Features of patients and fracture risk in hypoparathyroidism; a single center study.

PURPOSE: Patients with hypoparathyroidism (hypoPT) have low bone turnover and high bone mineral density (BMD). However, data on fracture risk are conflicting. The objectives of this study were: 1. To describe clinical/biochemical characteristics of hypoPT patients followed at a single medical center. 2. To identify postsurgical hypoPT patients and investigate their fracture rate compared with gender/age-matched post-surgical normocalcemic patients. METHODS: Retrospective analysis of patient's medical records treated at the tertiary medical center in 2010-2021 identified by computerized medical database search. RESULTS: The cohort included 133 patients (91% women, mean age 64 ± 13 years) of whom 105 (79%) had post-thyroidectomy hypoparathyroidism and the remainder had an autoimmune/idiopathic/other etiology. Mean follow-up time was 21 ± 12 and 27 ± 12 years, respectively. The control group included 142 post-thyroidectomy patients without hypoparathyroidism. Patients in the postsurgical hypoparathyroidism group were older and had higher calcium and PTH levels at diagnosis than the non-surgical hypoPT patients. Comparing the postsurgical hypoPT and postsurgical normocalcemic control patients revealed a significantly higher BMD in the hypoPT group. Yet, fracture rates were 31% in the postsurgical hypoparathyroidism group and 21% in the control group (P = 0.1) over a similar median follow-up period (17 and 18.4 years, respectively). In both groups the most common fracture site was the spine (50% and 70%, respectively; p = 0.33), mainly nonclinical morphometric fractures. Higher phosphorus blood level was associated with increased fracture risk. CONCLUSIONS: The relatively high BMD in patients with postsurgical hypoparathyroidism is not associated with lower fracture risk. Silent morphometric fractures are quite common in this group of patients.

Idiopathic central diabetes insipidus in a large cohort of patients: the hypopituitarism ENEA rare observational (HEROS) study.

Central Diabetes Insipidus (CDI) is mainly associated with structural pathologies of the hypothalamic-pituitary area. Etiologies underlying CDI are identified in most patients, however idiopathic CDI is reported in 13-17% of cases after excluding other etiologies. The Hypopituitarism ENEA Rare Observational Study (HEROS study) retrospectively collected data of patients with idiopathic CDI from 14 pituitary centers in 9 countries. The cohort included 92 patients (59 females 64%), mean age at diagnosis was 35.4 ± 20.7 years, and a mean follow up of 19.1 ± 13.5 years following CDI diagnosis. In 6 women, diagnosis was related to pregnancy. Of 83 patients with available data on pituitary imaging, 40(48%) had normal sellar imaging, and 43(52%) had pathology of the posterior pituitary or the stalk, including loss of the bright spot, posterior pituitary atrophy or stalk enlargement. Anterior pituitary hormone deficiencies at presentation included hypogonadism in 6 (6.5%) patients (5 females), and hypocortisolism in one; during follow-up new anterior pituitary deficiencies developed in 6 patients. Replacement treatment with desmopressin was given to all patients except one, usually with an oral preparation. During follow up, no underlying disease causing CDI was identified in any patient. Patients with idiopathic CDI following investigation at baseline are stable with no specific etiology depicted during long-term follow-up.

Denosumab-induced hypocalcemia in patients with osteoporosis: can you know who will get low?

