[The Tips of the Endocrine Assessment in the Case of Pituitary Tumor].

Pituitary tumors can cause an excess or deficiency of anterior pituitary hormones. Functional pituitary neuroendocrine tumors(PitNETs)include growth hormone(GH)-producing tumors, adrenocorticotropic hormone(ACTH)-producing tumors, thyroid-stimulating hormone(TSH)-producing tumors, and prolactin(PRL)-producing tumors. Comprehensive preoperative endocrine evaluation is essential for appropriate therapeutic decision-making and safe surgery. Here, we focus on the diagnosis and evaluation of PitNETs using endocrine function tests and intravascular catheterization for inferior petrosal sinus sampling for pituitary tumors.

Association between Urinary Creatinine Excretion and Hypothyroidism in Patients with Chronic Kidney Disease.

While hypothyroidism increases serum creatinine (Cr) levels, it is uncertain whether the elevation is mediated via a decline in the glomerular filtration rate (GFR) or the reflection of enhanced Cr production from the muscles or both. In the present study, we explored an association between urinary Cr excretion rate (CER) and hypothyroidism. A total of 553 patients with chronic kidney disease were enrolled in a cross-sectional study. Multiple linear regression analysis was performed to explore the association between hypothyroidism and urinary CER. The mean urinary CER was 1.01 ± 0.38 g/day and 121 patients (22%) had hypothyroidism. The multiple linear regression analysis revealed explanatory variables with urinary CER, including age, sex, body mass index, 24 h Cr clearance (24hrCcr), and albumin while hypothyroidism was not considered an independent explanatory variable. In addition, scatter plot analysis with regression fit line representing the association between estimated GFR calculated using s-Cr (eGFRcre) and 24hrCcr revealed that eGFRcre and 24hrCcr had strong correlations with each other in hypothyroid patients as well as euthyroid patients. Collectively, hypothyroidism was not considered an independent explanatory variable for urinary CER in the present study and eGFRcre is a useful marker to evaluate kidney function regardless of the presence of hypothyroidism.

Masked CKD in hyperthyroidism and reversible CKD status in hypothyroidism.

Introduction: While it is well known that thyroid function may affect kidney function, the transition of the chronic kidney disease (CKD) status before and after treatment for thyroid disorders, as well as the factors affecting this change, remains to be explored. In the present study, we focused on the change in kidney function and their affecting factors during the treatment for both hyperthyroidism and hypothyroidism. Methods: Eighty-eight patients with hyperthyroidism and fifty-two patients with hypothyroidism were enrolled in a retrospective and longitudinal case series to analyze the changes in kidney function and their affecting factors after treatment for thyroid disorders. Results: Along with the improvement of thyroid function after treatment, there was a significant decrease in estimated glomerular filtration rate (eGFR) in hyperthyroidism (an average ΔeGFR of -41.1 mL/min/1.73 m2) and an increase in eGFR in hypothyroidism (an average ΔeGFR of 7.1 mL/min/1.73 m2). The multiple linear regression analysis revealed that sex, eGFR, free thyroxine (FT4) and free triiodothyronine (FT3) could be considered independent explanatory variables for ΔeGFR in hyperthyroidism, while age, eGFR, and FT3 were detected as independent explanatory variables in hypothyroidism. In addition, the stratification by kidney function at two points, pre- and post-treatment for thyroid disorders, revealed that 4.5% of the participants with hyperthyroidism were pre-defined as non-CKD and post-defined as CKD, indicating the presence of "masked" CKD in hyperthyroidism. On the other hand, 13.5% of the participants with hypothyroidism presented pre-defined CKD and post-defined non-CKD, indicating the presence of "reversible" CKD status in hypothyroidism. Conclusions: We uncovered the population of masked CKD in hyperthyroidism and reversible CKD status in hypothyroidism, thereby re-emphasizing the importance of a follow-up to examine kidney function after treatment for hyperthyroidism and the routine evaluation of thyroid function in CKD patients as well as the appropriate hormone therapy if the patient has hypothyroidism.

