Medical management of prolactin-secreting pituitary adenomas

SFRP2 is a Novel Diagnostic Biomarker and Suppresses the Proliferation of Pituitary Adenoma

Pituitary adenoma (PA) constitutes one of the most common intracranial tumors. The present study was designed to identify potential diagnostic markers for PA. We used gene expression profiles (GEO: GSE26966 and GEO: GSE63357 datasets) derived from human PA and nontumor samples that were made freely accessible by the gene expression omnibus (GEO) datasets. Differentially expressed genes (DEGs) were screened between 14 normal specimens and 34 PA specimens by the use of the limma package of the R. The diagnostic genes were determined using a LASSO regression model and SVM-RFE analysis. SFRP2 expression in PA cells was analyzed using RT-PCR, and the effect of SFRP2 dysregulation on PA cell proliferation was measured using CCK-8 analysis. In this study, 361 DEGs were identified: 309 genes were downregulated and 52 genes were upregulated. The results of KEGG assays revealed that the 361 DEGs were mainly enriched in the PI3K-Akt signaling pathway, MAPK signaling pathway, growth hormone synthesis, secretion and action, and AGE-RAGE signaling pathway in diabetic complications. Results from the LASSO regression model and the SVM-RFE analysis indicated that LOC101060391 and SFRP2 were diagnostic genes. In contrast to normal tissue, the expressions of LOC101060391 and SFRP2 were much lower in PA samples. According to the ROC assays, high LOC101060391 and SFRP2 expression had an AUC value >0.9 for PA. Upregulation of SFRP2 distinctly inhibited the proliferative capacity of PA cells, as shown by CCK-8 analysis. Furthermore, knockdown of SFRP2 had an influence on cell growth in both the AtT-20 and HP75 cell lines. Taken together, our findings indicate that LOC101060391 and SFRP2 have diagnostic potential for PA. Furthermore, SFRP2 may be an antioncogene and a therapeutic target for PA.

The KBTBD6/7-DRD2 axis regulates pituitary adenoma sensitivity to dopamine agonist treatment

Pituitary adenoma (PA) is one of the most common intracranial tumors, and approximately 40% of all PAs are prolactinomas. Dopamine agonists (DAs), such as cabergoline (CAB), have been successfully used in the treatment of prolactinomas. The expression of dopamine type 2 receptor (DRD2) determines the therapeutic effect of DAs, but the molecular mechanisms of DRD2 regulation are not fully understood. In this study, we first demonstrated that DRD2 underwent proteasome-mediated degradation. We further employed the yeast two-hybrid system and identified kelch repeat and BTB (POZ) domain containing 7 (KBTBD7), a substrate adaptor for the CUL3-RING ubiquitin (Ub) ligase complex, as a DRD2-interacting protein. KBTBD6/7 directly interacted with, and ubiquitinated DRD2 at five ubiquitination sites (K221, K226, K241, K251, and K258). CAB, a high-affinity DRD2 agonist, induced DRD2 internalization, and cytoplasmic DRD2 was degraded via ubiquitination under the control of KBTBD6/7, the activity of which attenuated CAB-mediated inhibition of the AKT/mTOR pathway. KBTBD7 knockout (KO) mice were generated using the CRISPR-Cas9 technique, in which the static level of DRD2 protein was elevated in the pituitary gland, thalamus, and heart, compared to that of WT mice. Consistently, the expression of KBTBD6/7 was negatively correlated with that of DRD2 in human pituitary tumors. Moreover, KBTBD7 was highly expressed in dopamine-resistant prolactinomas, but at low levels in dopamine-sensitive prolactinomas. Knockdown of KBTBD6/7 sensitized MMQ cells and primary pituitary tumor cells to CAB treatment. Conversely, KBTBD7 overexpression increased CAB resistance of estrogen-induced in situ rat prolactinoma model. Together, our findings have uncovered the novel mechanism of DRD2 protein degradation and shown that the KBTBD6/7-DRD2 axis regulates PA sensitivity to DA treatment. KBTBD6/7 may thus become a promising therapeutic target for pituitary tumors.

A Brazilian multicentre study evaluating pregnancies induced by cabergoline in patients harboring prolactinomas

OBJECTIVE

To evaluate the maternal-fetal outcomes of CAB-induced pregnancies in patients with prolactinoma in a large cohort.

METHODS

The prevalence of tumor growth, miscarriage, preterm, low birth weight, congenital malformations and impairment in neuropsychological development in children among women treated with CAB were assessed in a Brazilian multicentre retrospective observational study, RESULTS: We included 194 women with a mean age of 31 (17-45) years, 43.6% presenting microadenomas and 56.4% macroadenomas, at prolactinoma diagnosis. In 233 pregnancies, CAB was withdrawn in 89%, after pregnancy confirmation. Symptoms related to tumor growth occurred in 25 cases, more frequently in macroadenomas. The overall miscarriage rate was 11%, although higher in the subgroup of patients with CAB maintainance after pregnancy confirmation (38% vs. 7.5%). Amongst the live-birth deliveries, preterm occurred in 12%, low birth weight in 6% and congenital malformations in 4.3%. Neuropsychological development impairment was reported in 7% of cases.

CONCLUSIONS

Our findings confirm previous results of safety in maternal and fetal outcomes in CAB-induced pregnancies; nevertheless, CAB maintenance after pregnancy confirmation was associated with higher miscarriage rate; result that must be further confirmed.

Exosome-Transmitted lncRNA H19 Inhibits the Growth of Pituitary Adenoma

CONTEXT

Our previous study demonstrated that the expression of long noncoding RNA (lncRNA) H19 was frequently downregulated in human primary pituitary adenomas and negatively correlated with tumor progression. However, the role of exosomal lncRNA H19 in the inhibition of pituitary tumor growth remains unclear.

OBJECTIVE

To investigate whether exosomal H19 could be transported across the cell membrane to exert its inhibitory effect on pituitary tumor growth.

DESIGN

Empty lentivirus GH3 cells with or without H19 overexpression were used to establish a xenograft model. Isolated exosomes were identified by transmission electron microscopy, nanoparticle tracking, and Western blotting. The expression levels of serum exosomal H19 from 200 healthy subjects and 206 patients with various subtypes of pituitary tumors were detected by ultracentrifugation and quantitative real-time PCR.

RESULTS

The growth of distal tumor cells was inhibited by transferring exosomal H19, which could be transported through cell membrane and exert its inhibitory effect. Cabergoline increased H19 expression and played a synergic therapeutic effect with exosomal H19. Exosomal H19 inhibited phosphorylation of the mTORC1 substrate 4E-BP1. Of note, the expression level of exosomal H19 in the patients with all subtypes of pituitary tumors was significantly lower than that in the healthy subjects. The change of plasma exosomal H19 level may be correlated with the prognosis or drug response of the patients.

CONCLUSION

Exosomal H19 inhibits the growth of distal pituitary tumors through inhibiting 4E-BP1 phosphorylation. Plasma exosomal H19 may serve as an important biomarker for predicting medical responses of patients with prolactinomas.

Ubenimex induces apoptotic and autophagic cell death in rat GH3 and MMQ cells through the ROS/ERK pathway

Purpose

Ubenimex, an aminopeptidase N (APN) inhibitor, is widely known for its use as an adjunct therapy for cancer therapy. However, in recent studies, it has also conferred antitumour effects in many cancers, but its anticancer mechanism is largely unknown. This study aims to investigate the specific anticancer activities and mechanisms of ubenimex in GH3 and MMQ cells.

