulation of the adreno-cortical response to ACTH.

Megavoltage pituitary irradiation in the management of Cushing's disease and Nelson's syndrome: long-term follow-up

We report the long-term follow-up of the clinical and biochemical effects of megavoltage pituitary irradiation (radiotherapy; RT), administered as primary or secondary therapy, for pituitary Cushing's disease and Nelson's syndrome in 52 patients. Irradiation was administered, from a 4-15 MeV linear accelerator, via a three-field technique (two lateral, one frontal), to a total dose of 4500 cGy (rad) in 25 fractions over 35 days. Twenty-one patients received RT as primary ablative therapy for Cushing's disease and were under follow-up 5.8 to 15.5 years later (median 9.5 years). All were initially treated with metyrapone to induce normal mean plasma cortisol levels, and all achieved clinical remission on this therapy. At latest follow-up, 12 (57%) are off all therapy, in clinical remission, with a normal mean cortisol through the day; however, only two show completely normal plasma cortisol responses to dynamic testing; four remain on medical therapy with metyrapone or op'DDD and all have required a steady dose reduction accompanied by falling plasma ACTH levels; five have required alternative therapy with bilateral adrenalectomy and/or transsphenoidal hypophysectomy. Fifteen patients received RT for Nelson's syndrome, developing after bilateral adrenalectomy, and have been followed up for 1.5 to 17.3 years (median 9.6 years). Fourteen patients showed progressive depigmentation, shrinkage of the pituitary adenoma and fall in plasma ACTH levels to 1-72% (median 16%) of the pre-RT basal value. In the remaining patient an initial fall in plasma ACTH was followed by tumour enlargement at 6 years, leading to death at 11 years after RT. Of the remaining patients, results are assessed in nine who received RT after unsuccessful transsphenoidal surgery, three after transfrontal surgery for aggressive macroadenomas, and four prophylactically after bilateral adrenalectomy. Radiotherapy remains a valuable second-line therapy for Cushing's disease and its complications.

Anterior and posterior pituitary function in brain-stem-dead donors. A possible role for hormonal replacement therapy

Blood samples were obtained, at the time of organ donation, from 31 consecutive brain-stem-dead (BSD) donors referred to one transplant coordinator during a 9-month period. Twenty-four cases (77%) had clinical diabetes insipidus (DI), which was poorly controlled with marked dehydration in a majority of cases (serum osmolality range 268-357; median 302 mOSM/kg). Serum triiodothyronine (T3) was subnormal in 25 (81%); all had normal or high serum reverse T3; and the serum free thyroxine (T4) index was subnormal in 9 (29%), and TSH was subnormal in 7 (23%). In no case were T4 and TSH both subnormal and results were typical of the sick euthyroid syndrome rather than TSH deficiency. Of 21 cases not receiving corticosteroids, 5 (24%) had a serum cortisol above 550 nmol/L (20 micrograms/dl), excluding ACTH deficiency, and only 1 had undetectable cortisol levels. Those with severe hypotension did not have significantly lower serum cortisol (mean 354 vs. 416; P greater than 0.5). Levels of prolactin, growth hormone, gonadotrophins, and gonadal steroids were variable, but only a minority were frankly deficient in these hormones. BSD donors frequently have DI, which is often managed poorly by nonspecialists and requires appropriate replacement therapy. In contrast most patients are not totally deficient in anterior pituitary hormones. Routine hormonal therapy with cortisol and T3 cannot, therefore, be justified on endocrinological grounds. Widespread introduction of such treatment should only follow controlled trials that clearly demonstrate clinically significant improvement in the transplanted organ function, without detriment to the donor.

