Hypothalamic-pituitary Tumors Research Articles

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.

Diagnosis and management of children and adult craniopharyngiomas: a French Endocrine Society/French Society for Paediatric Endocrinology & Diabetes Consensus Statement

Craniopharyngiomas are rare hypothalamic-pituitary tumors found in young children, adolescents and adults, and their multidisciplinary management required, calls for consistent practices for practicioners, patients and families. The French Endocrine Society and French Society for Pediatric Endocrinology & Diabetes enlisted and coordinated adult and paediatric endocrinologists, neurosurgeons, pathologists, radiotherapists as well as psychologists, dieticians and a patient association, to draft a reference document on this severe disease.The management of craniopharyngiomas remains complex due to their aggressive nature, invasive behavior, and propensity for recurrence, requiring a sequential and measured therapeutic approach and follow-up in expert centers. Although patient survival rates are high, the consequences of both the tumor and its treatment can lead to serious comorbidities and impaired quality of life, particularly in those patients with lesional hypothalamic syndrome. Recent advances have allowed the two described tumor types - papillary and adamantinomatous - to be associated with distinct molecular signatures, specific pathophysiological mechanisms and ipso facto, distinct therapeutic approaches, including innovative medications for hyperphagia, that will continue to evolve. This consensus statement covers all stages in the management of patients with craniopharyngioma, from diagnosis to therapeutic strategies including the long-term follow-up.

Clinical characteristics and efficacy of acromegaly treatment in the Udmurt Republic

Background: Acromegaly is a severe neuroendocrine disorder caused by chronic overproduction of growth hormone and insulin-like growth factor 1 and associated with a variety of clinical manifestations, debilitating complications and progressive disability, if no biochemical control has been achieved. The Russian registry of hypothalamic-pituitary tumors allows for evaluation of the epidemiological, demographic and clinical characteristics of patients with acromegaly, as well as of the effectiveness of various treatment methods.
 Aim: To identify epidemiological and clinical characteristics and treatment efficacy for acromegaly in the patients in the Udmurt Republic.
 Materials and methods: We performed a cross-sectional study based on the registry of hypothalamic-pituitary tumors of the Udmurt Republic as per June 2022. It contains data from 77 patients with acromegaly. The study included 59 (76.62%) patients with the information sufficient for evaluation of the disease stage and its complications.
 Results: According to the registry of hypothalamic-pituitary tumors, the prevalence of acromegaly in the Udmurt Republic was 6.71 cases per 100,000 of the population. Patients with acromegaly in Udmurt Republic had a high prevalence of arthralgia, abnormally large feet and hands, weakness/fatigue, snoring / sleep apnea, increased sweating, dizziness, peripheral edema, obesity, menstrual cycle abnormalities, diabetes mellitus, nodular goiter, pathological fractures and hypopituitarism. Neurosurgery has been performed in 74.57% (n = 44) of the patients, with a remission of acromegaly achieved in 18 (40.9%). Medical treatment was given to 25/59 (42.37%) of the patients, with 22 of them being treated with 1st generation long-acting somatostatin analogues. Radiation therapy has been administered to 13 patients (22.03%). Biochemical control was achieved in 40/59 (67.8%) of patients with acromegaly, related to neurosurgery in most patients, as well as to the use of a growth hormone receptor antagonist and/or combined medical treatment.
 Conclusion: The prevalence of acromegaly in the Udmurt Republic is consistent with international data. Clinical characteristics of acromegaly generally correspond to the classic disease course, although a number of symptoms are more commonly found in the Udmurt Republic patients than in the Russian Federation registry; this might be related to the quality of the registry management. The effectiveness of treatment for acromegaly in Udmurt Republic is comparable to the international data.

Social Cognition in Patients With Hypothalamic-Pituitary Tumors.

