ESE audit on management of Adult Growth Hormone Deficiency in clinical practice.

Guidelines recommend adults with pituitary disease in whom GH therapy is contemplated, to be tested for GH deficiency (AGHD); however, clinical practice is not uniform. AIMS: 1) To record current practice of AGHD management throughout Europe and benchmark it against guidelines; 2) To evaluate educational status of healthcare professionals about AGHD. DESIGN: On-line survey in endocrine centres throughout Europe. PATIENTS AND METHODS: Endocrinologists voluntarily completed an electronic questionnaire regarding AGHD patients diagnosed or treated in 2017-2018. RESULTS: Twenty-eight centres from 17 European countries participated, including 2139 AGHD patients, 28% of childhood-onset GHD. Aetiology was most frequently non-functioning pituitary adenoma (26%), craniopharyngioma (13%) and genetic/congenital mid-line malformations (13%). Diagnosis of GHD was confirmed by a stimulation test in 52% (GHRH+arginine, 45%; insulin-tolerance, 42%, glucagon, 6%; GHRH alone and clonidine tests, 7%); in the remaining, ≥3 pituitary deficiencies and low serum IGF-I were diagnostic. Initial GH dose was lower in older patients, but only women <26 years were prescribed a higher dose than men; dose titration was based on normal serum IGF-I, tolerance and side-effects. In one country, AGHD treatment was not approved. Full public reimbursement was not available in four countries and only in childhood-onset GHD in another. AGHD awareness was low among non-endocrine professionals and healthcare administrators. Postgraduate AGHD curriculum training deserves being improved. CONCLUSION: Despite guideline recommendations, GH replacement in AGHD is still not available or reimbursed in all European countries. Knowledge among professionals and health administrators needs improvement to optimize care of adults with GHD.

Prevalence of diabetes mellitus in 6050 hypopituitary patients with adult-onset GH deficiency before GH replacement: a KIMS analysis.

OBJECTIVE: GH deficiency (GHD) in adults is characterized by a tendency toward obesity and an adverse body composition with visceral fat deposit and may thus predispose to the development of type 2 diabetes mellitus. The aim of this study was to assess the observed prevalence proportion (PP) and observed PP over expected PP ratio (standardized prevalence proportion ratio, SPR) of diabetes according to International Diabetes Federation criteria in a large cohort of GH-untreated adult-onset GHD patients. DESIGN AND METHODS: Associations between baseline variables and diabetes prevalence in 6050 GHD patients from KIMS (Pfizer International Metabolic Database) were studied and robust Poisson-regression analyses were performed. Comparisons between baseline status and HbA1c categories in the nondiabetic patients were done with covariance analysis. P values <0.05 were considered statistically significant. RESULTS: PP was 9.3% compared with the expected 8.2%. SPR was 1.13 (95% confidence intervals (95% CIs), 1.04-1.23), which was significantly increased in females (1.23; 95% CI, 1.09-1.38%) but not in males (SPR 1.04; 95% CI, 0.92-1.17%). PP increased significantly by age, familial diabetes, country selection, BMI, waist circumference, number of pituitary deficiencies, and GHD etiology. SPR decreased significantly by age and increased significantly by BMI, waist circumference, and IGF1 SDS. Multiple regression model showed that the most important impact on SPR was from age and BMI. HbA1c values of 6.0-6.5% were found in 9.5% of nondiabetic patients and were associated with higher BMI and waist circumference. CONCLUSIONS: GHD is associated with an increased prevalence of diabetes, largely to be explained by the adverse body composition. These data urge toward early initiation of lifestyle modification measures.

Prevalence and characteristics of the metabolic syndrome in 2479 hypopituitary patients with adult-onset GH deficiency before GH replacement: a KIMS analysis.

