Unusual late development of dopamine agonist resistance in two women with hyperprolactinaemia associated with transition from micro to macroadenoma.
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Adult↗
Biomedical subjects
A B Atkinson
Publications and source records attributed to A B Atkinson.
Endothelial function, insulin action and cardiovascular risk factors in young healthy adult offspring of parents with Type 2 diabetes: effect of vitamin E in a randomized double-blind, controlled clinical trial.
BACKGROUND AND AIMS: Endothelial dysfunction, insulin resistance and oxidative stress are believed to be central and associated mechanisms in atherogenesis. We aimed to determine the effect of the antioxidant vitamin E on endothelial function, insulin action and cardiovascular risk markers in young healthy adult offspring of parents with Type 2 diabetes. METHODS: Healthy, glucose-tolerant adults (18-38 years), 14 (12 male/2 female) with at least one parent with Type 2 diabetes, and 14 (12 male/2 female) subjects with no family history of diabetes (controls) were studied. Insulin action was assessed by euglycaemic hyperinsulinaemic clamp (1 mU/kg/min). Endothelial function was assessed by forearm blood flow (FBF) responses to intra-brachial artery infusions of acetylcholine (ACh) (endothelium-dependent vasodilation), sodium nitroprusside (SNP) (endothelium-independent vasodilation) and N(G)-monomethyl L-arginine (LNMMA) (nitric oxide synthase inhibition). Thirteen offspring (18-38 years, 11 male/2 female, BMI < 30 kg/m2) completed a randomized, double-blind, crossover trial (12 weeks vitamin E 800 IU/day or placebo, 6-week washout). RESULTS: Exogenous glucose infusion rates to maintain euglycaemia were positively associated with response to acetylcholine in offspring (r = 0.61, P < 0.05), and were linked with triglycerides. Vitamin E had no effect on endothelial function, insulin action or cardiovascular risk markers in healthy adult offspring of parents with Type 2 diabetes. CONCLUSIONS: Our results support a positive association between insulin action and endothelial-dependent vasodilation in young healthy adult offspring of parents with Type 2 diabetes, but indicate no effect of vitamin E on these parameters.
Adolescent↗
The effect of manipulation of basal pulsatile insulin on insulin action in Type 2 diabetes.
AIM: Disordered insulin pulsatility is associated with insulin resistant states including Type 2 diabetes. However, whether abnormal basal insulin pulses play a role in the pathogenesis of insulin resistance or are simply an associated feature remains undetermined. We investigated this relationship further by studying the effect of overnight (10 h) pulsatile insulin infusion on subsequent insulin sensitivity. METHODS: We studied 17 Type 2 diabetic patients who underwent one of two protocols. In protocol A (10 patients) on two separate nights we infused insulin 0.1 mU/kg/min either in a constant infusion or in pulses every 13 min. Octreotide (0.43 microg/kg/h) was given to suppress endogenous insulin secretion and physiological replacement of glucagon (30 ng/kg/h) administered. Insulin sensitivity was measured using a hyperinsulinaemic euglycaemic clamp (2 mU/kg/min) next morning. In protocol B (seven patients), we employed the same experimental procedure but used a basal insulin infusion rate of 0.09 mU/kg/min in 7-min or 13-min pulses. RESULTS: Appropriate pulse patterns were confirmed in each protocol. In protocol A, after overnight infusions, glucose infusion rates required to maintain euglycaemia at steady state hyperinsulinaemia were similar (33.9 +/- 5.2 vs. 31.2 +/- 4.1 micromol/kg/min; P = NS). In protocol B, after overnight infusions the glucose infusion rates required during hyperinsulinaemia were significantly lower during 7-min pulses (39.9 +/- 5.7 vs. 44.7 +/- 5.6 micromol/kg/min; P < 0.05). CONCLUSION: There was no demonstrable priming effect derived from overnight pulsatile insulin compared with constant insulin infusion on subsequent insulin sensitivity in Type 2 diabetic subjects. The failure of 7-min pulses to exhibit an advantageous effect over 13-min pulses raises questions about the natural frequency of basal insulin pulses and their biological effect.
Blood Glucose↗
Authors' response: HPA axis testing after pituitary surgery.
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Diagnostic Tests, Routine↗
Poor responses to a test dose of subcutaneous octreotide predict the need for adjuvant therapy to achieve 'safe' growth hormone levels.
