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Darrell M. Wilson and Andrew R. Hoffman

Abstract. Acromegaly is rarely caused by the ectopic secretion of growth hormone releasing factor (GRF) from peripheral neuroendocrine tumours. We evaluated the ability of a recently developed somatostatin analogue (SMS 201-995, Sandoz) to reduce hormone levels and pituitary size in a young woman with acromegaly and Zollinger-Ellison syndrome secondary to a metastatic pancreatic islet cell tumour secreting GRF and gastrin. Gastrin, GRF, and growth hormone (GH) levels declined dramatically following the initiation of therapy with the analogue by continuous iv infusion. Although intermittent sc therapy was not effective in suppressing hormone levels, continuous sc infusion of SMS 201-995 has provided good control of both GRF and GH levels for nine months. Moreover, treatment with SMS 201-995 was associated with a substantial reduction in pituitary enlargement and an improvement in her gastric symptoms. Continuous sc infusion of SMS 201-995 may be useful in treating enlarged pituitaries resistant to other modes of therapy.

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Gian Paolo Ceda, Robert G. Davis and Andrew R. Hoffman

Abstract. Glucocorticoids have been shown to have both stimulatory and suppressive effects on GH secretion in vitro and in vivo. In order to study the kinetics of glucocorticoid action on the somatotrope, cultured rat pituitary cells were exposed to dexamethasone for varying periods of time. During short-term incubations (≤ 4 h), dexamethasone inhibited GHRH and forskolin-elicited GH secretion, but during longer incubation periods, the glucocorticoid enhanced both basal and GHRH-stimulated GH release. The inhibitory effect of brief dexamethasone exposure was also seen in cells which previously had been exposed to dexamethasone. In addition, growth hormone secretion from cultured rat and human somatotropinoma cells was inhibited by a brief exposure to dexamethasone. Thus, the nature of glucocorticoid action on the isolated cultured somatotrope is biphasic, with brief exposure inhibiting, and more prolonged exposure stimulating GH secretion.

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Adriana G Ioachimescu, Maria Fleseriu, Andrew R Hoffman, T Brooks Vaughan III and Laurence Katznelson

Background

Dopamine agonists (DAs) are the main treatment for patients with hyperprolactinemia and prolactinomas. Recently, an increasing number of reports emphasized DAs’ psychological side effects, either de novo or as exacerbations of prior psychiatric disease.

Methods

Review of prospective and retrospective studies (PubMed 1976, September 2018) evaluating the psychological profile of DA-treated patients with hyperprolactinemia and prolactinomas. Case series and case reports of psychiatric complications were also reviewed.

Results

Most studies were cross-sectional and had a control group of healthy volunteers or patients with nonfunctioning pituitary adenomas. There were few prospective studies, with/without control group, that included small numbers of patients. Compared with controls, patients with hyperprolactinemia generally had worse quality of life, anxiety, depression and certain personality traits. Patients receiving DAs had higher impulsivity scores than normoprolactinemic controls. Impulse control disorders (ICDs) were reported in both genders, with hypersexuality mostly in men. Multiple ICDs were sometimes reported in the same patient, usually reversible after DA discontinuation. In case reports, DA therapy was temporally associated with severe depression, manic episodes or psychosis, which improved after discontinuation and administration of psychiatric medications. Gender type of DA, dose and duration of therapy did not correlate with occurrence of psychiatric pathology.

Conclusion

Patients with hyperprolactinemia receiving DAs may develop changes in mood and behavior regardless of prior psychiatric history. Increased awareness for ICDs, depression, mania and other types of psychosis is needed by all physicians who prescribe DAs. Larger prospective controlled clinical studies are needed to delineate prevalence, risk stratification and management.

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Gian Paolo Ceda, Graziano Ceresini, Licia Denti, Dario Magnani, Lorenzo Marchini, Giorgio Valenti and Andrew R. Hoffman

Abstract.