OBJECTIVE: An increased risk of cardiovascular morbidity and mortality in adult GH deficiency (GHD) may be related to hypopituitarism but also to the presence of the metabolic syndrome (MetS). Our objective was to investigate the characteristics and prevalence of MetS as well as its comorbidities in adult GHD. Design In KIMS (Pfizer International Metabolic Database) 2479 patients with severe adult-onset GHD, naïve to GH replacement, with complete information on all MetS components were found. MetS was defined according to the National Cholesterol Education Program's Adult Treatment Panel III (NCEP) and the International Diabetes Foundation (IDF). METHODS: The prevalence of MetS was calculated and compared with previously published data from the normal population. Associations were assessed between background variables, baseline variables, comorbidities, and MetS. RESULTS: MetS was present in 43.1% (NCEP) and in 49.1% (IDF) of patients, clearly higher than data from the normal population (20-30%). MetS prevalence was related to age, GHD duration, and body mass index (BMI), but not to GHD severity, extent of hypopituitarism, or etiology of pituitary disease. Adjusted for age, gender, and BMI, patients with MetS had a higher prevalence ratio for diabetes mellitus: 4.65 (95% confidence interval (CI): 3.29-6.58), for cardiovascular morbidity: 1.91 (95% CI: 1.33-2.75), and for cerebrovascular morbidity: 1.77 (95% CI: 1.09-2.87) than patients without MetS. CONCLUSIONS: MetS is highly prevalent in GHD and is associated with a higher prevalence ratio for comorbidities. The presence of MetS in GHD may therefore contribute to the increased risk of cardiovascular morbidity and mortality found in these patients.

Rapid and sustained reduction of serum growth hormone and insulin-like growth factor-1 in patients with acromegaly receiving lanreotide Autogel therapy: a randomized, placebo-controlled, multicenter study with a 52 week open extension.

The study was designed to evaluate the long-term efficacy and safety of the 28-day prolonged-release Autogel formulation of the somatostatin analogue lanreotide (Lan-Autogel) in unselected patients with acromegaly. The study comprised four phases: washout; a double-blind comparison with placebo, at a single randomized dose (60, 90 or 120 mg) of Lan-Autogel; a single-blind, fixed-dose phase for four injections (placebo group was re-allocated to active treatment); and eight injections with doses tailored according to biochemical response. Serum samples were assessed for growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels, at weeks 4, 13, 14, 15, 16, 32 and 52. 108 patients were enrolled and 99 completed 52 weeks' treatment. Four weeks after the first injection, serum GH levels decreased by >50% from baseline in 63% of patients receiving Lan-Autogel compared with 0% receiving placebo (P < 0.001). After four injections, 72% of patients had a >50% reduction in GH levels; 49% patients achieved GH levels < or = 2.5 ng/ml; 54% had normalized IGF-1; and 38% achieved the combined criterion of GH level < or = 2.5 ng/ml and normalized IGF-1. The corresponding proportions by week 52 were 82, 54, 59 and 43%, respectively. In patients not requiring dose escalation to 120 mg, 85% achieved biochemical control (combined criterion). Treatment was well tolerated by all patients. In conclusion, Lan-Autogel was effective in controlling GH and IGF-1 hypersecretion in patients with acromegaly and showed a rapid onset of action.

Analysis of IMP3 expression in normal and neoplastic human pituitary tissues.

Insulin-like growth factor II mRNA-binding protein 3 (IMP3) is an oncofetal protein highly expressed in fetal tissue and malignant tumors but rarely found in adult benign tissues. In various tumors, IMP3 expression is correlated with increased tumor aggressiveness and reduced overall survival. To our knowledge, IMP3 expression has not been investigated in pituitary tumors. We analyzed the immunohistochemical expression of IMP3 in five normal pituitary tissues and 75 pituitary tumors (64 adenomas and 11 carcinomas) to determine if specific tumor types expressed IMP3 and if there were differences in IMP3 expression between adenomas and carcinomas. Immunohistochemical analysis showed that IMP3 was positive in four (80%) normal pituitaries with focal stain in a subset of normal anterior pituitary cells. IMP3 was expressed in 31% (20/64) of adenomas and in 36% (4/11) of carcinomas. A slightly higher level of IMP3 expression was observed in PRL-GH-TSH adenomas compared to the other types of pituitary adenomas. Expression of IMP3 was not significantly higher in carcinomas than in adenomas (p = 0.737). RT-PCR and Western Blotting supported the heterogeneous expression of IMP3. These results indicate that IMP3 is expressed both in normal and in neoplastic pituitary gland tissues without significant differences in expression levels in pituitary carcinomas.