Hypocalcemia was reported at low rates (0.05-1.7%) in denosumab-treated postmenopausal women with osteoporosis. This real-life study shows a 7.4% rate of denosumab-induced hypocalcemia in community-dwelling osteoporotic men and women. Pretreatment serum calcium and creatinine levels are major predictors for this complication. Serum-calcium monitoring may help to identify and prevent severe hypocalcemia. PURPOSE: RCTs have reported a 0.05-1.7% rate of hypocalcemia in denosumab-treated postmenopausal women with osteoporosis, but long-term real-life data are lacking. We assessed the rate of hypocalcemia in osteoporotic community-dwelling patients treated with denosumab. METHODS: A retrospective analysis was conducted based on medical records (2010-2018) from a large HMO. An albumin-adjusted serum calcium concentration lower than 8.5 mg/dL was defined as hypocalcemia. RESULTS: We included 2005 patients (93% women, mean age 76 ± 9 years). Hypocalcemia developed during treatment in 149 patients (7.4%; 1% less than 8 mg/dL): in 66 after 0.5-1 years; 48 after 1-2 years; 35 after > 2 years. On comparison of the hypocalcemic and normocalcemic patients, the strongest predictors of hypocalcemia were pretreatment levels of albumin-adjusted serum calcium (9.1 ± 0.4 vs. 9.4 ± 0.5 mg/dL, respectively; p < 0.05) and creatinine (0.9 ± 0.5 vs. 0.8 ± 0.3 mg/dL, respectively; p < 0.05). The hypocalcemia rate increased in parallel to a decrease in eGFR (p = 0.032 for the difference between eGFR ranges). Baseline calcium level ≤ 9.31 mg/dL predicted hypocalcemia with a sensitivity of 77% and specificity of 56%. A model of (- 2)*calcium + creatinine predicted hypocalcemia (3.7% when lower and 17.1% when higher than - 17.4). Gender, age, 25-hydroxyvitamin-D, parathyroid hormone, alkaline phosphatase, and whether denosumab was given as first or advanced line of osteoporotic therapy had no predictive value. CONCLUSION: Real-life rates of denosumab-induced hypocalcemia are higher than previously reported. Hypocalcemia might develop after each dose of denosumab in ongoing treatment. Adequate calcium and vitamin D supplementation are needed. Serum calcium monitoring is advised in high-risk patients for early detection of severe hypocalcemia.

Outcome of pregnancies in a large cohort of women with acromegaly.

OBJECTIVE: To assess the outcome of pregnancies in a large cohort of women with acromegaly. DESIGN AND METHODS: This is a retrospective analysis of 31 pregnancies in 20 patients with acromegaly. RESULTS: Twenty-seven pregnancies resulted in healthy offspring, and 4 resulted in abortion. Three patients underwent transsphenoidal surgery during pregnancy. IGF-1 levels remained elevated during pregnancy in 4 pregnancies and normalized in 23 cases. Fifteen cases were followed during pregnancy without any medical or surgical treatment, and 13 of these exhibited normal IGF-1 levels. Before or during pregnancy, somatostatin receptor ligands usage was not associated with higher risk for adverse outcomes. Arterial hypertension worsening (45%) and impairment of glucose levels (32%) were the most common complications during pregnancies. There were no maternal or neonatal deaths. One woman delivered twins. Two cases of congenital malformations and one with foetal macrosomia were observed. Caesarean delivery was performed in sixteen cases. CONCLUSION: Our study confirms the impact of gestation on IGF-1 levels. However, it also indicates that acromegaly still holds an increased risk for worsening of comorbidities, especially in uncontrolled patients.

Acute cortisol release during stereotactic fractionated radiotherapy to an ACTH-secreting pituitary macroadenoma.

A 33-year old male was diagnosed with Cushing's disease due to a large and invasive ACTH-secreting macroadenoma. After surgical failure ketoconazole therapy was initiated to control cortisol hypersecretion and his symptoms. He was referred to radiotherapy, and fractionated stereotactic radiotherapy in 30 fractions was delivered. After 12 daily fractions of radiotherapy the urinary cortisol release increased abruptly together with clinical deterioration. The daily ketoconazole dose was increased, and 10 days after concluding radiotherapy his urinary cortisol returned to normal values. Hormonal remission was observed less than 1 year following radiotherapy.

Total versus hemithyroidectomy for microscopic papillary thyroid cancer.