Objectives: The current study aimed to investigate whether childhood-onset craniopharyngioma patients are impaired in social-cognitive skills, and whether individual differences in task performance are modulated by the neurohormone oxytocin.Study design: We tested 31 adamantinomatous craniopharyngioma patients with and without hypothalamic lesions and 35 age- and gender-matched healthy controls. To test for between-group differences in social-cognitive skills, we experimentally assessed participants' abilities to interpret social signs or dispositions and to understand others' thoughts, feelings, and intentions. Associations between fasting oxytocin saliva concentrations and task performance were analyzed across the whole group of participants.Results: Compared to controls, patients with hypothalamic lesions were significantly less able to identify the correct emotional content of vocal expressions and to understand others' mental states. Judgements of trustworthiness were not different between patients and controls. There were no correlations between the primary measures of task performance and fasting oxytocin saliva concentrations.Conclusions: This is the first study to show that craniopharyngioma patients with hypothalamic lesions are impaired in some aspects of social cognition, which are of high relevance for everyday social interactions. These deficits suggest a disruption of the normal functionality of hypothalamic-fronto-limbic networks and/or additional areas of the social brain, which are at particular risk by hypothalamic location of the tumor and its treatment.

Metabolic syndrome and its components in adult hypopituitary patients.

To evaluate the prevalence of metabolic syndrome (MetS) and its components in adult hypopituitary patients. Retrospective, cross-sectional analysis of a cohort of hypopituitary adult patients followed in a single reference center for pituitary diseases. MetS was defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) criteria. Patients with 18 years or older, presenting two or more anterior pituitary deficiencies associated or not with diabetes insipidus (DI), were included, while patients with hypopituitarism due to Acromegaly or Cushing's disease were excluded. We studied 99 hypopituitary patients (52 males, mean age 50.1 ± 16.3 years, mean age at diagnosis 33.7 ± 17.6 years) who have been followed for a mean time of 15.9 ± 10.1 years. Hypothalamic-pituitary tumors and non-tumoral etiologies were observed in 53.4% and 46.6% of the cases, respectively. FSH/LH, GH, TSH, ACTH deficiency and DI was present in 99%, 98.6%, 96%, 81.8%, and 23.2%, respectively. The prevalence of MetS was 39.4% and was significantly higher in patients older than 50 years (p = 0.02), overweight/obese (p < 0.001), with hypopituitarism diagnosed in adult life (p = 0.02), who did not replace GH (p = 0.004) and in smokers (p = 0.007). In the logistic regression model, body mass index (BMI) and GH replacement were significantly associated with the presence of MetS. Reduced HDL cholesterol was the most prevalent component of MetS in hypopituitary patients. MetS is a common finding in adult hypopituitary patients, which is mainly influenced by increased BMI and untreated GH deficiency. Trial Registration number (Plataforma Brasil): CAAE 51008815.2.0000.0096 (May 31, 2017) .

Pièges diagnostiques des hyperprolactinémies chez la femme

Prolactin is a major hormone, involved in gonadotroph axis regulation. Hyperprolactinemia induces gonadotropin deficiency and therefore hypogonadotropic hypogonadism. It should be suspected in front of menstrual cycle abnormalities, infertility and/or galactorrhea. If drugs and/or PRL adenoma represent the vast majority of causes of hyperprolactinemia, other etiologies and misleading diagnosis of hyperprolactinemia should be searched for. After eliminating a pregnancy, in women of childbearing age, the first step is to interpret the result of hyperprolactinemia, according to the assay technique used. Indeed, the major active form of prolactin is the 23kDA non-glycosylated prolactin. However, some assays interfere with macroprolactinemia, an inactive form of prolactin, including glycosylated prolactin bound to an IgG immunoglobulin. Its presence in the serum is misleading as it may induce increased levels of prolactin, usually below 100ng/mL. The diagnosis of macroprolactinemia has major issues as pituitary MRI does not need to be performed. Furthermore, neither treatment nor follow-up of patients with macroprolactinemia are necessary. It should be suspected in the presence of normal menstrual cycles. Drugs inducing hyperprolactinemia usually raise prolactin levels below 100ng/mL. If prolactin level is higher than 250ng/mL, the main diagnosis is pituitary macro-adenoma. If prolactin ranges between 100 and 250ng/mL, it is usually related to a micro-adenoma or a necrotic macro-adenoma. A mixed PRL/GH should always be suspected. If prolactin level is below 150ng/mL, in the presence of a large hypothalamic-pituitary tumor, the major diagnosis is hyperprolactinemia due to pituitary disconnection. Ectopic secretions of prolactin remain very rare. A new etiology of hyperprolactinemia is loss of function mutation of prolactin receptor.

