Acquired prolactin deficiency indicates severe hypopituitarism in patients with disease of the hypothalamic-pituitary axis

Drug induced hypoprolactinemia

Prolactin levels can be influenced by multiple medications primarily through the interaction with dopamine receptors which regulate its secretion. Unlike hyperprolactinemia which has a well-defined clinical phenotype, the effects of hypoprolactinemia beyond inability to lactate are incompletely understood. Recent studies have raised concerns regarding detrimental changes in glucose metabolism, sexual function and psychological profile in patients with low prolactin levels. In contrast with anatomic and genetic etiologies, drug-induced hypoprolactinemia is usually reversible after dose reduction of the offending medication. The most common clinical scenario of drug-induced hypoprolactinemia in the endocrine clinic pertains to patients treated with cabergoline or bromocriptine for prolactin-secreting or other types of pituitary adenomas. Also, data has accumulated regarding hypoprolactinemia in patients receiving aripiprazole for schizophrenia and other psychiatric disorders. These patients warrant careful evaluation for comorbidities. This review aims to increase awareness about the potentially detrimental effects of drug-induced hypoprolactinemia, which should be considered in clinical practice decisions.

Diagnosis of hypoprolactinemia

Prolactin is a polypeptide hormone composed of 199 amino acids, synthesized by lactotroph cells. Its primary effects are on the mammary gland and gonadal axes, but it also influences different organs and systems, particularly metabolic functions. Current literature has mainly focused on the diagnosis, monitoring, and treatment of hyperprolactinemia. Due to the lack of a well-established effective treatment for hypoprolactinemia, it is not clinically emphasized. Therefore, data on its diagnosis is limited. Hypoprolactinemia has been associated with metabolic dysfunctions such as type 2 diabetes mellitus, fatty liver, dyslipidemia, fertility problems, sexual dysfunction, and increased cardiovascular disease. While often seen as a part of combined hormone deficiencies due to pituitary damage, isolated prolactin deficiency is rare. Hypoprolactinemia can serve as a marker for extensive pituitary gland damage and dysfunction.Low or undetectable serum prolactin levels and the absence of a sufficient prolactin peak in the thyrotropin-releasing hormone (TRH) stimulation test are considered diagnostic for hypoprolactinemia. Gender appears to influence both basal prolactin levels and TRH stimulation test responses. Basal prolactin levels of, at least, 5 ng/mL for males and 7 ng/mL for females can be used as cut-off levels for normal prolactin reserve. Minimum peak prolactin responses of 18 ng/mL for males and 41 ng/mL for females to TRH stimulation can exclude hypoprolactinemia. However, larger population studies across different age groups and sexes are needed to better define normal basal prolactin levels and prolactin responses to the TRH stimulation test.

Could low prolactin levels after radiotherapy predict the onset of hypopituitarism?

Both local and external cranial radiotherapy (RT) can induce neurotoxicity and vascular damage of the hypothalamic-pituitary area, which can promote neuroendocrine alterations. While anterior pituitary insufficiency after RT has been extensively characterized, data on the effect of RT on prolactin (PRL) secretion are limited and heterogeneous, with different patterns of PRL behavior described in the literature. A progressive decline in PRL levels, reflecting a time-dependent, slowly evolving radiation-induced damage to the pituitary lactotroph cells has been reported. To date, the association between hypopituitarism and hypoprolactinemia in patients undergoing RT has not yet been fully investigated. The few available data suggest that lower PRL levels can predict an extent damage of the pituitary tissue and a higher degree of hypothalamic dysfunction. However, most studies on the effect of RT on pituitary function do not properly assess PRL secretion, as PRL deficiency is usually detected as part of hypopituitarism and not systematically investigated as an isolated disorder, which may lead to an underestimation of hypoprolactinemia after RT. In addition, the often-inadequate follow-up over a long period of time may contribute to the non-recognition of PRL deficiency after RT. Considering that hypoprolactinemia is associated with various metabolic complications, there is a need to define appropriate diagnostic and management criteria. Therefore, hypoprolactinemia should enter in the clinical investigation of patients at risk for hypopituitarism, mainly in those patients who underwent RT.