BACKGROUND: No increased mortality has been reported in patients with thyroid papillary microcarcinoma (PMC); however, neck recurrences and distant metastases have been described. In this study, we compare patients' outcomes after total thyroidectomy vs hemithyroidectomy for treatment of thyroid PMC. METHODS: Two hundred and ninety-three patients from two major medical centers in Israel were included. The mean follow-up period was 7.2±6.8 yr. RESULTS: Total thyroidectomy was performed in 214 patients and hemithyroidectomy in 79 patients. Mean tumor size was 6.3±3 mm. Lymph-node (LN) metastases and extraglandular extension were more frequent in the total thyroidectomy group than in the hemithyroidectomy group, 24.8% vs 1.3% (p<0.001) and 11.7% vs 3.8% (p=0.042), respectively. The cumulative incidence of recurrence at the end of follow-up was 13.2% in the total thyroidectomy group and 14.3% in the hemithyroidectomy group (p=ns). The incidence of recurrence was higher in patients with LN involvement in both groups. Considering low risk patients only (monofocal tumors, no LN involvement, no extraglandular extension; no.=63 in the total thyroidectomy group vs no.=60 in the hemithyroidectomy group) neck recurrence was found in 10% of patients in the hemithyroidectomy group but none in the total thyroidectomy group. In the hemithyroidectomy group, all locoregional recurrences were diagnosed using ultrasonography, compared to 47.6% in the total thyroidectomy group. CONCLUSION: For patients with monofocal disease within the thyroid gland and no LN involvement, hemithyroidectomy can be considered an option, bearing in mind a higher risk for recurrence. For all other patients with PMC, we propose total thyroidectomy as initial treatment.

Prognostic value of post-thyroidectomy thyroglobulin levels in patients with differentiated thyroid cancer.

BACKGROUND: Thyroglobulin is an excellent biological marker of persistent or recurrent thyroid cancer during long-term follow-up. Most studies investigated its diagnostic value but not its prognostic value over time. We aim to study the prognostic value of thyroglobulin levels early after total thyroidectomy, before iodine ablation. METHODS: The study was based on the Rabin Medical Center registry of patients with non-medullary thyroid carcinoma. Data were collected on the clinical, laboratory, and outcome characteristics of 420 consecutive patients followed at our institution for whom early post-operative pre-ablation thyroglobulin values (baseline thyroglobulin) were available. RESULTS: Patients were classified into 4 groups by baseline thyroglobulin level: 0-2, 2-10, 10-100, and >100 ng/ml. Higher levels were associated with a shift toward male gender (p=0.01), larger tumor size (p=0.02), and a more extensive disease (p<0.0001). They were also related to disease persistence and evidence of disease at last follow-up (p<0.0001). The 10 ng/ml cut-off level identified patients with persistent disease with a sensitivity and specificity of 73%, positive predictive value of 43%, and negative predictive value of 89%. On multivariate analysis, the following variables were predictive of persistent disease: baseline thyroglobulin level, male gender, lymph-node involvement, distant metastases, higher tumor invasiveness, and larger tumor size. However, the predictive power of baseline thyroglobulin level was relatively weak (odds ratio 1.002, 95% confidence interval 1.00-1.04). CONCLUSIONS: In patients with well-differentiated thyroid cancer, a post-thyroidectomy thyroglobulin level <10 ng/ml is associated with a low probability of having persistent disease and can be used combined with other disease characteristics for decisions regarding treatment and follow-up.

The potential role of mTOR inhibitors in the treatment of endocrine tumors.

Mammalian target of rapamycin (mTOR), a main protein kinase in the phosphoinositide 3-kinase/Akt/p70S6K signaling pathway, is an important intracellular mediator involved in multiple cellular functions including proliferation, differentiation, apoptosis, longevity, tumorigenesis, and angiogenesis. Alterations of the normal activity of mTOR and of mTOR-related kinases in this pathway have been found in a diversity of human tumors, suggesting that mTOR may be an attractive target for the development of new anti-cancer therapies. The main objective of this article is to summarize the available pre-clinical and clinical data regarding a possible role of mTOR inhibitors in the treatment of different endocrine cancers.

Clinically silent chromaffin-cell tumors: Tumor characteristics and long-term prognosis in patients with incidentally discovered pheochromocytomas.