Evaluation of Carbohydrate and Lipid Metabolism and Risk of Obesity in Children after Brain Tumors Treatment

The aim of the study was to assess the carbohydrate and lipid metabolism disturbances as well as weight in children after brain tumors treatment. The study included 33 boys (53.2%) and 29 girls (46.8%) aged 11.6 ± 3.9. 22 patients underwent treatment for tumors of hypothalamic-pituitary(h-p) area: IA–surgery(19/22); IB–surgery and radiotherapy(3/22). 40 patients were treated for tumors outside the h-p area: IIA– with surgery, chemo-and radiotherapy(22/40); IIB–only with surgery(15/40); IIC–patients treated for optic nerve glioma with chemotherapy(3/40). BMI was assessed before and after the treatment. OGTT, HbA1c, lipid profile and WHtR after treatment were assessed. Indices of insulin resistance: HOMA-IR, Quickie, Matsuda and de Fronzo were calculated. 63% overweight/obese patients of IA-group and 27% of IIA-group were observed. Hyperinsulinemia was noted in 44% of IA-group, 20% of IIA-group, and insulin resistance in 38% of IA and 15% of IIA. DM2 was diagnosed in 1 patient of IA-group, IFG in 1 patient of IIB, IGT in 1 patient of IA and 1 patient of IIC. Dyslipidemia was noted in 47% of IA-group, elevated level of LDL-cholesterol in 30% of IIA-group. The excessive weight gain, hyperinsulinemia and dyslipidemia were observed primarily in children treated for hypothalamic-pituitary tumors.

Pituitary Ganglioneuroma: Case Report and Literature Review

We present a case of pituitary ganglioneuroma occurring in a 25 year old woman who presented with headache and hemianopsia. The histologic, immunohistochemical, and ultrastructural features of this tumor support the view that these rare hypothalamic-pituitary tumors are independently functioning neurohormonal units. Immunostaining is strongly positive for neuron-specific enolase (NSE) in all tumor cells and cell processes and for synaptophysin in a few cells and fibers. Few cells closely associated with tumor cells are positive for S100 protein. The cell processes are positive for neurofilament antigen. Ultrastructural analysis documents a spectacular neoplasm of neural derivation. The tumor consists of ganglion cells and areas of neuropil. The most typical tumor cells have relatively lucent spherical nucleus with large nucleolus, and abundant cytoplasm harbors compact sacks of RER membranes studded with ribosomes. Particular emphasis is given to the ultrastructural features which strongly support the functional relationship between the tumor components. It should be kept in mind that unusual and rare ganglionic tumors might show a progressive clinical course and needs surgical intervention as the major part of their treatment whereas ontogenetic and pathogenetic mechanisms taking part still need more work to enlighten pituitary neuronal tumorigenesis.

Endocrine Symptoms in Hypothalamic-Pituitary Tumors

Researchers at Universite Paris Descartes and other centers in Paris, France performed a retrospective, study of 176 patients (93 boys) aged 6 years (range 0.2-18 years) with hypothalamic-pituitary lesions to determine whether the time to diagnosis could be shortened by analyses of clinical and endocrine presenting symptoms.

Long‐term outcome of hypothalamic pituitary tumors in Langerhans cell histiocytosis

Hypothalamic-pituitary (HP) disease is the most common CNS manifestation of Langerhans cell histiocytosis (LCH) frequently leading to diabetes insipidus (DI) and anterior pituitary hormone deficiencies (APD). On MRI, loss of the normal posterior pituitary signal and thickening of the pituitary stalk have been described, as well as neurodegenerative signal changes associated with neuropsychological disabilities in some patients. The influence of therapy on the long-term course of HP tumors and neurodegeneration (ND) is not well-understood. In this retrospective survey we focused on patients with LCH and HP disease with clinical and MRI data available at diagnosis of HP disease and at least three follow up investigations. We collected clinical and MRI follow-up information for central review and analysis. We identified 22 patients with HP tumors (HPT) registered at the LCH study center. Many different treatment regimens were applied for variable periods, with more than one regimen in most patients. Regression of the tumor was seen in the majority, but all patients had APD or ND on MRI at last follow up. In none of the patients APD and ND regressed or resolved. A deterioration of radiological ND was noted in 17 patients leading to overt clinical neuropsychological impairment in five. Patients with HPT appear to be at high risk to develop permanent neuroendocrine consequences. Coordinated studies for patients with LCH and HP disease including thorough MRI monitoring and neuropsychological tests are needed.