Materials and methods

In this study, we investigated the anticancer effects of ubenimex in GH3 and MMQ cells. Cell viability and cell death were assessed by the Cell Counting Kit-8 kit (CCK-8) and a LIVE/DEAD cell imaging kit. Apoptosis and intracellular reactive oxygen species (ROS) generation were assessed by flow cytometry and fluorescence microscopy. Autophagosome formation was detected by transmission electron microscopy, and autophagic flux was measured with mRFP-GFP-LC3 adenoviral transfection. The protein expression level was detected by Western blotting.

Results

The results revealed that treatment with ubenimex induced apoptotic and autophagic cell death in GH3 and MMQ cells, which resulted in decreased viability, an increased proportion of apoptotic cells, and autophagosome formation. Further experiments showed that ubenimex induced ROS generation and activated the ROS/ERK pathway. The ROS scavenger NAC could attenuate ubenimex-induced apoptosis and autophagy.

Conclusion

Our studies revealed that ubenimex exerted anticancer effects by inducing apoptotic and autophagic cell death in GH3 and MMQ cells, rendering it a possible effective adjunctive therapy for pituitary treatment.

DEPTOR inhibits cell proliferation and confers sensitivity to dopamine agonist in pituitary adenoma

DEP domain-containing mechanistic target of rapamycin (mTOR)-interacting protein (DEPTOR) is an important modulator of mTOR, a highly conserved kinase whose hyperactivation is critically involved in a variety of human tumors. The role of DEPTOR playing in pituitary adenoma (PA) is largely unknown. Here, we reported that DEPTOR was downregulated in PA tissues, especially dopamine-resistant prolactinomas. Consistently, overexpression of DEPTOR inhibited pituitary tumor GH3 and MMQ cells proliferation in vitro and in vivo, and sensitized GH3 and MMQ cells to cabergoline (CAB), a dopamine agonist (DA). Conversely, knockdown of DEPTOR promoted GH3 and MMQ cells proliferation, and conferred cells resistance to CAB. Mechanistically, DEPTOR inhibited both mTOR Complex 1 (mTORC1) and 2 (mTORC2) activities in PA cells. In addition, DEPTOR expression level was increased to suppress mTOR kinase activity via decreasing E3 ubiquitin ligase, βTrCP1, in response to CAB. Furthermore, DEPTOR enhanced autophagy-dependent cell death to confer cells sensitivity to CAB. Taken together, our results suggest that DEPTOR may be a potential target for the treatment of PAs.

Bromocriptine and cabergoline induce cell death in prolactinoma cells via the ERK/EGR1 and AKT/mTOR pathway respectively

The treatment of hyperprolactinemia is based on the use of dopamine agonists, mainly bromocriptine (BRC) and cabergoline (CAB). They reduce tumour size effectively and restore gonadal function. However, there is a difference in drug sensitivity between CAB and BRC in patients with prolactinoma, although the underlying mechanisms are still unknown. Thus, we investigated whether there are differences in tumour sensitivity to CAB and BRC and their possible differential mechanisms in two prolactinoma cell lines. In our study, we found that GH3 cells are more sensitive to BRC and that MMQ cells are more sensitive to CAB. Moreover, BRC and CAB elicited cell death via different pathways; BRC induced prolactinoma cell death mainly through the apoptosis pathway, and CAB induced pituitary prolactinoma cell death mainly via the autophagic cell death pathway. Using gene microarray analysis, we found that BRC induces the apoptosis of prolactinoma cells through the ERK/EGR1 signalling pathway, whereas CAB induces autophagic death by inhibiting the AKT/mTOR signalling pathway. Our study showed the difference in tumour sensitivity and differential mechanisms in BRC- and CAB-treated prolactinoma cells, which provides a theoretical basis for the accurate treatment of prolactinoma.

Medical versus surgical treatment of prolactinomas: an analysis of treatment outcomes

INTRODUCTION

Prolactinomas are unique tumors that may go into both hormonal and radiographic remission with dopamine agonist therapy or transsphenoidal surgery. Regardless of modality, the goals of therapy remain the same: (1) biochemical remission, including reduction of prolactin and normalization of sex hormones; (2) radiographic tumor control, with a range including prevention of tumor growth, tumor regression, or complete tumor resolution; (3) resolution of preoperative symptoms, including those that are hormonal or neurologic; and (4) prevention of new hypopituitarism or new neurologic symptoms.

AREAS COVERED

In the following review, we performed a search of the literature using keywords 'prolactinoma,' 'dopamine agonist,' 'surgery,' 'cost-effectiveness,' 'recurrence,' and 'complication' to compare the relative merits of medical versus surgical therapy for prolactinoma, including special circumstances such as cystic tumors, pregnant patients, and the cost-effectiveness of different strategies.

EXPERT COMMENTARY

Medical therapy can offer a cure, but surgery provides an important adjunct to patients with resistance or intolerance to dopamine agonists, and offers excellent outcomes including when combined with continued postoperative medical therapy. Further head to head comparisons will benefit patients and practitioners weighing the relative risks and benefits of medical and surgical intervention, including the issue of their relative cost-effectiveness.

Expression of Stem Cell Markers and Dopamine D2 Receptors in Human and Rat Prolactinomas

Background

Dopamine agonists (DAs) are the first-line treatment for prolactinomas. DAs primarily target the dopamine D2 receptor (D2R). Tumor stem-like cells (TSLCs) are associated with the tolerance to radiotherapy and chemotherapy. TSLCs have also been identified in pituitary adenomas. We aimed to characterize the expression pattern of stem cell markers and D2R in human and rat prolactinomas.

Material/Methods

Human prolactinoma specimens (n=14) were obtained from patients with surgical resection. The xenograft model of rat prolactinomas was generated by endermically injecting MMQ cells, HE and PRL were confirmed by immunohistochemical staining of tumor sections, and the expression of serum PRL was measured by ELISA. The expression of stem cell markers (CD133, Nestin, Oct4, and Sox2) and D2R in prolactinomas was detected by immunofluorescence. The proportion of CD133-expressing cells after DA treatment was evaluated by flow cytometry in vitro.

Results

We found that a small subpopulation of cells expressing stem cell markers existed both in human and rat prolactinomas. Furthermore, the CD133-expressing cells showed negative D2R expression. Conversely, the D2R-expressing cells showed negative CD133 expression. The proportion of CD133-expressing cells in surviving tumor cells was significantly increased after DA treatment.

Conclusions

Our results confirmed the existence of cells expressing stem cell markers in human and rat prolactinomas. Additionally, the CD133-expressing cells might resist DA therapy due to the lack of D2R expression.

MRI follow-up is unnecessary in patients with macroprolactinomas and long-term normal prolactin levels on dopamine agonist treatment

OBJECTIVE

Both antitumor and antisecretory efficacies of dopamine agonists (DA) make them the first-line treatment of macroprolactinomas. However, there is no guideline for MRI follow-up once prolactin is controlled. The aim of our study was to determine whether a regular MRI follow-up was necessary in patients with long-term normal prolactin levels under DA.