The basal and GH-releasing hormone-stimulated secretion of GH declines in the elderly. We tested the ability of cytidine 5'-diphosphocholine, a drug used in the treatment of stroke and Parkinson's disease, to alter GH secretion in 11 healthy elderly volunteers, aged 69-84. Each subject received an iv infusion of 2 g of cytidine 5'-diphosphocholine or normal saline. GHRH and TRH were also administered during cytidine 5'diphosphocholine infusions. The infusion of cytidine 5'-diphosphocholine induced a 4-fold (p<0.05) increase in serum GH levels over basal values. A small increase in GH was seen after GHRH administration. However, the addition of GHRH to the cytidine 5'-diphosphocholine infusion resulted in a GH response which was significantly greater than that seen after GHRH alone; the integrated concentration of GH was more than 2-fold greater in the cytidine 5'-diphosphocholine treated group (706.85± 185.1 vs 248.9±61.4 μg · l−1 · (120 min)−1; p=0.01). The PRL and TSH responses to TRH were not significantly affected by cytidine 5'-diphosphocholine infusion, indicating that dopaminergic mechanisms are not involved. These studies demonstrate that cytidine 5'-diphosphocholine can enhance basal and GHRH-stimulated GH release in the elderly, but the mechanism of action of the drug remains unclear.

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Gian Paolo Ceda, Licia Denti, Graziano Ceresini, Gianni Rastelli, Claudio Dotti, Simona Cavalieri, Giorgio Valenti and Andrew R. Hoffman

Abstract. Calcitonin has been shown to modulate pituitary hormone secretion in a variety of ways. In this study we examined the effects of a salmon calcitonin infusion on GHRH-induced GH secretion in 5 normal men. In addition, in vitro experiments were performed using primary cultures of rat anterior pituitary cells in order to examine whether there is a direct pituitary effect of CT. Infusion of CT significantly blunted the GH response to GHRH in all subjects without affecting basal GH secretion or plasma calcium levels. Infusion of CT was accompanied by significant increases in ACTH, β-endorphin, cortisol and free fatty acid levels, and by a significant decrease in serum insulin levels. The addition of CT to primary cultures of rat pituitary cells did not alter basal or stimulated secretion of GH or ACTH. These results indicate that: 1) CT blunts the GH response to GHRH; 2) CT infusion results in the stimulation of the hypothalamicpituitary-adrenal axis, and 3) this effect is probably exerted at the hypothalamic level, since no direct activity of CT was documented in vitro on either GH or ACTH secretion.

Open access

Jens Sandahl Christiansen, Philippe F Backeljauw, Martin Bidlingmaier, Beverly M K Biller, Margaret C S Boguszewski, Felipe F Casanueva, Philippe Chanson, Pierre Chatelain, Catherine S Choong, David R Clemmons, Laurie E Cohen, Pinchas Cohen, Jan Frystyk, Adda Grimberg, Yukihiro Hasegawa, Morey W Haymond, Ken Ho, Andrew R Hoffman, Jeff M P Holly, Reiko Horikawa, Charlotte Höybye, Jens Otto L Jorgensen, Gudmundur Johannsson, Anders Juul, Laurence Katznelson, John J Kopchick, K O Lee, Kuk-Wha Lee, Xiaoping Luo, Shlomo Melmed, Bradley S Miller, Madhusmita Misra, Vera Popovic, Ron G Rosenfeld, Judith Ross, Richard J Ross, Paul Saenger, Christian J Strasburger, Michael O Thorner, Haim Werner and Kevin Yuen

Objective

The Growth Hormone (GH) Research Society (GRS) convened a workshop to address important issues regarding trial design, efficacy, and safety of long-acting growth hormone preparations (LAGH).

Participants

A closed meeting of 55 international scientists with expertise in GH, including pediatric and adult endocrinologists, basic scientists, regulatory scientists, and participants from the pharmaceutical industry.

Evidence

Current literature was reviewed for gaps in knowledge. Expert opinion was used to suggest studies required to address potential safety and efficacy issues.

Consensus process

Following plenary presentations summarizing the literature, breakout groups discussed questions framed by the planning committee. Attendees reconvened after each breakout session to share group reports. A writing team compiled the breakout session reports into a draft document that was discussed and revised in an open forum on the concluding day. This was edited further and then circulated to attendees from academic institutions for review after the meeting. Participants from pharmaceutical companies did not participate in the planning, writing, or in the discussions and text revision on the final day of the workshop. Scientists from industry and regulatory agencies reviewed the manuscript to identify any factual errors.

Conclusions

LAGH compounds may represent an advance over daily GH injections because of increased convenience and differing phamacodynamic properties, providing the potential for improved adherence and outcomes. Better methods to assess adherence must be developed and validated. Long-term surveillance registries that include assessment of efficacy, cost-benefit, disease burden, quality of life, and safety are essential for understanding the impact of sustained exposure to LAGH preparations.