Prescription patterns of somatostatin analogs in patients with acromegaly and neuroendocrine tumors.

PURPOSE: Acromegaly and neuroendocrine tumors are rare diseases that, under certain conditions, can be treated with somatostatin analogs. The aim was to determine the prescription patterns of somatostatin analogs in a group of patients with acromegaly and neuroendocrine tumors affiliated with the Colombian Health System. METHODS: A retrospective study. A cohort of patients from a drug dispensing database that collected all prescriptions of long-acting somatostatin analogs (octreotide, lanreotide, pasireotide). Sociodemographic variables, clinical variables (diagnosis and comorbidities) and pharmacological therapy variables (dose, changes, persistence of use, comedications) were considered. RESULTS: A total of 213 patients were identified, including 139 (65.3%) with acromegaly and 74 (34.7%) with neuroendocrine tumors. There was a predominance of women (58.7%) and a mean age of 59.7 ± 14.5 years. The most commonly used medications were lanreotide autogel (n = 107; 50.2%), octreotide LAR (n = 102; 47.9%) and pasireotide LAR (n = 4; 1.9%). During follow-up, 11.3% of patients experienced modifications of therapy, with a mean duration from the beginning of treatment to the change in medication of 25 ± 15.9 months. A total of 48.9% of the patients with acromegaly and 87.1% of individuals with neuroendocrine tumors received maximum approved doses of the drug. CONCLUSION: Patients with acromegaly and neuroendocrine tumors in Colombia are mainly women and are most frequently treated with lanreotide autogel for acromegaly and with octreotide LAR for neuroendocrine tumors. In addition, a high proportion are managed with maximum doses of long-acting somatostatin analogs.

Are there country-specific differences in the use of pegvisomant for acromegaly in clinical practice? An analysis from ACROSTUDY.

OBJECTIVE: A comprehensive picture of pegvisomant use for treating acromegaly in routine clinical practice in different countries is lacking. We aimed, therefore, to document country-specific behaviors in real-life pegvisomant use, and the main safety and effectiveness outcomes in the ACROSTUDY. DESIGN: ACROSTUDY is an open-label, non-interventional, post-marketing safety surveillance study. METHODS: A descriptive analysis was performed using data from the six top-recruiter ACROSTUDY countries, i.e., Germany (n = 548 patients), Italy (n = 466), France (n = 312), USA (n = 207), Spain (n = 200) and the Netherlands (n = 175). These nations accounted for > 85% of the ACROSTUDY cases. RESULTS: The mean pegvisomant dose at treatment start was lowest in the Netherlands (9.4 mg/day), whereas it ranged between 10.9 and 12.6 mg/day in the other countries. At year 5, the mean pegvisomant dose was around 15 mg/day in all countries, except France (18.1 mg/day). At starting pegvisomant, patients treated with monotherapy ranged between 15% in the Netherlands and 72% in Spain. Monotherapy remained lowest over time in the Netherlands. In all countries, the percentage of patients with normal IGF-1 increased steeply from < 20% at baseline to 43-58% at month 6 and 51-67% at year 1. After that, we observed minor changes in the rate of acromegaly control in all countries. The Netherlands peaked in disease control at year 2 (72%). The proportion of patients reporting changes in pituitary tumor size was generally low. Serious treatment-related adverse events were < 5% in all countries. CONCLUSIONS: Our study provided a detailed summary of real-life use of pegvisomant in the six top-recruiter ACROSTUDY nations.

Evaluation of depressive mood and cognitive functions in patients with acromegaly under somatostatin analogue therapy.

AIMS: Acromegaly is caused by a pituitary adenoma that releases excess growth hormone (GH) and a concomitant increase in insulin-like growth factor 1 (IGF-1). Acromegaly results not only in phenotypic changes, but also in neurologic complications as peripheral neuropathy and cognitive dysfunction. This study aimed to compare depressive mood and cognitive function in patients with acromegaly and in healthy controls as well as to determine the factors underlying cognitive dysfunction in the acromegalic patients. MATERIALS AND METHODS: This study included 42 patients with acromegaly that were receiving somatostatin analogue therapy and 44 healthy controls. Memory, attention, visuospatial function, inhibitory function, abstract thinking, verbal fluency, and depressive mood were measured in the patients and controls. RESULTS: Patients with acromegaly had lower learning (p = 0.01), planning (p = 0.03), complex attention and inhibitory function (p = 0.04) scores than the controls. There was no significant difference in depressive mood between the patients and controls (p > 0.05). Gamma knife radiosurgery did not negatively affect cognitive function (p > 0.05). CONCLUSION: The present findings show that acromegaly negatively affects learning, attention, and planning.

