Increase in bone mass after treatment of hyperprolactinemic amenorrhea

Skeletal fragility in pituitary disease: how can we predict fracture risk?

Pituitary hormones play a crucial role in regulating skeletal physiology, and skeletal fragility is a frequent complication of pituitary diseases. The ability to predict the risk of fracture events is crucial for guiding therapeutic decisions; however, in patients with pituitary diseases, fracture risk estimation is particularly challenging. Compared to primary osteoporosis, the evaluation of bone mineral density by dual X-ray absorptiometry is much less informative about fracture risk. Moreover, the reliability of standard fracture risk calculators does not have strong validations in this setting. Morphometric vertebral assessment is currently the cornerstone in the assessment of skeletal fragility in patients with pituitary diseases, as prevalent fractures remain the strongest predictor of future fracture events. In recent years, new tools for evaluating bone quality have shown promising results in assessing bone impairment in patients with pituitary diseases, but most available data are cross-sectional, and evidence regarding the prediction of incident fractures is still scarce. Of note, apart from measures of bone density and bone quality, the estimation of fracture risk in the context of pituitary hyperfunction or hypofunction cannot ignore the evaluation of factors related to the underlying disease, such as its severity and duration, as well as the specific therapies implemented for its treatment. Aim of this review is to provide an up-to-date overview of all major evidence regarding fracture risk prediction in patients with pituitary disease, highlighting the need for a tailored approach that critically integrates all clinical, biochemical, and instrumental data according to the specificities of each disease.

Impact of medical therapy for hormone-secreting Pituitary tumors on bone

PURPOSE

Bone health is often impaired in patients with hormone-secreting pituitary tumors. Since medical therapy is central to their care, understanding how its use impacts on this is highly important.

METHODS

This review summarizes a systemmatic review of the literature on the effects of medical therapies for hormone-secreting pituitary tumors on bone.

RESULTS

In acromegaly, medical therapy lowers bone turnover marker (BTM) levels, consistent with correction of the high bone turnover of active disease, and overall, areal bone mineral density (aBMD) does not change or increases. Somatostatin-receptor ligand (SRL) and pegvisomant-treated acromegaly patients have persistently reduced volumetric BMD and microarchitectural abnormalities of the peripheral skeleton, deficits that are similar to those in surgically-treated patients. Fracture risk remains elevated in medically-treated acromegaly patients but in conjunction with biochemical control the risk is lessened. Treatment of prolactin-secreting tumors with dopamine agonists is associated with improvements in aBMD, but this does not always fully normalize despite effective medical treatment of the prolactinoma. In one cross-sectional study, prolactinoma patients had lower total volumetric BMD and impaired microarchitecture suggesting that bone microstructure does not fully normalize despite dopamine agonist therapy. Cross-sectional studies show a high rate of VF in patients with prolactin-secreting tumors that is lowered on cabergoline therapy, but still the fracture rate of men and postmenopausal women is higher than that of controls in some studies. Studies on the effects of modern-day medical therapy for Cushing's disease on bone are lacking.

CONCLUSION

More research is needed on the effectsof medical therapies for hormone secreting pituitary tumors on bone health.

Diagnosis and Management of Pituitary Adenomas: A Review

Importance

Pituitary adenomas are neoplasms of the pituitary adenohypophyseal cell lineage and include functioning tumors, characterized by the secretion of pituitary hormones, and nonfunctioning tumors. Clinically evident pituitary adenomas occur in approximately 1 in 1100 persons.

Observations

Pituitary adenomas are classified as either macroadenomas (≥10 mm) (48% of tumors) or microadenomas (<10 mm). Macroadenomas may cause mass effect, such as visual field defects, headache, and/or hypopituitarism, which occur in about 18% to 78%, 17% to 75%, and 34% to 89% of patients, respectively. Thirty percent of pituitary adenomas are nonfunctioning adenomas, which do not produce hormones. Functioning tumors are those that produce an excess of normally produced hormones and include prolactinomas, somatotropinomas, corticotropinomas, and thyrotropinomas, which produce prolactin, growth hormone, corticotropin, and thyrotropin, respectively. Approximately 53% of pituitary adenomas are prolactinomas, which can cause hypogonadism, infertility, and/or galactorrhea. Twelve percent are somatotropinomas, which cause acromegaly in adults and gigantism in children, and 4% are corticotropinomas, which secrete corticotropin autonomously, resulting in hypercortisolemia and Cushing disease. All patients with pituitary tumors require endocrine evaluation for hormone hypersecretion. Patients with macroadenomas additionally require evaluation for hypopituitarism, and patients with tumors compressing the optic chiasm should be referred to an ophthalmologist for formal visual field testing. For those requiring treatment, first-line therapy is usually transsphenoidal pituitary surgery, except for prolactinomas, for which medical therapy, either bromocriptine or cabergoline, is usually first line.

Conclusions and Relevance

Clinically manifest pituitary adenomas affect approximately 1 in 1100 people and can be complicated by syndromes of hormone excess as well as visual field defects and hypopituitarism from mass effect in larger tumors. First-line therapy for prolactinomas consists of bromocriptine or cabergoline, and transsphenoidal pituitary surgery is first-line therapy for other pituitary adenomas requiring treatment.

Italian Association of Clinical Endocrinologists (AME) and International Chapter of Clinical Endocrinology (ICCE). Position statement for clinical practice: prolactin-secreting tumors

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.

Update on vertebral fractures in pituitary diseases: from research to clinical practice

Derangement of pituitary hormone axes can induce changes in bone remodeling and metabolism with possible alterations in bone microarchitectural structure and increased susceptibility to fractures. Vertebral fractures (VFs), which are a hallmark of skeletal fragility, have been described in a very large number of patients with pituitary diseases. These fractures are clinically relevant, since they predispose to further fractures and may negatively impact on patients' quality of life. However, the management of skeletal fragility and VFs in the specific setting of pituitary diseases is a challenge, since the awareness for this disease is still low, prediction of VFs is uncertain, the diagnosis of VFs cannot be solely based on a clinical approach and also needs a radiological and morphometric approach, the risk of fractures may not be decreased via treatment of pituitary hormone disorders, and the effectiveness of bone-active drugs in this setting is not always evidence-based. This review is an update on skeletal fragility in patients with pituitary diseases, with a focus on clinical and therapeutic aspects concerning the management of VFs.