Protein western array analysis in human pituitary tumours: insights and limitations.

The molecular analysis of pituitary tumours has received a great deal of attention, although the majority of studies have concentrated on the genome and the transcriptome. We aimed to study the proteome of human pituitary adenomas. A protein array using 1005 monoclonal antibodies was used to study GH-, corticotrophin- and prolactin-secreting as well as non-functioning pituitary adenomas (NFPAs). Individual protein expression levels in the tumours were compared with the expression profile of normal pituitary tissue. Out of 316 proteins that were detected in the pituitary tissue samples, 116 proteins had not previously been described in human pituitary tissue. Four prominent differentially expressed proteins with potential importance to tumorigenesis were chosen for validation by immunohistochemistry and western blotting. In the protein array analysis heat shock protein 110 (HSP110), a chaperone associated with protein folding, and B2 bradykinin receptor, a potential regulator of prolactin secretion, were significantly overexpressed in all adenoma subtypes, while C-terminal Src kinase (CSK), an inhibitor of proto-oncogenic enzymes, and annexin II, a calcium-dependent binding protein, were significantly underexpressed in all adenoma subtypes. The immunohistochemical analysis confirmed the overexpression of HSP110 and B2 bradykinin receptor and underexpression of CSK and annexin II in pituitary adenoma cells when compared with their corresponding normal pituitary cells. Western blotting only partially confirmed the proteomics data: HSP110 was significantly overexpressed in prolactinomas and NFPAs, the B2 bradykinin receptor was significantly overexpressed in prolactinomas, annexin II was significantly underexpressed in somatotrophinomas, while CSK did not show significant underexpression in any tumour. Protein expression analysis of pituitary samples disclosed both novel proteins and putative protein candidates for pituitary tumorigenesis, though validation using conventional techniques are necessary to confirm the protein array data.

No greater incidence or worsening of cardiac valve regurgitation with somatostatin analog treatment of acromegaly.

CONTEXT: Excess GH and IGF-I in acromegaly are associated with reduced life expectancy due to cardiovascular complications. OBJECTIVE: The objective of the study was to investigate the prevalence, incidence, and severity of cardiac valve regurgitation before and after somatostatin-analog treatment in acromegaly. DESIGN: This was a prospective, observer-blinded, multicenter, 12-month study. SETTING: The study was conducted at 33 specialist centers. PATIENTS: The study population consisted of 225 adult patients with acromegaly without significant cardiac valve abnormalities or prior valve-replacement surgery, matched for age, sex, and center/country/study. INTERVENTIONS: Interventions included initiation/continuation of lanreotide (n = 107) or octreotide treatment (n = 118), tailored for optimal disease control. MAIN OUTCOME MEASURES: Relative risk of new/worsening regurgitation in any valve at 12 months compared with baseline, was measured. RESULTS: At baseline, almost 80% of patients had some degree of cardiac valve regurgitation, although none was severe. The risk of developing new/worsening regurgitation in any valve at 12 months was nonsignificant and similar for the cohorts [adjusted odds ratio 0.86; 95% confidence interval (CI) 0.41-1.82; P = 0.694; relative risk 1.04; 95% CI 0.67-1.60; risk difference 0.01; 95% CI -0.13 to 0.16]. For 54% of patients, the severity of regurgitation stayed the same during the study. At baseline, significant valve regurgitation occurred in 18% of patients (lanreotide cohort) and 13% (octreotide cohort) and at 12 months in 18% of each cohort. CONCLUSIONS: The incidence of valve regurgitation did not change over 12 months of treatment with somatostatin analogs, and most cases were physiologic or mild in severity. There was no significant difference between somatostatin analogs in the risk of developing new/worsening valve regurgitation or significant regurgitation after 1 yr.