OBJECTIVE: Somatostatin analogues are an established treatment in acromegaly. This study was designed to evaluate whether the acute serum growth hormone (GH) response to a test dose of octreotide in acromegaly predicts longer-term response to the drug at 3 years. DESIGN AND METHODS: In 23 patients, GH responses across 8 h to a subcutaneous test dose (50 microg) of octreotide were compared with GH levels after 3 years of therapy. The majority had pituitary surgery as primary therapy and at 3 years were receiving at least 600 microg octreotide daily subcutaneously or 20 mg LAR monthly intramuscularly. RESULTS: Seven had a test day GH Nadir of 5 mU/l or less of whom 4 achieved GH < 5 mU/l at 3 years. Sixteen had a test day nadir GH of 10 mU/l or less and of these 8 achieved GH < 5 mU/l at 3 years. Seven of the 23 had a GH Nadir >10 mU/l and of these 3 had achieved GH <5 mU/l at 3 years. However all of these 3 had received external pituitary irradiation within 4 years of the 3 year assessment, as compared with 3 of the <5 mU/l nadir group and 5 of the <10 mU/l nadir group. CONCLUSIONS: In patients on optimal long-term doses of octreotide for acromegaly, absence of a nadir GH <10 mU/l in the 8 h after a test dose was associated with failure to achieve GH levels associated with a normal life expectancy (5 mU/l or less) unless adjunctive external pituitary irradiation was given. As well as testing tolerability a test dose of octreotide may help in determining which patients should be offered early external pituitary irradiation or therapy with a GH receptor antagonist if surgery has failed to achieve 'safe' GH levels.
Acromegaly↗
Plasmacytoma: an unusual cause of a pituitary mass lesion. A case report and a review of the literature.
A sixty six year old female presented with headache and decreased hearing. Clinical examination confirmed the presence of impaired hearing on the left side. Visual fields were full to confrontation and corrected visual acuity was normal. CT scan of brain revealed a pituitary mass. Preoperative anterior pituitary function was normal. Transsphenoidal decompression was performed, and histology was that of a plasmacytoma. Post operative pituitary function was normal. The patient had no symptoms or signs of multiple myeloma and subsequent investigations revealed no evidence of the disease. One year after diagnosis a course of radiotherapy was administered for local tumour recurrence. During seven years of follow-up, no evidence of multiple myeloma has emerged. Only thirteen similar cases have been described. Four of these had evidence of multiple myeloma at presentation and six progressed to it during follow-up. In twelve patients cranial nerve deficits were recorded. In any cases where it was documented, preoperative anterior pituitary function was normal. In a number of cases histology was reported initially as being that of a non-functioning adenoma, the true diagnosis being discovered, either by electron microscopy findings or after the development of multiple myeloma. Plasma cell tumours of the pituitary area are rare and can present with symptoms and signs indistinguishable from non-functioning adenoma. Atypical symptoms such as cranial nerve involvement or unexpected preservation of anterior pituitary function should arouse suspicion.
Adult↗
A new RVH for a new century: maintaining clinical excellence. Annual oration: Royal Victoria Hospital, Belfast, October 2003.
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Architecture↗
Comparison of the priming effects of pulsatile and continuous insulin delivery on insulin action in man.
Insulin is normally secreted in man in regular pulses every 5 to 15 minutes. Disordered pulsation has been demonstrated in several insulin-resistant states and it is unclear whether this represents a primary beta-cell defect contributing to impairment of peripheral insulin action or rather is a consequence of insulin resistance. Basal or near basal insulin administration by pulsatile infusion augments hypoglycemic effect and improves insulin-mediated glucose uptake compared with insulin by continuous infusion. To date no study has examined whether normal basal insulin pulsatility is required to preserve subsequent insulin sensitivity during hyperinsulinemia. We studied the effect of overnight pulsatile versus continuous basal insulin on a subsequent hyperinsulinemic euglycemic clamp. Nineteen normal volunteers (male:female ratio, 17:2; mean age +/- SEM, 26.1 +/- 2.3 years) were studied on 2 occasions each. Endogenous insulin secretion was inhibited by octreotide (0.43 microg kg(-1). h(-1)) and replaced overnight at 5.4 mU kg(-1). h(-1) either by continuous infusion or in 2-minute pulses every 13 minutes (n = 10) or every 7 minutes (n = 9). Glucagon was replaced at physiological concentration by continuous infusion (30 ng. kg(-1). h(-1)). Venous plasma glucose overnight was not significantly different between the pulsatile and continuous protocols. After discontinuing the overnight insulin infusion, insulin action was assessed during a hyperinsulinemic euglycemic clamp (1 mU kg(-1). h(-1)). Glucose infusion rates at steady-state during the hyperinsulinemic clamp were similar between continuous and both frequencies of pulsatile infusion (continuous 44.6 +/- 4.3 micromol. kg(-1). min(-1) v 13-minute pulsatile 41.7 +/- 5.9 micromol. kg(-1). min(-1), P =.27; continuous 34.6 +/- 2.5 micromol. kg(-1) min(-1) v 7-minute pulsatile 41.4 +/- 3.2 micromol. kg(-1). min(-1), P =.08). We conclude that overnight pulsatile compared with continuous insulin administration has no different effect on subsequent peripheral insulin-mediated glucose uptake. A priming effect cannot therefore explain the previously demonstrated association between endogenous insulin pulse frequency and peripheral insulin action.
