Idiopathic adult growth hormone deficiency

An Update on Advances in Hypopituitarism: Etiology, Diagnosis, and Current Management

This article provides an updated review of hypopituitarism (HP), an endocrine disorder characterized by a deficiency of one or more pituitary hormones. The various etiologies are reviewed, including pituitary neuroendocrine tumors (PitNETs), hypothalamic lesions, genetic mutations, and acquired factors such as head trauma, medications, neoplasms, and infiltrative diseases. It is noted that PitNETs are responsible for approximately half of the cases in adults, whereas in children the causes are predominantly congenital. Diagnosis is based on clinical evaluation and hormonal testing, with identification of the specific hormonal deficiencies essential for effective treatment. Laboratory tests present challenges and limitations that must be understood and addressed. Hormone replacement therapy is the mainstay of treatment, significantly improving patients' quality of life. It is important to know the possible interactions between hormone replacement therapies in HP. Recent advances in understanding the pathophysiology of HP and the importance of a multidisciplinary approach to the management of associated complications are discussed. This article emphasizes the need for comprehensive evaluation and continuous follow-up to optimize outcomes in patients with HP and highlights the importance of ongoing research to improve diagnostic and treatment strategies.

Clinical Management of Postoperative Growth Hormone Deficiency in Hypothalamic-Pituitary Tumors

The present review focuses on growth hormone (GH) deficiency in pediatric and adult patients following surgery for hypothalamic-pituitary tumors, with a special emphasis on hormone replacement therapy with recombinant human growth hormone (rhGH). The symptoms and metabolic changes associated with GH deficiency are reviewed, and the potential risks and therapeutic outcomes of rhGH treatment in these patients are discussed. This review emphasizes the importance of rhGH in the normalization of growth in children and the improvement of quality of life (QoL) and metabolic health in adults. Aspects related to efficacy, safety, dosage, duration of treatment, and QoL in this population are analyzed. The need for regular follow-up and dose adjustment to maintain the optimal IGF-I levels in these patients is emphasized, as is the importance of individualized assessment and collaboration with a specialized multidisciplinary medical team to make the appropriate therapeutic decisions. Furthermore, continuous follow-up are necessary to optimize the clinical outcomes in this patient population.

Baseline Clinical Factors Associated with Cessation of Growth Hormone Therapy in Patients with Severe Growth Hormone Deficiency - Real World Evidence

Background

Growth hormone replacement is indicated in adults with severe growth hormone (GH) deficiency, adult growth hormone deficiency assessment (AGHDA) score of at least 11 and are receiving treatment for other pituitary hormone deficiencies. There are no data looking at the cessation of GH replacement in adult patients with severe GH deficiency and the factors that predict the likelihood of patients continuing or stopping growth hormone replacement.

Methods

We audited patients on the GH register between January 2006 and January 2023 in Hull University Teaching Hospitals NHS foundation Trust, a UK tertiary hospital. Baseline characteristics, the cause of GH deficiency, AGHDA score at diagnosis and the reason for stopping GH were collected. Proportions were compared between patients adhering to GH replacement and those who had ceased it. Logistic regression analysis was used to identify factors independently associated with cessation of GH.

Results

The study comprised 141 adult patients with a mean age of 52 years, of which 75 (53%) were female. 54 (38%) individuals had discontinued GH replacement therapy. Predominant reasons for discontinuation were lack of therapeutic benefit (46%) and a change in clinical indication (26%). Among patients who discontinued GH therapy, the most frequent cause of GH deficiency was idiopathic (57%), while for those on GH replacement, pituitary surgery was the leading cause of GH deficiency (53%). Logistic regression analysis showed no baseline factor was statistically significantly associated with GH cessation, except female gender which had a borderline significance (P = 0.05).

Conclusions

In this real-world investigation of patients with severe GH deficiency, over two in five individuals who discontinued GH therapy cited the absence of perceived benefits. We show a borderline association of female gender with GH cessation and large population-based studies will be needed to investigate this and other causes of GH cessation.

Unusual and lesser-known rare causes of adult growth hormone deficiency

Growth hormone is among the most common hormones to be deficient in pituitary insult. It can occur either in isolation or combined with other hormone deficiencies. Growth hormone deficiency in adults (AGHD) can be due to causes acquired in adulthood or have a childhood-onset etiology, but the former is about three times more common. Usual causes of AGHD include mass effects due to a pituitary tumour, and/or its treatment (surgery, medical therapy, or radiotherapy), or radiotherapy to the head and neck region for non-pituitary lesions. The unusual or lesser-known causes of AGHD, are usually due to non-tumoral etiology and range from vascular and infective to inflammatory and miscellaneous causes. These not only expand the spectrum of AGHD but may also contribute to increased morbidity, adverse metabolic consequences, and mortality due to the primary condition, if unrecognised. The review features these lesser-known and rare causes of AGHD and highlights their clinical and diagnostic implications.

Nonalcoholic fatty liver disease and adult growth hormone deficiency: An under-recognized association?

Growth hormone (GH) plays an essential role not only in promoting growth in children, but also in many important metabolic processes in adults. One of the major metabolic functions of GH is its stimulatory effects on the liver in generating approximately 80% of circulating insulin-like growth factor 1 (IGF-1). Adult growth hormone deficiency (GHD) is an established clinical entity defined as a defect in endogenous GH secretion that is frequently associated with central obesity, loss of muscle mass, decreased bone mass, and impaired quality of life. Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are conditions that are often under-recognized in adults with GHD, and accordingly some studies have shown that GH and IGF-1 levels are decreased in patients with NAFLD. Furthermore, it has been reported that it can progress to end-stage liver cirrhosis in some adults and children with GHD. Due to their underlying mechanisms of action, GH and IGF-1 can act on hepatocytes, macrophages, and hepatic stellate cells to mitigate progression to steatosis and fibrosis. It is, thus, important to recognize NAFLD/NASH as important complications in adult and childhood GHD. Therefore, careful and thorough evaluation of NAFLD/NASH in adults with GHD and the consideration for GH replacement therapy is crucial in these patients, together with management of other metabolic risk factors, such as obesity and dyslipidemia. This review will focus on recent reports on the role of GH and IGF-1 in the liver and its clinical significance in the regulation of hepatic function.