Somatostatin analogues stimulate p27 expression and inhibit the MAP kinase pathway in pituitary tumours.

OBJECTIVES: Somatostatin (SST) analogues play an important role in the medical management of somatotroph pituitary adenomas and new agonists have the potential to be effective in a wider group of pituitary and other tumours. The anti-proliferative effect of SST occurs through multiple mechanisms, one of which is cell-cycle arrest, where p27, a cyclin-dependent kinase inhibitor, is an important regulator. We hypothesised that SST may upregulate p27 protein levels and downregulate the MAP kinase pathway in these tumours. METHODS: Human pituitary adenoma cells and rat pituitary cell line (GH3) were cultured and treated in vitro with octreotide and the broad-spectrum SST agonist SOM230 (pasireotide). Immunoblotting for p27 and phospho-ERK (pERK) was performed and proliferation assessed by [3H]-thymidine incorporation. Histological samples from acromegalic patients treated with octreotide before surgery were immunostained for p27 and compared to samples from untreated patients matched for sex, age, tumour size, extension and invasiveness. RESULTS: We detected upregulation of p27 protein levels with SST analogue treatment in vitro in human pituitary adenoma samples. pERK1/2 was inhibited by SST analogues in both the human samples and GH3 cells. SST and its analogues inhibited the proliferation of GH3 cells. p27 immunostaining was stronger in samples from patients with longer preoperative octreotide treatment (more than 6 months) than in samples from patients with shorter treatment periods. CONCLUSIONS: This study demonstrates that SST-mediated growth inhibition is associated with the downregulation of pERK and upregulation of p27. More potent and broader-spectrum SST analogues are likely to play an increasing role in the treatment of tumours, where the MAP kinase pathway is overactivated.

Determinants of cardiovascular risk in 2589 hypopituitary GH-deficient adults - a KIMS database analysis.

OBJECTIVE: The aim of the present study was to clarify the relationship between GH deficiency (GHD) and some cardiovascular risk factors and to analyse the effect of GH replacement therapy in a large number of patients over a prolonged period of time. DESIGN: Data for analysis were retrieved from KIMS (Pfizer International Metabolic Database). Serum concentrations of total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol and triglycerides were obtained from 2589 patients at baseline and from 1206 patients after 1 and 2 years of GH replacement therapy. Body mass index (BMI), waist and hip, resting blood pressure and body composition were also measured. RESULTS: At baseline, the unfavourable effects of GHD were most obvious in the lipid profile demonstrating elevated mean total and LDL-cholesterol, in the increased waist circumference and the elevated BMI. The cholesterol concentration, BMI and body composition were significantly adversely affected by a number of factors, including age, sex and the use of anti-epileptic drugs. The therapeutic effect of GH was essentially uniform across the whole population. GH replacement reduced significantly the mean total and LDL-cholesterol, the waist circumference and the fat mass and was maintained during 2 years. CONCLUSIONS: This analysis of a large number of patients confirmed that GHD adults present with an increased cardiovascular risk. The sustained improvement of the adverse lipid profile and body composition suggests that GH replacement therapy may reduce the risk of cardiovascular disease and the premature mortality seen in hypopituitary patients with untreated GHD.

Treatment of pituitary tumors: dopamine agonists.

The neurotransmitter/neuromodulator dopamine plays an important role in both the central nervous system and the periphery. In the hypothalamopituitary system its function is a dominant and tonic inhibitory regulation of pituitary hormone secretion including prolactin- and proopiomelanocortin-derived hormones. It is well known that dopamine agonists, such as bromocriptine, pergolide, quinagolide, cabergoline, and lisuride, can inhibit PRL secretion by binding to the D(2) dopamine receptors located on normal as well as tumorous pituitary cells. Moreover, they can effectively decrease excessive PRL secretion as well as the size of the tumor in patients having prolactinoma. Furthermore, dopamine agonists can also be used in other pituitary tumors. The major requirement for its use is that the tumor cells should express D(2) receptors. Therefore, in addition to prolactinomas, targets of dopamine agonist therapy are somatotroph tumors, nonfunctioning pituitary tumors, corticotroph pituitary tumors, Nelson's syndrome, gonadotropinomas, and thyrotropin-secreting pituitary tumors. It is also an option for the treatment of pituitary disease during pregnancy. Differences between the effectiveness and the resistance of different dopaminergic agents as well as the future perspectives of them in the therapy of pituitary tumors are discussed.