3-Hydroxybutyric Acid↗
Diagnosis and complications of Cushing's syndrome: a consensus statement.
In October 2002, a workshop was held in Ancona, Italy, to reach a Consensus on the management of Cushing's syndrome. The workshop was organized by the University of Ancona and sponsored by the Pituitary Society, the European Neuroendocrine Association, and the Italian Society of Endocrinology. Invited international participants included almost 50 leading endocrinologists with specific expertise in the management of Cushing's syndrome. The consensus statement on diagnostic criteria and the diagnosis and treatment of complications of this syndrome reached at the workshop is hereby summarized.
Cardiovascular Diseases↗
Effects of low-dose oral hydrocortisone replacement versus short-term reproduction of physiological serum cortisol concentrations on insulin action in adult-onset hypopituitarism.
OBJECTIVE: Hypercortisolism is associated with impaired glucose tolerance and insulin resistance. For many years hydrocortisone 30 mg was the standard total daily replacement dose in adult hypopituitarism. The use of this conventional dose has now been shown to result in mild biochemical hypercortisolism and might contribute to the increased cardiovascular risk reported in hypopituitarism. The use of lower doses of hydrocortisone replacement therapy might prevent some of the adverse metabolic effects seen with conventional doses. PATIENTS: In a randomized crossover study we assessed peripheral and hepatic insulin action in 15 ACTH-deficient patients with normal glucose tolerance on two occasions while receiving either a low-dose oral hydrocortisone replacement (LOR) therapy (15 mg at 0800, 5 mg at 1700) or a physiological hydrocortisone infusion (PHI), which achieved physiological serum cortisol concentrations. RESULTS: Exogenous glucose infusion rates required to maintain euglycaemia were similar for the LOR and the PHI protocols (26.2 +/- 0.4 vs. 23.8 +/- 0.6 micromol/kg/min, respectively). Endogenous glucose production was also similar (12.0 +/- 2.5 vs. 11.6 +/- 2.4 micromol/kg/min, respectively) and in the post-absorptive state suppressed to a similar extent following insulin (4.5 +/- 2.0 vs. 5.1 +/- 3.1 micromol/kg/min). CONCLUSION: Hydrocortisone replacement therapy at a dose of 15 mg with breakfast, 5 mg with evening meal does not increase peripheral or hepatic insulin resistance when compared to a hydrocortisone infusion designed to simulate physiological serum cortisol concentrations.
Administration, Oral↗
Primary medical therapy for acromegaly: an open, prospective, multicenter study of the effects of subcutaneous and intramuscular slow-release octreotide on growth hormone, insulin-like growth factor-I, and tumor size.