BACKGROUND: Chromaffin-cell tumors (CCT), a rare group of catecholamine producing endocrine neoplasms, are traditionally suspected and diagnosed in patients presenting with episodic hypertension, together with the classic triad of headache, sweating, and tachycardia. Asymptomatic CCT are increasingly diagnosed, frequently as "incidentalomas". We have conducted a multicenter retrospective study, to assess the characteristics of a group of patients with clinically silent CCT, compared with a group of patients with typical CCT. METHODS: Forty-three consecutive patients with CCT (24 with silent and 19 with typical tumors) have been retrospectively studied for a period of up to 20 yr (between 1989 and 2009); clinical picture, biochemical tests, as well as topographic and functional assessment were analyzed at diagnosis and periodically following treatment. Surgical samples were reviewed for neuroendocrine markers and for signs of invasiveness. RESULTS: Patients with clinically silent CCT were significantly older than the typical ones (56.3±3.4 vs 48.0±4.8 yr; p<0.05); 15 of them (63%) were completely asymptomatic, and 9 patients (37%) complained of non-specific abdominal symptoms. Hypertension was present in only 6 silent CCT patients (25%), it was well controlled [mean blood pressure (BP) 134/84 mmHg], and persisted after surgery in only 2 patients. Fourteen out of twenty-four silent CCT patients (58%) were managed pre-operatively with prophylactic combination of α and ß blockade, despite normal BP values. Clinically silent CCT were larger than typical CCT (mean diameter of 5.2±2.3 cm vs 4.6±1.5 cm, p<0.05) and secreted higher a mounts of normeta neph rines. All clinically silent CCT patients were defined as "cured" after surgery. CONCLUSION: Clinically silent CCT are more prevalent than previously reported. With an adequate pre-surgical diagnosis and patient preparation, the prognosis of silent tumors is usually excellent.

Cytokine-dependent gp130 receptor subunit regulates human fetal pituitary adrenocorticotropin hormone and growth hormone secretion.

We have shown recently that leukemia inhibitory factor (LIF) and oncostatin M (OSM), two members of the gp130-dependent cytokine family, stimulate murine proopiomelanocortin (POMC) transcription and adrenocorticotropin hormone (ACTH) secretion. LIF and corticotropin-releasing hormone (CRH) also synergistically induced in vivo ACTH secretion in fetal nonhuman primates. To elucidate the role of the gp130-related cytokines in human pituitary hormone regulation, we tested expression of gp130-related cytokine receptors in human fetal pituitaries. Using RT-PCR, mRNA expression of receptors for LIF, IL-6, and CRH, and the gp130 subunit, were all detected in fetal pituitaries of 18- and 31-wk gestation. Recombinant human IL-6, LIF, and OSM treatments of primary human fetal pituitary cultures (16-31 wk) increased ACTH secretion by up to 48% (P < 0.05) using doses of 1 nM, and when fetal cultures were cotreated with CRH, ACTH was induced five- to sixfold as compared to CRH alone (three- to fourfold; P = 0.01). Incubation with gp130-specific antibody suppressed basal and cytokine-stimulated ACTH secretion (alone or with CRH) from human fetal cells. Human POMC promoter -879/+6 fused to the luciferase reporter gene and transfected into AtT-20 cells, was stimulated by LIF (7-fold), which also exerted strong (22-fold) synergy with CRH on POMC transcription. Growth hormone (GH) release from fetal cultures was modestly stimulated (15-31%, P < 0.05), while other anterior pituitary hormones were not altered by these cytokines. Thus, physiologic concentrations of the gp130-related cytokines have direct effects on ACTH and GH regulation in the human pituitary, indicating that gp130-dependent signals serve as a paracrine system controlling early human pituitary function.

Heparin-binding secretory transforming gene (hst) facilitates rat lactotrope cell tumorigenesis and induces prolactin gene transcription.