PATIENTS AND METHODS

We conducted a retrospective multicenter study (Marseille, Paris La Pitie Salpetriere and Nancy, France; Liege, Belgium) including patients with macroprolactinomas (largest diameter: >10 mm and baseline prolactin level: >100 ng/mL) treated by dopamine agonists, and regularly followed (pituitary MRI and prolactin levels) during at least 48 months once normal prolactin level was obtained.

RESULTS

In total, 115 patients were included (63 men and 52 women; mean age at diagnosis: 36.3 years). Mean baseline prolactin level was 2224 ± 6839 ng/mL. No significant increase of tumor volume was observed during the follow-up. Of the 21 patients (18%) who presented asymptomatic hemorrhagic changes of the macroprolactinoma on MRI, 2 had a tumor increase (2 and 7 mm in the largest size). Both were treated by cabergoline (1 mg/week) with normal prolactin levels obtained for 6 and 24 months. For both patients, no further growth was observed on MRI during follow-up at the same dose of cabergoline.

CONCLUSION

No significant increase of tumor size was observed in our patients with controlled prolactin levels on DA. MRI follow-up thus appears unnecessary in patients with biologically controlled macroprolactinomas.

Suppression of mTOR pathway and induction of autophagy-dependent cell death by cabergoline

Cabergoline (CAB), the first-line drug for treatment of prolactinomas, is effective in suppressing prolactin hypersecretion, reducing tumor size, and restoring gonadal function. However, mechanisms for CAB-mediated tumor shrinkage are largely unknown. Here we report a novel cytotoxic mechanism for CAB. CAB induced formation of autophagosome in rat pituitary tumor MMQ and GH3 cells at the early stage through inhibiting mTOR pathway, resulting in higher conversion rates of LC3-I to LC3-II, GFP-LC3 aggregation, and increased autophagosome formation. Interestingly, CAB treatment augmented lysosome acidification and resulted in impaired proteolytic degradation within autolysosomes. This blocked the autophagic flux, leading to the accumulation of p62 aggregation and undigested autolysosomes. Knockdown of ATG7, ATG5, or Becn1, could significantly rescue the CAB-mediated cell death of MMQ cells (p < 0.05). CAB-induced autophagy and blockade of autophagy flux participated in antitumoral action in vivo. In conclusion, our study provides evidence that CAB concomitantly induces autophagy and inhibits the autophagic flux, leading to autophagy-dependent cell death. These findings elucidate novel mechanisms for CAB action.

Dopamine agonist resistance-related endocan promotes angiogenesis and cells viability of prolactinomas

Dopamine agonists (DAs) are the first-line treatment of prolactinomas. They function through the dopamine 2 receptor (D2R) in the tumor cells. Endocan, also called endothelial cell-specific molecule-1 (ESM1), has been described as a marker of neoangiogenesis. However, whether ESM1 promotes the resistance of prolactinomas to DA therapy is largely unknown. In our study, 25 patients with prolactinomas were divided into resistant- and sensitive- groups according to the clinical response to bromocriptine. We found that ESM1-microvessel density of resistant prolactinomas was significantly higher than that of sensitive prolactinomas (47.9 ± 11.6, n = 8, vs 13.1 ± 2.8, n = 17, p = 0.0006), indicating that ESM1 was a DA resistance-related gene. Immunostaining showed that ESM1 was expressed in tumor vessels and sporadic tumor cells, and ESM1 was overlapped with the Smooth Muscle Actin (SMA) and von Willebrand Factor (VWF) in the tumor vessels. Silencing of ESM1 markedly suppressed the viability of GH3 and MMQ cells in vitro, and furthermore, significantly increased the sensitivity of GH3 and MMQ cells to DA treatment. Additionally, silencing of ESM1 down-regulated the angiogenesis-associated genes, such as VEGFR2, FGF2, CD34, CD31, VWF, and EGFR. Knockdown of ESM1 decreased endothelial tube formation of HUVECs, and significantly increased the sensitivity of HUVECs to Avastin treatment. Therefore, we first demonstrate that DA resistance-related ESM1 promotes the angiogenesis and tumor cells growth of prolactinomas, suggesting that ESM1 may be a novel therapeutic target for prolactinomas.

Prolactinoma and pregnancy: From the wish of conception to lactation

Prolactinoma is a common cause of infertility in young women and treatment with dopamine agonists (DA) allows restoration of fertility in over 90% of the cases. Both bromocriptine and cabergoline have shown a good safety profile when administered during early pregnancy. In particular, data on exposure of the fetus or embryo to cabergoline during the first weeks of pregnancy have now been reported in more than 900 cases, and do indicate that cabergoline is safe in this context. There is no increase in the frequency of spontaneous miscarriage, premature delivery, multiple births or neonatal malformations, and follow-up studies of the children for up to 12years after fetal exposure to cabergoline did not show any physical or developmental abnormalities. These women should therefore continue DA treatment until pregnancy has been initiated. Treatment discontinuation is recommended at that time in women with microprolactinoma or non-compressive macroprolactinoma. For microprolactinomas, the risk of symptomatic tumour enlargement during pregnancy is very low (2-3%). It is higher for macroprolactinomas (20-30%) and careful follow-up is advised, including MRI without contrast injection if symptoms or visual disturbances develop. If a symptomatic tumour enlargement does occur, reinitiation of the dopamine agonist (BRC or CAB) is indicated rather than surgery. Breast-feeding has no harmful effect on tumour growth and DA treatment, if still needed, may be postponed as long as breast-feeding is desired. Finally, about 40% of women with a microprolactinoma or an intermediate size macroprolactinoma may be in prolonged remission after one or more pregnancies.

Development and characterization of a novel rat model of estrogen-induced mammary cancer

The ACI rat model of 17β-estradiol (E2)-induced mammary cancer is highly relevant for use in establishing the endocrine, genetic, and environmental bases of breast cancer etiology and identifying novel agents and strategies for preventing breast cancer. E2 treatment rapidly induces mammary cancer in female ACI rats and simultaneously induces pituitary lactotroph hyperplasia and adenoma. The pituitary tumors can result in undesired morbidity, which compromises long-term studies focused on mammary cancer etiology and prevention. We have defined the genetic bases of susceptibility to E2-induced mammary cancers and pituitary tumors and have utilized the knowledge gained in these studies to develop a novel inbred rat strain, designated ACWi, that retains the high degree of susceptibility to E2-induced mammary cancer exhibited by ACI rats, but lacks the treatment-related morbidity associated with pituitary lactotroph hyperplasia/adenoma. When treated with E2, female ACWi rats developed palpable mammary cancer at a median latency of 116 days, an incidence of 100% by 161 days and exhibited an average of 15.6 mammary tumors per rat following 196 days of treatment. These parameters did not differ from those observed for contemporaneously treated ACI rats. None of the E2-treated ACWi rats were killed before the intended experimental end point due to any treatment-related morbidity other than mammary cancer burden, whereas 20% of contemporaneously treated ACI rats exhibited treatment-related morbidity that necessitated premature killing. The ACWi rat strain is well suited for use by those in the research community, focusing on breast cancer etiology and prevention.