Prolactin deficiency in the context of other pituitary hormone abnormalities : Special issue: hypoprolactinemia: a neglected endocrine disorder

Prolactin deficiency is rare. It generally occurs when pituitary disorders, such as large pituitary tumors, pituitary apoplexy, and other conditions associated with sellar mass effect lead to global failure of pituitary function and hypopituitarism. In these situiations, prolactin is commonly the last pituitary hormone affected, after growth hormone and gonadotropins are lost and thyroid-stimulating hormone and adrenocorticotopic hormone secretion is impaired. Prolactin deficiency accompanies several congenital syndromes due to mutations in PROP1 and Pit1/ POU1F and in X-linked IGSF1 deficiency syndrome, and several aqcuired conditions including Sheehan syndrome, IgG4-related hypophysitis, and immune checkpoint-inhibitor-induced hypophysitis. In women, prolactin deficiency prevents lactation following childbirth among other symptoms associated with hypopituitarism. Human prolactin is not available commercially as replacement therapy. However, recombinant human prolactin administered daily to women with hypoprolactinemia and alactogenesis was found to lead to the production of significant milk volume sufficient for lactation.

What do we know about abnormally low prolactin levels in polycystic ovary syndrome? A narrative review

Hyper and hypoprolactinemia seem to be related to the occurrence of metabolic alterations in PCOS patients. In contrast, between significantly elevated and significantly low, prolactin levels seem to be protective against metabolic consequences. In the present review, we found 4 studies investigating hypoprolactinemia in patients with PCOS. We also identified 6 additional studies that reported low levels of PRL in PCOS patients. Although its prevalence is not considered high (13.2-13.9%), its contribution is certainly significant to the metabolic alterations observed in PCOS (insulin resistance, obesity, diabetes mellitus, and fatty liver disease). Dopamine inhibits the secretion of prolactin and GnRH. If dopamine levels are low or the dopamine receptor is less expressed or mutated, the levels of prolactin and GnRH increase, and consequently, LH also increases. On the other hand, hyperprolactinemia, in prolactinomas-typical levels, acting through kisspeptin inhibition causes GnRH suppression and hypogonadotropic hypogonadism. In situations of hypoprolactinemia due to excessive dopamine agonist treatment, dosage reduction is important to minimize the decrease in prolactin levels. Nevertheless, there is a lack of prospective studies confirming these hypotheses, as well as randomized clinical trials with appropriate drugs targeting both hyperprolactin and hypoprolactin in patients with PCOS.

Hypopituitarism and bone disease: pathophysiology, diagnosis and treatment outcomes

Hypopituitarism is a rare but significant endocrine disorder characterized by the inadequate secretion of one or more pituitary hormones. The intricate relationship between hypopituitarism and bone health is a topic of growing interest in the medical community. In this review the authors explore associations between hypopituitarism and bone health, with specific examination of the impact of growth hormone deficiency, central hypogonadism, central hypocortisolism, and central hypothyroidism. Pathogenesis, diagnosis, and treatment options as well as challenges posed by osteopenia, osteoporosis, and fractures in hypopituitarism are discussed.

Hypoprolactinemia. Does it matter? Redefining the hypopituitarism and return from a mumpsimus : "Absence of proof is not the proof of absence"

Prolactin (PRL) is secreted by the lactotroph cells in the anterior pituitary gland which is under inhibitory control of dopamine. The mature human PRL has more than 300 physiological actions including lactation, reproduction, homeostasis, neuroprotection, behavior, water and electrolyte balance, immunoregulation and embryonic and fetal development. PRL is involved in the growth and development of mammary gland, preparation of the breast for lactation in the postpartum period, synthesis of milk, and maintenance of milk secretion. Abnormalities in the synthesis and secretion of PRL may result in hyperprolactinemia or hypoprolactinemia. Although hyperprolactinemia has been extensively investigated in the literature, because of the subtle or unclearly defined symptoms, hypoprolactinemia is a less-known and neglected disorder. Failure of lactation is a well-known clinical manifestation of hypoprolactinemia. Recent studies reveal that hypoprolactinemia may have some effects beyond lactation such as increased risk for metabolic abnormalities including insulin resistance, abnormal lipid profile, obesity and sexual dysfunction. Very low level of PRL is suggested to be avoided in patients receiving dopamin agonist treatment to prevent unwanted effects of hypoprolactinemia. Another important point is that hypoprolactinemia is not included in the classification of hypopituitarism. Anterior pituitary failure is traditionally classified as isolated, partial and complete (panhypopituitarism) hypopituitarism regardless of prolactin level. Therefore, there are two kinds of panhypopituitarism: panhypopituitarism with normal or high PRL level and panhypopituitarism with low PRL level. In this review, we present two personal cases, discuss the diagnosis of hypoprolactinemia, hypoprolactinemia associated clinical picture and suggest to redefine the classification of hypopituitarism.

