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Marco Losa, Jochen Schopohl, O. Albrecht Müller, and Klaus von Werder

Abstract. The effect of an iv injection of growth hormone releasing factor (GRF) on Prl secretion in healthy volunteers and patients with active acromegaly was investigated. Thirteen normal subjects received 100 μg GRF 1-44, and 19 acromegalics received 100 μg GRF 1-44. Nine normals and 9 patients were given the diluent only and served as placebo control. In healthy volunteers GRF did not affect Prl secretion significantly when compared to placebo, whereas in acromegalics Prl levels after GRF were higher than after placebo.

We have divided acromegalics in Prl-responders to GRF (n = 11) and Prl-non-responders (n = 8) using the criterion of strict parallelism between GH and Prl secretion after GRF. In cases with no GH response to GRF a clear increase of Prl levels with the maximum 15–30 min after GRF was also regarded as a Prl response. Acromegalic Prl-responders and Prl-non-responders did not significantly differ in age, sex, previous therapy, and basal GH and Prl levels. However, Prl-non-responders had a significantly reduced response of both GH and Prl to TRH (GH: 147.3 ± 16.0 vs 590.1 ± 127.8%; mean ± se; Prl: 159.4 ± 32.6 vs 504.9 ± 109.3%). It is concluded that 50 or 100 μg GRF does not affect Prl secretion in normal subjects. In contrast, in acromegaly GRF leads to Prl secretion in more than half of all patients.

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Marco Losa, Carmine A Donofrio, Raffaella Barzaghi, and Pietro Mortini


Few data are available on the surgical results in patients with incidentally discovered nonfunctioning pituitary adenoma (NFPA). We investigated the efficacy and safety of surgery in patients with incidentally discovered NFPA.


Retrospective analysis of prospectively recorded outcomes.


From 1990 to 2011, of 804 consecutive patients undergoing surgery for NFPA, 212 cases had an incidentally discovered tumor (26.4%). Among them, 117 patients were asymptomatic, while 95 had some visual and/or hormonal deficit. The main outcome of the study was to evaluate the frequency of radical resection as judged on the first postoperative neuroimaging study and detection of recurring disease during long-term follow-up.


Postoperative residual tumor was detected in 8.9% of patients with asymptomatic incidentalomas as compared with 31.2% of patients with symptomatic incidentalomas (P<0.001) and 41.2% of patients in the control group (P<0.001). Multivariate analysis confirmed that having an asymptomatic incidentaloma was independently associated with a better outcome. The 5-year recurrence-free survival in patients with incidentaloma was 86.8% (95% CI 80.2–92.4%) as compared with 77.9% (95% CI 73.6–82.2%; P<0.01) in the control group. This difference was almost completely due to a lower frequency of relapse in asymptomatic patients. Multivariate analysis confirmed the independent lower risk of tumor recurrence in asymptomatic NFPA.


Our study shows for the first time that surgically treated patients with asymptomatic NFPA have a better early and long-term outcome that is independent from all the other demographic, clinical, and morphologic characteristics of the patients.

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Marco Losa, Lilian Bock, Jochen Schopohl, Günter K. Stalla, O. Albrecht Müller, and Klaus von Werder

Abstract. To evaluate the dynamics of GH-secretion after infusion of growth hormone releasing factor, human pancreatic growth hormone releasing factor (hpGRF1-44) was infused over 2 and 5 h at a dosage of 100 μg hpGRF1-44/h into 11 healthy subjects. The infusion was started and terminated with a 50 μg hpGRF1-44 bolus injection. In 5 subjects 200 μg TRH was given 4 h after starting the infusion. In addition, 4 healthy subjects received 50 μg hpGRF1-44 bolus injection every 2 h. GRF, somatostatin, GH, Prl, and TSH were measured by radioimmunoassay.

The initial 50 μg GRF bolus increased GH-levels in all 11 subjects with a maximum at 30 min (24.1 ± 5.1 ng/ml ± se). However, though hpGRF1-44 was continuously infused and GFR-levels remained elevated, GH decreased to a minimum 270 min after start of infusion (2.6 ± 0.6 ng/ml). The GH-response to the second bolus at the end of the infusion was lower compared to the first response (14.6 ± 3.4 ng/ml after 2 h and 7.6 ± 2.5 ng/ml after 5 h). TRH did not lead to a GH-increase during hpGRF1-44 infusion though Prl and TSH rose normally. The intermittent bolus injection of 50 μg hpGRF1-44 led to continuously decreasing GH-responses to the same GRF-dosage (I. bolus: 16.5 ± 1.6 ng/ml; II. bolus: 4.2 ± 0.8 ng/ml; III. bolus: 3.4 ± 0.5 ng/ml). No change in somatostatin levels was observed.