Isolated growth hormone (GH) deficiency in adult patients: baseline clinical characteristics and responses to GH replacement in comparison with hypopituitary patients. A sub-analysis of the KIMS database.

BACKGROUND: Isolated growth hormone deficiency (IGHD) provides the ideal model to characterize GHD without interference from other pituitary deficiencies or their treatment. No study has addressed the question whether adult patients with IGHD differ in clinical presentation or in responsiveness to GH replacement from adult patients with multiple pituitary hormone deficiencies (MPHD) receiving conventional replacement therapy. PATIENTS AND METHODS: Data were retrieved from the outcomes research database KIMS (Pfizer international metabolic database). Patients with IGHD accounted for 9.6% (274/2868) of all GHD patients. Patients were separated according to the timing of onset. In the adult-onset (AO) group, 167 patients with IGHD were compared to 1992 patients with MPHD. In the childhood-onset (CO) group, 107 patients with IGHD were compared to 602 patients with MPHD. To assess the effect of GH replacement after one year, a longitudinal sub-analysis in the AO group was performed comparing 89 IGHD patients to 1234 MPHD patients. The same study was done in the CO group comparing 66 IGHD patients to 386 MPHD patients. Because IGHD patients were significantly younger than MPHD patients, data analysis was also performed after adjustment for gender and age. RESULTS: In the AO group, non-functioning and secreting pituitary adenomas were the most common primary diagnoses in both IGHD and MPHD. Medical history revealed a high prevalence of hypertension and fractures in both subgroups, but also of non-insulin dependent diabetes mellitus. The prevalence of obesity was high and the waist circumference was elevated. The lipid profile was unfavourable in both IGHD and MPHD. IGF-I concentration and SDS were comparable in both subgroup. Quality of life assessed by QoL-AGHDA was equally poor in both IGHD and MPHD. GH replacement therapy induced favourable changes without distinction. In the CO group, the most common cause in both subgroups was idiopathic. Fracture rate was similarly prevalent in both IGHD and MPHD. Obesity was prominent in both subgroups, but BMI and waist circumference were lower in IGHD. Adverse lipid changes were similarly found in both IGHD and MPHD. IGF-I concentration and SDS were significantly higher in the IGHD subgroup compared to the MPHD subgroup. The QoL-AGHDA score was equally abnormal in both IGHD and MPHD. GH replacement achieved similar significant improvement in both subgroups. CONCLUSIONS: GHD patients with AO-IGHD and AO-MPHD present with a similar clinical expression and respond similarly to GH replacement. Patients with CO-IGHD are less severely affected by GHD than CO-MPHD patients, but, nevertheless, both groups show a comparable adverse lipid profile and poor quality of life and respond favourably to GH replacement. These findings support the concept that GH alone is responsible for most if not all metabolic aspects of hypopituitary patients receiving conventional replacement therapy, regardless of age of onset or aetiology. As a consequence, GH replacement therapy not only has potential benefit in GHD patients with additional hormonal deficits, but also the indication of treatment must be extended to patients with isolated GHD.

Sheehan's syndrome: baseline characteristics and effect of 2 years of growth hormone replacement therapy in 91 patients in KIMS - Pfizer International Metabolic Database.