Hyperprolactinemia after menopause: Diagnosis and management

Most prolactinomas are diagnosed in women of reproductive age and are generally microadenomas. Prolactinomas diagnosed in postmenopausal women are less common and are not usually associated with the typical syndrome induced by prolactin excess, including infertility and oligo-amenorrhea. This implies that the diagnosis of prolactinomas after menopause may be delayed and require greater clinical effort. Limited data are available on the management and prognosis of prolactinomas in postmenopausal women. However, the physiologic decline of prolactin levels during menopause and the lack of fertility concerns, which represent specific indications for medical treatment with dopamine agonists, might require a careful reassessment of therapeutic management in such patients. Postmenopausal women with microprolactinoma may be successfully withdrawn from medical therapy with dopamine agonists, whereas in those with macroprolactinomas greater caution is advisable before dopamine agonists are discontinued, considering the potential, although rare, tumor enlargement. This review focuses on the diagnostic challenges and therapeutic management of prolactinomas in postmenopausal women.

Endocrine interventions in the intensive care unit

Following the onset of any life-threatening illness that requires intensive medical care, alterations within the neuroendocrine axes occur which are thought to be essential for survival, as they postpone energy-consuming anabolism, activate energy-producing catabolic pathways, and optimize immunological and cardiovascular functions. The hormonal changes present in the acute phase of critical illness at least partially resemble those of the fasting state, and recent evidence suggests that they are part of a beneficial, evolutionary-conserved adaptive stress response. However, a fraction of patients who survive the acute phase of critical illness remain dependent on vital organ support and enter the prolonged phase of critical illness. In these patients, the hypothalamic-pituitary-peripheral axes are functionally suppressed, which may have negative consequences by which recovery may be hampered and the risk of morbidity and mortality in the long-term increased. Most randomized controlled trials of critically ill patients that investigated the impact on the outcome of treatment with peripheral hormones did not reveal a robust morbidity or mortality benefit. In contrast, small studies of patients in the prolonged phase of critical illness documented promising results with the infusion of hypothalamic-releasing hormones. The currently available data corroborate the need for well-designed and adequately powered RCTs to further investigate the impact of these releasing factors on patient-centered outcomes.

The benefit and risk of stereotactic radiosurgery for prolactinomas: an international multicenter cohort study

OBJECTIVE

The most common functioning pituitary adenoma is prolactinoma. Patients with medically refractory or residual/recurrent tumors that are not amenable to resection can be treated with stereotactic radiosurgery (SRS). The aim of this multicenter study was to evaluate the role of SRS for treating prolactinomas.

METHODS

This retrospective study included prolactinomas treated with SRS between 1997 and 2016 at ten institutions. Patients' clinical and treatment parameters were investigated. Patients were considered to be in endocrine remission when they had a normal level of prolactin (PRL) without requiring dopamine agonist medications. Endocrine control was defined as endocrine remission or a controlled PRL level ≤ 30 ng/ml with dopamine agonist therapy. Other outcomes were evaluated including new-onset hormone deficiency, tumor recurrence, and new neurological complications.

RESULTS

The study cohort comprised 289 patients. The endocrine remission rates were 28%, 41%, and 54% at 3, 5, and 8 years after SRS, respectively. Following SRS, 25% of patients (72/289) had new hormone deficiency. Sixty-three percent of the patients (127/201) with available data attained endocrine control. Three percent of patients (9/269) had a new visual complication after SRS. Five percent of the patients (13/285) were recorded as having tumor progression. A pretreatment PRL level ≤ 270 ng/ml was a predictor of endocrine remission (p = 0.005, adjusted HR 0.487). An increasing margin dose resulted in better endocrine control after SRS (p = 0.033, adjusted OR 1.087).

CONCLUSIONS

In patients with medically refractory prolactinomas or a residual/recurrent prolactinoma, SRS affords remarkable therapeutic effects in endocrine remission, endocrine control, and tumor control. New-onset hypopituitarism is the most common adverse event.

Hyperprolactinemia and bone

Prolactin (PRL) has direct and indirect effects on bone metabolism. Experimental studies showed that in the presence of high PRL levels bone resorption was increased as well as bone formation was suppressed. Increased PRL levels in humans caused a reduction in sex hormone levels which turn may have detrimental effects on bone. Patients with hyperprolactinemia did have often decreased bone mineral density as well as an increased risk of fractures. Since PRL control may be relevant to bone health it is a clinical open issue the inclusion of skeletal health in future guidelines as indication to proactive screening, prevention and treatment particularly in high risk patients such as hyperprolactinemic women after menopause and patients with drug induced hyperprolactinemia.

How to manage osteoporosis before the age of 50

This narrative review discusses several aspects of the management of osteoporosis in patients under 50 years of age. Peak bone mass is genetically determined but can also be affected by lifestyle factors. Puberty constitutes a vulnerable period. Idiopathic osteoporosis is a rare, heterogeneous condition in young adults due in part to decreased osteoblast function and deficient bone acquisition. There are no evidence-based treatment recommendations. Drugs use can be proposed to elderly patients at very high risk. Diagnosis and management of osteoporosis in the young can be challenging, in particular in the absence of a manifest secondary cause. Young adults with low bone mineral density (BMD) do not necessarily have osteoporosis and it is important to avoid unnecessary treatment. A determination of BMD is recommended for premenopausal women who have had a fragility fracture or who have secondary causes of osteoporosis: secondary causes of excessive bone loss need to be excluded and treatment should be targeted. Adequate calcium, vitamin D, and a healthy lifestyle should be recommended. In the absence of fractures, conservative management is generally sufficient, but in rare cases, such as chemotherapy-induced osteoporosis, antiresorptive medication can be used. Osteoporosis in young men is most often of secondary origin and hypogonadism is a major cause; testosterone replacement therapy will improve BMD in these patients. Diabetes is characterized by major alterations in bone quality, implying that medical therapy should be started sooner than for other causes of osteoporosis. Primary hyperparathyroidism, hyperthyroidism, Cushing's syndrome and growth hormone deficiency or excess affect cortical bone more often than trabecular bone.

Prolactin - a pleiotropic factor in health and disease

The principal role of prolactin in mammals is the regulation of lactation. Prolactin is a hormone that is mainly synthesized and secreted by lactotroph cells in the anterior pituitary gland. Prolactin signalling occurs via a unique transmembrane prolactin receptor (PRL-R). The structure of the PRL-R has now been elucidated and is similar to that of many biologically fundamental receptors of the class 1 haematopoietic cytokine receptor family such as the growth hormone receptor. The PRL-R is expressed in a wide array of tissues, and a growing number of biological processes continue to be attributed to prolactin. In this Review, we focus on the newly discovered roles of prolactin in human health and disease, particularly its involvement in metabolic homeostasis including body weight control, adipose tissue, skin and hair follicles, pancreas, bone, the adrenal response to stress, the control of lactotroph cell homeostasis and maternal behaviour. New data concerning the pathological states of hypoprolactinaemia and hyperprolactinaemia will also be presented and discussed.