The association between hypothyroidism and proteinuria in patients with chronic kidney disease: a cross-sectional study.

Hypothyroidism is known to be correlated with kidney function and nephrotic range proteinuria. However, it is uncertain whether non-nephrotic proteinuria is associated with hypothyroidism. This study aimed to evaluate the association of proteinuria and hypothyroidism in chronic kidney disease (CKD) patients. We conducted a cross-sectional study composed of 421 CKD patients in a single hospital with measurements of 24-h urine protein excretion (UP) and thyroid function tests. Spearman correlation analysis revealed that 24-h Cr clearance (24hrCcr) was positively (r = 0.273, p < 0.001) and UP was negatively (r = - 0.207, p < 0.001) correlated with free triiodothyronine. Frequency distribution analysis stratified by CKD stage and UP for hypothyroidism revealed that the prevalence of hypothyroidism was higher among participants with higher CKD stage and nephrotic range proteinuria. Multivariate logistic regression analysis revealed that 24hrCcr and UP were significantly correlated with hypothyroidism (24hrCcr/10 mL/min decrease: odds ratio [OR], 1.29; 95% confidence interval [CI], 1.18-1.41; UP/1 g increase: OR, 1.10; 95% CI, 1.03-1.17). In addition, nephrotic range proteinuria, but not moderate UP (UP: 1.5-3.49 g/day), was significantly correlated with hypothyroidism compared to UP < 0.5 g/day. In summary, decreased kidney function and nephrotic range proteinuria, not non-nephrotic proteinuria, are independently associated with the hypothyroidism.

Effects of Wnt-ß-Catenin Signaling and Sclerostin on the Phenotypes of Rat Pheochromocytoma PC12 Cells.

Pheochromocytomas and paragangliomas (PPGLs) are classified into 3 major categories with distinct driver genes: pseudohypoxia, kinase signaling, and Wnt-altered subtypes. PPGLs in the Wnt-altered subtype are sporadic and tend to be aggressive with metastasis, where somatic gene fusions affecting mastermind-like 3 (MAML3) and somatic mutations in cold shock domain containing E1 (CSDE1) cause overactivation of Wnt-ß-catenin signaling. However, the relation between Wnt-ß-catenin signaling and the biological behavior of PPGLs remains unexplored. In rat pheochromocytoma PC12 cells, Wnt3a treatment enhanced cell proliferation and suppressed mRNA expression of tyrosine hydroxylase (TH), the rate-limiting enzyme of catecholamine biosynthesis, and dopamine secretion. We identified the expression of sclerostin in PC12 cells, which is known as an osteocyte-derived negative regulator for Wnt signaling-driven bone formation. Inhibition of endogenous Wnt pathway by XAV939 or sclerostin resulted in attenuated cell proliferation and increased TH expression. Furthermore, Wnt3a pretreatment suppressed bone morphogenetic protein (BMP)-induced Smad1/5/9 phosphorylation whereas BMPs enhanced sclerostin expression in PC12 cells. In the Wnt-altered subtype, the increased Wnt-ß-catenin pathway may contribute the aggressive clinical behavior with reduced catecholamine production. Furthermore, upregulated expression of sclerostin by BMPs may explain the osteolytic metastatic lesions observed in metastatic PPGLs.

Clinical Challenges in Diagnosis, Tumor Localization and Treatment of Tumor-Induced Osteomalacia: Outcome of a Retrospective Surveillance.