We have shown previously that human prolactinomas express transforming sequences of the heparin-binding secretory transforming gene (hst) which encodes fibroblast growth factor-4 (FGF-4). To elucidate the role of hst in pituitary tumorigenesis we treated primary rat pituitary and pituitary tumor cell cultures with recombinant FGF-4 and also stably transfected pituitary cell lines with full-length human hst cDNA. Transfectants were screened for hst mRNA expression and FGF-4 production. FGF-4 (0.1-50 ng/ml) caused a dose-dependent 2.5-fold increase of prolactin (PRL) secretion (P < 0.001) in GH4 cells and up to 60% (P < 0.05) in primary cultures, while decreasing growth hormone release (P < 0.001). GH4 hst transfectants displayed markedly enhanced basal PRL secretion (threefold, P < 0.001) and also proliferated faster (P < 0.001). FGF-4 treatment of wild-type GH4 cells, transiently transfected with an expression construct (rPRL.luc) containing a luciferase reporter driven by the rPRL promoter, resulted in a dose-dependent increase of up to 3.3-fold in PRL transcriptional activity. Tumors derived from in vivo subcutaneous injection of GH4 hst-transfected cells strongly expressing FGF-4 grew more aggressively as assessed by histologic invasiveness and proliferating cell nuclear antigen staining (P < 0.01). The results indicate that hst overexpression mediates lactotrope tumor growth and potently stimulates PRL synthesis. Thus, hst may directly facilitate prolactinoma development via paracrine or autocrine action of its secreted protein, FGF-4.

Somatostatin receptor (SSTR) subtype-selective analogues differentially suppress in vitro growth hormone and prolactin in human pituitary adenomas. Novel potential therapy for functional pituitary tumors.

Previously, we have shown somatostatin receptor (SSTR) subtype-specific regulation of growth hormone (GH), thyroid-stimulating hormone, and prolactin (PRL) secretion in human fetal pituitary cultures, where GH and thyroid-stimulating hormone are mediated by both SSTR2 and SSTR5, whereas SSTR2 preferentially mediates PRL secretion. We now tested SSTR subtype-selective analogues in primary human GH- and PRL-secreting pituitary adenoma cultures. Analogue affinities determined by membrane radioligand binding in cells stably expressing human SSTR forms were either SSTR2 or SSTR5-selective. Analogues preferential either for SSTR2, including octreotide, lanreotide, and novel compounds with improved affinity for SSTR2, or new SSTR5-selective compounds suppressed GH in tumor cell cultures (up to 44% of control; P < 0.0005). However, novel analogues from both groups were 30-40% more potent than octreotide and lanreotide in suppressing GH (P < 0.05). Heterologous analogue combinations containing both SSTR2- and SSTR5-selective compounds were more potent in decreasing GH than analogues used alone (P < 0.05), or than combinations of compounds specific for the same receptor subtype (P < 0.005). In contrast, SSTR2-selective analogues did not suppress PRL release from six cultured prolactinomas studied. However, new SSTR5-selective analogues suppressed in vitro PRL secretion (30-40%; P < 0.05) in four of six prolactinomas. These results suggest that both SSTR2 and SSTR5 are involved in GH regulation in somatotroph adenoma cells, whereas SSTR5 exclusively regulates PRL secretion from prolactinoma cells. Thus, somatostatin analogues with improved selective binding affinity for these receptor subtypes may be effective in the treatment of either GH- or PRL-secreting adenomas.

Somatostatin receptor subtype specificity in human fetal pituitary cultures. Differential role of SSTR2 and SSTR5 for growth hormone, thyroid-stimulating hormone, and prolactin regulation.

Somatostatin (SRIF), a hypothalamic inhibitor of pituitary growth hormone (GH) and thyroid-stimulating hormone (TSH) secretion, binds to five distinct receptor (SSTR) subtypes. We therefore tested SSTR subtype-specific SRIF analogs in primary human fetal pituitary cultures (23-25-wk gestation) to elucidate their role in regulating human pituitary function. Using reverse transcription-PCR, mRNA expression of SSTR2 and SSTR5 were detected in fetal pituitary by 25 wk. SRIF analog affinities were determined by membrane radioligand binding in cells stably expressing the human SSTR forms. GH secretion was suppressed equally (40-60%, P < 0.005) by analogs preferential for either SSTR2 (IC50 for receptor binding affinity, 0.19-0.42 nM) or SSTR5 (IC50, 0.37 nM), and compounds with enhanced affinity for SSTR2 were more potent (EC50 for GH suppression, 0.05-0.09 nM) than Lanreotide (EC50, 2.30 nM) and SRIF (EC50, 0.19 nM). Similarly, analogs with high affinity for SSTR2 or SSTR5 decreased TSH secretion (30-40%, P < 0.005). However, prolactin was effectively inhibited only by compounds preferentially bound to SSTR2 (20-30%, P < 0.05). Luteinizing hormone was modestly decreased (15-20%) by SSTR2- or SSTR5-specific analogs. An SSTR5-specific analog also exclusively inhibited GH in acromegalic tumor cells. Thus, SRIF regulation of GH and TSH in primary human fetal pituitary cells is mediated by both SSTR2 and SSTR5, both of which are abundantly expressed by 25 wk. In contrast, suppression of prolactin is mediated mainly by SSTR2. These results indicate that SSTR5 is critical for physiologic regulation of GH and TSH. SRIF analogs with selective affinity for this receptor may therefore be more effective in the treatment of hormone-secreting pituitary adenomas.