Long-term Effectiveness and Safety of GH Replacement Therapy in Adults ≥60 Years: Data From NordiNet® IOS and ANSWER

Context

Effectiveness and safety data on GH replacement therapy (GHRT) in older adults with adult GH deficiency (AGHD) are limited.

Objective

To compare GHRT safety and clinical outcomes in older (≥60 years and, for some outcomes, ≥75 years) and middle-aged (35-<60 years) patients with AGHD.

Design/setting

Ten-year follow-up, real-world data from 2 large noninterventional studies-NordiNet® International Outcome Study (IOS) and the American Norditropin® Studies: Web-Enabled Research (ANSWER) Program-were analyzed.

Patients

GH-naïve and non-naïve patients with AGHD.

Intervention

Norditropin® (somatropin).

Main outcome measures

Outcomes included GH exposure, IGF-I standard deviation scores (SDS), body mass index (BMI), glycated hemoglobin (HbA1c), serious and nonserious adverse reactions (SARs and NSARs, respectively), and serious adverse events (SAEs). Adverse reactions were events with possible/probable causal relationship to GHRT.

Results

The effectiveness analysis set comprised 545 middle-aged and 214 older patients (19 aged ≥75 years) from NordiNet® IOS. The full analysis set comprised 1696 middle-aged and 652 older patients (59 aged ≥75 years) from both studies. Mean GH doses were higher in middle-aged vs older patients. For both age groups and sexes, mean IGF-I SDS increased following GHRT, while BMI and HbA1c changes were similar and small.Incidence rate ratios (IRRs) did not differ statistically between older and middle-aged patients for NSARs [IRR (mean, 95% confidence interval) 1.05 (.60; 1.83)] or SARs [.40 (.12; 1.32)]. SAEs were more frequent in older than middle-aged patients [IRR 1.84 (1.29; 2.62)].

Conclusion

Clinical outcomes of GHRT in AGHD were similar in middle-aged and older patients, with no significantly increased risk of GHRT-related adverse reactions in older patients.

Reduced CV risk with long-term GH replacement in AGHD: data from two large observational studies

Adult growth hormone deficiency (AGHD) is associated with an increased risk of cardiovascular (CV) disease. Long-term growth hormone (GH) treatment could improve CV outcomes. The objective of this study was to evaluate CV disease risk in patients with AGHD who received GH replacement therapy for up to 10 years as part of NordiNet® IOS (NCT00960128) and the ANSWER Program (NCT01009905). The studies were observational, non-interventional and multicentre, monitoring long-term effectiveness and safety of GH treatment. NordiNet® IOS involved 23 countries (469 sites) across Europe and the Middle East. The ANSWER Program was conducted in the USA (207 sites). This analysis included patients aged 18-75 years who were GH naïve at study entry, who had ≤10 years of GH treatment data and who could be assessed for CV risk for at least 1 follow-up year. The main outcome measure was risk of CV disease by age 75 years, as calculated with the Multinational Cardiovascular Risk Consortium model (Brunner score) using non-high-density lipoprotein cholesterol adjusted for age, sex and CV risk factors. The results of this analysis showed that CV risk decreased gradually over the 10-year period for GH-treated patients. The risk was lower for patients treated for 2 and 7 years vs age- and sex-matched control groups (not yet started treatment) (14.51% vs 16.15%; P = 0.0105 and 13.53% vs 16.81%; P = 0.0001, respectively). This suggests that GH treatment in people with AGHD may reduce the risk of CV disease by age 75 years compared with matched controls.

Isolated anterior pituitary dysfunction in adulthood

Hypopituitarism is defined as a complete or partial deficiency in one or more pituitary hormones. Anterior hypopituitarism includes secondary adrenal insufficiency, central hypothyroidism, hypogonadotropic hypogonadism, growth hormone deficiency and prolactin deficiency. Patients with hypopituitarism suffer from an increased disability and sick days, resulting in lower health status, higher cost of care and an increased mortality. In particular during adulthood, isolated pituitary deficits are not an uncommon finding; their clinical picture is represented by vague symptoms and unclear signs, which can be difficult to properly diagnose. This often becomes a challenge for the physician. Aim of this narrative review is to analyse, for each anterior pituitary deficit, the main related etiologies, the characteristic signs and symptoms, how to properly diagnose them (suggesting an easy and reproducible step-based approach), and eventually the treatment. In adulthood, the vast majority of isolated pituitary deficits are due to pituitary tumours, head trauma, pituitary surgery and brain radiotherapy. Immune-related dysfunctions represent a growing cause of isolated pituitary deficiencies, above all secondary to use of oncological drugs such as immune checkpoint inhibitors. The diagnosis of isolated pituitary deficiencies should be based on baseline hormonal assessments and/or dynamic tests. Establishing a proper diagnosis can be quite challenging: in fact, even if the diagnostic methods are becoming increasingly refined, a considerable proportion of isolated pituitary deficits still remains without a certain cause. While isolated ACTH and TSH deficiencies always require a prompt replacement treatment, gonadal replacement therapy requires a benefit-risk evaluation based on the presence of comorbidities, age and gender of the patient; finally, the need of growth hormone replacement therapies is still a matter of debate. On the other side, prolactin replacement therapy is still not available. In conclusion, our purpose is to offer a broad evaluation from causes to therapies of isolated anterior pituitary deficits in adulthood. This review will also include the evaluation of uncommon symptoms and main etiologies, the elements of suspicion of a genetic cause and protocols for diagnosis, follow-up and treatment.