Tumor-induced osteomalacia (TIO) is an acquired fibroblast growth factor 23 (FGF23)-related hypophosphatemic osteomalacia caused by phosphaturic mesenchymal tumors (PMTs) developed in the bone or soft tissue. Diagnostic delay should be addressed, and ideal techniques to localize PMTs and efficient treatment options should be explored to improve the outcomes of this rare disease. To clarify the detailed clinical course and outcomes of TIO patients, retrospective questionnaire surveys were conducted among physicians from the Japanese Society for Bone and Mineral Research (JSBMR) and the Japan Endocrine Society (JES). The primary survey collected the number of TIO patients between January 2007 and December 2018. The secondary survey aimed to obtain the detailed characteristics, laboratory data, and outcomes. Eighty-eight patients (52 males, mean: 52 years old) were included, and 24 patients were clinically diagnosed with TIO without localized PMTs. The median duration from the onset to detection of high FGF23 levels was 3.4 years, with 77 patients being initially misdiagnosed. Among the methods used to detect small, localized PMTs (≤10 mm), fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography and somatostatin receptor scintigraphy were less sensitive than somatostatin receptor positron emission tomography/computed tomography (SRPET/CT). Systemic venous sampling (SVS) of FGF23 was performed in 53 patients; among them, SVS was considered useful for detecting localized PMTs in 45 patients with diverse tumor sizes. Finally, 45 patients achieved biochemical remission by surgery, 39 patients continued pharmaceutical treatment, including burosumab (11 patients), and four patients died. These results encouraged us to further increase the awareness of TIO and to improve the accessibility of SRPET/CT and SVS. Further evidence about the efficacy of new pharmaceutical treatments is awaited. © 2022 American Society for Bone and Mineral Research (ASBMR).

Pembrolizumab-induced hypothyroidism caused reversible increased serum creatinine levels: a case report.

BACKGROUND: The advent of immune checkpoint inhibitors (ICIs) has significantly improved the prognosis of patients with advanced malignancies. On the other hand, these drugs might cause immune-related adverse events (irAEs) including endocrinopathies and nephropathies. Thyroid dysfunction is one of the most common irAEs. For ICIs-induced nephropathies, most cases are due to tubulointerstitial nephritis, which might require steroid treatment. Here, we report a patient with non-small cell lung cancer treated with ICI who developed increased serum creatinine (s-Cr) levels due to ICIs-induced hypothyroidism. CASE PRESENTATION: A 57-year-old Asian man with refractory non-small cell lung cancer under ICIs therapy (pembrolizumab, an anti-programmed cell death-1 monoclonal antibody) developed increased s-Cr levels 5 months after the pembrolizumab initiation. His laboratory data, renal biopsy, and Gallium-67 scintigraphy findings denied pembrolizumab-induced tubulointerstitial nephritis. His renal function was correlated with thyroid function. Despite the increase of s-Cr levels, serum cystatin C levels were normal, which could be explained by the hypothyroidism. Levothyroxine treatment improved renal function as well as thyroid function. Then pembrolizumab was resumed, and both his thyroid and renal function remained normal level. Ultimately, we concluded that the increased s-Cr levels were caused by pembrolizumab-induced hypothyroidism. CONCLUSION: All clinicians involved in ICI treatment need to recognize the possible increase in s-Cr levels caused by ICIs-induced hypothyroidism, and we propose monitoring serum cystatin C levels to differentiate ICIs-induced hypothyroidism from tubulointerstitial nephritis before invasive renal biopsies or steroid treatment, which are recommended by the prescribing information for pembrolizumab, are performed.

Orexin A modulates prolactin production by regulating BMP-4 activity in rat pituitary lactotorope cells.