OBJECTIVE: Sheehan's syndrome occurs as a result of ischaemic pituitary necrosis due to severe postpartum haemorrhage. It is one of the most important causes of hypopituitarism, and hence growth hormone deficiency (GHD), in developing countries. However, little is known about the effects of growth hormone (GH) replacement therapy in patients with Sheehan's syndrome. DESIGN: The demographic background characteristics of 91 GH-deficient patients with Sheehan's syndrome (mean age +/- s.d., 46.3 +/- 9.4 years) were compared with those of a group of 156 GH-deficient women (mean age +/- s.d., 51.5 +/- 13.1 years) with a non-functional pituitary adenoma (NFPA). The baseline characteristics and the effects of 2 years of GH replacement therapy were also studied in the 91 patients with Sheehan's syndrome and an age-matched group of 100 women with NFPA (mean age +/- s.d. 44.5 +/- 10.2 years). RESULTS: All patients were enrolled in KIMS (Pfizer International Metabolic Database). Patients with Sheehan's syndrome were significantly younger at pituitary disorder onset, diagnosis of GHD and at entry into KIMS than patients with NFPA (P < 0.01), and had significantly lower insulin-like growth factor I levels (P < 0.001). At baseline, quality of life (QoL) was significantly (P < 0.05) reduced in patients with Sheehan's syndrome compared with those with NFPA (P < 0.001). With regard to treatment effects, lean body mass increased significantly (P < 0.05), QoL improved significantly (P < 0.05) and total and low-density lipoprotein-cholesterol decreased significantly (P < 0.05) in patients with Sheehan's syndrome after 1 year of GH replacement therapy. Similar significant changes in QoL and lipid profiles occurred in patients with NFPA after 2 years of GH replacement. Blood pressure remained unchanged in patients with Sheehan's syndrome, but decreased significantly (P < 0.01) in the group with NFPA after 1 year, before returning to pretreatment levels at 2 years. CONCLUSIONS: In conclusion, patients with Sheehan's syndrome have more severe GHD compared with individuals with NFPA. GH replacement therapy in patients with Sheehan's syndrome may have beneficial effects on QoL, body composition and lipid profile.

Traumatic brain injury as a relevant cause of growth hormone deficiency in adults: A KIMS-based study.

OBJECTIVES: To characterize further the clinical manifestations and the efficacy of growth hormone (GH) replacement therapy in patients with adult-onset growth hormone deficiency (GHD) reported in the KIMS (Pfizer's international metabolic database) as caused by traumatic brain injury (TBI) and to compare them with nonirradiated patients whose GHD was due to a nonfunctioning pituitary adenoma (NFPA). DESIGN: Observational study. SETTING: Subjects selected from the KIMS database. PARTICIPANTS: Fifty-one patients with GHD resulting from TBI and 688 patients with GHD resulting from NFPA. Both groups were selected from the KIMS and had adult-onset GHD with GH replacement therapy only after KIMS entry and before and after KIMS entry. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Age, body mass index, age at disease onset, age at disease diagnosis, age at KIMS entry, final height, GH peak at testing, GH replacement dose, routine biochemical analysis, clinical manifestations of disease, and quality of life measurements. RESULTS: Patients with TBI were significantly younger at study entry and were younger both at pituitary disease onset and at GHD diagnosis, but they showed a significant delay in treatment. When comparing patients not treated with GH before entering in the KIMS, patients with TBI were significantly shorter (167.2+/-1.7 cm) than those with NFPA (171.6+/-0.4 cm) in final height. TBI patients had lower GH reserves than NFPA patients, and although the latter group experienced more positive changes, both groups benefited from GH replacement therapy. CONCLUSIONS: Patients with GHD due to TBI showed a significant reduction in height and a reduction in pituitary GH reserve and were diagnosed and treated with inappropriate delay.

Epidemiology of thyroid microcarcinoma found in autopsy series conducted in areas of different iodine intake.