Acquired prolactin deficiency in patients with disorders of the hypothalamic-pituitary axis.

UNLABELLED: Acquired PRL deficiency occurs when the anterior pituitary is functionally destroyed, and it usually accompanies other pituitary hormone deficiencies. We retrospectively investigated in an outpatient endocrine clinic of a major tertiary medical center the prevalence and clinical characteristics of acquired PRL deficiency in patients with diseases of the hypothalamic-pituitary axis. The study included 100 consecutive patients, 61 men and 39 women, aged 4-79 yr at diagnosis. Patients were divided by PRL level to normal (>5 ng/ml), mild (3-5 ng/ml), and severe deficiency (<3 ng/ml). Twenty-seven patients (27%) had PRL deficiency, 13 mild deficiency and 14 severe deficiency. Patients with severe PRL deficiency tend to be younger at diagnosis (mean age, 37.5+/-21.8 yr) than patients with normal PRL (46+/-18.5 yr; ns). Underlying diseases including pituitary apoplexy, non-functioning pituitary adenoma, craniopharyngioma, and idiopathic hypogonadotropic hypogonadism were associated with PRL deficiency. The incidence of severe PRL deficiency rose with an increase in the number of other pituitary hormone deficits (ACTH, TSH, gonadotropin, vasopressin), from 0 in patients with no other deficits to 38% in patients with 4 deficits (p=0.006). Patients with severe deficiency had a mean of 3 hormone deficits compared to 1.8 in the other groups (p=0.006). PRL deficiency was significantly associated with TSH, ACTH and GH deficiency. CONCLUSIONS: PRL deficiency is common in patients with hypothalamic-pituitary disorders, especially pituitary apoplexy and craniopharyngioma. Acquired severe PRL deficiency can be considered a marker for extensive pituitary damage and a more severe degree of hypopituitarism.

Adrenal incidentaloma: clinical characteristics and comparison between patients with and without extraadrenal malignancy.

UNLABELLED: Adrenal incidentaloma (AI) is frequently found in patients with a history of malignancy and, as such, is not always considered a true incidental finding. OBJECTIVE: To compare the short-term clinical and biochemical behavior of adrenal incidentalomas between oncology and non-oncology patients. DESIGN: Retrospective comparative case series of 100 consecutive patients with adrenal incidentaloma, followed from 1995 to 2005 in the endocrinology clinic of a tertiary university medical center. MAIN OUTCOME: A history of malignancy was present in 32 patients. Median follow-up was 24 months. Mean tumor size was 24+/-10 mm. Endocrine evaluation yielded functional abnormalities in 12.2% (subclinical Cushing's 7.4%, Cushing's syndrome 1.1%, hyperaldosteronism 1.3%, pheochromocytoma 3.6%). During follow-up, adrenal function remained unchanged in all patients, but tumor growth was seen in 12.5%. Compared to the non-oncology patients, the oncology group had a higher mean age (67.5+/-9.6 vs 59.4+/-1.3 yr, p=0.001) and greater tumor growth (23.3% vs 7%, p=0.035), with no significant differences for tumor size, functional abnormalities, and extent of change in tumor size. Surgery was performed in 9 patients (3 oncologic) and revealed metastasis in one. None of the other patients had clinical or radiological findings suggesting adrenal malignancy. CONCLUSION: Our study suggests a similar clinical behavior of adrenal incidentaloma in oncology and non-oncology patients. More studies are needed to assist clinicians in selecting oncology patients with AI for whom a more conservative approach can be recommended.