The impact of orexins on anterior pituitary function has yet to be clarified. We studied the effects of orexin A and its interaction with the bone morphogenetic protein (BMP) system on the regulatory role of prolactin synthesis using rat lactotrope GH3 cells expressing BMP-4. Orexin type 1 receptor (OX1R), but not type 2 receptor (OX2R), was predominantly expressed in GH3 cells. Orexin A suppressed forskolin-induced, but not basal, prolactin mRNA expression without reducing cAMP levels. Of note, orexin A suppressed BMP-4-induced prolactin mRNA and cAMP synthesis. Impairment of the effects of orexin by chemical inhibitors suggested involvement of the P38 pathway in the OX1R activity that suppresses BMP-4-induced PRL expression. Given that inhibition of BMP-receptor signaling reduced prolactin mRNA levels, endogenous BMP action is likely to be linked to the activation of prolactin synthesis by GH3 cells. Orexin A was revealed to suppress Smad1/5/9 phosphorylation and Id-1 transcription induced by BMP-4, which was restored in the presence of orexin-receptor antagonists, suggesting that the inhibitory effect of orexin A occurred via OX1R. Orexin A also reduced ALK-3 expression but increased inhibitory Smad6/7 expression, while BMP-4 treatment downregulated OX1R expression. These results indicated that orexin A plays an inhibitory role in prolactin production through suppression of endogenous BMP activity in GH3 cells, suggesting that a new functional role of the interaction between orexin and BMP-4 is modulation of prolactin levels in lactotrope cells.

Delayed postoperative hyponatremia after endoscopic transsphenoidal surgery for pituitary adenoma.

BACKGROUND: Hyponatremia generally occurs after transsphenoidal surgery (TSS) in a delayed fashion. Most patients with delayed postoperative hyponatremia (DPH) are asymptomatic or only express non-specific symptoms; consequently, DPH is associated with prolonged hospitalization. No consensus has been reached on which patients are at greatest risk of developing DPH. We reviewed patients with DPH and evaluated predictive factors for DPH. METHODS: We retrospectively analyzed 107 consecutive patients who underwent endoscopic TSS for pituitary adenoma (January 2010-December 2016). Patients with DPH (hyponatremia group) and without DPH (normonatremia group) were compared according to their nadir sodium levels on postoperative days 3 to 10. We documented the patients' demographics, clinical features, and postoperative physiological characteristics. RESULTS: Twenty-five (23.4%) patients developed DPH after endoscopic TSS. The patients' mean age was 54 ± 17 years, and 63.6% of the patients were female. The overall prevalence of DPH was 23.4%. The non-parametric χ2 test and the Mann-Whitney U test revealed statistically significant differences in age, use of antihypertensive drugs, nonfunctioning pituitary adenoma, and higher yet normal preoperative thyroid-stimulating hormone level between the hyponatremia and normonatremia groups (P < 0.05). Logistic regression analysis revealed that only older age was a useful independent predictive factor for DPH (odds ratio, 1.05; 95% confidence interval, 1.01-1.08; P = 0.01). The serum sodium levels on postoperative day 2 were significantly lower in the hyponatremia than normonatremia group (P < 0.01) and were negatively correlated with age (r = - 0.25, P < 0.05). The cut-off age for predicting DPH was 55 years. The hospital stay was significantly longer in the hyponatremia than normonatremia group (P < 0.01). CONCLUSIONS: Age of more than 55 years was an independent predictive factor for DPH even after adjusting for potential confounders. Older age was negatively correlated with the serum sodium level on postoperative day 2. Preventing early decreases in the sodium level could reduce the risk of DPH. TRIAL REGISTRATION: 1707-027.

Runx3 regulates folliculogenesis and steroidogenesis in granulosa cells of immature mice.

We previously demonstrated that female Runx3 knockout (Runx3-/-) mice were anovulatory and their uteri were atrophic and that Runx3 mRNA was expressed in granulosa cells. To clarify how Runx3 regulates folliculogenesis and ovulation, we examine the effects of Runx3 knockout on the gene expression of growth factors associated with folliculogenesis and enzymes associated with steroidogenesis. In Runx3-/- mouse ovaries, the numbers of primary and antral follicles were lower than those in wild-type (wt) mice at 3 weeks of age, indicating that the loss of Runx3 affects folliculogenesis. The expression of genes encoding activin and inhibin subunits (Inha, Inhba and Inhbb) was also decreased in ovaries from the Runx3-/- mice compared with that in wt mice. Moreover, the expression of the genes Cyp11a1 and Cyp19a1 encoding steroidogenic enzymes was also decreased. In cultured granulosa cells from 3-week-old mouse ovaries, Cyp19a1 mRNA levels were lower in Runx3-/- mice than those in wt mice. Follicle-stimulating hormone (FSH) treatment increased Cyp19a1 mRNA levels in both wt and Runx3-/- granulosa cells in culture but the mRNA level in Runx3-/- granulosa cells was lower than that in wt ones, indicating that granulosa cells could not fully function in the absence of Runx3. At 3 weeks of age, gonadotropin α subunit, FSHß subunit and luteinizing hormone (LH) ß subunit mRNA levels were decreased in Runx3-/- mice. These findings suggest that Runx3 plays a key role in female reproduction by regulating folliculogenesis and steroidogenesis in granulosa cells.