Conventional surgery and radiotherapy for acromegaly have limitations. There are few data on the use of the somatostatin analog octreotide (Oct) as primary medical therapy. An open prospective study of 27 patients with newly diagnosed acromegaly was conducted in nine endocrine centers in the United Kingdom. Twenty patients had macroadenomas, and 7 had microadenomas. For the first 24 wk (phase 1), patients received sc Oct in an initial dose of 100 microg, 3 times daily, increased to 200 micro g three times daily after 4 wk in the 13 patients whose mean serum GH remained greater than 5 mU/liter (2 microg/liter). Five-point GH profiles were performed at 0, 4, 12, and 24 wk, and high resolution pituitary imaging using a standard protocol was performed at 0, 12, and 24 wk (magnetic resonance imaging in 25 patients and computed tomography in 2). Tumor dimensions and volumes were calculated by a central, reporting neuroradiologist, and the results were audited by a second, independent neuroradiologist. After 24 wk, 15 patients proceeded to phase 2 of the study with a direct switch to monthly injections of the depot formulation of Oct, Sandostatin long-acting release (Oct-LAR). Further GH profiles were performed at 36 and 48 wk, and pituitary imaging was performed at 48 wk. The median pretreatment serum GH concentration was 30.7 mU/liter (range, 6.7-141.4). During sc Oct, serum GH fell to less than 5 mU/liter in 9 patients (38%), and IGF-I fell to normal in 8 patients (33%). All 27 tumors shrank during sc Oct; for microadenomas the median tumor volume reduction was 49% (range, 12-73), and for macroadenomas it was 43% (range, 6-92). After 24 wk of Oct-LAR (end of phase 2), the GH level was less than 5 mU/liter in 11 of 14 patients (79%), and IGF-I was normal in 8 of 15 patients (53%). In the 15 patients given Oct-LAR (10 macroadenomas), wk 48 scans showed a further overall median tumor volume reduction of 24%. At the end of the study 79% of patients had mean serum GH levels below 5 mU/liter, 53% had normal IGF-I levels, and 73% showed greater than 30% tumor shrinkage. Twenty-nine percent of patients achieved all 3 targets, but no patient with pretreatment GH levels above 50 mU/liter did so at any stage of the study. Primary medical therapy with Oct offers the prospect of normalization of GH/IGF-I levels together with substantial tumor shrinkage in a significant subset of acromegalic patients. This is most likely to occur in patients with pretreatment GH levels less than 50 mU/liter (20 microg/liter).
Acromegaly↗
Insulin action and skeletal muscle blood flow in patients with Type 1 diabetes and microalbuminuria.
Our objective was to determine whether Type 1 diabetic patients with microalbuminuria are less sensitive to the effects of insulin on glucose metabolism and skeletal muscle blood flow, compared to those with normal albumin excretion, after careful matching for confounding variables. We recruited 10 normotensive Type 1 diabetic patients with microalbuminuria and 11 with normoalbuminuria matched for age, sex, body mass index, duration of diabetes and HbA(1c). Peripheral and hepatic insulin action was assessed using a two-step euglycaemic hyperinsulinaemic clamp (2 h at 0.4 mU x kg(-1) x min(-1), 2 h at 2.0 mU x kg(-1) x min(-1)) combined with isotope dilution methodology. Skeletal muscle blood flow was determined by venous occlusion plethysmography. During the clamps, glucose infusion rates required to maintain euglycaemia were similar in the microalbuminuric subjects and controls (step 1, 8.2+/-1.4 (SE) vs 9.2+/-1.3 micromol x kg(-1) x min(-1): step 2, 30.9+/-2.7 vs 32.0+/-3.8 micromol x kg(-1) x min(-1)), as was hepatic glucose production basally and at steady state in step 1. In step 2, hepatic glucose production was lower in the microalbuminuric group (2.9+/-0.9 vs 6.4+/-0.7 micromol x kg(-1) x min(-1), P=0.005). During step 2, skeletal muscle blood flow increased significantly above baseline in the normoalbuminuric group (4.1+/-0.5 vs 3.2+/-0.4 ml x 100-ml(-1) x min(-1), P=0.01) but not in the microalbuminuric group (2.4+/-0.3 vs 2.3+/-0.4 ml x 100-ml(-1) x min(-1)). In conclusion, microalbuminuria in Type 1 diabetes was found to be associated with impairment of insulin-mediated skeletal muscle blood flow, but not with insulin resistance.
Adult↗
Prevalence of diabetes and impaired glucose tolerance in adult hypopituitarism on low dose oral hydrocortisone replacement therapy.
OBJECTIVE: The conventional dosage of hydrocortisone, used for many years in the management of hypopituitarism (30 mg per day), has now been shown to be more than is physiologically necessary. On this conventional corticosteroid therapy studies have demonstrated an increased prevalence of diabetes and impaired glucose tolerance, which may contribute to the increased vascular morbidity and mortality reported in the condition. In these studies no information is available on oral glucose tolerance test (OGTT) timing in relation to administration of oral steroid and variable hydrocortisone doses were employed. PATIENTS: In order to assess glucose tolerance in patients treated with lower, more physiological doses, we performed a 75-g OGTT at least 1 month after hydrocortisone therapy was adjusted to 15 mg at 0800 h and 5 mg at 1700 h in 45 adult onset hypopituitary patients (30 M, 15 F). Mean (+/- SD) duration of hypopituitarism was 12 +/- 10 years, mean age 52 +/- 14 years and BMI 29.3 +/- 5.1 kg/m2. All were on hydrocortisone, 43 on thyroxine, 31 on sex steroids, 9 on desmopressin and 33 had documented growth hormone deficiency. Hydrocortisone 15 mg was taken at 0800 and the OGTT commenced at 0900. RESULTS: Using standard WHO criteria 36 patients (80%) had normal glucose tolerance, 1 (2%) had newly diagnosed diabetes and 8 (18%) had impaired glucose tolerance. Using the recently announced American Diabetes Association criteria for diagnosis 96% had normal glucose tolerance, 2% had diabetes and 2% impaired fasting glucose. CONCLUSION: The markedly reduced prevalence of diabetes and impaired glucose tolerance on lower hydrocortisone replacement doses in our series of patients with hypopituitarism, not previously known to be diabetic, is of great interest. This lower prevalence may eventually result in reduced vascular complication rates.