Pituitary disorders in pregnancy

The pituitary gland is significantly affected during gestation in terms of both size and function. Due to this physiologic adaptation, endocrine evaluation and interpretation of imaging is far more complex than in the non-pregnant state. Pituitary disorders are rare in pregnancy, as they are usually associated with gonadal dysfunction, thereby posing difficulties with fertility. This review will focus on pituitary adenomas (prolactinomas, GH-secreting and ACTH-secreting), their diagnostic handicaps and the recommendations for treatment. We will also discuss the two pituitary disorders encountered in pregnancy, Sheehan's syndrome and lymphocytic hypophysitis.

Outcome of prolactinoma after pregnancy and lactation: a study on 73 patients

CONTEXT

Prolactinoma is the most frequent pituitary tumour among women of child-bearing age. Only a few studies have addressed the outcome of prolactinoma after pregnancy.

OBJECTIVE

To study remission, defined as prolactin normalization without medical treatment, after pregnancy and lactation in women with prolactinoma.

PATIENTS AND METHODS

A retrospective study conducted in 2 Belgian academic centres including 73 patients (54 microprolactinomas and 19 macroprolactinomas) with 104 pregnancies continuing beyond first trimester. Dopamine agonists were stopped in early pregnancy in all treated cases. Prolactin level and adenoma size at pituitary magnetic resonance imaging (MRI) were recorded before pregnancy and throughout follow-up.

RESULTS

Thirty of 73 women (41%) were in remission after a median follow-up of 22 months after delivery or cessation of lactation. Adenoma size at diagnosis was smaller in women in remission (5 vs 8 mm). There was a nonsignificant higher rate of remission for microprolactinomas than for macroprolactinoma (46% vs 26%). The first pituitary MRI after pregnancy and lactation showed no tumour and a decreased adenoma size in 23% and 39% of women, respectively. MRI normalization was associated with remission. The number of pregnancies per woman as well as breastfeeding and its duration did not influence remission rate.

CONCLUSION

More than 40% of women with previous diagnosis of prolactinoma have normal PRL level without medical treatment for a median follow-up of 22 months after pregnancy and lactation. The likelihood of remission is associated with a smaller initial adenoma size and normalization of pituitary MRI after pregnancy.

Dopamine receptor D2S gene transfer improves the sensitivity of GH3 rat pituitary adenoma cells to bromocriptine

Bromocriptine, a dopamine agonist (DA), has been used in the treatment of prolactinomas. Recent studies have indicated that dopamine 2 receptor short isoform (D2S) may play an important role in suppressing PRL synthesis and prolactinoma cell growth under DA treatment. In the current study, we investigated the role of D2S in the therapeutic action of bromocriptine in GH3 using both in vitro and in vivo approaches. Infection of adenovirus-D2S increased D2S expression in GH3 cells (P<0.05). D2S expression significantly decreased the GH3 cell viability subjected to bromocriptine treatment in vitro (P<0.05). In nude mice, adenovirus-D2S transfection sensitized GH3 xenograft to bromocriptine treatment evidenced by the significant inhibition of D2S expressed tumor growth as compared with vector control. Furthermore, decrease of Bcl-2 expression, increase of Bax, and active Caspase-3 were found in D2S expressed GH3 xenograft subjected to bromocriptine treatment. In summary, our study indicates that D2S expression plays a critical role in the therapeutic action of bromocriptine in pituitary adenomas and that adenovirus-mediated D2S gene transfer combined with bromocriptine may provide a novel treatment for DA-resistant prolactinomas.

Prolactin-secreting tumors: what’s new?

Prolactinomas are a common cause of reproductive/sexual dysfunction. Once other causes of hyperprolactinemia have been excluded with a careful history and physical examination, routine chemistries, a pregnancy test and a thyroid-stimulating hormone, imaging with magnetic resonance imaging or computed tomography will delineate the size and extent of the tumor. Medical therapy with cabergoline or bromocriptine is the initial treatment of choice. When infertility is the primary indication for treatment, bromocriptine use has an extensive safety experience and is preferred by some clinicians. However, for other indications, cabergoline appears to be more efficacious and better tolerated. Transsphenoidal surgery remains an option, especially for patients with microadenomas, when medical therapy is ineffective or not tolerated.

Differential effects of nerve growth factor on expression of dopamine 2 receptor subtypes in GH3 rat pituitary tumor cells

Nerve growth factor (NGF) can increase expression of dopamine 2 receptors (D2R) in GH3 rat pituitary tumor cells (GH3 cells). As D2R exists in long (D2L) and short (D2S) isoforms, effects of NGF on D2R subtypes have not been accurately evaluated. In this study, we compared mRNA levels of D2R subtypes in GH3 cells treated with or without NGF with real-time RT-PCR. In addition, we also evaluated the relationship between GH3 cell growth after bromocriptine treatment and mRNA levels of D2R subtypes. We found that D2R total, D2L, and D2S mRNA in GH3 cells were significantly increased after NGF treatment, compared with the vehicle group. Moreover, NGF increased the ratio of D2S to D2L. GH3 cell survival rate after bromocriptine treatment was negatively correlated with D2R total mRNA, and D2S may be more potent than D2L in inhibiting cell growth. Cell apoptosis rate was highly elevated in GH3 cells treated with NGF and bromocriptine, compared with the control group or the group treated with NGF or bromocriptine alone. Our data provide preliminary evidence that the effect of NGF was more prominent on expression of D2S than D2L, in addition, D2S might have a greater impact suppressing GH3 cells growth than D2L.

Transsphenoidal surgery for microprolactinomas in women: results and prognosis

BACKGROUND

Long-term dopamine agonist (DA) therapy is recommended as a first-line approach for the management of microprolactinomas. However, DA therapy may be poorly tolerated by some patients, and therefore some patients continue to prefer surgery over DA therapy.

AIM

The aim of our study was to evaluate factors associated with favorable outcomes after surgical treatment of microprolactinomas in women.

METHODS

Thirty-two women (mean age 31.0 ± 8.2 years) with confirmed microprolactinomas who were operated using transsphenoidal approach were included to the study. Twenty-two (61 %) women had previous DA therapy and ten (39 %) women preferred surgery as a first treatment. Mean follow-up was 4.2 ± 2.7 years. Surgery was considered to be effective and remission achieved if serum prolactin was normal without DA therapy and there were no signs of tumor re-growth on neuroimaging.

RESULTS

Nine (47.4 %) patients in whom remission was achieved did not receive preoperative DA therapy when compared to one (7.7 %) patient in whom remission was not achieved (p = 0.02). Remission after operation was achieved in nine out of ten (90 %) patients who did not receive DA therapy compared to ten out of 22 patients (45.5 %) who were treated with DAs (p = 0.01). The independent factor associated with good outcome following surgical treatment was no preoperative DA therapy (RR = 14.57 (1.43-148.1), p = 0.02). Surgical complications were permanent diabetes insipidus in two patients (6.3 %) and transient DI in five (15.6 %) patients.

CONCLUSIONS

The main factor associated with favorable microprolactinoma surgery outcome in women was the absence of preoperative DA therapy.

Medically treated prolactin-secreting pituitary adenomas: when should we operate?

BACKGROUND

The incidence of medical failure for prolactin (PRL)-secreting pituitary tumours is not well known. Object. The purpose of this study is to report clinical, radiographic and laboratory findings of PRL-secreting tumours that predict failed medical management.