GH Deficiency and Replacement Therapy in Hypopituitarism: Insight Into the Relationships With Other Hypothalamic-Pituitary Axes

GH deficiency (GHD) in adult patients is a complex condition, mainly due to organic lesion of hypothalamic-pituitary region and often associated with multiple pituitary hormone deficiencies (MPHD). The relationships between the GH/IGF-I system and other hypothalamic-pituitary axes are complicated and not yet fully clarified. Many reports have shown a bidirectional interplay both at a central and at a peripheral level. Signs and symptoms of other pituitary deficiencies often overlap and confuse with those due to GH deficiency. Furthermore, a condition of untreated GHD may mask concomitant pituitary deficiencies, mainly central hypothyroidism and hypoadrenalism. In this setting, the diagnosis could be delayed and possible only after recombinant human Growth Hormone (rhGH) replacement. Since inappropriate replacement of other pituitary hormones may exacerbate many manifestations of GHD, a correct diagnosis is crucial. This paper will focus on the main studies aimed to clarify the effects of GHD and rhGH replacement on other pituitary axes. Elucidating the possible contexts in which GHD may develop and examining the proposed mechanisms at the basis of interactions between the GH/IGF-I system and other axes, we will focus on the importance of a correct diagnosis to avoid possible pitfalls.

Immune dyscrasia in adult growth hormone deficiency: Evaluation of hemolytic complement activity (CH50) and IgG subclasses

CH50 is a screening assay for the activation of the classical complement pathway, the immunoglobulins-mediated one, activated in several inflammatory diseases. Adult growth hormone deficiency (aGHD) is recognized as a chronic inflammatory condition, although poorly evaluated under the profile of inflammatory biomarkers. The aim of this case-control observational study is to analyze CH50 and immunoglobulins G (IgG) subclasses production in aGHD, comparing this condition to healthy controls. 38 subjects were included and divided as follows: aGHD (n = 18, 6 females and 12 males); healthy controls (n = 20, 10 females and 10 males). GHD was diagnosed with dynamic test using Growth Hormone-Releasing Hormone (GHRH 50 μg i.v. + arginine 0,5 g/Kg), with a peak GH response < 9 μg/L when BMI was <30 kg/m² or < 4 μg/L when BMI was >30 kg/m². The two groups were evaluated for hormonal and metabolic parameters, CH50 and IgG subtypes. IgG1 and IgG2 were significantly higher in controls than in aGHD, while IgG3 and IgG4 showed a trend to higher levels in controls, although not significant. Furthermore, CH50 levels were significantly higher in aGHD. These data substantiate the hypothesis of a dyscrasia in IgG subclasses production in aGHD. As IgG levels decrease, CH50 levels do not.

Diagnosis and Treatment of Growth Hormone Deficiency: A Position Statement from Korean Endocrine Society and Korean Society of Pediatric Endocrinology

Growth hormone (GH) deficiency is caused by congenital or acquired causes and occurs in childhood or adulthood. GH replacement therapy brings benefits to body composition, exercise capacity, skeletal health, cardiovascular outcomes, and quality of life. Before initiating GH replacement, GH deficiency should be confirmed through proper stimulation tests, and in cases with proven genetic causes or structural lesions, repeated GH stimulation testing is not necessary. The dosing regimen of GH replacement therapy should be individualized, with the goal of minimizing side effects and maximizing clinical improvements. The Korean Endocrine Society and the Korean Society of Pediatric Endocrinology have developed a position statement on the diagnosis and treatment of GH deficiency. This position statement is based on a systematic review of evidence and expert opinions.

Preoperative growth hormone (GH) peak values during a GH releasing peptide-2 test reflect the severity of hypopituitarism and the postoperative recovery of GH secretion in patients with non-functioning pituitary adenomas

Non-functioning pituitary adenoma (NFPA) is one common cause of adult growth hormone deficiency (AGHD). In Japan, a GH-releasing peptide (GHRP)-2 test is used to evaluate GH secretion. Although the cut-off for peak GH during a GHRP-2 test for severe AGHD is ≤9 ng/mL, severe AGHD may further diminish responses (range, nearly no-response to ≤9 ng/mL). We studied whether the peak GH responses during a GHRP-2 test could be predicted based on clinical characteristics of patients with NFPA. We compared patients with almost no-response during a GHRP-2 test with other patients considered as severe AGHD. Among the 76 patients with NFPA who were admitted to our institution, 36 patients (mean age, 61 years; male/female, n = 23/n = 13) were diagnosed with severe AGHD based on a preoperative GHRP-2 test. Based on the preoperative median peak GH concentration (2.83 ng/mL), patients were divided into two groups (<median = low or group L, n = 18; ≥median = moderate or group M, n = 18). Clinical manifestations, body mass index, severity of hypopituitarism and tumor size, volume, and extension were analyzed retrospectively. Compared with group M, group L patients were significantly older and more gonadotropin and ACTH deficient. A lower peak GH release during a GHRP-2 test was associated with a higher number of anterior pituitary hormone deficiencies across all 76 patients. Postoperatively, seven in group M and no patient in group L were assessed as having no longer severe AGHD, respectively. Preoperative peak GH concentrations assessed during a GHRP-2 test reflected the severity of hypopituitarism and the recovery of postoperative GH secretion.

From JMV-1843 to Macrilen

Growth hormone deficiency (GHD) is a severe pathology that greatly affects the quality of life, and increases morbidity and mortality of patients owing to the augmentation of cardiovascular events. Treatment of GHD is challenging, mainly because there is no specific characteristic sign or symptom that can be used to make a clear diagnosis. There is need for an unequivocal diagnosis of GHD to avoid unnecessary treatment with GH, because the available provocative tests (GH stimulation tests) are not specific and sensitive enough, and are contraindicated in some patients. Ghrelin is an endogenous peptide that stimulates GH secretion by interacting with a G-protein-coupled receptor named ghrelin receptor (GH secretagogue receptor 1a, GHS-R1a). Given this, a GH stimulation test using ghrelin or its analogues appears to be attractive. In this paper, a modified tripeptide first named JMV-1843 in the laboratory is briefly presented. It is potent and selective in stimulating the release of GH and is orally active. It has been recently commercialised for the diagnosis of adult GH deficiency under the tradename Macrilen. The test using this compound appears to be reliable, well tolerated, and simple.