These findings show that GRF infusion or bolus injection in short intervals does not sustain elevated GH-levels. Pituitary GH is either not readily available for continuous GRF-stimulation or GH-secretion may be antagonized by increasing portal somatostatin levels which are not reflected in the peripheral circulation.

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Marco Losa, Roland Huss, August König, O. Albrecht Müller, and Klaus von Werder

Abstract. Theophylline enhances GH-secretion in vitro, whereas in vivo a slight decrease of basal GH-levels has been observed. In the present study the effect of theophylline on the GH-responsiveness to acute and continuous administration of growth hormone releasing hormone (GHRH) was investigated. The following protocol was performed.

  1. GHRH study. Fifty μg GHRH was given as an iv bolus followed by constant GHRH-infusion (100 μg/h) over 2 h after which another GHRH bolus of 50 μg was given.

  2. GHRH plus theophylline study. GHRH was administered as in the first study and theophylline was infused at a constant rate of 3.56 mg/min over 3 h, starting one h before the GHRH bolus.

  3. Theophylline study. Only saline and theophylline were infused.

GHRH alone led to a GH-rise within 30 min with a maximum of 22.8 ± 7.2 ng/ml (mean ± se) after which GH-levels decreased despite continuous GHRH-infusion to a nadir of 12.1 ± 4.4 ng/ml at 105 min. The second GHRH bolus led to a minimal GH-increase (13.3 ± 6.4 ng/ml at 135 min). Theophylline administration resulted in blunting of the GH-response to GHRH in all volunteers, with GH levels fluctuating between 4–6 ng/ml throughout GHRH-administration. Theophylline alone did not affect GH-levels in three subjects studied, whereas in the other one a GH secretory episode 90 min after administration of the drug was observed. Prl showed a minimal increase only after the second GHRH bolus (from 254.2 ± 7.7 μU/ml to 317.3 ± 96.0 μU/ml in study 1, and from 139.3 ± 26.9 μU/ml to 193.0 ± 32.6 μU/ml in study 2), TSH-levels did not change during any of the test-procedures and GHRH-levels were comparable in both study 1 and 2. Free fatty acids (FFA) rose progressively after theophylline administration (from 0.68 ± 0.10 mEq/l to 1.06 ± 0.08 mEq/l in study 2, and from 0.64 ± 0.12 mEq/l to 1.09 ± 0.05 mEq/l in study 3), but also after GHRH alone (from 0.50 ± 0.05 mEq/l to 0.78 ±0.11 mEq/l). This shows that therapeutical doses of theophylline blunt the GH-response to GHRH in normal subjects. The mechanisms involved may be a competition for the adenosine receptor at the pituitary, or an indirect effect mediated by the rise of FFA levels.

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Maura Arosio, Marco Losa, Nicoletta Bazzoni, Domenico Bochicchio, Eva Palmieri, Claudio Nava, and Giovanni Faglia


The influence of β-adrenergic blockade by oral propranolol on the variability of GH responses to GHRH and on GH responsiveness to repeated GHRH administrations was investigated. Eight normal volunteers underwent three tests on three separate occasions. Each test consisted of two administrations of 80 μg GHRH at 2-h intervals without other medication (test 1) or combined with oral administration of 80 mg propranolol 90 min before the first (test 2) or the second GHRH injection (test 3). In test 1 GH levels increased significantly after the first, but not the second GHRH bolus (net incremental area under the curve [nAUC], mean ± sd: 1453 ± 974 and 178 ± 309 μg·l−1·(120 min)−1, respectively). In test 2 basal GH secretion was not influenced by propranolol administration, whereas the GH response to the first GHRH injection was significantly greater than in test 1 (2327 ± 1814 μg·l−1·(120 min)−1; p<0.05). However, individual subjects showed the same variability of GH response as in test 1. The GH response to the second GHRH bolus remained negligible. In test 3 administration of propranolol 90 min before the second GHRH bolus led to a clear GH increase (690±1002 μg·l−1·(120 min)−1), not significantly different from the GH response to the first bolus (1796±1375 μg·l−1·(120 min)−1). However, only 4 subjects showed a marked restoration of the GH responsiveness to the second GHRH administration. In conclusion, oral administration of propranolol is able to increase GH responsiveness to GHRH without changing the great individual variability. The response to a repeated GHRH stimulation is only partially restored by propranolol.