Incretins modulate progesterone biosynthesis by regulating bone morphogenetic protein activity in rat granulosa cells.

The effects of incretins on ovarian steroidogenesis have not been clarified. In this study, we investigated the effects of incretins, including GIP and GLP-1, on ovarian steroidogenesis using rat primary granulosa cells. Treatment with incretins significantly suppressed progesterone synthesis in the presence of FSH, and the effect of GIP was more potent than that of GLP-1. In contrast, incretins had no significant effect on estrogen synthesis by rat granulosa cells. In accordance with the effects of incretins on steroidogenesis, GIP and GLP-1 suppressed the expression of progesterogenic factors and enzymes, including StAR, P450scc, 3ßHSD, but not P450arom, and cellular cAMP synthesis induced by FSH. In addition, incretins moderately increased FSHR mRNA expression in granulosa cells. Of note, treatment with GIP, but not treatment with GLP-1, augmented Smad1/5/8 phosphorylation and transcription of the BMP target gene Id-1 induced by BMP-6 stimulation, suggesting that GIP upregulates BMP receptor signaling that can inhibit FSH-induced progesterone synthesis in rat granulosa cells. On the other hand, BMP-6 treatment suppressed the expression of GIP receptor but not that of GLP-1 receptor. Expression of the BMP type-I receptor ALK-3 was upregulated by treatment with GIP and GLP-1 and that of ALK-6 was also increased by GIP, while inhibitory Smad6 expression was impaired by GIP and GLP-1 in rat granulosa cells. Collectively, the results indicate that incretins, particularly GIP, impair FSH-induced progesterone production, at least in part, by upregulating BMP signaling in rat granulosa cells. The modulatory effects of incretins on endogenous BMP activity may be applicable to treatment of dysregulated steroidogenesis such as polycystic ovary syndrome.

Regulatory role of melatonin and BMP-4 in prolactin production by rat pituitary lactotrope GH3 cells.

The effects of melatonin on prolactin production and its regulatory mechanism remain uncertain. We investigated the regulatory role of melatonin in prolactin production using rat pituitary lactotrope GH3 cells by focusing on the bone morphogenetic protein (BMP) system. Melatonin receptor activation, induced by melatonin and its receptor agonist ramelteon, significantly suppressed basal and forskolin-induced prolactin secretion and prolactin mRNA expression in GH3 cells. The melatonin MT2 receptor was predominantly expressed in GH3 cells, and the inhibitory effects of melatonin on prolactin production were reversed by treatment with the receptor antagonist luzindole, suggesting functional involvement of MT2 action in the suppression of prolactin release. Melatonin receptor activation also suppressed BMP-4-induced prolactin expression by inhibiting phosphorylation of Smad and transcription of the BMP-target gene Id-1, while BMP-4 treatment upregulated MT2 expression. Melatonin receptor activation suppressed basal, BMP-4-induced and forskolin-induced cAMP synthesis; however, BtcAMP-induced prolactin mRNA expression was not affected by melatonin or ramelteon, suggesting that MT2 activation leads to inhibition of prolactin production through the suppression of Smad signaling and cAMP synthesis. Experiments using intracellular signal inhibitors revealed that the ERK pathway is, at least in part, involved in prolactin induction by GH3 cells. Thus, a new regulatory role of melatonin involving BMP-4 in prolactin secretion was uncovered in lactotrope GH3 cells.