METHODS

An analysis of 92 consecutive patients was performed that met the inclusion criteria. Decision for surgery was made based on failure of dopamine agonists to either control clinical symptoms and normalise hormonal level or diminish mass effect on follow-up evaluation.

RESULTS

Of the 92 patients treated, 14 patients (15%) required trans-nasal, trans-sphenoidal pituitary surgery (TSS). One patient underwent surgery for repair of a skull defect and 13 patients (14%) required surgery after failed medical management. Higher initial PRL was statistically significant regarding the need for surgical intervention, but a persistently abnormal level after initiation of treatment was a more significant predictor (Fisher exact test, p = 0.005 vs. p < 0.001). Size was also a statistically significant factor (p = 0.014); macroadenomas had a relative risk of 9.27 (95% CI: 1.15-74.86) for needing surgery compared to microadenomas. In addition, macroadenomas with cavernous sinus (CS) extension and pre-operative visual field deficit demonstrated a strong tendency for surgical intervention.

CONCLUSION

Medical management remains the most effective treatment option for prolactinomas. A partial hormonal response to medical management seems to be the most significant predictive factor but adenomas > 20 mm, visual field deficit and invasion of the CS may help predict the need for surgery. We suggest a minimum trial period (at least 8 weeks) of medical treatment prior to the consideration of surgery.

High prevalence of radiological vertebral fractures in women with prolactin-secreting pituitary adenomas

Hyperprolactinemia may cause bone loss but data on fractures are scanty. The aim of this study was to evaluate the prevalence of vertebral fractures in women with prolactin (PRL)-secreting adenoma. In this cross-sectional study, 78 women (median age 45.5 years, range: 20-81) with PRL-secreting pituitary adenoma (66 with microadenoma and 12 with macroadenoma) and 156 control subjects, with normal PRL values and with comparable age to patients with hyperprolactinemia, were evaluated for vertebral fractures by a morphometric approach and for bone mineral density (BMD) by a dual-energy X-ray absorptiometry at lumbar spine. Vertebral fractures were shown in 25 patients with PRL-secreting adenoma (32.6%) and in 20 controls (12.8%, P < 0.001). Fractured patients were significantly older (P < 0.001) and had lower BMD T-score (P < 0.001), longer duration of disease (P < 0.001), higher serum PRL (P = 0.004) and lower serum IGF-I (P < 0.001) values as compared to patients who did not fracture. The prevalence of vertebral fractures was significantly (P < 0.001) higher in post-menopausal women with PRL-secreting adenoma as compared to pre-menopausal patients. Fractures occurred more frequently (P = 0.01) in patients with untreated hyperprolactinemia versus patients treated with cabergoline. Logistic regression analysis demonstrated that duration of disease maintained a significant correlation with vertebral fractures (odds ratio 1.16, C.I. 95% 1.02-1.33) even after correction for age, menopausal status, treatment with cabergoline, BMD, serum IGF-I and serum PRL values. Hyperprolactinemia is associated with high prevalence of radiological vertebral fractures in women with PRL-secreting adenoma.

Clinical Problem Solving: Monster on the Hook—Case Problems in Neurosurgery

BACKGROUND AND OBJECTIVE:

Nonfunctioning and functioning pituitary tumors can present in numerous ways. They may be difficult to diagnose correctly and, even with proper treatment, may lead to complications.

METHODS:

We present the case of a patient who presented with a large, invasive sellar mass and underwent both medical and surgical treatment for this lesion. The patient's course did not progress as was expected from his initial workup.

RESULTS:

The patient's history, physical examination, laboratory values, pathologic specimens, and radiologic findings are discussed. His management before, during, and after medical therapy and surgery is reviewed by pituitary experts from 2 different institutions. Aspects of diagnosis and management of sellar lesions are presented and reviewed in the literature.

CONCLUSION:

Neurosurgeons frequently treat patients with sellar lesions and should remember that despite modern laboratory, pathologic, and radiologic techniques, the diagnosis and treatment of these lesions is not always clear.

Dopamine agonist-resistant prolactinomas

The authors' object in this paper was to review the definition, epidemiology, biology, resistance mechanisms, and treatment options for dopamine agonist-resistant prolactinomas (DARPs). Prolactinomas are relatively unique among primary brain tumors in that medical treatment alone using dopamine agonists carries a high probability of disease control or even radiographic and endocrine remission, and thus has replaced surgery as the first line of therapy. Unfortunately, slightly less than 10% of patients with prolactinomas do not experience normalization of their prolactin levels in response to dopamine agonists, and harbor tumors that are resistant to dopamine agonist therapy. A literature review underscores that in male patients these DARPs are more likely to be invasive macroadenomas than dopamine agonist-responsive prolactinomas and that they are also more angiogenic, more proliferative, and more likely to exhibit cellular atypia. Estrogen receptor antagonists and temozolomide are the most commonly applied medical therapies in cases in which resection and radiosurgery have not induced remission of the hyperprolactinemia. Dopamine agonist-resistant prolactinomas exhibit aggressive behavior and tend to be large, invasive, hyperangiogenic tumors with high mitotic indices, which makes their management via surgery, radiosurgery, or alternative medical therapies challenging, thus underscoring the need for novel medical therapies or treatment regimens that target these lesions.

Casticin, a flavonoid isolated from Vitex rotundifolia, inhibits prolactin release in vivo and in vitro

AIM

to investigate the anti-hyperprolactinemia activity of casticin, a flavonoid isolated from Vitex rotundifolia, and elucidate its molecular mechanism.

METHODS

hyperprolactinemia (MIHP) was induced by administration of metoclopramide dihydrochloride (50 mg/kg, tid, ip, for 10 d) in SD rats and the primary pituitary cells were prepared from the pituitary glands of the SD rats. Prolactin concentrations were measured using a radioimmunoassay. Cell viability was measured using an MTT assay. The mRNA expression of estrogen receptor alpha and beta in rat pituitary cells was measured using semi-quantitative RT-PCR analysis.

RESULTS

the level of serum prolactin in the MIHP model group was 2.1 fold higher than that in the untreated control group (P<0.01). Casticin (10, 20, and 40 mg/kg, ip, for 7 d) reduced serum prolactin levels by 33.9%, 54.3%, and 64.7%, respectively (P<0.01). The positive control drug bromocriptine 1 mg/kg decreased the serum prolactin concentration in MIHP rats by 44.9%. 17β-Estradiol (E2) significantly increased the proliferation of pituitary cells and casticin (1 and 10 micromol/L) markedly inhibited E2-induced pituitary cell proliferation by 27.7% and 42.1%, respectively. Stimulation of pituitary cells with E2 increased prolactin secretion into the cell culture supernatants, and casticin (0.1, 1, and 10 micromol/L) significantly inhibited the prolactin release stimulated by E2 in a concentration-dependent manner. Casticin (1 and 10 micromol/L) significantly inhibited ERα mRNA expression in pituitary cells stimulated with E2 (P<0.01) but increased ERβ mRNA expression at a concentration of 10 micromol/L (P<0.01). However, casticin had no effects on proliferation and prolectin release of the unstimulated primary pituitary cells in vitro.

CONCLUSION

casticin inhibited the release of prolactin from pituitary cells of SD rats stimulated with E2 in vivo and in vitro. These effects might be related with inhibiting the ERα mRNA expression and increasing the ERβ mRNA expression.