The effect of ovine corticotrophin-releasing factor on the hormonal response to insulin-induced hypoglycaemia

In order to investigate the role of hypothalamic corticotrophin-releasing factor (CRF41) in the mediation of the pituitary ACTH response to hypoglycaemia, eight normal adult males were studied on four occasions. Commencing at 0830 h after an overnight fast, each received, in double-blind, random order, intravenous boluses of: A, normal saline control; B, soluble insulin 0.15U/kg; C, ovine CRF41 (oCRF41) 100 micrograms; D, soluble insulin 0.15U/kg followed immediately by oCRF41 100 micrograms. Adequate hypoglycaemia (blood glucose less than 2.2 mmol/l) was achieved in each subject when insulin was given alone or with oCRF41, and there was no difference in the glucose nadir between the 2 days. Peak plasma ACTH was significantly higher after insulin plus oCRF41 than after insulin alone (P less than 0.05) or oCRF41 alone (P less than 0.01) and this enhancement of ACTH release was most marked in the first phase of the response at 30 min (P less than 0.001, b vs d). There was no difference in the peak serum cortisol response whether oCRF41 and insulin were given alone or together and although the area under the cortisol curve was greater after insulin plus oCRF41, this difference was explicable simply on the basis of the earlier onset of the cortisol response to oCRF41. There were no differences in the serum GH responses to hypoglycaemia on the 2 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolactinomas presenting as primary amenorrhoea and delayed or arrested puberty: response to medical therapy

Fourteen patients presented with arrested pubertal development associated with prolactin-secreting pituitary tumours; serum prolactin ranged from 4000-104,300 mU/l in the ten females and 920-68,000 in four males. Skull X-ray showed a markedly expanded pituitary fossa in eight patients. CT scan and/or air encephalography showed macroadenomas in nine, of whom seven had large suprasellar extensions to their tumours, yet only five had complained of headache and only two had visual field defects. All were treated with bromocriptine (7.5-60 mg/day) which lowered prolactin substantially in all and into the normal range in 11 (range less than 60-3090, median 105 mU/l). Puberty thereafter progressed spontaneously in 13, but in one patient, whose prolactin did not suppress completely, menarche could be induced only with clomiphene. Anterior pituitary function improved on bromocriptine. In seven patients with macroadenomas, tumour shrinkage into the pituitary fossa was complete and in two others incomplete shrinkage was followed by transsphenoidal hypophysectomy. Seven patients received pituitary irradiation, six after bromocriptine-induced shrinkage and one after transsphenoidal surgery. At follow-up 6 months to 10 years (median 5 years) after presentation, ten remain on bromocriptine with a suppressed serum prolactin, one has a normal prolactin after surgery, and three are off bromocriptine with residual hyperprolactinaemia (418-4680 mU/l). To date, four females have become pregnant and one male has fathered two children. Prolactinomas are an important, albeit rare, cause of arrested puberty and should therefore be sought. Most patients respond well to bromocriptine, with or without pituitary irradiation.

Antenatal fetal heart rate variation in relation to the respiratory and metabolic status of the compromised human fetus

Three groups of women were delivered by caesarean section before labour: for an abnormal fetal heart rate (FHR) trace (21 cases, group 1), or for maternal deterioration in severe pre-eclampsia without gross fetal heart rate abnormalities (20 cases, group 2), or to avoid mechanical difficulties in labour at term (30 cases, group 3). The mean gestational ages of the first two groups were 32 weeks with a high proportion of infants small-for-gestational-age. In group 1, FHR variation (mean range of pulse intervals) was less than half (20.6 SE 1.2 ms) of the normal value at the same age (44.4 SE 1.5 ms). This was associated with hypoxaemia (mean umbilical artery PO2 of 6 mmHg at delivery), with evidence of compensation shown by an elevated amniotic fluid erythropoietin. The fetuses were hypoglycaemic and had greater umbilical artery blood alanine concentrations, but no large changes in adenine nucleotide or endorphin plasma concentrations. Although there was a minor degree of respiratory acidaemia at birth, there was not significant metabolic acidaemia. The results demonstrate that the reduced variation of 'suboptimal' and 'decelerative' fetal heart rate records is associated with fetal hypoxaemia and evidence of nutritional deprivation, but not with asphyxia.