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Marco Losa, Julia Alba-Roth, Sylwester Sobieszczyk, Jochen Schopohl, O. Albrecht Müller, and Klaus von Werder

Abstract. We investigated the pattern of GH secretion in response to repetitive TRH administration in patients with active acromegaly and in normal subjects. Nine acromegalic patients and 10 normal subjects received three doses of 200 μg of TRH iv at 90-min intervals. There was a marked serum GH rise in acromegalic patients after each TRH dose (net incremental area under the curve [nAUC]: first dose = 4448 ± 1635 μg · min · 1−1; second dose = 3647 ± 1645 μg · min · 1−1; third dose = 4497 ± 2416 μg · min · 1−1; NS), though individual GH responses were very variable. In normal subjects TRH did not elicit GH secretion even after repeated stimulation. Each TRH administration stimulated PRL release in acromegalic patients, though the nAUC of PRL was significantly higher after the first (1260 ± 249 μg · min · 1−1) than after the second and the third TRH administration (478 ± 195 and 615 ± 117 μg · min · 1−1, respectively; P < 0.01). In normal subjects too, PRL secretion was lower after repeated stimulation (first dose = 1712 ± 438 μg · min · 1−1; second dose = 797 ± 177 μg · min · 1−1; third dose = 903 ± 229 μg · min · 1−1 P < 0.01), though different kinetics of PRL secretion were evident, when compared with acromegalic patients. TSH secretion, assessed in only 4 patients, was stimulated after each TRH dose, though a minimal but significant reduction of nAUC of TSH after repeated TRH challenge occurred. Both T3 and T4 increased steadily in the 4 patients. The same pattern of TSH, T3, and T4 secretion occurred in normal subjects. Our study demonstrates that repetitive TRH administration in acromegalic patients leads to similar, but individually heterogeneous GH responses. A qualitative difference in PRL responsiveness occurred in acromegalic patients compared with normal subjects, whereas TSH, T3, and T4 secretion was qualitatively and quantitatively similar in both groups.

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Marco Losa, Elena Mazza, Maria Rosa Terreni, Ann McCormack, Anthony J Gill, Micaela Motta, Maria Giulia Cangi, Anna Talarico, Pietro Mortini, and Michele Reni


The prognosis of either pituitary carcinoma or aggressive pituitary adenoma resistant to standard therapies is poor. We assessed the efficacy of treatment with temozolomide, an oral second-generation alkylating agent, in a consecutive series of six patients with aggressive pituitary adenomas.


This was a 1-year prospective study of temozolomide therapy in six consecutive patients with pituitary carcinoma (one case) or atypical pituitary adenoma (five cases) resistant to standard therapies. There were three males and three females. Age at enrollment ranged between 52 and 64 years. Temozolomide was given orally at a dose of 150–200 mg/m2 per day for 5 days every 4 weeks for a maximum of 12 cycles.


Response assessment was based on measurable change in tumor size, as assessed on magnetic resonance imaging, and hormone levels. Response was defined as reduction of at least 50% of tumor size and hormone levels.


Four patients completed the 12 cycles of temozolomide treatment, as planned. Two patients stopped the drug after 3 and 6 months respectively because of the progression of disease. Two patients responded to temozolomide, while the remaining two patients had stable disease. Immunohistochemistry for O 6-methylguanine-DNA methyltransferase (MGMT) in tumor sample showed a partial association with treatment response.


Temozolomide treatment has a wide range of efficacy in patients with pituitary carcinoma or locally aggressive pituitary adenoma. Positive staining for MGMT seems likely to predict a lower chance of response.

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Emanuele Ferrante, Monica Ferraroni, Tristana Castrignanò, Laura Menicatti, Mascia Anagni, Giuseppe Reimondo, Patrizia Del Monte, Donatella Bernasconi, Paola Loli, Marco Faustini-Fustini, Giorgio Borretta, Massimo Terzolo, Marco Losa, Alberto Morabito, Anna Spada, Paolo Beck-Peccoz, and Andrea G Lania

Objective: The long-term outcome of non-functioning pituitary adenoma (NFPA) patients is not clearly established, probably due to the low annual incidence and prolonged natural history of these rare tumors. The aim of this study was to evaluate clinical data at presentation and long-term post-surgery and radiotherapy outcome in a cohort of patients with NFPA.

Design and methods: A computerized database was developed using Access 2000 software (Microsoft Corporation, 1999). Retrospective registration of 295 NFPA patients was performed in seven Endocrinological Centers of North West Italy. Data were analyzed by STATA software.