The prevalence of thyroid microcarcinomas found at autopsies is 100-1000 times higher than in clinical cancer. The epidemiological and histological characteristics of thyroid microcarcinomas in consecutive series of autopsies performed in two areas of different iodine intake were investigated. Iodine deficient (ID) area: n = 222 (M = 109, F = 113), median age: 74-76 years, median iodine excretion (MIE) of nursing home residents from this area: 70 microg/g creatinine. Iodine sufficient (IS) area: n = 221 (M = 132, F = 89), median age: 68 years, MIE: 500 microg/g creatinine. When compared to the IS area, the results obtained in the ID area showed a higher thyroid weight (mean 27.75 g +/- 18.43 g vs. 16.5 g +/- 9.6 g, p < 0.0001) and a larger number of goitrous glands (50/222 vs. 5/221, p < 0.0001). Altogether 21 microcarcinomas were found (4.74%) with no iodine intake- or gender-related difference: ID n = 11 (4.95%), M/F = 8/3; IS n = 10 (4.52%), M/F = 6/4. Microcarcinomas seemed to be more prevalent in the 40-59-year age group. All microcarcinomas were of the papillary type. In conclusion, compared to clinical cancer, thyroid microcarcinomas are characterized by a two-scale higher prevalence, are not related to iodine intake, gender or nodularity, are most exclusively of the papillary type.

Effect of growth hormone replacement therapy on pituitary hormone secretion and hormone replacement therapies in GHD adults.

OBJECTIVE: We tested the impact of commencement of GH replacement therapy in GH-deficient (GHD) adults on the circulating levels of other anterior pituitary and peripheral hormones and the need for re-evaluation of other hormone replacement therapies, especially the need for dose changes. METHODS: 22 GHD patients were investigated in a double-blind randomized study and 90 GHD patients in an open study at baseline and after 6 and 12 months of GH replacement therapy. RESULTS: In the placebo-controlled trial, the FT(3) levels increased after 6 months in the GH-treated group, and in the open study the FT(3) levels tended to increase. Other hormone concentrations did not change in either part of the study. Four patients required an increase in thyroxine dose, while 2 patients needed dose reduction. One originally euthyroid patient required thyroxine replacement. Two patients with originally conserved pituitary-adrenal function developed ACTH insufficiency. The hydrocortisone dose was increased in 1 and decreased in 1 of the 66 patients with secondary hypocortisolism. None of the females required any adjustment of sex hormone replacement therapy. Two of 37 males needed dose increase of testosterone, while 1 needed dose reduction. CONCLUSION: GH replacement therapy required dose adjustments regarding other hormone replacement therapies in 12.2% (n = 11), while initiation of new hormone replacement was performed in 3.3% (n = 3) of the 90 patients during the 1-year follow-up. Monitoring of pituitary hormone axes is advisable after commencement of GH replacement therapy, since changes of hormone replacement therapy was observed in a small but clinically significant number of patients.

Thyrotropin secretion during oral glucose tolerance test in acromegalic patients and control subjects.

It has been suggested that acute hyperglycemia stimulates somatostatin release from the hypothalamus, thus causing inhibition of growth hormone and thyrotropin secretion. Abnormal growth hormone secretory pattern to glucose load is characteristic of acromegaly, and it might reflect alterations in somatostatin release. We evaluated the sensitivity of serum thyrotropin response to presumed somatostatin inhibition during oral glucose tolerance test in 29 patients with active acromegaly, in 13 patients with inactive disease, and in 19 control persons suspected of impaired glucose tolerance. Both the acromegalic patients and the control subjects were euthyroid. Serum insulin, growth hormone, thyrotropin, free triiodthyronine, free thyroxine, and glucose were collected before and 30, 60, 90, and 120 min after the ingestion of 75 g glucose. While the free triiodthyronine and free thyroxine values did not change during the glucose test, the thyrotropin levels progressively and significantly declined in all groups. The basal to nadir thyrotropin ratio was higher in active acromegaly than in inactive disease and in control subjects (p < 0.01), suggesting that the glucose load inhibited thyrotropin stronger in active acromegalic patients. These data suggest that there is a possible strong somatostatin response to glucose load in acromegalic patients, which inhibits thyrotropin secretion. These data do not support the concept of decreased somatostatin drive in acromegaly.