Pituitary Diseases and Bone

Neuroendocrinology of bone is a new area of research based on the evidence that pituitary hormones may directly modulate bone remodeling and metabolism. Skeletal fragility associated with high risk of fractures is a common complication of several pituitary diseases such as hypopituitarism, Cushing disease, acromegaly, and hyperprolactinemia. As in other forms of secondary osteoporosis, pituitary diseases generally affect bone quality more than bone quantity, and fractures may occur even in the presence of normal or low-normal bone mineral density as measured by dual-energy X-ray absorptiometry, making difficult the prediction of fractures in these clinical settings. Treatment of pituitary hormone excess and deficiency generally improves skeletal health, although some patients remain at high risk of fractures, and treatment with bone-active drugs may become mandatory. The aim of this review is to discuss the physiological, pathophysiological, and clinical insights of bone involvement in pituitary diseases.

An Economic Analysis of Bromocriptine Versus Trans-Sphenoidal Surgery for the Treatment of Prolactinoma

Prolactinomas account for ∼40% of all pituitary adenomas and are important causes of infertility and gonadal dysfunction. In general, most prolactinomas are treated medically with dopaminergic agonists, while surgery is reserved for patients intolerant or nonresponsive to these medications. The aim of this study was to carry out a comparative analysis of the cost-effectiveness of medical therapy with bromocriptine and surgical therapy with trans-sphenoidal surgery. A Markov model was developed based on retrospective data from 126 patients with prolactinoma treated in our hospital between October 2008 and May 2009, and from data published previously. For patients with microadenoma, the cost of medical treatment was estimated to be ¥20,555, while the cost of surgery was calculated to be ¥22,527. For patients with macroadenoma, the cost of therapy with bromocriptine was ¥31,461 in males and ¥27,178 in females, while the cost of surgery was ¥42,357 in males and ¥44,094 in females. Sensitivity analyses (carried our using variations in patient age, bromocriptine therapeutic dose, bromocriptine maintenance dose, and the success rate of bromocriptine withdrawal) indicated that our model showed good stability, although our results were most heavily influenced by variations in the bromocriptine maintenance dose. It is concluded that, from an economic viewpoint, medical therapy with bromocriptine should be the first-line treatment option for patients with prolactinoma, irrespective of whether this is a microadenoma or macroadenoma.

Prolactinoma through the female life cycle

Prolactinomas are the most common secretory pituitary adenoma. They typically occur in women in the 3rd-6th decade of life and rarely in the pediatric population or after menopause. Most women present with irregular menses and/or infertility. Dopamine (DA) agonists, used in their treatment, are safe during pregnancy, but in most cases are discontinued at conception with close monitoring for signs or symptoms of tumor growth. Breastfeeding is safe postpartum, provided there was no significant growth during pregnancy. Some women will experience normalization of prolactin levels postpartum. Menopause may also decrease prolactin levels and even those with macroprolactinomas may consider discontinuing their DA agonist with close follow-up. Prolactinomas may be associated with decreased quality of life scores in women, and play a role in bone health and cardiovascular risk factors. This review discusses the current literature and clinical understanding of prolactinomas throughout the entirety of the female life cycle.

Hyperprolactinaemia - a problem in patients from the reproductive period to the menopause

Hyperprolactinaemia especially affects women in reproductive age (90/100,000) but also often is diagnosed in menopause age and leads to disturbances in functioning of LH-RH neurons and, as a consequence, to a decrease of FSH and LH, which causes inhibition of oestradiol production. Prolactin is a peptide hormone, phylogenetically one of the oldest, stimulating cells of various organs, which is produced and secreted mainly by lactotrophic acidophilic cells of the anterior lobe of the pituitary. It influences the increase in the mass of the mammary glands, and stimulation and maintenance of lactation after delivery. There are a number of factors apart of pregnancy, delivery, and lactation than can influence secretion of the hormone in other physiological and pathological circumstances, like high-protein diet, stress, REM sleep, or neoplastic tumours, inflammatory diseases, chronic systematic diseases, thyroid hormonal changes, and drug intake. The purpose of this review is to summarise the current knowledge regarding the proper diagnosis and possible influence of hyperprolactinaemia on fertility and menopause symptoms and current treatment methods.

SERUM LEVELS OF FIBROBLAST GROWTH FACTOR-23, OSTEOPROTEGERIN, AND RECEPTOR ACTIVATOR OF NUCLEAR FACTOR KAPPA B LIGAND IN PATIENTS WITH PROLACTINOMA

OBJECTIVE

The aim of this study to was to evaluate the effect of fibroblast growth factor-23 (FGF-23), osteoprotegerin (OPG), receptor activator nuclear κB ligand (RANKL), and vitamin D hormones on bone loss in patients with hyperprolactinemia due to pituitary prolactinoma.

METHODS

We recruited 46 premenopausal female patients with prolactinoma and age and sex-matched healthy controls (Group 3, n = 20) for this cross-sectional study. Prolactinoma patients were divided into 2 groups as patients newly diagnosed (Group 1, n = 26) and those under cabergoline treatment (Group 2, n = 20). Anthropometric and metabolic variables; hormonal profiles; and osteocalcin, deoxypyridinoline (DOP), and bone mineral density measurements were performed for all participants. FGF-23, OPG, and RANKL levels were analyzed in all groups.

RESULTS

FGF-23, OPG, calcium, phosphorus, and parathormone levels were similar between all groups despite significantly higher levels in the control group in terms of vitamin D and RANKL levels than in patients. Bone loss was found more in Group 2, particularly observed in Z scores of femur and spinal bone (P<.05). Correlation analysis revealed a negative correlation between FGF-23 and femur neck T score (r = -0.0433, P = .05) in patients with active prolactinoma. A positive correlation was also observed between parameters of DOP and OPG (r = 0.673, P = .02). In patients with remission there were a negative correlation between prolactin and luteinizing hormone (r = -600, P = .08). Additionally, a negative correlation was found between osteocalcin and osteoprotegerin in patients in remission (r = -0.73, P = .01).