Results: The main presenting symptoms were visual defects (67.8%) and headache (41.4%) and the most frequent pituitary deficit was hypogonadism (43.3%), since almost all tumors were macroadenomas (96.5%). Surgery was the first choice treatment (98% of patients) and total debulking was achieved in 35.5%. Radiotherapy was performed as adjuvant therapy after surgery in 41% of patients. At the follow-up, recurrence occurred in 19.2% of patients without post-surgical residual tumor after 7.5 ± 2.6 years, regrowth in 58.4% of patients with post-surgical remnant after 5.3 ± 4.0 years and residue enlargement in 18.4% of patients post-surgically treated with radiotherapy after 8.1 ± 7.3 years.

Conclusions: Our database indicates that the goal of a definitive surgical cure has been achieved during the last decade in a low percentage of patients with NFPA. This tumor database may help to reduce the delay between symptom onset and diagnosis, to assess prognostic parameters for the follow-up of patients with different risk of recurrence and to define the efficacy and safety of different treatments and their association with mortality/morbidity.

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Erika Hubina, Alexandra M Nanzer, Matthew R Hanson, Enrica Ciccarelli, Marco Losa, Daniela Gaia, Mauro Papotti, Maria Rosaria Terreni, Sahira Khalaf, Suzanne Jordan, Sándor Czirják, Zoltán Hanzély, György M Nagy, Miklós I Góth, Ashley B Grossman, and Márta Korbonits

Objectives: Somatostatin (SST) analogues play an important role in the medical management of somatotroph pituitary adenomas and new agonists have the potential to be effective in a wider group of pituitary and other tumours. The anti-proliferative effect of SST occurs through multiple mechanisms, one of which is cell-cycle arrest, where p27, a cyclin-dependent kinase inhibitor, is an important regulator. We hypothesised that SST may upregulate p27 protein levels and downregulate the MAP kinase pathway in these tumours.

Methods: Human pituitary adenoma cells and rat pituitary cell line (GH3) were cultured and treated in vitro with octreotide and the broad-spectrum SST agonist SOM230 (pasireotide). Immunoblotting for p27 and phospho-ERK (pERK) was performed and proliferation assessed by [3H]-thymidine incorporation. Histological samples from acromegalic patients treated with octreotide before surgery were immunostained for p27 and compared to samples from untreated patients matched for sex, age, tumour size, extension and invasiveness.

Results: We detected upregulation of p27 protein levels with SST analogue treatment in vitro in human pituitary adenoma samples. pERK1/2 was inhibited by SST analogues in both the human samples and GH3 cells. SST and its analogues inhibited the proliferation of GH3 cells. p27 immunostaining was stronger in samples from patients with longer preoperative octreotide treatment (more than 6 months) than in samples from patients with shorter treatment periods.

Conclusions: This study demonstrates that SST-mediated growth inhibition is associated with the downregulation of pERK and upregulation of p27. More potent and broader-spectrum SST analogues are likely to play an increasing role in the treatment of tumours, where the MAP kinase pathway is overactivated.

Open access

Renato Cozzi, Maria Rosaria Ambrosio, Roberto Attanasio, Claudia Battista, Alessandro Bozzao, Marco Caputo, Enrica Ciccarelli, Laura De Marinis, Ernesto De Menis, Marco Faustini Fustini, Franco Grimaldi, Andrea Lania, Giovanni Lasio, Francesco Logoluso, Marco Losa, Pietro Maffei, Davide Milani, Maurizio Poggi, Michele Zini, Laurence Katznelson, Anton Luger, Catalina Poiana, and AME

Prolactinomas are the most frequent pituitary adenomas. Prolactinoma may occur in different clinical settings and always require an individually tailored approach. This is the reason why a panel of Italian neuroendocrine experts was charged with the task to provide indications for the diagnostic and therapeutic approaches that can be easily applied in different contexts. The document provides 15 recommendations for diagnosis and 54 recommendations for treatment, issued according to the GRADE system. The level of agreement among panel members was formally evaluated by RAND-UCLA methodology. In the last century, prolactinomas represented the paradigm of pituitary tumors for which the development of highly effective drugs obtained the best results, allowing to avoid neurosurgery in most cases. The impressive improvement of neurosurgical endoscopic techniques allows a far better definition of the tumoral tissue during surgery and the remission of endocrine symptoms in many patients with pituitary tumors. Consequently, this refinement of neurosurgery is changing the therapeutic strategy in prolactinomas, allowing the definitive cure of some patients with permanent discontinuation of medical therapy.