Adult↗
Insulin action and insulin secretion in polycystic ovary syndrome treated with ethinyl oestradiol/cyproterone acetate.
Polycystic ovary syndrome (PCOS) is associated with abnormalities of insulin action and insulin secretion. Ethinyl oestradiol/cyproterone acetate is a common agent used to treat the symptoms of PCOS, but its effects on insulin action and insulin pulsatility have not been examined. We investigated the relationship between insulin action and insulin secretion in 11 patients with PCOS, at diagnosis and after 3 months of treatment with ethinyl oestradiol/cyproterone acetate, and in 13 controls. Insulin action was assessed using the euglycaemic hyperinsulinaemic clamp (2 mU/kg/min for 2 h). Insulin pulsatility was examined over 90 min by 2 min sampling. Short-term insulin pulses were identified using PULSAR. Treatment with ethinyl oestradiol/cyproterone acetate resulted in significant reductions in testosterone (3.3+/-0.7 vs. 1.9+/-0.2 nmol/l, p<0.05), free androgen index (10.2+/-0.7 vs. 1.2+/-0.2, p<0.05) and LH/FSH ratio (2.6+/-0.5 vs. 1.0+/-0.2, p<0.05). During hyperinsulinaemic clamps, the glucose infusion rate (GIR) required to maintain euglycaemia was lower in PCOS compared to controls (33.6+/-2.7 vs. 45.1+/-3.5 micromol/kg/min, p<0.05) but similar in PCOS before and after treatment (33.6+/-2.8 vs. 33.6+/-2.7 micromol/kg/min, p=0.9). Numbers of pulses identified in PCOS and controls were similar and unaltered by ethinyl oestradiol/cyproterone acetate. There was no correlation between GIR and frequency of insulin pulses in PCOS before or after treatment (r=0.2, p=0.6; post r=-0.5, p=0.1) unlike controls (r=-0.6, p=0.04). Despite considerable improvement in androgen profile, treatment with ethinyl oestradiol/cyproterone acetate did not alter insulin action in PCOS, and this insulin resistance does not appear to be determined by insulin pulse frequency.
Adult↗
The effects on insulin action in adult hypopituitarism of recombinant human GH therapy individually titrated for six months.
There is controversy about the effect of replacement GH on insulin action in adult hypopituitary patients. GH replacement calculated from weight leads to unacceptable side effects in some patients. Recent studies suggest it should be individually titrated in adults using serum IGF-I levels. We have assessed the effect of titrated GH replacement on peripheral and hepatic insulin action in 13 adult-onset hypopituitary patients (8 males and 5 females; ages 47 +/- 10 yr, mean duration of hypopituitarism 6 yr) with confirmed GH deficiency (GHD; maximum GH <5 mU/liter during insulin induced hypoglycemia), ACTH deficiency, and normal glucose tolerance. All patients were on stable hydrocortisone replacement (15 mg with breakfast, 5 mg with evening meal) for at least 2 months before the trial. Insulin action was assessed by the euglycemic hyperinsulinemic glucose clamp technique (1 mU/kg x min) before and after 6 months of GH therapy. GH was started at 0.8 IU sc daily and titrated monthly until the serum IGF-I increased to within 1-2 SD of the mean of normal age-matched controls. Body mass index did not change significantly during the 6 months of GH therapy. Fasting plasma glucose and HbA1c increased significantly after 6 months (5.2 +/- 0.0 vs. 5.5 +/- 0.0 mmol/liter, P < 0.0001, and 4.5 +/- 0.1 vs. 4.7 +/- 0.1%, P < 0.0005, respectively). There was no increase in fasting serum insulin (51.6 +/- 10.2 vs. 60.0 +/- 10.2 pmol/liter, P = 0.12). Exogenous glucose infusion rates required to maintain euglycemia were similar after GH (23.0 +/- 0.4 vs. 21.1 +/- 0.3 micromol/kg x min, P = 0.6). Endogenous glucose production in the fasting state was also unchanged following GH (11.8 +/- 0.7 vs.12.3 +/- 0.9 micromol/kg x min, P = 0.5) and suppressed to a similar extent following insulin (4.4 +/- 0.8 vs. 5.5 +/- 0.8 micromol/kg x min, P = 0.3). In summary, GH therapy for 6 months, with serum IGF-I maintained in the upper physiological range, increased fasting plasma glucose and HbA1c. There was no effect on peripheral or hepatic insulin sensitivity. Patients receiving GH therapy require long-term monitoring of glucose tolerance.