Prevalence of low lean mass in patients with adult growth hormone deficiency with or without low-dose growth hormone therapy

OBJECTIVE

The importance of muscle mass has been emphasized in various studies, and growth hormone (GH) deficiency is tightly associated with lean mass loss. Therefore, we aimed to investigate the prevalence of low lean mass in patients with adult growth hormone deficiency (AGHD) who received or did not receive GH therapy.

METHODS

In this retrospective study, we included patients diagnosed with AGHD by using the insulin tolerance test (ITT) in our hospital. Patients without completed follow-up data were excluded, and data for 56 patients were analysed. Twenty-six patients who had received GH therapy for more than 6 months, based on the medical record, were included in the GH group and received recombinant human growth hormone (rhGH) at a dose of 0.5 IU/d. Thirty patients who had not previously received GH treatment were included in the non-GH group. Many anthropometric and blood biochemical indicators were measured. Body composition was measured on a dual-energy X-ray-absorptiometry (DXA) scanner. Low lean mass was defined as a skeletal muscle index (SMI) <7.0 kg/m² in males or 5.7 kg/m² in females. Statistical analyses were performed using GraphPad Prism 5.0.

RESULTS

Compared to the non-GH group, the patients who received GH therapy had significantly lower total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c) and fasting plasma glucose (FPG). The percentage of patients with low lean mass in GH and non-GH groups was 30.77% and 60%, respectively. The percentage of total lean was lower in the GH group than in the non-GH group, but the difference in total lean mass was not statistically significant. Conversely, patients with GH treatment had significantly lower fat mass and percentage than non-GH-treated patients (P < 0.05). The GH group had significantly higher serum levels of both IGF-1 and IGFBP3. Moreover, both IGF-1 and IGFBP3 were significantly correlated with SMI (r²  = 0.275, P = 0.003, and r²  = 0.138, P = 0.005, respectively).

CONCLUSIONS

Our data showed that AGHD patients who received low-dose GH treatment had a lower prevalence of low lean mass than those who did not receive GH treatment. Patients with GH treatment had significantly lower cardiovascular risk factors, especially the lipid profile.

MECHANISMS IN ENDOCRINOLOGY: Lessons from growth hormone receptor gene-disrupted mice: are there benefits of endocrine defects?

Growth hormone (GH) is produced primarily by anterior pituitary somatotroph cells. Numerous acute human (h) GH treatment and long-term follow-up studies and extensive use of animal models of GH action have shaped the body of GH research over the past 70 years. Work on the GH receptor (R)-knockout (GHRKO) mice and results of studies on GH-resistant Laron Syndrome (LS) patients have helped define many physiological actions of GH including those dealing with metabolism, obesity, cancer, diabetes, cognition and aging/longevity. In this review, we have discussed several issues dealing with these biological effects of GH and attempt to answer the question of whether decreased GH action may be beneficial.

Update on GH therapy in adults

Over the last three decades, short- and long-term observational studies, clinical trials, systematic reviews, and meta-analyses have provided relevant information on the efficacy and safety of growth hormone (GH) replacement therapy in adults with GH deficiency (AGHD). The knowledge acquired during this time has been compiled into different guidelines that offer clinicians an evidence-based, practical approach for the management of AGHD. There are, however, still open questions in some key areas in which recommendations are supported by only moderate or weak evidence. In the last recent years, the development of long-acting GH preparations has created new therapeutic possibilities by decreasing injection frequency, improving adherence and thereby potentially maximizing clinical outcomes. The aims of this review are to advance our understanding on the diagnosis and treatment of AGHD and to present an update and future perspectives on the use of long-acting GH preparations.

Pituitary growth hormone (GH) secretion is partially rescued in HIV-infected patients with GH deficiency (GHD) compared to hypopituitary patients

Biochemical growth hormone deficiency is prevalent among human immunodeficiency virus-infected patients, but if this condition is clinically relevant remains challenging. The aim is to prospectively compare the growth hormone deficiency/insulin-like growth factor-1 status of 71 human immunodeficiency virus-infected patients with impaired growth hormone response to growth hormone releasing hormone + Arginine with that of 65 hypopituitary patients affected by a true growth hormone deficiency secondary to pituitary disease. The main outcomes were: basal serum growth hormone, insulin-like growth factor-1, insulin-like growth factor binding protein 3, growth hormone peak and area under the curve after growth hormone response to growth hormone releasing hormone + Arginine test, body mass index, waist and hip circumference, and body composition by dual energy X-ray absorptiometry. Insulin-like growth factor-1 binding protein 3, basal growth hormone (p < 0.005), growth hormone peak and area under the curve after growth hormone response to growth hormone releasing hormone + Arginine, waist to hip ratio, insulin-like growth factor-1, fasting glucose, insulin, and triglycerides (p < 0.0001) were lower in hypopituitary than human immunodeficiency virus-infected patients. Total and trunk fat mass by dual energy X-ray absorptiometry were higher in hypopituitary than in human immunodeficiency virus-infected patients (p < 0.0001). In all the patients total body fat was associated with both growth hormone peak and area under the curve at stepwise linear regression analysis. The degree of growth hormone deficiency is more severe in hypopituitary than in human immunodeficiency virus-infected patients, suggesting that the function of growth hormone/insulin-like growth factor-1 axis is partially rescued in the latter thanks to a preserved pituitary secretory reserve. Data from the current study suggest that human immunodeficiency virus-infected patients with peak growth hormone < 9 mg/L may have partial growth hormone deficiency and clinicians should be cautious before prescribing recombinant human growth hormone replacement treatment to patients living with human immunodeficiency virus.