Efficacy and Safety of Pegvisomant in the Treatment of Acromegaly.

Pegvisomant, the first and currently only clinically available growth hormone receptor antagonist, is an effective therapeutic option for the medical treatment of acromegaly, a rare disorder characterized by excessive growth hormone secretion. With now over 20 years of real world experience, its safety and efficacy is well-established. However, several aspects of its clinical use are still controversially discussed. The high cost of pegvisomant has limited its use in several countries, and recent studies have reported a lower efficacy than the initial clinical trials. A reported increase in tumor volume under therapy varies between studies and has been attributed to either actual growth or re-expansion after cessation of somatostatin receptor ligand therapy. Furthermore, different combinations of pegvisomant and other therapeutic agents aiming at reduction of acromegaly disease activity have been proposed to increase or retain effectiveness while lowering side effects and cost. This review aims to assess current clinical data on the safety and efficacy of pegvisomant while also addressing controversies surrounding its use.

Impulse Control Disorders in Patients with Pituitary Tumors Treated with Dopamine Agonists: A Systematic Review.

BACKGROUND: The increased prevalence of Impulse Control Disorders (ICDs) in dopamine agonist (DA) treated patients with Parkinson's disease is well described. Despite the frequent use of DAs in the management of pituitary tumors, the relationship between DAs and prevalence of ICDs in patients with pituitary tumours is unclear. AIMS: To establish the prevalence of ICDs in patients with prolactinoma or acromegaly and determine whether prevalence differs in those on DAs to those treated without. METHODS: Systematic review of the literature (registered a priori) reporting prevalence of ICDs in patients with prolactinoma or acromegaly (conducted June 2023). A narrative synthesis describing prevalence of ICDs according to assessment method was performed. Prevalence comparisons between patients with prolactinoma or acromegaly treated with DAs, to patients treated without, were summarised. RESULTS: Studies were largely retrospective, observational and heterogenous, with few patients with prolactinoma and acromegaly treated without DA. Prevalence of ICDs varied between 0-60% in patients with prolactinoma, and from 5-23% in studies with at least five patients with acromegaly. In most studies comparing DA exposed to non-DA exposed cases, DA use was not associated with ICDs. CONCLUSIONS: Reported prevalence of ICDs in patients with prolactinoma and acromegaly varies considerably. Given ICDs were reported to be highly prevalent in some studies, clinicians should be mindful of these potentially serious disorders. ICD screening tools validated for use in patients with pituitary tumors combined with prospective studies including appropriate controls, are necessary to accurately establish prevalence of ICDs and true impact of DAs in their development.

Patient's point of view on the diagnosis, treatment, and follow-up in acromegaly: single-center study from a tertiary center.

OBJECTIVE: We aimed to evaluate the awareness and perspectives of acromegaly patients in the diagnosis and treatment processes and to evaluate basic clinical and demographic features. METHODS: This cross-sectional study was conducted at the Endocrinology Department of Yildirim Beyazit University between March 2019 and April 2020. A total of 58 acromegalic patients were enrolled. All patients were identified from our database and called for a clinical visit and filling the questionnaire forms. RESULTS: A total of 58 patients were included in this study (41.4% female). The mean age of the patients was 52±10.8 years. Median year from symptom to diagnosis (min-max) was 2 (1-12). Notably, 55.2% of the patients did not graduate from high school. Of the 58 patients, 30 (51.7%) patients had knowledge about the etiology of their disease. While 12 (20.7%) patients identified their initial symptoms themselves, 75% of the patients reported their symptoms during the clinical history taken by a health care professional. The majority of patients were diagnosed by an endocrinologist (69%). Acromegaly did not affect social life but affected work life and caused early retirement. Transsphenoidal surgery was performed as primary treatment in 96.6% of the patients (n=56). In all, 46 (79.3%) patients received medical treatment with somatostatin receptor ligands (e.g., octreotide or lanreotide long-acting release [LAR]) with or without cabergoline. Overall disease control was achieved in 38 (65.5%) patients. CONCLUSIONS: Acromegaly is usually detected incidentally by clinicians. The diagnosis of acromegaly is delayed in most patients and disease-related complications have already developed at the time of diagnosis. Therefore, increasing the awareness of the society and health care professionals will reduce both disease-related comorbidities and the economic burden on the health system.