3-Hydroxybutyric Acid↗
Laboratory and clinical experience in 55 patients with macroprolactinemia identified by a simple polyethylene glycol precipitation method.
PRL exists in different forms in human serum. The predominant form is little PRL (molecular mass 23 kDa) with smaller amounts of big PRL (molecular mass 50--60 kDa) and at times big big or macroprolactin (molecular mass 150--170 kDa). The frequency and clinical consequences of macroprolactinemia have not been clearly established, mainly because of difficulty in identifying these patients biochemically. This previously required the use of gel filtration chromatography, which could not be used routinely. Recently, a screening test using polyethylene glycol (PEG) has been used to identify macroprolactin in serum. Consequently, this study was designed to examine the use of PEG precipitation in the identification of patients with a predominance of macroprolactin and to establish the clinical characteristics of such a cohort. Over 12 months, 18,258 requests for serum PRL were received and of these 1225 patients had a serum PRL more than 700 mU/L. A total of 322 of these patients (26%) had a percentage recovery after PEG precipitation of less than 40%, thus indicating the presence of a predominance of macroprolactin. Fifty-five of these patients were referred for detailed clinical assessment. Symptoms typical of hyperprolactinemia were not common in this cohort. None had sustained amenorrhea and eight have had oligomenorrhea at age less than 40 yr. One had galactorrhea. All had pituitary imaging, and four had a microadenoma with none having a macroadenoma. PEG precipitation allows easy identification of macroprolactin in routine clinical practice. As the clinical consequences of this entity at this stage seem relatively benign, referral and intensive investigation of these patients may not be necessary. However, follow-up of a large cohort is required to ensure that the long-term outlook is likewise benign. This would have important implications for both patients and healthcare systems.
Adult↗
Immunohistochemical evaluation of the post-translational processing of chromogranin A in human pituitary adenomas.
Chromogranin A (CgA), pancreastatin (PST), intervening-peptide (IP) and WE-14 antisera were employed to investigate the proteolysis of CgA in 50 pituitary adenomas. All non-functioning (NF) pituitary tumours (n = 28) exhibited CgA immunoreactivity. PST, IP and WE-14 immunostaining was observed in 85%, 89% and 67%, respectively. CgA, PST and IP immunostaining were comparable in the majority of NF tumours, while less intense WE-14 immunoreactivity was detected in a subpopulation of NF tumour cells. Approximately half of the functioning pituitary tumours expressed CgA immunoreactivity. Six of nine ACTH-secreting tumours displayed CgA and IP immunostaining; four of these tumours displayed PST immunoreactivity. WE-14 immunoreactivity was detected in one corticotroph tumour. Three of six growth hormone (GH) secreting tumours displayed CgA immunostaining, two exhibited PST and IP, and one exhibited WE-14 immunoreactivity. Clusters of WE-14 immunopositive cells were detected in one GH tumour. One of seven prolactinomas exhibited weak CgA immunostaining, while weak IP and WE-14 immunostaining was detected in an additional tumour. No PST immunostaining was detected in prolactinomas. Therefore CgA is a valuable marker of NF pituitary tumours, however it is a more sporadic marker of functioning adenomas. In general, the cellular pattern and intensities of CgA, PST and IP immunoreactivity were comparable in the majority of pituitary adenomas. In contrast, WE-14 immunostaining was observed in a subpopulation of tumour cells. The pathophysiological significance of the proteolysis of CgA to generate bioactive peptides in both NF and functioning pituitary adenomas remains to be established.
Adenoma↗
New causes of Cushing's syndrome: abnormal adrenal regulation of cortisol production.
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Adrenal Cortex↗