CRF in the differential diagnosis of Cushing's syndrome: a comparison with the dexamethasone suppression test

Accurate differential diagnosis of the precise cause of Cushing's syndrome can be difficult, and conventional tests such as those based on the use of dexamethasone may be misleading. We have therefore studied the cortisol and ACTH responses to ovine corticotrophin-releasing factor (CRF-41) in 28 consecutive patients with Cushing's syndrome, and compared the diagnostic value of this test with that of the high-dose dexamethasone suppression test (8 mg/day for 48 h). Of 20 patients with confirmed Cushing's disease (pituitary-dependent Cushing's syndrome), only 16 (80%) showed the expected 50% or more suppression of serum cortisol following high-dose dexamethasone administration. Four patients each with adrenal adenomas and three patients with the ectopic ACTH syndrome failed to suppress, while a child with probable Cushing's disease showed a variable response depending on the dose used. Following CRF stimulation, 15 out of the 20 patients (75%) with Cushing's disease showed an excessive rise in serum cortisol, outside the normal range, while in five the response to CRF-41 was normal on at least one occasion. None of the patients with adrenal adenomas or the ectopic ACTH syndrome showed a cortisol response to CRF. Thus, either test on its own may be misleading in differentiating Cushing's disease from other causes of the syndrome. Every patient with Cushing's disease, however, showed either suppression in response to high-dose dexamethasone or an excessive cortisol response to CRF testing. It appears, therefore, that the combination of the high-dose dexamethasone and the CRF test, with measurement of serum cortisol, is superior to either test alone in the differential diagnosis of Cushing's syndrome.

Characterization of immunoreactive dynorphin in human phaeochromocytomas

The prodynorphin-derived opioids, dynorphin (DYN) and alpha-neoendorphin (alpha NE) were studied in 24 human phaeochromocytomas and related tumours. Nineteen tumours, extracted in HCl (0.1 mol/l), contained concentrations of immunoreactive DYN (ir-DYN) ranging from less than 0.5 to 794 pmol/g wet weight. None of the extracts in HCl contained ir-alpha NE (all less than 2.4 pmol/g). Sephadex G-50 gel filtration chromatography of ir-DYN in HCl (0.1 mol/l) extracts of six tumours revealed three small peaks of ir-DYN of higher molecular size (approximately 12,000, 6000 and 3000 daltons), a minor peak of ir-DYN eluting just after DYN(1-17), and a broad major peak, consisting of at least three components, which was significantly retarded and eluted after the salt volume of the column. High-pressure liquid chromatography (HPLC) of these extracts revealed multiple peaks of ir-DYN, most of which did not coelute with any synthetic DYN peptides. On both gel filtration chromatography and HPLC, one of the minor peaks coeluted with DYN(1-32). None of the peaks of ir-DYN coeluted with DYN(1-17) which had been acetylated using acetic anhydride. Extracts of the same tumours in acetic acid (0.1 mol/l) yielded similar values for ir-DYN content, but parallelism in the assay was improved. Sephadex G-50 chromatography revealed a different pattern of ir-DYN with a major peak coeluting with DYN(1-17) and, in two tumours, a minor peak coeluting with DYN(1-8). Studies with HPLC revealed, however, that substantial degradation of synthetic DYN occurred during extraction in acetic acid (0.1 mol/l) in spite of the precautions taken. Phaeochromocytomas frequently contain ir-DYN in concentrations which may approach that of the mammalian pituitary. These tumours did not, however, contain ir-alpha NE and, with the possible exception of a small amount of DYN(1-32), the ir-DYN present did not correspond with any known sequences. Thus, whilst prodynorphin is expressed in phaeochromocytomas, it does not seem to be processed to the usual end-products, and post-translational modifications therefore seem likely. Enzymatic degradation of DYN may occur during extraction in acetic acid (0.1 mol/l), and this medium should, therefore, be avoided in studies of such labile peptides.