Partial response to first generation SSA guides the choice and predict the outcome of second line therapy in acromegaly.

INTRODUCTION: Treatment of acromegaly resistant to first generation somatostatin analogues (first gen-SSA) is often difficult. We aimed to investigate the role of partial response and resistance to first gen-SSA in the choice of second line treatments and their outcomes. PATIENTS AND METHODS: A retrospective and multicenter study was conducted on 100 SSA-resistant acromegaly patients and treated with Pasireotide Lar (Pasi-Lar), Peg-V in monotherapy (m-Peg-V) or in combination with first gen-SSA (c-Peg-V). RESULTS: Thirty-three patients (33%) were treated with m-Peg-V, 36 (36%) with c-Peg-V and 31 with Pasi-Lar (31%). According to logistic regression, m-Peg-V was chosen in older patients (p = 0.01) and with not-invasive adenomas (p = 0.009), c-Peg-V therapy in younger patients (p = 0.001), with invasive adenomas (p = 0.02), Pasi-Lar was in invasive adenomas (p = 0.01) and in patients partially responsive to first-gen SSA (p = 0.01). At the last follow-up, 68 patients (68%) reached the acromegaly control: 22 with m-Peg-V (32.4%), 23 with c-Peg-V (33.8%) and 23 with Pasi-Lar (33.8%). Patients non-responsive to c-Peg-V had higher IGF-I levels (median 3.2 x ULN, IQR: 1.6, p < 0.001) and required higher Peg-V dosage (median 30 mg/daily IQR: 10, p = 0.002) as compared to responsive patients (median IGF-I x ULN: 2.1 IQR: 1.4; median Peg-V dosage 20 mg/daily IQR: 10). All patients responsive to Pasi-Lar were partially responsive to first gen-SSAs (p = 0.02). CONCLUSION: Our data showed that c-Peg-V and Pasi-Lar are chosen for the treatment of invasive tumors. The partial response to first gen-SSA seems to be the main determinant for the choice of Pasi-Lar and positively predicts the treatment outcome.

Interferon-ß treatment associated with a biochemical profile suggestive of acromegaly. A case report of a patient treated for multiple sclerosis.

We describe a 34-year-old female treated with IFN-ß for 8 years with a biochemical profile suggestive of acromegaly. The patient presented with elevated serum insulin-like growth factor-I (IGF-I) and insufficient suppression of growth hormone (GH) during oral glucose tolerance test (OGTT). There were no clinical features of acromegaly. A 5-day profile showed higher GH levels on the 3 days following IFN-ß injections. Total and bioactive IGF-I were also elevated but did not fluctuate. Four weeks off IFN-ß normalized suppression of GH during OGTT but did not reduce serum IGF-I or bioactive IGF-I. In conclusion, IFN-ß treatment mimicked acromegaly biochemically. The changes were partially reversible.

Insulin resistance and pseudoacromegaly: A case report.

Patients with acromegaly have soft tissue overgrowth that induced characteristic clinical presentation. A growth hormone-secreting adenoma of the anterior pituitary gland is the most common cause of acromegaly. Metabolic and somatic features of acromegaly caused by high serum concentrations of insulin-like growth factor-I (IGF-I) and excess growth hormone (GH) production. we present a case of 'pseudoacromegaly' with an acromegaloid features, suppressed IGF-I levels and marked elevation of serum insulin. Endocrinologists should consider this diagnosis when assessing patients with clinical features of acromegaly and insulin resistance, in the absence of elevated levels of GH and IGF-I.

Insulin-mediated pseudoacromegaly: a case report and review of the literature.

A 23 year old female patient presented with oligoamenorrhea. She had excessive weight gain and had noticed hirsutism, enlargement of the jaw, increase in her ring and shoe size, increased sweating and darkening of her skin in flexural areas. Examination revealed a large framed woman with coarse facial features, large hands and feet, prognathism, acanthosis nigricans, hirsutism, acne and many skin tags. GH and IGF-1 were normal. MRI of pituitary showed a 7mm microadenoma, believed to be non-secretory with normal pituitary hormonal workup. She had marked elevation of serum insulin, elevated testosterone and mixed hyperlipidemia. The occurrence of acromegaloid manifestations is an unusual phenomenon seen in a subset of patients with insulin resistance. In vitro studies in fibroblasts obtained from such patients have revealed impairment of metabolic, but preservation of mitogenic insulin signaling. Insulin-mediated pseudoacromegaly is an unusual syndrome that combines severe insulin resistance and an acromegaloid phenotype. Physicians should consider this possibility while evaluating patients with similar clinical and laboratory features.