Growth hormone deficiency and human immunodeficiency virus

Treatment with highly active antiretroviral drugs (HAART) is associated with several endocrine and metabolic comorbidities. Pituitary growth hormone (GH) secretion seems to be altered in human immunodeficiency virus (HIV) infection, and about one-third of patients have biochemical GH deficiency (GHD). We undertake a historical review of the functioning of the GH/insulin-like growth factor-1 (IGF-1) axis in patients with acquired immunodeficiency syndrome, and provide an overview of the main changes of the GH/IGF-1 axis occurring today in patients with HIV. Both spontaneous GH secretion and GH response to provocative stimuli are reduced in patients with HIV infection, especially in those with HIV-related lipodystrophy. The role of fat accumulation on flattened GH secretion is discussed, together with all factors able to potentially interfere with the pituitary secretion of GH. Several factors contribute to the development of GHD, but the pathophysiologic mechanisms involved in the genesis of GHD are complex and not yet fully elucidated owing to the difficulty in separating the effects of HIV infection from those of HAART, comorbidities and body changes. An update on the putative mechanisms involved in the pathogenesis of altered GH secretion in these patients is provided, together with an overview on the therapeutic strategies targeting the GH/IGF-1 axis to counteract fat redistribution associated with HIV-related lipodystrophy. The clinical significance of GHD in the context of HIV infection is discussed. The administration of tesamorelin, a GH releasing hormone analogue, is effective in reducing visceral fat in HIV-infected patients with lipodystrophy. This treatment is promising and safer than treatment with high doses of recombinant human growth hormone, which has several side-effects.

Etiology of Hypopituitarism in Adult Patients: The Experience of a Single Center Database in the Serbian Population

There are only a few published studies related to the population-based etiology of hypopituitarism. New risks for developing hypopituitarism have been recognized in the last 10 years. Aim. To present data regarding the etiology of hypopituitarism collected in a tertiary center over the last decade. This is a cross-sectional database study. Patients and Methods. We included 512 patients (pts) with hypopituitarism, with a mean age of 45.9 ± 1.7 yrs (range: 18-82; male: 57.9%). Results. Nonfunctional pituitary adenomas were presented in 205 pts (40.5%), congenital causes in 74 pts (14.6%), while acromegaly and prolactinomas were presented in 37 (7.2%) and 36 (7.0%) patients, respectively. Craniopharyngiomas were detected in 30 pts (5.9%), and head trauma due to trauma brain injury-TBI and subarachnoid hemorrhage-SAH in 27 pts (5.4%). Survivors of hemorrhagic fever with renal syndrome (HFRS) and those with previous cranial irradiation were presented in the same frequency (18 pts, 3.5% each). Conclusion. The most common causes of hypopituitarism in our database are pituitary adenomas. Increased awareness of the other causes of pituitary dysfunction, such as congenital, head trauma, extrapituitary cranial irradiation, and infections, is the reason for a higher frequency of these etiologies of hypopituitarism in the presented database.

Metabolic alterations in paediatric GH deficiency

Growth hormone (GH) has a large number of metabolic effects, involving lipid and glucose homoeostasis, lean and fat mass. Growth hormone deficiency (GHD) is associated with a metabolic profile similar to the Metabolic Syndrome which is characterized by dyslipidemia, insulin resistance, haemostatic alterations, oxidative stress, and chronic inflammation. GH replacement treatment in GHD children improves these cardiovascular risk factors, while cessation of GH is associated with a deterioration of most of these risk factors. However, it is unclear whether the changes of these risk factors are associated with an increased risk of cardiovascular diseases especially after discontinuing GH treatment. GH treatment itself can lead to insulin resistance, which probably also influences the cardiovascular health status. Therefore, longitudinal studies with the primary outcome cardiovascular diseases are needed in GHD children. Furthermore, new approaches such as metabolomic studies might be helpful to understand the relationship between GHD, GH treatment, and cardiovascular diseases.

Hormonal Replacement in Hypopituitarism in Adults: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

To formulate clinical practice guidelines for hormonal replacement in hypopituitarism in adults.

PARTICIPANTS

The participants include an Endocrine Society-appointed Task Force of six experts, a methodologist, and a medical writer. The American Association for Clinical Chemistry, the Pituitary Society, and the European Society of Endocrinology co-sponsored this guideline.

EVIDENCE

The Task Force developed this evidence-based guideline using the Grading of Recommendations, Assessment, Development, and Evaluation system to describe the strength of recommendations and the quality of evidence. The Task Force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

One group meeting, several conference calls, and e-mail communications enabled consensus. Committees and members of the Endocrine Society, the American Association for Clinical Chemistry, the Pituitary Society, and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines.

CONCLUSIONS

Using an evidence-based approach, this guideline addresses important clinical issues regarding the evaluation and management of hypopituitarism in adults, including appropriate biochemical assessments, specific therapeutic decisions to decrease the risk of co-morbidities due to hormonal over-replacement or under-replacement, and managing hypopituitarism during pregnancy, pituitary surgery, and other types of surgeries.

Safety and PK/PD correlation of TV-1106, a recombinant fused human albumin-growth hormone, following repeat dose administration to monkeys

PURPOSE

TV-1106 is a recombinant human albumin genetically fused to growth hormone which is intended to reduce the frequency of injections for GH therapy users. We report the safety, tolerability, pharmacokinetics and pharmacodynamics of repeated subcutaneous injections of TV-1106 in Cynomolgus monkeys.

METHOD

Cynomolgus monkeys received four weekly subcutaneous injections of 0, 5, 10 or 20mg/kg TV-1106 and were monitored for safety signals throughout the study. Serum levels of TV-1106 and insulin-like growth factor 1 (IGF-1) were assayed.

RESULTS

Treated animals showed no adverse effects or histopathological changes. TV-1106 serum concentrations showed sustained exposure to the drug. Exposure increased in a dose-dependent manner with peak concentrations at approximately 24h post-dosing and elimination half-lives in the range of 12 to 24h. IGF-1 serum concentrations were elevated throughout the entire study duration, indicative of the pharmacological response. There was a clear correlation between change in IGF-1 levels and dose or exposure to TV-1106.