A bromocriptine-responsive corticotroph adenoma secreting alpha-MSH in a patient with Cushing's disease

Clinical and in-vitro investigations have been performed on a corticotroph adenoma removed from a patient suffering from Cushing's disease. Prior to surgery, the patient's Cushing's disease had been successfully controlled, clinically and biochemically, by long term administration of bromocriptine. After selective adenomectomy, tumour tissue was investigated by a perfused isolated cell column technique. It was shown that the tumour cells secreted immunoreactive- (IR)- ACTH and IR-alpha-MSH and that the release of both peptides was promptly suppressed by dopamine. Chromatographic analysis of the secreted IR-alpha-MSH revealed a high proportion of acetylated alpha-MSH; smaller amounts of desacetyl alpha-MSH and diacetyl alpha-MSH were present. The relevance of these findings to the proposal that certain corticotroph adenomas are derived from the intermediate lobe of the pituitary is discussed. It is concluded that there is little direct evidence for involvement of the residual zona intermedia of the adult human pituitary in the development of Cushing's disease.

Puberty due to a mixed germ cell tumour of the hypothalamus secreting BhCG and alpha-fetoprotein

A 14 year-old boy presented with visual impairment due to a large suprasellar tumour secreting beta-human chorionic gonadotrophin (BhCG) and alpha-fetoprotein (alpha FP). He was sexually mature with an advanced bone age of 17 years, and suffering from partial hypopituitarism. Treatment with external radiotherapy resulted in a reduction of tumour size and fall of the serum testosterone BhCG and alpha FP levels. We conclude that pubertal development had been initiated and maintained by ectopic hCG production from his intracerebral mixed germ cell tumour. Patients with tumours in the pineal and suprasellar regions should be screened for elevated levels of BhCG and alpha FP. We suspect that many of these tumours cause precocious puberty by secreting BhCG.

Immunocytochemical study of 18 tumours causing ectopic Cushing's syndrome

Eighteen cases of Cushing's syndrome caused by ectopic production of peptide hormones were investigated by histological and immunocytochemical methods and the findings correlated with clinical and biochemical observations. Immunocytochemistry showed immunoreactive adrenocorticotrophic hormone (ACTH) or peptides derived from the ACTH precursor (pro-opiomelanocortin (POMC], or both, in a total of 10 cases: five of these also contained immunoreactive-alpha-melanocyte stimulating hormone, indicating more extensive translational processing of POMC than normally occurs in healthy corticotrophs of the anterior pituitary; in two further cases peptides capable of stimulating ACTH release from the anterior pituitary were present. In the remaining six cases immunocytochemistry failed to show the presence of ACTH, other POMC derived peptides, or peptides with ACTH releasing properties. These findings correlate well with the histological and clinical observations, in that the six tumours had been clinically overt, caused rapid death, and histologically seemed to be highly malignant. In contrast, the 12 other tumours were occult to radiological examination, patients had a much improved survival rate, and histologically the tumours seemed to be less aggressive. All but one of the tumours in this series showed a degree of neuroendocrine differentiation, indicated by the presence of neuron specific enolase. These results suggest that one feature of highly malignant tumours, which cause an ectopic endocrine syndrome, is a high secretion of peptide hormones, leaving amounts that are too small to be shown by immunocytochemistry.

Diagnosis and management of ACTH-dependent Cushing's syndrome: comparison of the features in ectopic and pituitary ACTH production

The clinical features, diagnosis and management of 16 consecutive patients with ectopic ACTH production are described and biochemical data are compared with those of 48 consecutive patients with pituitary-dependent Cushing's disease. In 10 cases the ectopic ACTH secreting tumour was completely occult to routine clinical and radiological investigation, and no basal or dynamic investigation of adrenal-pituitary function was able clearly to differentiate these patients from those with Cushing's disease. High dose dexamethasone suppression testing assessed by plasma cortisol was usually helpful but unexpected responses were seen in both diagnostic groups; the metyrapone test yielded no useful information and should now be abandoned. Hypokalaemia was seen in all patients with ectopic ACTH production but in only 10% of those with Cushing's disease who were not on diuretics at presentation. Successful diagnosis and tumour localization was most frequently achieved by a combination of CT scanning of the chest and abdomen and venous catheter sampling for ACTH. All patients in whom the ectopic ACTH-secreting tumour was obvious at presentation died of their primary tumour within 8 months, whereas seven of the 10 patients with occult tumours at presentation are alive 1.5-16.5 years later, and appear cured. Occult ectopic ACTH secretion may be impossible to distinguish from pituitary Cushing's disease. Multiple and repeated investigations are often required to make this differential diagnosis, essential for appropriate therapy.