The Approach to the Adult with Newly Diagnosed Adrenal Insufficiency

Adrenal insufficiency, primarily presenting as an adrenal crisis, is a life-threatening emergency and requires prompt therapeutic management including fluid resuscitation and stress dose hydrocortisone administration. Primary adrenal insufficiency is most frequently caused by autoimmune adrenalitis, and hypothalamic-pituitary tumors represent the most frequent cause of secondary adrenal insufficiency. However, the exact underlying diagnosis needs to be confirmed by a stepwise diagnostic approach, with an open eye for other differential diagnostic possibilities. Chronic replacement therapy with glucocorticoids and, in primary adrenal insufficiency, mineralocorticoids requires careful monitoring. However, current replacement strategies still require optimization as evidenced by recent studies demonstrating significantly impaired subjective health status and increased mortality in patients with primary and secondary adrenal insufficiency. Future studies will have to explore the potential of dehydroepiandrosterone replacement and modified delayed-release hydrocortisone to improve the prospects of patients with adrenal insufficiency.

Mechanisms related to the pathophysiology and management of central hypothyroidism

Central hypothyroidism (CH) is defined as hypothyroidism due to insufficient stimulation of the thyroid gland by TSH, for which secretion or activity can be impaired at the hypothalamic or pituitary levels. Patients with CH frequently present with multiple other pituitary hormone deficiencies. In addition to classic CH induced by hypothalamic-pituitary tumors or Sheehan syndrome, novel causes include traumatic brain injury or subarachnoid hemorrhage, bexarotene (a retinoid X receptor agonist) therapy, neonates being born to mothers with insufficiently controlled Graves disease, and lymphocytic hypophysitis. Growth hormone therapy, which may be used in children and adults, is now also recognized as a possible cause of unmasking CH in susceptible individuals. In addition, mutations in genes, such as TRHR, POU1F1, PROP1, HESX1, SOX3, LHX3, LHX4 and TSHB, have been associated with CH. The difficulty in making a clear diagnosis of CH is that the serum TSH levels can vary; values are normal in most cases, but in some might be low or slightly elevated. Levels of endogenous T(4) in serum might also be subnormal. Appropriate doses of levothyroxine for T(4) replacement therapy have not been confirmed, but might need to be higher than presently used empirically in patients with CH and should be adjusted according to age and other hormone deficiencies, to achieve free T(4) concentrations in the upper end of the normal range.

Diencephalic Syndrome due to Hypothalamic Tumor: A Model of the Relationship between Weight and Puberty Onset

Changes in body weight, statural growth rate, and puberty may be the presenting symptoms of hypothalamic-pituitary tumors. The objective of the study was to assess the relationship between the tumor and its treatment and the weight, growth rate, and onset of puberty, using the diencephalic syndrome of emaciation as model. Eleven patients seen before 1 yr of age, except one aged 9 yr, for diencephalic syndrome of emaciation due to hypothalamic pilocytic astrocytoma, were treated by surgical resection (n = 9), cranial irradiation (n = 7), and/or chemotherapy (n = 10). At diagnosis, growth rate was normal, despite the emaciation, and there was no hypothalamic-pituitary deficiency, except in the oldest patient. After tumor treatment, all had GH and thyroid-stimulating hormone deficiencies, but only three, who underwent major surgical resection, also had ACTH deficiency and diabetes insipidus. Eight became obese, and all but the oldest had transient precocious puberty. Plasma leptin concentrations were very low at diagnosis, increased after tumor treatment, and decreased transiently in one boy when the testosterone increased. The plasma soluble leptin receptor concentrations changed in the opposite direction, leading to an increase in the free leptin index, including in the three patients whose tumor was reduced without surgery. The body mass index was correlated positively with plasma leptin (rho = 0.73, P = 0.0004) and free leptin index (rho = 0.63, P < 0.004) and negatively with ghrelin (rho = -0.49, P < 0.03) concentrations. The obesity that occurs after treatment of hypothalamic tumors is not due to dysregulation of leptin secretion because it and plasma soluble leptin receptor remain regulated by factors like testosterone. This study also shows the influence of weight, possibly via leptin secretion, on the transient hypothalamic-pituitary-gonadal activation that occurs during the first year of life.