Pneumocystis Pneumonia Concomitant with Ectopic ACTH Syndrome Caused by a Large Cell Neuroendocrine Carcinoma of the Thymus.

We herein report the case of a 44-year-old man who was diagnosed with pneumocystis pneumonia (PCP) concomitant with ectopic adrenocorticotropic hormone (ACTH) syndrome, which had been caused by a large cell neuroendocrine carcinoma of the thymus. Chest computed tomography revealed ground-glass opacities in the lungs. PCP was diagnosed by a polymerase chain reaction with bronchoalveolar lavage. The levels of cortisol were slowly corrected with an adrenal enzyme inhibitor, and the exacerbation of PCP was successfully avoided. Our case indicates that in addition to prophylaxis, the early diagnosis of PCP and the slow correction of hypercortisolemia should be considered in order to prevent an exacerbation due to the reconstitution of the immune function in patients with ectopic ACTH syndrome.

Combined Effects of Androgen and Growth Hormone on Osteoblast Marker Expression in Mouse C2C12 and MC3T3-E1 Cells Induced by Bone Morphogenetic Protein.

Osteoblasts undergo differentiation in response to various factors, including growth factors and steroids. Bone mass is diminished in androgen- and/or growth hormone (GH)-deficient patients. However the functional relationship between androgen and GH, and their combined effects on bone metabolism, remains unclear. Here we investigated the mutual effects of androgen and GH on osteoblastic marker expression using mouse myoblastic C2C12 and osteoblast-like MC3T3-E1 cells. Combined treatment with dihydrotestosterone (DHT) and GH enhanced BMP-2-induced expression of Runx2, ALP, and osteocalcin mRNA, compared with the individual treatments in C2C12 cells. Co-treatment with DHT and GH activated Smad1/5/8 phosphorylation, Id-1 transcription, and ALP activity induced by BMP-2 in C2C12 cells but not in MC3T3-E1 cells. The insulin-like growth factor (IGF-I) mRNA level was amplified by GH and BMP-2 treatment and was restored by co-treatment with DHT in C2C12 cells. The mRNA level of the IGF-I receptor was not significantly altered by GH or DHT, while it was increased by IGF-I. In addition, IGF-I treatment increased collagen-1 mRNA expression, whereas blockage of endogenous IGF-I activity using an anti-IGF-I antibody failed to suppress the effect of GH and DHT on BMP-2-induced Runx2 expression in C2C12 cells, suggesting that endogenous IGF-I was not substantially involved in the underlying GH actions. On the other hand, androgen receptor and GH receptor mRNA expression was suppressed by BMP-2 in both cell lines, implying the existence of a feedback action. Collectively the results showed that the combined effects of androgen and GH facilitated BMP-2-induced osteoblast differentiation at an early stage by upregulating BMP receptor signaling.

Melatonin regulates catecholamine biosynthesis by modulating bone morphogenetic protein and glucocorticoid actions.