Subacute thyroiditis: clinical characteristics and treatment outcome in fifty-six consecutive patients diagnosed between 1999 and 2005.

OBJECTIVE: To identify predictive factors of clinical outcome of subacute thyroiditis. DESIGN: Retrospective case series of 56 consecutive patients treated in 3 outpatient clinics between 1999 and 2005. Medical records were reviewed for demographic data, seasonal disease distribution, laboratory and clinical course, treatment, and short-term outcome. MAIN OUTCOME: Mean age was 48.6+/-12 yr; 70% were females. Twenty-five percent had antithyroid antibodies and 9% had recurrent disease. Differences in occurrence by season were not significant (p=0.28). Ultrasound, performed in 35 patients, revealed thyroid nodules in 25 (median size, 17 mm). Ten patients received no treatment, and 43 received either non-steroidal anti-inflammatory drugs (NSAID) (no.=25) or glucocorticoids (no.=18); data for 3 patients were missing. Median disease duration was 77 days; mean peak free T4 (FT4) level was 43.7+/-25.3 pmol/l. A hypothyroid phase was documented in 31 patients, and remained permanent in 6. Peak FT4 level, but not erythrocyte sedimentation rate or clinical score, was positively correlated with the highest TSH level and with disease duration. Untreated patients had less severe clinical disease than treated patients, but a similar outcome. Patients given glucocorticoids had a shorter overall disease duration (p=0.03), with no differences in duration of hyperthyroidism, peak FT4 or highest TSH levels, compared with patients given NSAID. CONCLUSION: Subacute thyroiditis follows an unpredictable clinical course that is hardly affected by its clinical features or treatment.

Treatment of clinically nonfunctioning pituitary adenomas with dopamine agonists.

OBJECTIVE: Clinically nonfunctioning pituitary adenoma (NFPA) remains the only pituitary tumor subtype for which no effective medical therapy is available or recommended. We evaluated dopamine agonist (DA) therapy for preventing growth of postsurgical pituitary tumor remnants. DESIGN: The study design included historical cohort analysis of clinical results at two pituitary referral centers with different standard practices for postoperative NFPA management: DA therapy or conservative follow-up. METHODS: Seventy-nine patients followed for 8.8±6.5 years were treated with DA, initiated upon residual tumor detection on postoperative MRI (preventive treatment (PT) group, n=55), or when tumor growth was subsequently detected during follow-up (remedial treatment (RT) group, n=24). The control group (n=60) received no medication. Tumoral dopamine and estrogen receptor expression assessed by quantitative RT-PCR and immunostaining were correlated with response to treatment. RESULTS: Tumor mass decreased, remained stable, or enlarged, respectively, in 38, 49, and 13% of patients in the PT group, and in 0, 53, and 47% of control subjects; shrinkage or stabilization was achieved in 58% of enlarging tumors in the RT group, P < 0.0001.Fifteen-year progression-free survival rate was 0.805, 0.24, and 0.04, respectively, for PT, RT, and control groups (P<0.001). About 42% of patients in the control group required additional surgery or radiotherapy, compared with 38 and 13% subjects in the RT and PT groups, respectively (P=0.002). Outcome measures were not related to NFPA D2R abundance. CONCLUSIONS: Dopamine agonist therapy in patients with NFPA is associated with decreased prevalence of residual tumor enlargement after transsphenoidal surgical resection.

Human fetal pituitary expresses functional growth hormone-releasing peptide receptors.