CONCLUSION

Our data indicated that FGF-23 and OPG levels do not play a critical role on the development of bone decrease in patients with hyperprolactinemia. However, further prospective studies in larger numbers of participants should be designed to clarify this issue.

ABBREVIATIONS

BFP = body fat percentage BMD = bone mineral density BMI = body mass index CV = coefficient of variation DOP = deoxypyridinoline ELISA = enzyme-linked immunosorbent assay FGF-23 = fibroblast growth factor-23 HOMA-IR = homeostatic model assessment of insulin resistance OPG = osteoprotegerin RANKL = receptor activator nuclear κB ligand.

Eulogy for the clinical research center

The extramural General Clinical Research Center (GCRC) program has been funded for more than 50 years, first by the National Center for Research Resources, NIH, and more recently as part of the Clinical Translational Science Award (CTSA) program through the newly formed National Center for Advancing Translation Sciences (NCATS). The GCRCs represent the federally funded laboratories that employ a highly trained cadre of research nurses, dietitians, and other support staff and in which generations of clinical investigators trained and performed groundbreaking human studies that advanced medical science and improved clinical care. Without the opportunity for adequate discussion, NCATS has now stopped funding these Research Centers. In this "eulogy," we review the origins and history of the GCRCs, their contributions to the advancement of medicine, and the recent events that have essentially defunded them. We mourn their loss.

Electrolyte Imbalance in Patients with Sheehan's Syndrome

BACKGROUND

We investigated the prevalence of electrolyte imbalance and the relationship between serum electrolyte and anterior pituitary hormone levels in patients with Sheehan's syndrome.

METHODS

In a retrospective study, we investigated 78 patients with Sheehan's syndrome. We also included 95 normal control subjects who underwent a combined anterior pituitary hormone stimulation test and showed normal hormonal responses.

RESULTS

In patients with Sheehan's syndrome, the serum levels of sodium, potassium, ionized calcium, magnesium, and inorganic phosphate were significantly lower than those in control subjects. The prevalence of hyponatremia, hypokalemia, hypocalcemia, hypomagnesemia, and hypophosphatemia in patients with Sheehan's syndrome was 59.0% (n=46), 26.9% (n=21), 35.9% (n=28), 47.4% (n=37), and 23.1% (n=18), respectively. Levels of sodium and ionized calcium in serum were positively correlated with levels of all anterior pituitary hormones (all P<0.05). Levels of potassium in serum were positively correlated with adrenocorticotrophic hormone (ACTH) and growth hormone (GH) levels (all P<0.05). Levels of inorganic phosphate in serum were positively correlated with levels of thyroid-stimulating hormone, prolactin, and GH (all P<0.05), and levels of magnesium in serum were positively correlated with delta ACTH (P<0.01).

CONCLUSION

Electrolyte imbalance was common in patients with Sheehan's syndrome. Furthermore, the degree of anterior pituitary hormone deficiency relates to the degree of electrolyte disturbance in patients with this disease.

Osteoporosis in pituitary diseases: lessons for the clinic

Osteoporosis is a systemic disease characterized by bone mass and density loss leading to fragility fractures. Osteoporosis due to endocrine disorders is an example of secondary osteoporosis. The harmful effects on bones are common in patients harboring pituitary tumors (acromegaly, prolactinoma, Cushing's disease) and suffering from hypopituitarism. Increased fracture risk and high healthcare costs of fractured patients are their consequences. The coexistence of some of these disorders and hypogonadism results in severe osteoporosis. The influence of the certain diseases, their activity and therapy and accompanying hypogonadism on bone turnover, bone mineral density and fracture incidence is presented.

Pituitary diseases and bone

Pituitary hormones have direct and indirect effects on bone remodeling, and skeletal fragility is a frequent complication of pituitary diseases. Fragility fractures may occur in many patients with prolactinomas, acromegaly, Cushing disease, and hypopituitarism. As in other forms of secondary osteoporosis, pituitary diseases generally affect bone quality more than bone quantity, and fractures may occur even in the presence of normal or low-normal bone mineral density, making difficult the prediction of fractures in these settings. Treatment of excess and defective pituitary hormone generally improves skeletal health, although some patients remain at high risk for fractures, necessitating treatment with bone-active drugs.

Treatment of hyperprolactinemia in post-menopausal women: pros

The incidence of hyperprolactinemia in women peaks during the 3rd-4th decade and then greatly decreases after the menopause. Apart from the effects on the hypothalamic-pituitary-gonadal axis, prolactin can act directly on bone metabolism. Hyperprolactinemia is a recognized cause of secondary osteoporosis, and treatment with dopamine agonists can lead to improved BMD. Moreover, hyperprolactinemia has been linked to weight gain and insulin resistance, which can be ameliorated following medical treatment. Although relatively rare, prolactinomas can be observed in post-menopausal women and are frequently large and invasive; dopamine agonists appear to be as effective in these patients as in younger women to induce reduction of prolactin levels and tumour shrinkage. Here, we review data potentially favouring medical treatment with dopamine agonists in post-menopausal women diagnosed with hyperprolactinemia.

Effects of hypogonadism on bone metabolism in female adolescents and young adults

Gonadal steroids, including androgens and oestrogens, play a critical part in bone metabolism, and conditions associated with a deficiency of gonadal steroids can reduce BMD in adults and impair bone accrual in adolescents. In addition, other associated hormone alterations, for example, insulin-like growth factor 1 deficiency or high cortisol levels, can further exacerbate the effect of hypogonadism on bone metabolism, as can factors such as calcium and vitamin D deficiency, low body weight and exercise status. This Review discusses the effects of different hypogonadal states on bone metabolism in female adolescents and young adults, with particular emphasis on conditions associated with low energy availability, such as anorexia nervosa and athletic amenorrhoea, in which many factors other than hypogonadism affect bone. In contrast to most hypogonadal conditions, in which replacement of gonadal steroids is sufficient to normalize bone accrual rates and BMD, gonadal steroid replacement may not be sufficient to normalize bone metabolism in these states of energy deficit.

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.

Antipsychotic-induced hyperprolactinaemia

BACKGROUND AND OBJECTIVES

Antipsychotic medications are a potential cause of hyperprolactinaemia and may be implicated in the development of pituitary adenomas. This review examines the effect of different antipsychotic medications on prolactin and sexual function, and provides practical guidelines for investigation and management of antipsychotic-induced hyperprolactinaemia.

METHOD

Literature review.