CONCLUSIONS

The safety, pharmacokinetic and pharmacodynamic findings support the further development of TV-1106 as a once-weekly administered treatment for patients with GHD.

Skin manifestations of growth hormone-induced diseases

The human skin is a well-organized organ bearing different types of cells in a well-structured interference to each other including epidermal and follicular keratinocytes, sebocytes, melanocytes, dermal papilla cells and fibroblasts, endothelial cells, sweat gland cells as well as nerves. Several hormones act on different cell types of the skin, while it is also considered an endocrine organ secreting hormones that act at several sites of the organism. GH receptors are found in almost all cell types forming the skin, while IGF-1 receptors' expression is restricted to the epidermal keratinocytes. Both Growth Hormone (GH) excess, as in the case of Acromegaly in adults, or Gigantism in growing children, and GH deficiency states lead to skin manifestations. In case of GH excess the main dermatological findings are skin thickening, coarsening of facial features, acrochordons, puffy hands and feet, oily skin and hyperhidrosis, while GH deficiency, on the contrary, is characterized by thin, dry skin and disorder of normal sweating. Moreover, special disorders associated with GH excess may have specific characteristics, as is the case of café-au-lait spots in Neurofibromatosis, or big café-au-lait skin hyperpigmented regions with irregular margins, as is the case in McCune-Albright syndrome. Meticulous examination of the skin may therefore contribute to the final diagnosis in cases of GH-induced disorders.

Influence of body weight on bone mass, architecture and turnover

Weight-dependent loading of the skeleton plays an important role in establishing and maintaining bone mass and strength. This review focuses on mechanical signaling induced by body weight as an essential mechanism for maintaining bone health. In addition, the skeletal effects of deviation from normal weight are discussed. The magnitude of mechanical strain experienced by bone during normal activities is remarkably similar among vertebrates, regardless of size, supporting the existence of a conserved regulatory mechanism, or mechanostat, that senses mechanical strain. The mechanostat functions as an adaptive mechanism to optimize bone mass and architecture based on prevailing mechanical strain. Changes in weight, due to altered mass, weightlessness (spaceflight), and hypergravity (modeled by centrifugation), induce an adaptive skeletal response. However, the precise mechanisms governing the skeletal response are incompletely understood. Furthermore, establishing whether the adaptive response maintains the mechanical competence of the skeleton has proven difficult, necessitating the development of surrogate measures of bone quality. The mechanostat is influenced by regulatory inputs to facilitate non-mechanical functions of the skeleton, such as mineral homeostasis, as well as hormones and energy/nutrient availability that support bone metabolism. Although the skeleton is very capable of adapting to changes in weight, the mechanostat has limits. At the limits, extreme deviations from normal weight and body composition are associated with impaired optimization of bone strength to prevailing body size.

Pituitary Medicine From Discovery to Patient-Focused Outcomes

CONTEXT

This perspective traces a pipeline of discovery in pituitary medicine over the past 75 years.

OBJECTIVE

To place in context past advances and predict future changes in understanding pituitary pathophysiology and clinical care.

DESIGN

Author's perspective on reports of pituitary advances in the published literature.

SETTING

Clinical and translational Endocrinology.

OUTCOMES

Discovery of the hypothalamic-pituitary axis and mechanisms for pituitary control, have culminated in exquisite understanding of anterior pituitary cell function and dysfunction. Challenges facing the discipline include fundamental understanding of pituitary adenoma pathogenesis leading to more effective treatments of inexorably growing and debilitating hormone secreting pituitary tumors as well as medical management of non-secreting pituitary adenomas. Newly emerging pituitary syndromes include those associated with immune-targeted cancer therapies and head trauma.

CONCLUSIONS

Novel diagnostic techniques including imaging genomic, proteomic, and biochemical analyses will yield further knowledge to enable diagnosis of heretofore cryptic syndromes, as well as sub classifications of pituitary syndromes for personalized treatment approaches. Cost effective personalized approaches to precision therapy must demonstrate value, and will be empowered by multidisciplinary approaches to integrating complex subcellular information to identify therapeutic targets for enabling maximal outcomes. These goals will be challenging to attain given the rarity of pituitary disorders and the difficulty in conducting appropriately powered prospective trials.

Three-year experience with access to nationally funded growth hormone (GH) replacement for GH-deficient adults

OBJECTIVE

Treatment of growth hormone (GH)-deficient adults with GH has been shown to improve a range of metabolic abnormalities and enhance quality of life. However, the results of access to nationally funded treatment have not been reported.

DESIGN

Retrospective case series auditing nationally funded treatment of defined GH-deficient adults in New Zealand, with carefully designed entry and exit criteria overseen by a panel of endocrinologists.

PATIENTS

Applications for 201 patients were assessed and 191 approved for funded treatment over the initial 3 years since inception. The majority had GH deficiency following treatment of pituitary adenomas or tumours adjacent to the pituitary.

RESULTS

After an initial 9-month treatment period using serum IGF-I measurements to adjust GH dosing, all patients reported a significant improvement in quality of life (QoL) score on the QoL-AGHDA(®) instrument (baseline (95%CI) 19 (18-21), 9 months 6 (5-7.5)), and mean serum IGF-I SD scores rose from -3 to zero. Mean waist circumference decreased significantly by 2.8 ± 0.6 cm. The mean maintenance GH dose after 9 months of treatment was 0.39 mg/day. After 3 years, 17% of patients had stopped treatment, and all of the remaining patients maintained the improvements seen at 9 months of treatment.

CONCLUSION

Carefully designed access to nationally funded GH replacement in GH-deficient adults was associated with a significant improvement in quality of life over a 3-year period with mean daily GH doses lower than in the majority of previously reported studies.