Physiological and pathological angiogenesis in the endocrine system.

Formation of new blood vessels occurs in many physiological states (during development of the embryo, cycling changes of the female reproductive tract), as well as in pathological processes (such as diabetic retinopathy and wound healing). Angiogenesis has been shown to be related to tumor formation, prognosis, and response to treatment in many tumor types. Intratumoral microvessels can be related to tumor behavior or hormone secretion in different endocrine tumors. For example, invasive prolactinomas are more vascular than noninvasive adenomas; a surgical approach is more successful in macroprolactinomas with lower microvessel density. A higher number of microvessels have been found in papillary thyroid carcinomas during recurrences. A correlation between microvessel count and prognosis in papillary and medullary thyroid carcinomas has been suggested. Several stimulating and inhibiting factors involved in the regulation of angiogenesis have been identified. Among them, vascular endothelial growth factor (VEGF) has been shown to be critically involved in angiogenesis and also in the neovascularization of solid tumors. Dopamine agonists (already in clinical use for prolactinomas) have potent inhibitory actions on VEGF signaling, and thus may be a new tool in antiangiogenic therapy. Secretion of VEGF in the great majority of human pituitary adenomas is inhibited by dexamethasone. This suggests that glucocorticoids can be considered in the treatment of certain pituitary tumors. The cyclic nature of angiogenesis in the female reproductive tract indicates that stimulation or inhibition of paracrine angiogenic factors may lead to new approaches for being able to influence reproductive endocrine disorders. Experimental and clinical aspects of interactions between angiogenic factors and tumor growth of the endocrine system are also discussed.

Macroprolactinemia: the consequences of a laboratory pitfall.

The objective of this study was to assess the prevalence of macroprolactin, a macromolecule with reduced bioactivity, in hyperprolactinemic patients. Prolactin was measured before and after precipitation of macroprolactin by polyethylene glycol in 306 patients. Only patients with prolactin values >700 mIU/L (n = 270) entered the study. In 23% of the patients, macroprolactinemia was found. In women, the occurrence of macroprolactinemia increased with advancing age (< 30 yr: 16%; 30-45 yr: 28%; > 45 yr: 42%; p < 0.05). A priori clinical signs of hyperprolactinemia (morphological abnormalities in pituitary imaging, galactorrhea infertility) occurred significantly less frequently in macroprolactinemia than in true hyperprolactinemia. In eight females macroprolactinemia and true hyperprolactinemia appeared simultaneously. To avoid diagnostic and therapeutic pitfalls, the screening for macroprolactinemia of all patients with prolactin levels of > 700 mIU/ L is recommended.

Dexamethasone and adrenocorticotropin suppress prolactin secretion in humans.

It has been demonstrated that the regulatory pathways mediating basal and/or stimulus-induced prolactin (PRL) release in mammals are highly sensitive to adrenal corticoid inhibitory influence. We have investigated the effect of four different doses of dexamethasone (DEX) and the effect of adrenocorticotropin on PRL secretion in 197 patients (169 female, 28 male; age: 18-66 yr) with suspected hypercortisolemia--but only those with a normal glucocorticoid suppression test were involved in the study--and in 66 female patients (age: 18-39 yr) with suspected adrenocorticotropin-dependent hyperandrogenism. Overnight (1 mg), low-dose (0.5 mg every 6 h for 2 d), high-dose (2 mg every 6 h for 2 d), and long-lasting administration of DEX (0.5 mg every 6 h for 5 d) resulted in a significant decrease in PRL levels compared to the baseline. Similarly, a reduction in PRL levels could be detected following injection of adrenocorticotropin (250 microg). In hyperprolactinemic patients, the DEX-induced increase in PRL (APRL, expressed in percentage of baseline) was significantly larger compared with normoprolactinemic subjects in all groups except those who received high-dose DEX) or adrenocorticotropin. These data clearly indicate that the secretory function of PRL cells in humans is sensitive to changes in the activity of the hypothalamo-pituitary-adrenal axis in a dose-dependent manner.