RESULTS AND CONCLUSIONS

Antipsychotic-induced hyperprolactinaemia occurs overall in up to 70% of patients with schizophrenia, depending on the medications used. It is associated with significant levels of hypogonadism and sexual dysfunction, which in general relates to the degree of prolactin elevation. A consequence of the hypogonadism is clinically significant bone loss which may lead to osteoporosis and increased risk of minimal trauma fracture. Where the potentially offending drug cannot be safely withdrawn to document a normal prolactin, imaging with MRI should be undertaken to exclude a structural pituitary lesion. The management strategy of choice is switching to a prolactin-sparing antipsychotic. Sex steroid replacement can reverse many of the adverse effects including the hypogonadal symptoms and bone loss. Low dose dopamine agonist therapy should be used with caution as a third line treatment, since there have been cases of dopamine agonist-induced exacerbation of psychosis. There is a need for a randomised controlled trial of low dose dopamine agonist therapy versus sex steroid replacement to establish the relative safety and efficacy of each approach.

Medical treatment of prolactinomas

Prolactinomas, the most prevalent type of neuroendocrine disease, account for approximately 40% of all pituitary adenomas. The most important clinical problems associated with prolactinomas are hypogonadism, infertility and hyposexuality. In patients with macroprolactinomas, mass effects, including visual field defects, headaches and neurological disturbances, can also occur. The objectives of therapy are normalization of prolactin levels, to restore eugonadism, and reduction of tumor mass, both of which can be achieved in the majority of patients by treatment with dopamine agonists. Given their association with minimal morbidity, these drugs currently represent the mainstay of treatment for prolactinomas. Novel data indicate that these agents can be successfully withdrawn in a subset of patients after normalization of prolactin levels and tumor disappearance, which suggests the possibility that medical therapy may not be required throughout life. Nevertheless, multimodal therapy that involves surgery, radiotherapy or both may be necessary in some cases, such as patients who are resistant to the effects of dopamine agonists or for those with atypical prolactinomas. This Review reports on efficacy and safety of pharmacotherapy in patients with prolactinomas.

Treatment for prolactinomas and hyperprolactinaemia: a lifetime approach

BACKGROUND

Prolactinomas are the most common hormone-secreting pituitary tumours and are amenable to medical therapy with dopamine agonists. Indication for treatment will most commonly result from hypogonadism, infertility or symptoms related to tumour size. Thus, both diagnosis and treatment will essentially depend on the patients' stage of life, namely prepubertal, reproductive or postreproductive stage. This review will focus on a lifespan-dependent diagnosis and treatment for prolactinoma and hyperprolactinaemia.

METHODS

PubMed, the Cochrane Library, the Web of Science and EMBASE were searched electronically. No restriction was made with respect to language. Relevant current articles will be included in this review.

RESULTS

Prevalence of prolactinomas and clinical symptoms are age group-specific, and treatment of first choice is dopamine agonists over the whole lifespan. Open questions in the treatment for hyperprolactinaemia include optimal choice and duration of pharmacological treatment. In addition, concerns have been raised on the safety of dopamine agonists since a reported association of valvular heart disease with dopaminergic treatment in patients with Parkinson's disease.

CONCLUSIONS

Clinical presentation and consequences of hyperprolactinaemia and prolactinoma will differ in the specific stages of reproductive life and require an adequate lifetime-dependent diagnostic and therapeutic approach.

Hyperprolactinemia associated with psychotropics--a review

INTRODUCTION

Different classes of psychotropics can cause hyperprolactinemia to varying degrees. Among antipsychotics, typical agents and risperidone are the most frequent and significant offenders. In this review we discuss the pathophysiology, offending medications, assessment and management of hyperprolactinemia.

METHODS

We did a literature review between 1976 and 2008 using PubMed, MEDLINE, PsychINFO and Cochrane database. Search terms used were prolactin, hyperprolactinemia, psychotropics, antipsychotics, typical antipsychotics, atypical antipsychotics, antidepressants and SSRIs.

RESULTS

Prolactin elevation is more common with antipsychotics than with other classes of drugs. Typical antipsychotics are more prone to cause hyperprolactinemia than atypical agents. Management options include discontinuation of offending medication, switching to another psychotropic, supplementing concurrent hormonal deficiencies and adding a dopamine agonist or aripiprazole.

CONCLUSION

Clinicians need to be alert about the potential for hyperprolactinemia and its manifestations with these medications. Prolactin levels need to be monitored and other causes of hyperprolactinemia ruled out in suspected cases.

Pituitary tumours: the prolactinoma

This review focus on the epidemiology, diagnosis and treatment of prolactinomas. In particular, attention was given to recent data showing a high prevalence of these tumours in the general population, 3-5 times higher than previously reported. The diagnosis of hyperprolactinaemia has been simplified in recent years, and only prolactin (PRL) assay and magnetic resonance imaging of the sella are required. Nonetheless, macroprolactinaemia should be assessed in patients with hyperprolactinaemia in the absence of clinical symptoms of elevated PRL levels. The recent evidence that medical therapy with dopamine agonists should be continued lifelong has been confirmed by several studied. The patients achieving disappearance of the tumours and suppression of PRL levels during treatment are those showing the highest likelihood to have persistent remission of hyperprolactinaemia after treatment withdrawal.

Hormone replacement therapy for osteoporosis: clinical and pathophysiological aspects

The pathogenetic role of oestrogen deficiency in osteoporosis was first postulated by Fuller Albright in 1941 and has subsequently become well established. Hormone replacement therapy prevents menopausal bone loss and is the only treatment which has convincingly been shown to reduce fracture risk at both the spine and hip. The mechanisms by which oestrogens affect bone, however, are poorly understood and many aspects of treatment remain ill-defined, in particular with respect to the duration of therapy and its long-term risks and benefits.

The effects of hyperprolactinemia on bone and fat

Many patients with prolactin secreting pituitary tumors have decreased bone mineral. The bone loss is associated with an increase in bone resorption and is secondary to prolactin-induced hypogonadism. In both sexes trabecular bone in the spine and hip is more affected than cortical bone in the distal radius. Normalization of prolactin and restoration of gonadal function increases bone density but is not associated with normalization of bone mass. It is not known whether the bone loss in hyperprolactinemic subjects represents a failure to achieve peak bone mass or is due to accelerated bone loss. Despite low bone density hyperprolactinemic subjects do not demonstrate increased fractures. The association between prolactin, weight gain and obesity suggests that prolactin may also be a modulator of body composition and body weight. It is not known whether hyperprolactinemia associated weight gain is due to stimulation of lipogenesis or due to disruption of central nervous system dopaminergic tone. Hyperprolactinemia is also associated with insulin resistance and endothelial dysfunction which may improve after normalization of prolactin. The clinical significance of these findings and the precise role of prolactin in regulation of weight and metabolism remain to be elucidated.