Severe growth hormone deficiency and empty sella in obesity: a cross-sectional study

Obesity is associated with blunted growth hormone (GH) secretion. In some individuals, hypothalamic-pituitary (HP) structural lesions may contribute to GH deficiency (GHD). We explored pituitary morphology in obese patients with suspected GHD and its association with cardiovascular risk factors, body composition, and cardiac morphology. One hundred and eighty-four adults obese patients with symptoms and signs of GHD (147 females and 37 males; mean age 46.31 ± 12.11 years), out of 906 consecutive white obese outpatients, were evaluated. The main measures were anthropometric data, blood pressure, lipid profile, glycemic parameters, pituitary hormones, and insulin-like growth factor-1 values, echocardiography, magnetic resonance imaging (MRI) of the HP region, body composition, and growth hormone-releasing hormone plus arginine test. Seventy patients had GHD (GH peak values <4.2 μg/mL). GHD patients showed significantly higher body mass index and fat mass, lower lumbar bone mineral density, increased left ventricular mass index, and epicardial fat thickness. The MRI of the HP region showed empty sella (ES) in 69 and normal pituitary in one of the 70 GHD patients; the 114 patients with normal GH response had ES (n = 62, 54 %), normal pituitary (n = 37, 32 %), microadenomas (n = 10, 8 %), and other pituitary abnormalities (n = 5, 4 %). ES was a significant independent predictor of GH secretory capacity as determined by multiple regression analysis. The close relationship between ES and GH secretory capacity points out to the possibility of the organic nature of GHD in a portion of obese individuals and opens a new scenario with regard to the potential of GH treatment on metabolic consequences of obesity.

Multiple Ca2+ channel-dependent components in growth hormone secretion from rat anterior pituitary somatotrophs

The involvement of L-type Ca(2+) channels in both 'basal' and 'stimulated' growth hormone (GH) secretion is well established; however, knowledge regarding the involvement of non-L-type Ca(2+) channels is lacking. We investigated whether non-L-type Ca(2+) channels regulate GH secretion from anterior pituitary (AP) cells. To this end, GH secretion was monitored from dissociated AP cells, which were incubated for 15 min with 2 mm K(+) ('basal' secretion) or 60 mm K(+) ('stimulated' secretion). The role of non-L-type Ca(2+) influx was investigated using specific channel blockers, including ω-agatoxin-IVA, ω-conotoxin GVIA or SNX-482, to block P/Q-, N- or R-type Ca(2+) channels, respectively. Our results demonstrate that P/Q-, N- and R-type Ca(2+) channels contributed 21.2 ± 1.9%, 20.2 ± 7.6% and 11.4 ± 1.8%, respectively, to 'basal' GH secretion and 18.3 ± 1.0%, 24.4 ± 5.4% and 14.2 ± 4.8%, respectively, to 'stimulated' GH secretion. After treatment with a 'cocktail' that comprised the previously described non-L-type blockers, non-L-type Ca(2+) channels contributed 50.9 ± 0.4% and 45.5 ± 2.0% to 'basal' and 'stimulated' GH secretion, respectively. Similarly, based on the effects of nifedipine (10 μM), L-type Ca(2+) channels contributed 34.2 ± 3.7% and 54.7 ± 4.1% to 'basal' and 'stimulated' GH secretion, respectively. Interestingly, the relative contributions of L-type/non-L-type Ca(2+) channels to 'stimulated' GH secretion were well correlated with the relative contributions of L-type/non-L-type Ca(2+) channels to voltage-gated Ca(2+) influx in AP cells. Finally, we demonstrated that compartmentalisation of Ca(2+) channels is important for GH secretion. Lipid raft disruption (methyl-β-cyclodextrin, 10 mm) abrogated the compartmentalisation of Ca(2+) channels and substantially reduced 'basal' and 'stimulated' GH secretion by 43.2 ± 3.4% and 58.4 ± 4.0%, respectively. In summary, we have demonstrated that multiple Ca(2+) channel-dependent pathways regulate GH secretion. The proper function of these pathways depends on their compartmentalisation within AP cell membranes.

Evaluation of long-term pituitary functions in patients with severe ventricular arrhythmia: a pilot study

INTRODUCTION

Traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), stroke and cerebrovascular disease (CVD) are identified as risk factors for hypopituitarism. Pituitary dysfunction after TBI, SAH, and CVD may present in the acute phase or later in the course of the event. Chronic hypopituitarism, particularly growth hormone (GH) deficiency is related to the increased cardiovascular morbidity and mortality. In patients with serious ventricular arrhythmias, who need cardiopulmonary resuscitation, brain tissue is exposed to short-term severe ischemia and hypoxia. However, there are no data in the literature regarding pituitary dysfunction after ventricular arrhythmias.

PATIENTS AND METHODS

Forty-four patients with ventricular arrhythmias [ventricular tachycardia (VT), ventricular fibrillation (VF)] (mean age, 55.6 ± 1.8 years; 37 men, 7 women) were included in the study. The patients were evaluated after mean period of 21.2 ± 0.8 months from VT-VF. Basal hormone levels, including serum free triiodothyronine (fT3), free thyroxine (fT4), TSH, ACTH, prolactin, FSH, LH, total testosterone, estradiol, IGF-1, and cortisol levels were measured in all patients. To assess (GH)-insulin like growth factor-1 (IGF-1) axis, glucagon stimulation test was performed and 1 µg ACTH stimulation test was used for assessing hypothalamic-pituitary-adrenal (HPA) axis.

RESULTS

The frequencies of GH, gonadotropin and TSH deficiency were 27.2, 9.0, 2.2%, respectively. Mean IGF-1 levels were lower in GH deficiency group, but it was not statistically significant.

CONCLUSION

The present preliminary study showed that ventricular arrhythmias may result in hypopituitarism, particularly in growth hormone deficiency. Unrecognized hypopituitarism may be responsible for some of the cardiovascular problems at least in some patients.

Is growth hormone treatment in children associated with weight gain?--longitudinal analysis of KIGS data

OBJECTIVE

Growth hormone (GH) increases lean body mass and reduces fat mass. However, the long-term changes in weight status during growth hormone treatment, according to age and weight status at onset of treatment, have not previously been reported in large data sets.