MECHANISMS IN ENDOCRINOLOGY: Clinical and pharmacogenetic aspects of the growth hormone receptor polymorphism.

Pharmacogenetics aims to maximize the beneficial effects of a medical therapy by identifying genetic finger prints from responders and non-responders and, thereby improving safety and efficacy profile of the drug. Most subjects who are deficient in growth hormone (GHD) are candidates for recombinant human GH (rhGH) therapy. To date, it is well established that even after adjustments for several clinical variables, such as age, gender, body composition and the age at onset of the GHD, response to rhGH treatment is highly variable among individuals, part of which is believed to be due to genetic factors within the GH system. As the first genetic variant to potentially influence the individual response to rhGH therapy in children with growth disorders, polymorphism in the GH receptor (GHR) has attracted a great interest as a target for pharmacogenetics. Studies have been conducted to compare the functional and molecular effects of the full-length GHR (fl-GHR) isoform with the exon 3 deleted (d3-GHR) isoform in children and adults treated with rhGH therapy. Additionally, the impact of the GHR polymorphism has been investigated in relation to the clinical status and response to medical treatment in acromegaly, especially to the GHR antagonist drug pegvisomant. We have performed a narrative review of the studies performed to date on the association of GHR polymorphism with rhGH response in children and adults, and its potential influence in the medical management of acromegaly. In addition, data from studies on the general population and in other chronic diseases examining a role of this genetic variant in the regulation of growth and metabolism are summarized.

Treatment of growth hormone excess in dogs with the progesterone receptor antagonist aglépristone.

Acromegaly or hypersomatotropism in dogs is almost always due to progestin-induced hypersecretion of GH originating from the mammary gland. The aim of this study was to investigate whether aglépristone, a progesterone receptor antagonist, can be used to treat this form of canine acromegaly. In five Beagle bitches hypersomatotropism was induced by administration of MPA for over 1 year. Subsequently, aglépristone was administered. Blood samples were collected before MPA administration, immediately before, during, and 3.5 and 5.5 weeks after the last administration of aglépristone for determination of the plasma concentrations of GH and IGF-I. In addition, blood samples for the determination of the 6-h plasma profile of GH were collected before MPA administration, before aglépristone administration, and 1 week after the last aglépristone treatment. MPA administration resulted in a significant increase of the mean plasma IGF-I concentration, whereas analysis of the pulsatile plasma profile demonstrated a trend (P=0.06) for a higher mean basal plasma GH concentration and a higher mean AUC(0) for GH. Treatment with aglépristone resulted in a significant decrease of the mean plasma GH and IGF-I concentrations. Analysis of the pulsatile plasma profile showed a trend (P=0.06) for a lower mean basal plasma GH concentration and a lower mean AUC(0) for GH 1 week after the last aglépristone treatment compared with these values before aglépristone administration. Three and a half and 5.5 weeks after the last aglépristone administration the mean plasma IGF-I concentration increased again. In conclusion, aglépristone can be used successfully to treat dogs with progestin-induced hypersomatotropism.

Considering GH replacement for GH-deficient adults with a previous history of cancer: a conundrum for the clinician.

Previous studies have shown that GH and IGF-I may enhance tumorigenesis, metastasis, and cell proliferation in humans and animals. Evidence supporting this notion is derived from animal model studies, epidemiological studies, experience from patients with acromegaly, molecular therapeutic manipulation of GH and IGF-I actions, and individuals with GH receptor and congenital IGF-I deficiencies. Prior exposure to radiation therapy, aging, family history of cancer, and individual susceptibility may also contribute to increase this risk. Therefore, the use of GH replacement in patients with a history of cancer raises hypothetical safety concerns for patients, caregivers, and providers. Studies of GH therapy in GH-deficient adults with hypopituitarism and childhood cancer survivors have not convincingly demonstrated an increased cancer risk. Conversely, the risk of occurrence of a second neoplasm (SN) in childhood cancer survivors may be increased, with meningiomas being the most common tumor; however, this risk appears to decline over time. In light of these findings, if GH replacement is to be considered in patients with a previous history of cancer, we propose this consideration to be based on each individual circumstance and that such therapy should only be initiated at least 2 years after cancer remission is achieved with the understanding that in some patients (particularly those with childhood cancers), GH may potentially increase the risk of SNs. In addition, close surveillance should be undertaken working closely with the patient's oncologist. More long-term data are thus needed to determine if GH replacement in GH-deficient adults with a history of cancer is associated with the development of de novo tumors and tumor recurrence.