Understanding osteoporosis

Osteoporosis is a common skeletal condition that results in significant morbidity, mortality and health care costs. There is an increased awareness of bone health in people with severe mental illness (SMI). These people appear to be at a higher risk of low bone density and fracture, and also have a poorer outcome following hip fracture. The reason for the increased risk of osteoporosis is multifactorial and includes general as well as disease-specific factors, such as antipsychotic medication and hyperprolactinaemia. Clinical history and examination followed by dual energy x-ray absorptiometry are required to assess the risk of osteoporosis. Therapies should begin with lifestyle measures, such as physical activity and dietary supplementation, with the use of bone-specific agents reserved for those at high absolute risk.

Antipsychotic-induced hyperprolactinaemia, hypogonadism and osteoporosis in the treatment of schizophrenia

Treatment of schizophrenic illness usually involves the long-term administration of antipsychotic drugs. Most antipsychotic agents antagonise the actions of endogenous dopamine (DA) at DA-2 receptors in the brain. The relative affinity for, and binding time to, DA-2 receptors was considered to be one of the key determinants of the antipsychotic potency of classical antipsychotic drugs. Some newer atypical antipsychotics, of which clozapine is the prototype, have a relatively poor affinity for DA-2 receptors; whereas other atypical antipsychotics are potent DA-2 antagonists. The propensity of antipsychotic agents to cause hyperprolactinaemia is related to their potency in antagonising DA-2 receptors on the anterior pituitary. In our studies, bone loss was consistently related to DA-2 antagonist potency of antipsychotic drugs, rather than their classification using conventional 'typical' versus 'atypical' systems. It is established that hyperprolactinaemia causes suppression of the reproductive endocrine axis and consequent bone mineral density (BMD) loss. Results from our group and others have demonstrated that a similar pathophysiological process is occurring in individuals with antipsychotic-induced hyperprolactinaemia. We found high rates of osteoporosis and osteopenia in those taking long-term antipsychotic drugs, and this was related to the dose and duration of treatment. Bone loss was associated with hypogonadism in male and female groups. Young Caucasian women appear to be particularly vulnerable to developing hyperprolactinaemia and the associated hypogonadism and bone loss. The occurrence of menstrual dysfunction should alert clinical suspicions of hyperprolactinaemia and bone de-mineralisation. Lastly, there are no published trials examining the effects of hormone replacement on BMD in those taking long-term antipsychotic drugs, but preliminary findings from our studies suggest that active management of bone loss in those with antipsychotic-associated bone disease may halt or even reverse this process.

Hyperprolactinemia and prolactinomas

Any process interfering with dopamine synthesis, its transport to the pituitary gland, or its action at the level of lactotroph dopamine receptors can cause hyperprolactinemia. As described in this article, considering the complexity of prolactin regulation, many factors could cause hyperprolactinemia, and hyperprolactinemia can have clinical effects not only on the reproductive axis. Once any drug effects are excluded, prolactinomas are the most common cause of hyperprolactinemia. The most frequent symptom is hypogonadism in both genders. Medical and surgical therapies generally have excellent results, and most prolactinomas are well controlled or even cured in some cases.

Bone density in women with prolactinoma treated with dopamine agonists

OBJECTIVES

(1) to evaluate bone density in women with prolactinoma treated with dopamine agonists and healthy controls, using dual energy x-ray absorptiometry (DXA), (2) to classify the results according to the current International Society for Clinical Densitometry (ISCD) criteria, and (3) to correlate bone density with lean and fat masses, biochemical data and clinical aspects of prolactinomas.

MATERIALS AND METHODS

A cross-sectional study was performed in two University referral centers. Forty-five premenopausal women with prolactinoma were submitted to DXA and blood analysis (prolactin, estradiol, testosterone, SHBG, calcium, phosphorus, PTH, C-telopeptides of type 1 collagen, and osteocalcin) by the time of their clinical evaluation. They were compared with 25 control women of similar age and body mass index distribution.

RESULTS

Women with prolactinoma had lower lumbar spine Z-score than controls. Femoral neck, trochanter, and total proximal femur Z-scores were similar in patients and controls. Twenty-two percent of the patients had Z-scores below the expected age range vs. 4% in the control group. Lumbar spine, femoral neck, and total proximal femur Z-scores were mainly correlated with the amenorrhea duration. The trochanter Z-score was associated with the gynoid lean/fat mass ratio.

CONCLUSIONS

Based on the current ISCD criteria, bone density evaluation in women with prolactinoma reveals bone loss, especially of trabecular type. Bone density in these patients was particularly associated with the duration of amenorrhea, which reinforces the importance of the adequate disease control in women with prolactinoma in order to avoid complications of this disease.

Bone mineral density changes over a year in young females with schizophrenia: relationship to medication and endocrine variables

INTRODUCTION

Hyperprolactinaemia is associated with the use of potent dopamine-2 receptor blocking anti-psychotic agents in schizophrenia and with bone loss in the general population. Significantly higher rates of reduced bone mineral density (BMD) have been identified in young pre-menopausal females with schizophrenia receiving prolactin-raising anti-psychotics compared to those receiving prolactin-sparing anti-psychotics. This prospective study compared BMD alterations over a period of 1 year in patients maintained on either prolactin-raising (e.g. risperidone, amisulpride or depot anti-psychotics) or prolactin-sparing (olanzapine) anti-psychotics. The effects of specific interventions to improve BMD were also examined in the context of whether patients were receiving either prolactin-raising or anti-psychotics or Olanzapine.

METHODS

Pre-menopausal females (n=38) with a diagnosis of schizophrenia, who had received exclusively either prolactin-raising (n=25) or prolactin-sparing (n=13) anti-psychotics during their treatment history, had clinical, endocrine and bone marker assessments performed at baseline and every 3 months for a period of 1 year. BMD was measured by DEXA scan at baseline and at 1-year follow-up. Patients from both groups either received specific interventions (n=16) or no interventions (n=16) to improve bone density.