The synthetic hexapeptide GH-releasing peptide (GHRP) stimulates a dose-dependent release of GH in humans in vivo and in animals both in vitro and in vivo via a specific receptor in the hypothalamus and pituitary. To determine the action of GHRP in the human fetal pituitary, reverse transcription-PCR was performed, and GHRP receptor messenger ribonucleic acid expression was detected in fetal pituitaries of 18- and 31-week gestation. Therefore, primary human fetal pituitary cultures (second and third trimesters) were treated with GHRP-6. GHRP-6 dose-dependently increased GH secretion from human fetal pituitary cultures by up to 80% (P < 0.001; maximal effect achieved with 100 nmol/L), whereas GHRH (10 nmol/L) stimulated GH by up to 120% (P < 0.001). However, GHRP together with GHRH was additive (up to 2.8-fold GH induction) with no evidence of further positive synergy. In contrast to GHRH, GHRP-6 did not alter human ACTH and PRL levels. A treatment time of 2 h was required for maximal GH stimulation. GHRP-6 reversed suppressed GH levels in cultures cotreated with either insulin-like growth factor I (P < 0.0001) or somatostatin (P < 0.05). GHRP-6 and GHRP-2 (100 nmol/L) had similar effects in stimulating human GH release. These results show a direct in vitro action of GHRP on human pituitary cells. GHRP is less potent than GHRH in directly releasing GH from human somatotrophs, and only additive effects of these two peptides occur at the level of the human fetal pituitary.

Prolactin (PRL)-releasing peptide stimulates PRL secretion from human fetal pituitary cultures and growth hormone release from cultured pituitary adenomas.

The hypothalamic peptide PRL-releasing peptide (PrRP) has recently been cloned and identified as a ligand of an orphan pituitary receptor that stimulates in vitro PRL secretion. PrRP also induces PRL release in rats in vivo, especially in normal cycling females. However, no information on the effects of PrRP in the human is available. To elucidate the role of PrRP in regulating human anterior pituitary hormones, we used human PrRP-31 in primary cultures of human pituitary tissues, including fetal (20--27 weeks gestation) and normal adult pituitaries, as well as PRL- and GH-secreting adenomas. PrRP increased PRL secretion from human fetal pituitary cultures in a dose-dependent manner by up to 35% (maximal effect achieved with 10 nM), whereas TRH was slightly more potent for PRL release. Coincubation with estradiol resulted in enhanced fetal PRL response to PrRP, and GH release was only increased in the presence of estradiol. Although PRL secretion from PRL-cell adenomas was not affected by PrRP, PrRP induced PRL release from cultures of a GH-cell adenoma that cosecreted PRL. PrRP enhanced GH release in several GH-secreting adenomas studied by 25--27%, including GH stimulation in a mixed PRL-GH-cell tumor. These results show for the first time direct in vitro effects of PrRP-31 on human pituitary cells. PrRP is less potent than TRH in releasing PRL from human fetal lactotrophs and is unable to release PRL from PRL-cell adenomas in culture, but stimulated GH from several somatotroph adenomas. Thus, PrRP may participate in regulating GH, in addition to PRL, in the human pituitary.

Intact leptin receptor is selectively expressed in human fetal pituitary and pituitary adenomas and signals human fetal pituitary growth hormone secretion.

Leptin, a circulating hormone secreted by adipocytes, communicates peripheral nutritional status to hypothalamic centers affecting satiety, energy expenditure, and body weight. The intact leptin receptor (OB-R), a single membrane-spanning peptide containing an approximately 300-amino acid intracellular domain, is highly expressed in the hypothalamus, whereas shorter OB-R isoforms with truncated cytoplasmic regions resulting from alternative splicing have also been identified. We studied expression of OB-R isoforms in human fetal pituitaries, adult anterior pituitaries, and human pituitary adenomas. Using RT-PCR, messenger ribonucleic acid expression of the OB-R intact isoform was detected in fetal anterior pituitary tissues, but not in adult anterior pituitary glands, whereas both fetal and adult tissues expressed the short forms. Messenger ribonucleic acid of both intact and short OB-R isoforms were expressed in 4 of 5 GH-secreting, all 9 PRL-secreting, and 26 of 29 nonfunctioning pituitary adenomas. Recombinant human leptin (3-6 nmol/L) specifically stimulated GH secretion from primary human fetal pituitary cultures by 40-90% (P < 0.05) without altering fetal ACTH, PRL, or gonadotropin secretion. Thus, the intact OB-R is selectively expressed in human fetal and adult pituitary tumor tissues, but not in normal adult pituitary. Leptin specifically stimulates GH release from normal fetal somatotrophs, substantiating the functionality of its intact receptor in the fetal pituitary. Thus, pituitary adenomas appear to revert to a fetal phenotype of leptin receptor expression.