RIA/chromatographic evidence for novel opioid peptide(s) in Squilla mantis ganglia

Proteins extracted from suboesophageal ganglia of Squilla mantis, an arthropod shown to be sensitive in vivo to opiates and to contain native opioid like peptide(s), were fractionated by gel filtration into three pools according to their molecular weight: A (Mr greater than 65,000), B (10,000 less than Mr less than 65,000) and C (Mr less than 10,000). None of these pools showed any immunoreactivity when radioimmunoassayed using antisera raised against Met-enkephalin either before or after sequential trypsin/carboxypeptidase B proteolysis. Further purification of pool C by HPLC followed by RIA using antibodies directed to Met-O-enkephalin,Leu-enkephalin,Dynorphin 1-13 and human beta-endorphin, showed only a trace amount of Met-enkephalin cross-reactivity (about 10 fmoles/mg of protein extract). No detectable amount of Leu- or Met-enkephalin was found after HPLC fractionation of proteolyzed pool B. Radioreceptor assay of HPLC fractions derived from trypsin/carboxypeptidase B treated pools B and C showed major areas of activity common to both pools, but nevertheless with differing retention times compared to the standard opioid peptides used.

Cushing's syndrome

Cushing's syndrome remains one of the most challenging problems in clinical endocrinology. Cushing's disease is caused in the majority of cases by basophil pituitary microadenomas which may be successfully treated by trans-sphenoidal hypophysectomy. Treatment with metyrapone or o,p'-DDD can always induce a clinical remission but not a cure, and neurotransmitter therapy may be effective in a minority of cases. Pituitary irradiation cures about half of cases in the long-term and may be used for surgical failures. Tumours producing ectopic ACTH are frequently benign, small and occult and may produce a syndrome clinically indistinguishable from Cushing's disease. Biochemical investigations cannot absolutely distinguish pituitary from ectopic sources of ACTH and therefore body CT scanning and percatheter venous sampling are essential diagnostic investigations. Tumour localization may result in resection and complete cure, although even small tumours may have a malignant potential. Adrenal tumours are readily diagnosed by plasma ACTH measurement and adrenal CT scanning. Adrenal adenomas are cured by adrenalectomy. Carcinomas may be treated by a combination of adrenalectomy, radiotherapy and o,p'-DDD, but long-term prognosis is poor.

The role of endorphins in septicaemic shock: a pilot study in burned patients

There is recent evidence that circulating opioid peptides, or 'endorphins', act as chemical messengers responsible for the induction of the complex cardiovascular changes leading to hypotension in septicaemic shock. The pilot study of an investigation of opioid peptides in septicaemia in burned patients is presented. Serial measurements of plasma beta-endorphin and metenkephalin were performed throughout the recovery of six patients with large burns (20-70 per cent BSA). Our preliminary findings concur with previous evidence that opioid peptides may play a role in the hypotension of septicaemic shock.