RESULTS

There was an overall gain in lumbar BMD values in the prolactin-sparing subgroup, compared to an overall loss in the prolactin-raising subgroup (p=0.02), for the groups that received no specific interventions to improve BMD. Within the group that received specific interventions, the subgroup receiving prolactin-sparing anti-psychotics had a significant increase in lumbar (p=0.01) and hip (p=0.01) BMD over time, whereas alterations in the prolactin-raising subgroup were not significant.

DISCUSSION

Women taking prolactin-raising anti-psychotics and not receiving specific interventions to improve bone density had evidence of ongoing bone demineralisation over a year; whereas women taking prolactin-sparing anti-psychotics had a modest overall increase in BMD. Most clinical interventions appeared to be helpful, but were significantly more effective in those taking prolactin-sparing anti-psychotics.

Relation between Bone Mass and Catecholamines in the General Population

BACKGROUND

The relation between the sympathetic nervous system and bone metabolism has been known for some time, although diverse experimental studies do not show uniformity in their evaluation of the different data. The aim of this paper is to determine the relation between urinary catecholamines, as an expression of sympathetic activity, and bone mass among the general population.

METHODS

A study was made of 274 individuals (124 males and 150 females), who formed part of the Hortega cohort. All underwent measurement of fractionated catecholamines in urine (dopamine, noradrenaline and adrenaline) and calcaneal density, using a Pixi-Lunar (Lunar Corp., Madison, Wisc., USA).

RESULTS

The linear correlation study revealed a statistically significant association of dopamine with bone mass (r = 0. 229, p = 0.0001), which was not observed with the other catecholamines. The effect was shown in men (r = 0.184, p = 0.04) and women (r = 0.251, p = 0.002). When a multiple correlation analysis was performed, the effect of the dopamine (p = 0.038) persisted.

CONCLUSIONS

Our study shows that dopamine is an independent, positive variable for bone mass in men and women in the general population, and for the latter, it is independent of their hormonal state.

Management of resistant prolactinomas

Resistance to dopamine agonists occurs in a subset of patients with prolactin-secreting pituitary tumors. The resistance is mediated by loss of pituitary D2 receptors and occurs in both microadenomas and macroadenomas. Cabergoline is the most effective dopamine agonist and tumors that do not respond to bromocriptine or quinagolide frequently respond to cabergoline. Treatment options include maximizing the dose of the dopamine agonist, changing agonists, trans-sphenoidal surgery and radiation therapy. The goal of therapy is to restore and maintain gonadal and neurologic function, and this might occur in the absence of a normal prolactin level or a significant change in tumor size. Trans-sphenoidal pituitary surgery should be reserved for patients who are intolerant of medical therapy, or in whom this has failed. Radiation therapy has a limited role in treatment of resistant prolactinomas and should be reserved for patients in whom medical and surgical therapy has failed.

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.

Advances in the treatment of prolactinomas

Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. The ultimate goal of therapy for prolactinomas is restoration or achievement of eugonadism through the normalization of hyperprolactinemia and control of tumor mass. Medical therapy with dopamine agonists is highly effective in the majority of cases and represents the mainstay of therapy. Recent data indicating successful withdrawal of these agents in a subset of patients challenge the previously held concept that medical therapy is a lifelong requirement. Complicated situations, such as those encountered in resistance to dopamine agonists, pregnancy, and giant or malignant prolactinomas, may require multimodal therapy involving surgery, radiotherapy, or both. Progress in elucidating the mechanisms underlying the pathogenesis of prolactinomas may enable future development of novel molecular therapies for treatment-resistant cases. This review provides a critical analysis of the efficacy and safety of the various modes of therapy available for the treatment of patients with prolactinomas with an emphasis on challenging situations, a discussion of the data regarding withdrawal of medical therapy, and a foreshadowing of novel approaches to therapy that may become available in the future.

Drug Insight: cabergoline and bromocriptine in the treatment of hyperprolactinemia in men and women

Prolactinoma is the most frequent pituitary tumor histotype. Men generally have macroadenomas whereas women generally have microadenomas. The major objectives of treating prolactinomas are to suppress excessive hormone secretion and its clinical consequences, to remove the tumor mass while preserving the residual pituitary function, and possibly to prevent disease recurrence or progression. Primary therapy of prolactinomas is based on use of dopamine-receptor agonists. Bromocriptine induces normalization of prolactin levels in 80-90% of patients with microprolactinomas and approximately 70% of those with macroprolactinomas. Tumor-mass shrinkage and improvement of visual-field defects are found in the majority of treated macroprolactinomas, but bromocriptine often causes side effects. Cabergoline is very effective and well tolerated in more than 90% of patients with either microprolactinomas or macroprolactinomas. Cabergoline treatment also induces tumor shrinkage in the majority of patients with macroprolactinomas. Tumor shrinkage is more evident if patients have not previously been treated with other dopamine agonists. Fewer results are available for men than for women, but there is no evidence that men are less responsive to dopamine agonists than are women.

Antipsychotic-induced hyperprolactinaemia: mechanisms, clinical features and management

Hyperprolactinaemia is an important but neglected adverse effect of antipsychotic medication. It occurs frequently with conventional antipsychotics and some atypical antipsychotics (risperidone and amisulpride) but is rare with other atypical antipsychotics (aripiprazole, clozapine, olanzapine, quetiapine, ziprasidone). For this reason the terms 'prolactin-sparing' and 'prolactin-raising' are more useful than 'atypical' and 'conventional' when considering the effect of antipsychotic drugs on serum prolactin. During antipsychotic treatment prolactin levels can rise 10-fold or more above pretreatment values. In a recent study approximately 60% of women and 40% of men treated with a prolactin-raising antipsychotic had a prolactin level above the upper limit of the normal range. The distinction between asymptomatic and symptomatic hyperprolactinaemia is important but is often not made in the literature. Some symptoms of hyperprolactinaemia result from a direct effect of prolactin on target tissues but others result from hypogonadism caused by prolactin disrupting the normal functioning of the hypothalamic-pituitary-gonadal axis. Symptoms of hyperprolactinaemia include gynaecomastia, galactorrhoea, sexual dysfunction, infertility, oligomenorrhoea and amenorrhoea. These symptoms are little researched in psychiatric patients. Existing data suggest that they are common but that clinicians underestimate their prevalence. For example, well conducted studies of women treated with conventional antipsychotics have reported prevalence rates of approximately 45% for oligomenorrhoea/amenorrhoea and 19% for galactorrhoea. An illness-related under-function of the hypothalamic-pituitary-gonadal axis in female patients with schizophrenia may also contribute to menstrual irregularities. Long-term consequences of antipsychotic-related hypogonadism require further research but are likely and include premature bone loss in men and women. There are conflicting data on whether hyperprolactinaemia is associated with an increased risk of breast cancer in women. In patients prescribed antipsychotics who have biochemically confirmed hyperprolactinaemia it is important to exclude other causes of prolactin elevation, in particular tumours in the hypothalamic-pituitary area. If a patient has been amenorrhoeic for 1 year or more, investigations should include bone mineral density measurements. Management should be tailored to the individual patient. Options include reducing the dose of the antipsychotic, switching to a prolactin-sparing agent, prescribing a dopamine receptor agonist and prescribing estrogen replacement in hypoestrogenic female patients. The efficacy and risks of the last two treatment options have not been systematically examined. Antipsychotic-induced hyperprolactinaemia should become a focus of interest in the drug treatment of psychiatric patients, particularly given the recent introduction of prolactin-sparing antipsychotics. Appropriate investigations and effective management should reduce the burden of adverse effects and prevent long-term consequences.