Melatonin is functionally involved in the control of circadian rhythm and hormonal secretion. In the present study, we investigated the roles of melatonin in the interaction of catecholamine synthesis with adrenocortical steroids by focusing on bone morphogenetic protein (BMP)-4 expressed in the adrenal medulla using rat pheochromocytoma PC12 cells. Melatonin treatment significantly reduced the mRNA expression of catecholamine synthases, including the rate-limiting enzyme tyrosine hydroxylase (Th), 3,4-dihydroxyphenylalanine decarboxylase and dopamine-ß-hydroxylase expressed in PC12 cells. In accordance with changes in the expression levels of enzymes, dopamine production and cAMP synthesis determined in the culture medium and cell lysate were also suppressed by melatonin. The MT1 receptor, but not the MT2 receptor, was expressed in PC12 cells, and luzindole treatment reversed the inhibitory effect of melatonin on Th expression, suggesting that MT1 is a functional receptor for the control of catecholamine synthesis. Interestingly, melatonin enhanced the inhibitory effect of BMP-4 on Th mRNA expression in PC12 cells. Melatonin treatment accelerated BMP-4-induced phosphorylation of SMAD1/5/8 and transcription of the BMP target gene Id1. Of note, melatonin significantly upregulated Alk2 and Bmpr2 mRNA levels but suppressed inhibitory Smad6/7 expression, leading to the enhancement of SMAD1/5/8 signaling in PC12 cells, while BMP-4 did not affect Mt1 expression. Regarding the interaction with adrenocortical steroids, melatonin preferentially enhanced glucocorticoid-induced Th mRNA through upregulation of the glucocorticoid receptor and downregulation of Bmp4 expression, whereas melatonin repressed Th mRNA expression induced by aldosterone or androgen without affecting expression levels of the receptors for mineralocorticoid and androgen. Collectively, the results indicate that melatonin plays a modulatory role in catecholamine synthesis by cooperating with BMP-4 and glucocorticoid in the adrenal medulla.

[A Case of an Adrenocorticotropic Hormone-Producing Pituitary Adenoma Removed via Electromagnetic-Guided Neuroendoscopy].

The use of navigation systems is safe and reliable for neurological surgery. We performed endoscopic transsphenoidal surgery to totally resect an adrenocorticotropic hormone (ACTH)-producing pituitary adenoma associated with oculomotor nerve palsy. A 70-year-old woman developed right ptosis 4 months before admission. She developed anisocoria 2 months later and was referred to the department of neurology from clinic. Brain magnetic resonance imaging(MRI)showed an intrasellar tumor that partially invaded the right cavernous sinus, and she was then referred to our department. She exhibited a round face ("moon face") and central obesity. Laboratory test results showed a high urinary cortisol level and high serum ACTH level, and neither the serum cortisol nor ACTH level was suppressed by a low-dose dexamethasone test. We performed transsphenoidal surgery using high-dimensional endoscopy under electromagnetic navigation. The tumor invading the cavernous sinus was visualized via endoscopy and confirmed on navigation using a flexible needle probe. Postoperative MRI showed total removal of the tumor, and the serum ACTH level recovered to the normal range. The patient's right oculomotor palsy resolved within 1 week postoperatively. In summary, electromagnetic navigation was useful for total resection of a pituitary tumor invading the cavernous sinus, contributing to normalization of the ACTH level and improvement in neurological symptoms.

BMP-6 modulates somatostatin effects on luteinizing hormone production by gonadrotrope cells.

The effects of somatostatin analogs and roles of BMP-6 in the regulation of luteinizing hormone (LH) secretion were investigated using mouse gonadotrope LßT2 cells. LH mRNA expression and LH secretion induced by GnRH were suppressed by treatments with somatostatin analogs, including octreotide and pasireotide, in LßT2 cells. Of note, the inhibitory effects of somatostatin analogs on LH secretion were enhanced by the action of BMP-6. BMP-6 increased the expression levels of somatostatin receptor (SSTR)5, suggesting that BMP-6 upregulates SSTR activity that leads to reduction of GnRH-induced LH secretion. In addition, GnRH-induced phosphorylation of MAPKs including ERK, but not P38 or SAPK, was suppressed by pasireotide in the presence of BMP-6. Given that each inhibitor of ERK, JNK or P38 signaling suppressed GnRH-induced LH transcription, MAPKs are individually involved in the induction of LH production by LßT2 cells. Somatostatin analogs also impaired BMP-6-induced Smad1/5/8 phosphorylation by suppressing BMPRs and augmenting Smad6/7 expression. Collectively, the results indicate that somatostatin analogs have dual effects on the modulation of GnRH-induced MAPK signaling and BMP activity. The pituitary BMP system may play a regulatory role in GnRH-induced LH secretion by tuning the responsiveness to somatostatin analogs in gonadotrope cells.