Medical treatment of Cushing's disease: Overview and recent findings

Cushing's disease, due to pituitary adrenocorticotropic hormone (ACTH) hypersecretion, is the most common etiology of spontaneous excess cortisol production. The majority of pituitary tumors causing Cushing's disease measure <1 cm and the excess morbidity associated with these tumors is mostly due to the effects of elevated, nonsuppressible, ACTH levels leading to adrenal steroid hypersecretion. Elevated circulating cortisol levels lead to abnormal fat deposition, hypertension, diabetes, coronary artery disease, osteoporosis, muscle weakness and psychological disturbances. At experienced centers, initial surgical remission rate via transnasal, transphenoidal resection approaches 80% for tumors less than 1 cm, but may be as low as 30% for larger lesions and long-term recurrence in all groups approaches 25%. Residual disease may be managed with more radical surgery, pituitary-directed radiation, bilateral adrenalectomy, or medical therapy. This paper addresses current and novel therapies in various stages of development for Cushing's disease.

Long-term outcome of patients with macroprolactinomas initially treated with dopamine agonists

OBJECTIVE

Dopamine agonists are the first line therapy for the treatment of prolactinomas. The aim of this study was to assess the outcome of macroprolactinomas during long-term follow-up after initial treatment with dopamine agonists.

DESIGN

Retrospective follow-up study.

PATIENTS

We included 72 consecutive patients (age 39+/-17 years, men 46%) diagnosed with macroprolactinoma, and initially treated with dopamine agonists between 1980 and 2004.

RESULTS

Initial presentation included headache in 49%, and visual field defects in 38% of the patients. Nine patients were already treated with dopamine agonists at presentation. Median prolactin level of the untreated patients was 460 microg/L (range 96-35,398 microg/L) at presentation. Hypopituitarism, other than hypogonadism, was present in 6% of the patients. Mean duration of follow-up was 10.2+/-6.1 years. Additional transsphenoidal surgery was necessary in 35% of the patients, because of resistance and/or intolerance of dopamine agonists. Postoperative radiotherapy was provided to 18% of all patients. During long-term follow-up, normoprolactinemia was present in 85% of the patients, but biochemical remission (normal prolactin levels in the absence of dopamine agonists) was present in only 22% of the patients. Tumor shrinkage was evident on MRI in 57% of the patients. Hypopituitarism developed in 39% of the patients, especially in those who received additional surgery with or without radiotherapy.

CONCLUSION

Dopamine agonists are effective in normalizing prolactin values, and inducing tumor shrinkage. However, in one-third of the patients, additional therapy was necessary due to dopamine agonist resistance and/or intolerance, associated with a high incidence of hypopituitarism.

Prolactin-Producing Adenoma. Clinical Presentation in Adult Sudanese Patients

Objectives: To describe the clinical features of prolactin-producing pituitary adenoma (prolactinoma) in adult patients.

Methods: In a prospective hospital-based study, adult patients with prolactinoma presenting to the National Center for Neurological diseases and the National Center for cancer in Khartoum, Sudan were enrolled in the period from January 2001 to February 2005. The diagnosis was based on finding a pituitary adenoma on cranial MRI and an associated elevated blood prolactin level above 200 pig/L. The size of the adenoma was classified as either microadenoma ( < 10 mm without sellar enlargement or extrasellar extension) ormacroadema (>10 mm). The hormone profile done on each patient included blood level of prolactinand other pituitary trophic hormones, free triiodothyronine and free thyroxine hormones.

Results: Sixteen (14 females and 2 males) were identified as having a prolactinoma. The female to male ratio was 7:1. Their mean age was 24 ± 5.1 years. The prolactinoma was macroadenoma in 9 cases and microademoma in 7. Galactorrhea, amenorrhea and infertility (primary or secondary) were the commonest presenting symptom followed by headache. Affection of the visual pathway, either as bitemporal hemianopia (41.2%) or optic atrophy (11.8%), was the major neurological deficit. The mean prolactin level in macroadenoma was 2053 ± 442.6 jig/L and in microadenoma was 853.6 ± 77.8 jig/L.

Conclusions: Our prolactinoma patients, when reaching the appropriate medical attention, are more likely having an expanded macroadeoma that is compromising the visual pathway. Early recognition and referral to specialized clinics is necessary and that should have a favorable prognostic implication.

Long-term control of macroprolactinomas

Hyperprolactinemia is the most prevalent hypothalamic-pituitary dysfunction, with prolactinomas being its main cause. Microprolactinomas (diameter < 10 mm) represent approximately 60% of the prolactin-secreting adenomas, and are far more common in women than in men, whereas macroadenomas have roughly the same prevalence in both genders. The treatment of patients harboring macroprolactinomas is highly gratifying, with more than 80% of them adequately controlled by dopamine-agonist (DA) drugs: cabergoline being the most efficacious to date. Emerging evidence points to remission of the disease after long-term DA therapy in a significant number of patients. The remaining cases, mainly those with enclosed tumors, may be treated successfully by pituitary surgery. Radiotherapy is reserved for cases with dopaminergic drug resistance not surgically cured. The development of new therapeutic approaches may turn the control of the subset of macroprolactinomas refractory to both DA and surgery into reality.

Rational design of competitive prolactin/growth hormone receptor antagonists

There is increasing evidence that prolactin (PRL) and growth hormone (GH) act as growth-promoters of breast tumors. Recent arguments have accumulated to suggest that when they are locally-produced within the mammary tissue, these hormones, acting by an autocrine-paracrine mechanism may have enhanced, or even specific functions compared to endocrine PRL and GH. Classical drugs blocking pituitary hormone production (dopamine and somatostatin analogs) are ineffective on extrapituitary expression of PRL/GH genes, therefore the undesirable effects of these locally-produced hormones remain a target of interest for alternative strategies. This has encouraged the development of competitive PRL and/or GH receptor antagonists, which involve engineered variants of natural receptor ligands (PRL or GH) aimed at blocking receptor activation rather than hormone production in peripheral tissues. This article overviews the rational design of this new class of molecules, their specific molecular features (receptor specificity, biological properties, etc.) and whenever available, the data that have been obtained in cell or animal models of breast cancer.

Operative treatment of prolactinomas: indications and results in a current consecutive series of 212 patients

OBJECTIVE

Medical therapy with dopamine agonists (DA) is the primary treatment of choice in most patients with prolactinomas. 'Classical' surgical indications are intolerance or lack of efficiency of DA therapy. Focusing on a possible shift of recent indications, we retrospectively analyzed our results of surgical treatment in prolactinomas.

PATIENTS AND METHODS

Between 1990 and 2005, we have operated on 212 consecutive patients with prolactinomas. Surgical indications were divided into 'classical' indications and 'modern' indications defined as cystic prolactinomas or patients with microprolactinomas who individually decided on a primary surgical treatment.

RESULTS

Initial overall remission was accomplished in 53.2% including giant prolactinomas. However, in microadenomas, the remission rate was significantly higher with 91.3%. Overall remission at the latest follow-up was 42.7%, but 72.5% in intrasellar tumors, 80% in cystic prolactinomas, and 84.8% in microprolactinomas. The overall recurrence rate was 18.7%. Relapse of hyperprolactinemia in microprolactinomas was 7.1%. In our series, continually less patients were surgically treated for 'classical' indications. By contrast, the number of patients who individually decided on a primary surgical therapy has increased considerably.