Safety and specificity of the growth hormone suppression test in patients with diabetes.

The purpose of this study was to evaluate the safety of the oral glucose tolerance test (OGTT) and its capacity to suppress growth hormone (GH) in diabetic patients without acromegaly. A total of 135 diabetic patients submitted to the OGTT for GH suppression were studied. The following selection criteria were applied: age between 20 and 70 years; body mass index≥18.5 and ≤27 kg/m2; absence of kidney, liver, or thyroid disease; no use of estrogens, androgens, corticosteroids, or levothyroxine. Adequate suppression of GH was defined as a nadir below the cut-off established for a sample of 200 normoglycemic subjects (<0.25 µg/L for men, <0.74 µg/L for premenopausal women, and <0.5 µg/L for postmenopausal women). Acromegaly was diagnosed in five patients. Among the 130 diabetic patients without known pituitary disease or a clinical suspicion of acromegaly, 95.5% of men, 94% of premenopausal women, and 96.6% of postmenopausal women presented adequate GH suppression (vs 97.5% of normoglycemic controls). In all patients without acromegaly, the lowest GH levels (nadir) were achieved after the administration of glucose and not during baseline measurement. None of the patients had acute complications [ketoacidosis, hyperosmolar state, and symptomatic marked hyperglycemia (>300 mg/dL)] on the day of the test and up to 3 days thereafter. We demonstrated the safety of the OGTT and its capacity to suppress GH in diabetic patients without acromegaly. In addition, we suggest the adoption of a protocol to prevent possible risks of the OGTT in patients with diabetes.

Grwoth hormone, prolactin, and cortisol in dogs developing mammary nodules and an acromegaly-like appearance during treatment with medroxyprogesterone acetate.

PIP: Concentrations of (GH) growth hormone, (PRI) prolactin, cortisol, progesterone, and (MPA) medroxyprogesterone acetate were determined by RIA in blood sera collected from beagle bitches 17 months after initiating treatment with MPA (75 mg/kg.3 months; n = 12) MPA vehicle (controls; n = 12), or progesterone implants which produced physiological levels of progesterone (13.8 + or - 2.1 ng/ml; n = 12). In the MPA-treated bitches, mean MPA levels were 104 + or - 6 ng/ml, mean GH levels were elevated (9.5 + or - 3.0 vs. 0.4 + or - 0.1 ng/ml; P 0.01); mean PRL levels were unchanged (13.7 + or - 2.8 vs. 12.6 + or - 1.2 ng/ml); and mean cortisol levels were suppressed (1.7 + or - 0.2 vs. 13.7 + or - 1.4 ng/ml; P 0.01) in comparison to those in control animals. None of these parameters was significantly affected by progesterone treatment. External signs of an acromegaly-like condition and large mammary gland nodules (diameters, 5 mm) were noted in, and limited to, 9 bitches with elevated ( 2.5 ng/ml) GH levels (12.8 + or - 3.0 ng/ml). These were 8 MPA-treated bitches which developed the acromegal-like condition during treatment and 1 progesterone-treated bitch which appeared acromegalic before treatment and in which the condition was considered to have developed spontaneously. The data suggest that the acromegaly-like changes and large mammary nodules in dogs administered the contraceptive progestin MPA occurred as a result of MPA-induced elevations in GH. The results do not preclude the possibility that the MPA-induced suppression of cortisol and/or the direct action of MPA on the mammary glands also contributed to mammary nodule formation. MPA-treated dogs may also provide a unique experimental model for studying chronic elevations in endogenous GH levels and for testing compounds for their ability to suppress GH levels.^ieng

Acromegaly associated with transient overproduction of growth hormone in a dog.

A 6-year-old female crossbred Belgian Shepherd Dog with features of acromegaly was monitored for almost 4 years. The history of frequent and excessive administration of a progestational agent suggested that the progestational drug induced the acromegaly. During the monitoring period. soft tissue changes diminished and there was normalization of several factors: plasma growth hormone concentration, response of plasma insulin and glucose to an oral glucose load, and response of plasma glucose hormone to the injection of insulin.