MRI in Children with Occult Hypothalamic-Pituitary Tumor

MRI in Children with Occult Hypothalamic-Pituitary Tumor

Ten Best Readings on Hypothalamic-Pituitary Tumors

Ten Best Readings on Hypothalamic-Pituitary Tumors

Serum levels of insulin-like growth factor I in 152 patients with growth hormone deficiency, aged 19-82 years, in relation to those in healthy subjects.

Serum insulin-like growth factor I (IGF-I) levels within normal range for age have been reported to be common in adults with GH deficiency (GHD). Therefore, serum IGF-I levels were determined in 152 consecutive patients (71 women and 81 men) with evidence of hypothalamic-pituitary disorders or previous cranial radiation, who fulfilled the presently used criteria for GHD i.e. peak GH response below 3 microg/L at stimulation test. Patients treated for acromegaly were excluded. Forty-three patients, aged 19-63 yr, had childhood onset GHD, and 109, aged 23-82 yr, had adult-onset GHD. Their IGF-I levels were expressed in SD scores in relation to normal reference values based on 448 healthy subjects, aged 20-96 yr (247 women and 201 men). In healthy subjects a linear inverse correlation, without gender difference, was found between logarithmic transformed IGF-I levels and age (r = -0.774; P < 0.001). In contrast, no age dependency was found in GHD patients. All patients with childhood-onset GHD had IGF-I values below -2 SD, significantly lower than those in adult-onset GHD patients (-6.2 +/- 0.3 vs. -3.2 +/- 0.2 SD score; P < 0.001). In patients with adult-onset GHD, 34% of the IGF-I levels were within normal range, increasing to 40% in the subgroup above 60 yr of age, in whom 86% were diagnosed with hypothalamic-pituitary tumors. Normal IGF-I was more common in men than in women, but no difference was observed between patients with panhypopituitarism and those with partial pituitary insufficiency. High frequencies of IGF-I levels within the normal range were found in GHD patients with pituitary tumors (20 of 57 nonsecreting pituitary adenomas, 5 of 15 prolactinomas, 6 of 12 Cushing's disease, and 4 of 25 craniopharyngiomas), but in only 2 of 43 patients with GHD due to other causes. In conclusion, an IGF-I level below -2 SD seems to be of diagnostic value in GHD with onset in childhood or early adulthood, whereas values within normal range are common in patients over 60 yr of age, especially those with pituitary tumors. The outcome of GH replacement therapy may reveal whether the addition of IGF-I as a diagnostic criterion is of predictive value in older patients.

Treatment of hypothalamic-pituitary tumors--experiences at Hiroshima University School of Medicine

Hypothalamic-pituitary tumors are unique tumors which are present with various disorders of the cerebrum, cranial nerve, and endocrine system, and which critically ruin the patients' quality of life. However, during the past two decades, hypothalamic-pituitary tumor treatment has developed dramatically. The curative method of the pituitary adenoma had not yet been introduced in the mid-1970s, but was accomplished several years after and spread rapidly through out the world. The main contributors which led to this development were the introduction of micro-neurosurgery (including transsphenoidal surgery), the development of new imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI), and the introduction of newer, more effective medicine. Other kinds of hypothalamic-pituitary tumor are also being cured by function-oriented surgery, drugs, and radiation therapy, which give the long-term useful life to patients. Regrettably, there are some malignant tumors which still resist to any multidisciplinary remedy. Efforts to prolong the useful lives of patients with malignant hypothalamic-pituitary tumors and also to improve the quality of life of patients with benign tumors should be continued. The most important point in managing hypothalamic pituitary tumors is to focus on "patient-oriented treatment" tailoring treatment to individual symptoms and needs.