METHODS

Changes in BMI-SDS between starting GH treatment and attaining near adult height (NAH) were analysed in 2643 children with idiopathic GH deficiency (IGHD), 281 children small for gestational age (SGA), 1661 girls with Turner syndrome (TS), and 142 children with Prader-Willi syndrome (PWS) in the KIGS database.

RESULTS

BMI-SDS increased significantly between onset of GH treatment and NAH (IGHD:+0·29, SGA:+0·69, TS:+0·48) except in PWS (-0·02). These increases were greater in children with younger age at onset of GH treatment (significant in all indications) and with lower doses of GH treatment (significant in IGHD & TS) in multiple linear regression analyses also including gender, duration of GH treatment, BMI-SDS and height-SDS at onset of treatment, and birth weight-SDS. Obese children at onset of GH treatment decreased their BMI-SDS, while underweight and normal weight children at onset of GH treatment increased their BMI-SDS independently of GH treatment indication.

CONCLUSIONS

Long-term GH treatment was associated with changes in weight status, which were beneficial for underweight and obese children independent of the indication for GH. However, the increase in BMI-SDS in normal weight children treated with GH needs to be investigated in future prospective longitudinal studies to analyse whether this represents an increase of fat mass, lean body mass or both.

Neurologic complications of nondiabetic endocrine disorders

PURPOSE OF REVIEW

This article provides an overview of the neurologic complications found in the various endocrine disorders affecting adult patients. Specifically, disorders in pituitary hormones (prolactin, growth hormone, vasopressin, and oxytocin), thyroid hormones, adrenal hormones (glucocorticoids), and sex hormones (estrogen and testosterone) will be covered, with an emphasis on identifying the signs and symptoms in addition to diagnosing and managing these disorders.

RECENT FINDINGS

Hyperthyroidism in the young was found to increase the risk for ischemic stroke in a recent prospective case-cohort study. The cognitive effects of hormonal therapy in postmenopausal women remain controversial, but a recent study found no benefit or risk in cognitive function when treating younger (50 to 55 years of age) postmenopausal women with hormonal therapy.

SUMMARY

Endocrine disorders can cause various neurologic complications, from insidious myopathy to acute encephalopathy. Diagnosing the endocrine disorder as the cause of the neurologic impairment is essential, as treating the underlying hormonal dysfunction will often rapidly reverse the neurologic symptoms. Ongoing research is needed to further clarify the role of hormonal dysfunction in neurologic disorders.

Gender differences in GH response to GHRH+ARG in lipodystrophic patients with HIV: a key role for body fat distribution

OBJECTIVE

Gender influence on GH secretion in human immunodeficiency virus (HIV)-infected patients is poorly known.

DESIGN AND METHODS

To determine the effect of gender, we compared GH response to GH-releasing hormone plus arginine (GHRH+Arg), and body composition in 103 men and 97 women with HIV and lipodystrophy. The main outcomes were IGF1, basal GH, GH peak and area under the curve (AUC) after GHRH+Arg, body composition, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT).

RESULTS

Men had lower GH peak and AUC than women (P<0.001). Of the study population, 21% of women and 37% of men had biochemical GH deficiency (GHD; GH peak <7.5 μg/l). VAT-to-SAT ratio was higher in men than in women with GHD (P<0.05). Unlike women, VAT, SAT, and trunk fat were greater in men with GHD than in men without GHD. IGF1 was significantly lower in women with GHD than in women without GHD, but not in men. At univariate analysis, BMI, trunk fat mass, VAT, and total adipose tissue were associated with GH peak and AUC in both sexes (P<0.05). BMI was the most significant predictive factor of GH peak, and AUC at multiregression analysis. Overall, abdominal fat had a less pronounced effect on GH in females than in males.

CONCLUSIONS

These data demonstrate that GH response to GHRH+Arg is significantly lower in HIV-infected males than females, resulting in a higher percentage of GHD in men. Adipose tissue distribution more than fat mass per se seems to account for GH gender differences and for the alteration of GH-IGF1 status in these patients.

Long- but not short-term adult-onset, isolated GH deficiency in male mice leads to deterioration of β-cell function, which cannot be accounted for by changes in β-cell mass

Developmental models of GH deficiency (GHD) and excess indicate that GH is positively associated with β-cell mass. Therefore, the reduction in GH levels observed with age and weight gain may contribute to the age-related decline in β-cell function. To test this hypothesis, β-cell mass and function were assessed in a mouse model of adult-onset, isolated GHD (AOiGHD). β-Cell mass did not differ between low-fat (LF)-fed AOiGHD and controls. However, high fat-fed AOiGHD mice displayed impaired expansion of β-cell mass and a reduction of bromodeoxyuridine-labeled islet cells, whereas in vitro β-cell function (basal and glucose-stimulated insulin secretion [GSIS]) did not differ from controls. In contrast, duration of AOiGHD differentially altered in vitro β-cell function in LF-fed mice. Specifically, islets from young LF-fed AOiGHD mice showed significant reductions in insulin content and basal insulin secretion, but GSIS was similar to that of controls. A similar islet phenotype was observed in a developmental model of isolated GHD (GH-releasing hormone knockout). Given that LF- and high fat-fed AOiGHD mice, as well as GH-releasing hormone knockout mice, display improved insulin sensitivity, islet changes may be due to reduced insulin demand, rather than primary β-cell dysfunction. However, islets from older LF-fed AOiGHD mice exhibited impaired GSIS, associated with reduced expression of genes important to maintain glucose sensing, suggesting that factors secondary to AOiGHD can alter β-cell function with age. AOiGHD mice exhibited postprandial hypertriglyceridemia and increased pancreatic expression of lipid/inflammatory stress response genes (activating transcription factor 3 and peroxisome proliferator activator receptor β/δ). Therefore, we speculate that these changes may initially protect the AOiGHD β-cell, but with age, lipotoxicity may impair β-cell function.