Prevalence of osteopenia in men with prolactinoma

The aim of this cross-sectional study was to analyze bone mineral density (BMD) and prevalence of osteopenia and osteoporosis in 30 men with prolactinoma, and compare them to 22 control subjects. BMD of lumbar spine and femur was evaluated by dual-energy X-ray absorptiometry. PRL, testosterone, estradiol, sexual hormone-binding globulin and free androgen and estrogen indexes (FAI and FEI, respectively) were measured in all the subjects. In patients with prolactinoma, mean values of PRL and testosterone were calculated for the 12-month period that preceded the study. The mean T-score of the four sites analyzed by bone densitometry was lower in men with prolactinoma than in controls (p-values: lumbar spine=0.015, femoral neck <0.0001, trochanter=0.037, total femur=0.036), and 55.6% of the former presented osteopenia or osteoporosis at one or more sites (p =0.035). The lumbar spine was the most seriously affected site, where 29.6% had osteopenia and 14.8% had osteoporosis. By the time of BMD determination, significant associations were found between BMD and PRL, testosterone, FAI, estradiol, FEI, and duration of hypogonadism. Considering the period of 12 months that preceded BMD evaluation, trochanter BMD was associated with mean PRL levels, while there was an association between lumbar spine BMD and mean testosterone levels. However, the multiple regression analysis showed that estradiol was the main determinant of BMD. In conclusion, men with prolactinoma have high prevalence of osteopenia and osteoporosis. Bone loss in such patients is associated with hyperprolactinemia and hypogonadism, and mainly influenced by estrogen.

Maternal zinc deficiency raises plasma prolactin levels in lactating rats

There is an inverse relation between zinc (Zn) intake and plasma prolactin in men and nonpregnant women. Whether a relation exists in lactating women is unknown, despite the potential consequences of perturbations in prolactin regulation on lactation performance. We examined the effects of low Zn intake on prolactin concentration, the prolactin regulatory pathway in the pituitary gland, and lactation performance in lactating rats. Female rats were fed diets containing 7 (zinc deficient; ZD), 10 (marginally zinc deficient; MZD) or 25 mg Zn/kg (control) from 70 d preconception to lactation d 11. Rats were killed, pituitary glands dissected, and tissues and plasma collected and analyzed for prolactin concentration. Pituitary gland pituitary factor 1 (Pit-1), dopamine 2 receptor (D2R), and prolactin receptor mRNA expression were measured in the pituitary gland. Liver, mammary gland, plasma, and milk Zn were measured. Milk intake of the pups was also recorded. Plasma prolactin concentration was higher in rats fed the ZD (125.9 microg/L) diet compared with control rats (21.7 microg/L). Pituitary gland prolactin concentration was higher in rats fed the ZD diet (69.8 mg/g total protein) compared with controls (29.0 mg/g). Plasma Zn concentration was lower in rats fed the MZD and ZD diets, and mammary gland and milk Zn concentrations were lower in rats fed the ZD diet compared with control rats. Rats fed the ZD diet had lower D2R, prolactin receptor, and Pit-1 mRNA levels, whereas rats fed the MZD diet had lower prolactin receptor and Pit-1 mRNA levels compared with control rats. Milk intake was lower in pups of rats fed the MZD and ZD diets. Our results suggest that marginal Zn nutriture may compromise milk production despite increased prolactin levels. In addition, increased circulating prolactin concentration is not due to altered nursing behavior, but may be due to alterations in the prolactin regulatory pathway in the pituitary gland.

Contemporary management of prolactinomas

Prolactin-secreting pituitary adenomas--prolactinomas--are the most common type of functional pituitary tumor. Treatment of hyperprolactinemia is indicated because of the consequences of infertility, gonadal dysfunction, and osteoporosis. Making the correct diagnosis is important because the first line of therapy is medical management with dopamine agonists. Medical therapy is effective in normalizing prolactin levels in more than 90% of patients, but longterm treatment may be required in some patients. Transsphenoidal surgery is usually indicated in those patients in whom medical therapy fails or cannot be tolerated, or in patients who harbor microprolactinomas. In experienced hands, a hormonal and oncological cure can be achieved in more than 90% of patients after transsphenoidal removal of microprolactinomas with minimal risks. Thus, surgery may be an option for microprolactinomas in a young patient who desires restoration of fertility and avoidance of long-term medical therapy. The authors review the diagnosis and management of prolactinomas, including medical therapy, surgical therapy, and stereotactic radiosurgery.

Antipsychotic-induced hyperprolactinaemia in women: pathophysiology, severity and consequences. Selective literature review

BACKGROUND

Hyperprolactinaemia has for decades been an inevitable and neglected side-effect of antipsychotic medication. The recent introduction of prolactin-sparing antipsychotic agents makes a re-examination of this problem timely.

AIMS

To review the literature on antipsychotic-induced hyperprolactinaemia and its consequences.

METHOD

A search was made of the Medline database (1966-2002) for key articles, supplemented by cross-referencing.

RESULTS

During antipsychotic treatment prolactin concentrations can rise to ten times normal levels or above, and existing data indicate that 17-78% of female patients have amenorrhoea with or without galactorrhoea. Survey data, however, suggest that clinicians underestimate the prevalence of these conditions. Long-term consequences of antipsychotic-related hypo-oestrogenism require further research but are likely to include premature bone loss.

CONCLUSIONS

Antipsychotic-induced hyperprolactinaemia should become a focus of interest in the drug treatment of psychiatric patients.