Acromegaly in the dog.

The main characteristic findings in canine acromegaly are a visible increase in soft tissue mass, prominent skin folds, abdominal enlargement, and/or radiographic evidence of an increase in soft tissue mass in the orolingual, oropharyngeal, and orolaryngeal region. Acromegalic dogs almost invariably show some degree of respiratory stridor. Enlargement of the interdental spaces can be seen, but it is felt that these changes are less specific for the disease. Other possible findings include hyperglycemia, PU/PD, elevated SAP levels, and lowered PCV. For a conclusive diagnosis, the demonstration of elevated GH levels and, preferably, the demonstration of nonsuppressibility of these high GH levels is required. Basal plasma GH levels in acromegalic dogs varies considerably (for example, from 10 ng per ml to approximately 1500 ng per ml). GH-dependent circulating growth factor (that is, insulin-like growth factor I) is drastically elevated. Acromegaly is encountered in intact female dogs that were treated with progestagens to prevent estrus and in dogs during diestrus (progesterone phase). Progestagen withdrawal and/or ovariohysterectomy will result in a reduction of plasma GH and GH-dependent insulin-like growth factor concentrations and appreciable clinical improvement.

Use of proligestone in the management of three German shepherd dogs with pituitary dwarfism.

Three German shepherd dogs were diagnosed with pituitary dwarfism and subsequently treated with proligestone. Treatment resulted in development of an adult hair coat, increased bodyweight and elevated insulin-like growth factor-1 concentration. Two dogs received thyroid supplementation during proligestone therapy. Adverse effects (cystic endometrial hyperplasia and acromegaly) were reported in two cases. No side effects were reported in the remaining case. This is the first report of the use of proligestone in the management of pituitary dwarfism.

[Clinical and metabolic effects of recombinant human growth hormone in cardiac insufficiency]. / Kliniczne i metaboliczne efekty dzialania rekombinowanego ludzkiego hormonu wzrostu u chorych z niewydolnoscia serca.

Growth hormone (GH) acting through locally produced insulin--like growth factors stimulates myocardial hypertrophy and increases myocyte contractility. Many people with growth hormone deficiency (GHD) present a lower left ventricular mass, reduced ejection fraction and lower exercise tolerance. Recombinant human growth hormone (rhGH) administration gives a chance to correct these disturbances. On the other hand excessive levels of GH (for example in acromegaly) may induce heart failure too. Initially, cardiac hypertrophy is an adaptive response, but with time, in untreated cases, it leads to congestive heart failure. Mentioned information inclined many authors to undertake researches on rhGH application in severe heart failure in patient with idiopathic dilated cardiomyopathy and coronary disease. RhGH improved treatment let these patients reach heart transplantation.

Organohalogenated contaminants in domestic cats' plasma in relation to spontaneous acromegaly and type 2 diabetes mellitus: a clue for endocrine disruption in humans?

It was recently hypothesized that pets may serve as sentinels to explore human exposure to organohalogenated chemicals (OHCs) via indoor environments and adverse health effects. The current study investigates OHCs contamination in domestic cats suffering from diabetes mellitus (DM), particularly DM induced by acromegaly and a form of DM akin to human type 2 DM (T2DM). Plasma from three groups of domestic cats was analyzed: acromegaly induced DM, T2DM and age matched control cats without DM. Analytes targeted included organochlorine pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), together with their hydroxylated (HO-) metabolites. Similar PCB profiles were measured in cat plasma compared to humans, while the PBDE profile (dominated by BDE-99 (48%-55%) and BDE-47 (19%-25%)), the PCB and PBDE metabolite profiles were different in cat plasma than found in humans. Significantly higher OHC concentrations were recorded in plasma of acromegalic cats compared to the other two groups. Group differences in the PCBs/HO-PCBs ratios suggest that acromegalic cats have a lower capacity to metabolize persistent OHCs, like PCBs, than diabetic cats or cats without an endocrinopathy. As pituitary tumorigenesis in animals can be induced by estrogens, and PCBs may act as xenoestrogens, further investigation into whether there could be a causative link with the induction of feline acromegaly is warranted. Interestingly, BDE-47/BDE-99 ratios in cats were similar to the ratios in house dust. The results of this study suggest that domestic cats may represent a good model to assess human exposure to chemicals present in indoor dust.