Bombesin-like peptides in human endocrine tumors: quantitation, biochemical characterization, and secretion

Bombesin-like immunoreactivity (BLI) in 20 human endocrine tumors was studied using an antiserum directed toward the C-terminal region of bombesin. Additionally, plasma BLI was assayed in normal subjects and patients with known BLI-containing tumors. In 7 tumors (medullary carcinoma of the thyroid, n = 2; carcinoid of the lung, n = 3; hepatic carcinoid, n = 1; pheochromocytoma, n = 1), the BLI content ranged from 6-2000 pg/mg wet wt of tissue. Sephadex G-50 gel chromatography of tumor extracts under acid-dissociating conditions revealed 2 peaks of BLI: 1 coeluting with porcine gastrin-releasing peptide (GRP) and 1 with bombesin. Reverse phase ODS silica HPLC analysis of the G-50 peaks using a methanol-trifluoroacetic acid gradient showed that human tumor BLI more closely resembled porcine GRP and its C-terminal fragment GRP-(14-27) than bombesin itself. Partial tryptic digestion of the tumor GRP-like peptide generated a product which, on HPLC, was similar to GRP-(14-27). Elevated plasma BLI was detected in the peripheral circulation of three subjects and in the vessels draining the tumor metastases of one of these patients. BLI was undetectable in normal subjects. These results indicate 1) that BLI is present in and may be secreted by various human endocrine tumors, and 2) that human tumor BLI closely resembles porcine GRP and its C-terminal fragment GRP-(14-27).

Pituitary ACTH dependent Cushing's syndrome due to ectopic production of a bombesin-like peptide by a medullary carcinoma of the thyroid

A 41-year-old man presented with Cushing's syndrome and the biochemical features of ectopic ACTH production. Investigation revealed mediastinal metastases from a medullary carcinoma of the thyroid. The peripheral plasma contained grossly elevated levels of bombesin-like immunoreactivity (irBombesin) as well as calcitonin; blood sampling via a venous catheter confirmed a gradient of irBombesin, but not of ACTH, in the mediastinal vein draining the tumour. On extraction the tumour contained a bombesin-like peptide, but not vasopressin or corticotrophin releasing factor and only very low levels of ACTH; immunohistochemical studies showed positive immunostaining for bombesin and calcitonin but none for ACTH or CRF. No ACTH was released from dispersed tumour cells in vitro. However an extract of the tumour stimulated ACTH release in vitro from perifused dispersed rat anterior pituitary cells. This is the first reported case of Cushing's syndrome due to ectopic production of a bombesin-like peptide, causing excessive pituitary ACTH secretion.

Release of beta endorphin and met-enkephalin during exercise in normal women: response to training

Plasma beta endorphin and met-enkephalin concentrations were measured in response to treadmill exercises in 15 normal women before, during, and after an intensive programme of exercise training. Significant release of beta endorphin occurred in all three test runs, and the pattern and amount of release were not altered by training. Before training dramatic release of met-enkephalin was observed in seven subjects and smaller rises observed in a further four, and this response was almost abolished by training. This represents the first observed "physiological" stimulus to met-enkephalin release. Endogenous opioid peptides play a part in adaptive changes to exercise training and probably contribute to the menstrual disturbances of women athletes.

'Dynorphin' in plasma: enzymatic artifact and authentic immunoreactivity

The potent opioid peptide dynorphin (DYN) is found in posterior pituitary vasopressinergic neurones and in adrenal medullary cells suggesting that secretion into plasma is likely. We have developed a sensitive radioimmunoassay in order to study plasma DYN in man. It transpired that extraction prior to assay was essential since unextracted plasma caused gross and non-parallel inhibition of binding of tracer. Plasma extracted using leached silica glass ( Vycor ) caused inhibition of tracer binding which diluted in parallel to synthetic DYN suggesting the presence of substantial amounts of DYN-like immunoreactivity ( irDYN ) in plasma. Further investigation however demonstrated that this irDYN was artifactual and caused by enzymatic degradation of tracer. Although use of Seppak C18 cartridges resulted in reliable extraction of synthetic porcine DYN from acidified plasma, we have not detected irDYN in any plasma so far studied using this technique. However, extraction of non-acidified plasma using our antibody coupled to Sepharose CNBr-activated 4B followed by gel filtration chromatography demonstrated a single peak of irDYN of molecular size similar to DYN. These data suggested that a small amount of a DYN-like peptide does circulate in human plasma although this is not identical to porcine DYN(1-17). The implication of our results for the measurement of other similar peptides in plasma is discussed.