CONCLUSION

Remission rates after surgical treatment of prolactinomas remain excellent, particularly in microadenoma and intrasellar macroadenomas, whereas morbidity of transsphenoidal surgery is low in the hands of experienced pituitary surgeons. Our remission rates not only confirm the already interdisciplinarily accepted surgical indications, but also emphasize the value of primary transsphenoidal surgery as a discussion-worthy alternative to dopaminergic therapy in young patients with microprolactinomas or cystic tumors.

Bromocriptine during pregnancy in systemic lupus erythematosus: a pilot clinical trial

Bromocriptine (BRC) prevents postpartum flare in lupus patients. However, its potential role in protecting lupus pregnancy from maternal-fetal complications has not been studied. The objective of the study was to explore the role of oral BRC during pregnancy in patients with systemic lupus erythematosus (SLE). Pregnant SLE patients were randomized into two groups: group 1 received BRC 2.5 mg/day and prednisone 10 mg/day; group 2 received prednisone 10 mg/day. These treatments were administered from 25 to 35 weeks of gestation. Prolactin (PRL) levels were determined at 25, 30, and 35 weeks. The SLE Pregnancy Disease Activity Index, maternal-fetal outcome including preterm birth, fetal loss, premature rupture of membrane (PRM), low birth weight, and preeclampsia/eclampsia were evaluated. We studied 20 patients (10 in each group). A significant decrease of PRL levels in group 1 compared to group 2 at week 30 and at week 35 was found. No patients in the BRC group had flares and three from group 2 had SLE activity. None of the patients in group 1 had PRM but three patients in group 2 did. Eighty percent of pregnancies ended in birth at term in group 1 and 50% in group 2. There was no fetal loss in both groups. Mean birth weight was higher in group 1 than in group 2 (P < NS). BRC was well tolerated. This is the first clinical trial of BRC in SLE pregnancy. Our pilot study suggests that BRC may play a role in the prevention of maternal-fetal complications, such as PRM, preterm birth, and active disease.

Anti-nociceptive and anti-hyperprolactinemia activities of Fructus Viticis and its effective fractions and chemical constituents

Vitex rotundifolia L. is widely distributed along the sea coast of China. The aim of this study was to investigate the anti-nociceptive and anti-hyperprolactinemia activities of substances isolated from Fructus Viticis (the fruit of Vitex rotundifolia), which may be effective in the treatment of pre-menstrual symptoms, using acetic-acid-induced writhing and metoclopramide-dihydrochloride-induced hyperprolactinemia in mice. The fractions effective in terms of anti-nociceptive and anti-hyperprolactinemia activities were obtained from Fructus Viticis by elution through macro-porous resin, and polyamide and silica gel column chromatography. The standardization of the fractions obtained from the separation procedures was carried out by means of high-performance liquid chromatography (HPLC)-fingerprint. In this study, the flavone-enriched fraction (Fraction 6) showed a higher inhibitory rate than indomethacin (69.4% vs. 56.4%) at a dose of 50 mg/kg body wt., and significantly reduced the prolactin level as compared to HPRL-treated mice (8.2 ng/ml vs. 25.5 ng/ml). Furthermore, this fraction showed anti-nociceptive activity in a dose-dependent manner (10-50 mg/kg body wt., i.g.). On further purification with silica gel, Casticin was isolated from this fraction and it decreased abnormal serum levels of prolactin by approximately 50% (p < 0.01). Using bioassay-screening methods, our results indicate that the presence of flavonoids such as Casticin in this plant may be responsible for the activity effects. Casticin has potent analgesic and anti-hyperprolactinaemia properties, is likely to be one of the active components of Fructus Viticis, and may have a role in treating PMS (premenstrual syndrom).

Parity, pregnancy and neonatal outcomes in women treated for hyperprolactinaemia compared with a control group

OBJECTIVE

Infertility is a common problem in women with hyperprolactinaemia. There are limited data on the fertility and pregnancy course among these women. The objective was to study parity, pregnancy and neonatal outcomes in women with hyperprolactinaemia as compared with a control group.

DESIGN

Register study.

PATIENTS

Two hundred and seventy-one female patients treated for primary hyperprolactinaemia were identified in the hospital record archives between 1974 and 2002. For each patient four comparison subjects, matched by sex, birth year and county of residence were identified in the Register of Population. Data were retrieved from the Swedish medical birth register and were analysed using logistic regression and analysis of variance. Measurements Parity, maternal age at first delivery, weeks of gestation, induction of labour, caesarean delivery, multiple birth, Apgar score, birth weight, length, sex, congenital malformations, neonatal care.

RESULTS

One hundred and sixty-two deliveries in the hyperprolactinaemia group and 1220 deliveries in the control group were analysed.

PATIENTS

with hyperprolactinaemia were significantly older at their first pregnancy than their controls: 29.0 (+/- 4.4) and 27.2 (+/- 4.8) years, respectively (P = 0.0002). Furthermore, parity was inversely associated with hyperprolactinaemia status (P for trend = 0.0009). The odds of having three or more children were threefold lower among the patients (OR 0.31 (95% CI 0.16, 0.60)). There were no differences between patients and controls with respect to pregnancy complications, delivery or neonatal outcome variables.

CONCLUSIONS

We found no evidence of increased risk of pregnancy complications or adverse pregnancy outcomes in women with treated hyperprolactinaemia. However, the patients were older at their first pregnancy and had a reduced overall parity.

Technology insight: measuring prolactin in clinical samples

Measurement of prolactin is one of the most commonly undertaken hormonal investigations in evaluating patients with reproductive disorders. Hyperprolactinemia is found in up to 17% of such cases. Diagnostic evaluation of hyperprolactinemia is difficult but is facilitated by a logical approach where a thorough patient history is obtained, secondary causes of hyperprolactinemia are excluded, and the limitations of current prolactin assays are appreciated. Once hyperprolactinemia has been confirmed, attempts to establish the underlying cause can start. Given current workloads, laboratories rely on automated platforms to measure prolactin, most of which employ two-site immunoassay sandwich methods. Although generally robust and reliable, such immunoassays are susceptible to interference, and good collaboration between clinicians and the laboratory helps to minimize problems. A major challenge facing laboratories is correct differentiation of patients with true hyperprolactinemia from those with macroprolactinemia. Macroprolactin is a high-molecular-mass, biologically inactive form of prolactin that is detected to varying degrees by all prolactin immunoassays. Conservative estimates suggest that the presence of macroprolactin leads to misdiagnosis in as many as 10% of all reported instances of biochemical hyperprolactinemia. In the absence of specific testing, macroprolactin represents a diagnostic pitfall that results in the misdiagnosis and mismanagement of large numbers of patients.

Temozolomide in the treatment of an invasive prolactinoma resistant to dopamine agonists

Prolactinomas are common tumors of the anterior pituitary gland. While conventional therapies, including dopamine agonists, transsphenoidal surgery and radiotherapy, are usually effective in controlling tumor growth, some patients develop treatment-resistant tumors. In this report, we describe a patient with an invasive prolactinoma resistant to conventional therapy that responded to the administration of the alkylating agent, temozolomide.