Serum growth hormone-binding protein is unchanged in adult panhypopituitarism.

The role of GH in regulating GH-binding protein (GHBP) and GH receptor concentrations in humans is not clear. Studies performed mostly in children and on a minor scale in adults are somewhat controversial. The key question as to whether GHBP levels are altered in hypopituitarism before GH treatment is instituted remains unanswered. In this study, we have selected a severely GH-deficient group of adult patients with panhypopituitarism, acquired as a result of surgery and irradiation of hypothalamic-pituitary tumors, to evaluate the GHBP/receptor status by measuring GHBP activity in plasma. Twenty panhypopituitary patients (8 males and 12 females; age range, 20-74 yr) and 20 age (22-68 yr)- and sex-matched normal subjects were studied. GH deficiency was confirmed by insulin-induced hypoglycemia and arginine infusion tests; the peak GH response was less than 2 micrograms/L. Plasma insulin-like growth factor-I levels were below or in the low normal range (mean +/- SD, 88.3 +/- 53.6 micrograms/L) and were significantly different from insulin-like growth factor-I (IGF-I) levels in the normal group (mean +/- SD, 189 +/- 49.8 micrograms/L; P < 0.01). Plasma GHBP activity, measured using a GH-binding/gel chromatography assay, showed similar values in the GH-deficient group (mean +/- SD, 14.1 +/- 3.83%) and the control group (mean +/- SD, 13.7 +/- 3.79%), with no statistically significant difference. Neither the intra- nor intergroup comparison of GHBP levels according to age and sex showed statistically significant differences or age trends. In the light of these data and considering that GHBP activity in plasma probably reflects the GH receptor status in tissues, we may assume that the GH receptor was unaffected by chronic GH deficiency. These findings also support the previously reported concept that the GHBP/receptor level is a relatively fixed determinant of growth, established individually and independently of GH secretory status in early life, perhaps on a genetic basis.

The Therapy for Hypothalamic-Pituitary Tumors

Pituitary-hypothalamic tumors may profoundly affect endocrine functions. Although these are generally rare tumors of the central nervous system, they prominently figure into the differential diagnosis of children and adolescents with disorders of growth or puberty.

Serum growth hormone response to growth hormone-releasing hormone in non-obese and obese adults with hypopituitarism

The clinical consequences of growth hormone (GH) deficiency (GHD) in adults have not been defined. Standard methods of measuring GH reserve in children may not be reliable in adults. In addition, obesity in normal adults diminishes GH responsiveness to provocative stimuli; this inhibition of GH release is reversed with pyridostigmine (PD). We investigated the use of GH-releasing hormone (GHRH) as a method to assess pituitary GH secretory reserve (as defined by peak GH response to GHRH) in both non-obese and obese (ie, > 115% ideal body mass index [BMI]) adults with hypothalamic-pituitary tumors. Nine non-obese patients (NOP) and 10 obese patients (OP) were studied with 11 non-obese controls (NOC) and 10 obese controls (OC). All study groups received GHRH (1 μg/kg intravenous bolus) with blood sampling at −15, 0, 15, 30, 45, 60, 75, and 90 minutes. OC and OP received 120 mg PD orally 1 hour before GHRH injection. Mean serum GH responses in NOC and OC were significantly higher ( P < .05) than those in NOP and OP, respectively, 15 minutes after GHRH injection, and remained so throughout the time-course of the test. Mean ± standard error of the mean (SEM) peak GH level (μg/L) was lower in NOP than in NOC (5.1 ± 1.6 v 21.2 ± 4.4, P < .01) and lower in OP than in OC (4.6 ± 1.8 v 15.5 ± 2.2, P < .01). Mean ± SEM peak GH level was also lower in NOP than in OC (5.1 ± 1.6 v 15.5 ± 2.2 μg/L, P < .01). Patient subgroups defined by gonadal hormone status consistently displayed lower mean peak GH levels when compared with controls. Our findings indicate that GHRH-stimulation 0testing may be useful in identifying decreased GH secretory reserve in a group of adults with hypothalamic-pituitary tumors. PD administration to obese adults allows GHRH testing to remain an effective means of testing for GH reserve.