Objective criteria for successful transsphenoidal removal of suprasellar nonfunctioning pituitary adenomas. A prospective study

BACKGROUND

Despite ample experience with transsphenoidal surgery, objective data on which suprasellar tumour expansion and growth pattern allows for radical adenoma resection are still sparse. Hence, we have performed a prospective study to establish the predictive value of tumour dimension and shape for the intra-operative descent of the diaphragma, the completeness of tumour resection and the outcome of patients harbouring pituitary adenomas with suprasellar extension.

METHOD

Included in the study were 105 patients with nonfunctioning pituitary adenomas and suprasellar extension who underwent primary transsphenoidal surgery between January 1998 and December 2005. The precise suprasellar extension, the degree of dumbbell-shape, the configuration of the adenomas and the depth of the pituitary fossa were evaluated. Completeness of resection was assessed by MRI at 3 months postoperatively.

FINDINGS

The mean cranio-caudal diameter of the tumours was 28.0 mm (range 9.2-57.8 mm). On average, the suprasellar extension measured 11.9 mm (range 2.1-25.8 mm). Total removal of the suprasellar tumour was accomplished in 83% (87 of 105) of the patients. A second operation for residual adenoma was only indicated in 2 cases. The vertical intracranial extension was the strongest independent predictor of subtotal resection (p < 0.001). Irregular and multilobular configuration was a second highly-significant and independent predictor for incomplete resection (p < 0.003). In contrast, dumbbell-shape and shallow pituitary fossa were not independent predictive factors for incomplete tumour resection. The complication rate was very low. None of our patients suffered postoperative rhinorrhea, meningitis or visual deterioration.

CONCLUSIONS

One-stage transsphenoidal surgery allows total or near-total resection of most suprasellar pituitary adenomas with low surgical morbidity. Quantitative assessment of tumour dimension and configuration contributes to establishing guidelines for the selection of the appropriate approach and prediction of surgical outcome.

Drug Insight: prolactin-receptor antagonists, a novel approach to treatment of unresolved systemic and local hyperprolactinemia?

Prolactin is a polypeptide hormone whose major biological actions are related to normal lactation and reproduction. Abnormally high prolactin levels, referred to as hyperprolactinemia, can result in various reproductive disorders. Currently, therapeutic management of hyperprolactinemia relies on dopamine agonists, since dopamine is the primary physiological suppressor of pituitary prolactin production. Epidemiologic studies have shown that prolactin levels in the high-normal range, as well as medications that interfere with dopamine action (e.g. certain antipsychotic drugs), might correlate with increased breast cancer risk. In addition to circulating prolactin, it is now well established that prolactin is also produced locally within various tissues, including breast and prostate. Increasing evidence, mainly from animal studies at present, suggests that excess locally produced prolactin may promote the growth of breast and prostate tumors via an autocrine or paracrine mechanism. These findings have renewed the interest in finding alternative strategies to suppress prolactin actions when dopamine agonists are ineffective. Our studies of the relationship between prolactin structure and function have resulted in the development of pure prolactin-receptor antagonists. These molecules prevent endogenous prolactin from exerting its actions via a competitive mechanism for receptor binding. In this review, we discuss the possible future therapeutic utility of this novel class of compounds.

[Treatment of pituitary gland hyperfunction: from acromegaly to prolactinoma]

Evidence based drug therapy is currently available for the treatment of prolactinomas and growth hormone secreting adenomas (acromegaly). Dopamine agonists such as bromocriptine, quinagolide or cabergoline represent the standard therapy for the treatment of micro- and macro-prolaktinomas. In pregnancy, more differentiated, individual and patient-adapted therapeutic procedures have to be considered. Transsphenoidal adenomectomy is the treatment of choice for patients suffering from acromegaly. If biochemical cure (defined by normalized IGF-1 serum levels or by a GH nadir <1 microg/l during a 3-h oral glucose tolerance test) cannot be achieved, somatostatin analogues such as octreotide and lanreotide are effective. In some cases, dopamine agonists can be added. In therapy-resistant cases, growth hormone receptor antagonists can be used.

Do the limits of serum prolactin in disconnection hyperprolactinaemia need re-definition? A study of 226 patients with histologically verified non-functioning pituitary macroadenoma

BACKGROUND

The differentiation of a pituitary non-functioning macroadenoma from a macroprolactinoma is important for planning appropriate therapy. Serum PRL levels have been suggested as a useful diagnostic indicator. However, values between 2500 and 8000 mU/l are a grey area and are currently associated with diagnostic uncertainty.

OBJECTIVE

We wished therefore, to investigate the serum PRL values in a large series of patients presenting with apparently non-functioning pituitary macroadenomas.

PATIENTS AND METHODS

All patients presenting to the Department of Endocrinology in Oxford with clinically non-functioning pituitary macroadenomas (later histologically verified) between 1990 and 2005 were studied. Information documented in the notes on the medications and on the presence of conditions capable of affecting the serum PRL levels at the time of blood sampling was also collected.

RESULTS

Two hundred and twenty-six patients were identified (median age at diagnosis 55 years, range 18-88 years; 146 males/80 females; 143 gonadotroph, 46 null cell, 25 plurihormonal and 12 silent ACTH adenomas). All tumours had suprasellar extension. At the time of blood sampling 41 subjects were taking medications capable of increasing serum PRL. Hyperprolactinaemia was found in 38.5% (87/226) of the patients. The median serum PRL values in the total group were 386 mU/l (range 16-3257) (males: median 299 mU/l, range 16-1560; females: median 572 mU/l, range 20-3257) and in those not taking drugs capable of increasing serum PRL 363 mU/l (range 16-2565) (males: median 299 mU/l, range 16-1560; females: median 572 mU/l, range 20-2565). Serum PRL < 2000 mU/l was found in 98.7% (223/226) of the total group and in 99.5% (184/185) of those not taking drugs. Among the three subjects with serum PRL > 2000 mU/l, two were taking oestrogen preparations.

CONCLUSIONS

Based on a large series of histologically confirmed cases, serum PRL > 2000 mU/l is almost never encountered in nonfunctioning pituitary macroadenomas. Values above this limit in the presence of a macroadenoma should not be surrounded by diagnostic uncertainty (after acromegaly or Cushing's disease have been excluded); a prolactinoma is the most likely diagnosis and a dopamine agonist should be considered as the treatment of choice.

Guidelines of the Pituitary Society for the diagnosis and management of prolactinomas

In June 2005, an ad hoc Expert Committee formed by the Pituitary Society convened during the 9th International Pituitary Congress in San Diego, California. Members of this committee consisted of invited international experts in the field, and included endocrinologists and neurosurgeons with recognized expertise in the management of prolactinomas. Discussions were held that included all interested participants to the Congress and resulted in formulation of these guidelines, which represent the current recommendations on the diagnosis and management of prolactinomas based upon comprehensive analysis and synthesis of all available data.

Breastfeeding a baby with mother on Bromocripine

Prolactinomas, the most common pituitary adenomas, are important causes of infertility. Bromocriptine remains the treatment of choice for managing hyperprolactinemia in most of these cases. Breastfeeding in mothers receiving bromocriptine is often doubtful and matter of concern for most people. Here we report a case, where by timely intervention and skilled counseling, exclusive breastfeeding could be established in a mother receiving bromocriptine for the treatment of hyperprolactinemia.