Traumatic brain injury and prolactin

Traumatic brain injury (TBI) is a well-known etiologic factor for pituitary dysfunctions, with a prevalence of 15% during long-term follow-up. The most common hormonal disruption is growth hormone deficiency, followed by central adrenal insufficiency, central hypogonadism, and central hypothyroidism in varying order across studies. The prevalence of serum prolactin disturbances ranged widely from 0 to 85%. Prolactin release is mainly regulated by hypothalamic dopamine inhibition, and mediators such as TRH, serotonin, cytokines, and neurotransmitters have modulatory effects. Many factors, such as hypothalamic and/or pituitary gland injuries, as well as fluctuations in dopaminergic activity and other mediators and stress response, may cause derangements in serum prolactin levels after TBI. Although it is challenging to investigate the direct effects of TBI on serum prolactin levels due to many confounders, basal prolactin measurements and stimulation tests provide insight into the functionality of the hypothalamus and pituitary gland after TBI. Moreover, during the acute phase of TBI, prolactin levels appear to correlate with TBI severity. In contrast, in the chronic phase, hypoprolactinemia may function as an indirect indicator of pituitary dysfunction and reduced pituitary volume. Further investigations are needed to elucidate the pathophysiologic mechanisms underlying the prolactin trend following TBI, its significance, and its associations with other pituitary hormone dysfunctions. In this article, we re-evaluated our patients' TBI data regarding prolactin levels during prospective long-term follow-up, and reviewed the literature regarding the prevalence, pathophysiology, and clinical implications of serum prolactin disturbances during acute and chronic phases following TBI.

Neuropsychological complications of hypoprolactinemia

Prolactin (PRL) is primarily produced by the pituitary lactotrophic cells and while initially named for its role in lactation, PRL has several other biological roles including immunomodulation, osmotic balance, angiogenesis, calcium metabolism, and appetite regulation. Most of the PRL-related literature has traditionally focused on hyperprolactinemia, whereas hypoprolactinemia has received little attention. There is evidence to suggest that PRL receptors are widely distributed within the central nervous system including the limbic system. Furthermore, PRL has been shown to play key role in the stress regulation pathway. Recent data also suggest that hypoprolactinemia may be associated with increased sexual dysfunction, anxiety, and depression. In this paper we discuss the current understanding regarding the neuropsychological impact of hypoprolactinemia and highlight the need for adequately defining hypoprolactinemia as an entity and consideration for future replacement therapies.

Hypopituitarism

Partial or complete deficiency of anterior or posterior pituitary hormone production leads to central hypoadrenalism, central hypothyroidism, hypogonadotropic hypogonadism, growth hormone deficiency, or arginine vasopressin deficiency depending on the hormones affected. Hypopituitarism is rare and likely to be underdiagnosed, with an unknown but rising incidence and prevalence. The most common cause is compressive growth or ablation of a pituitary or hypothalamic mass. Less common causes include genetic mutations, hypophysitis (especially in the context of cancer immunotherapy), infiltrative and infectious disease, and traumatic brain injury. Clinical features vary with timing of onset, cause, and number of pituitary axes disrupted. Diagnosis requires measurement of basal circulating hormone concentrations and confirmatory hormone stimulation testing as needed. Treatment is aimed at replacement of deficient hormones. Increased mortality might persist despite treatment, particularly in younger patients, females, and those with arginine vasopressin deficiency. Patients with complex diagnoses, pregnant patients, and adolescent pituitary-deficient patients transitioning to adulthood should ideally be managed at a pituitary tumour centre of excellence.

Diagnosing and treating the elderly individual with hypopituitarism

Hypopituitarism in the elderly is an underestimated condition mainly due to the non-specific presentation that can be attributed to the effects of aging and the presence of comorbidities. Diagnosis and treatment of hypopituitarism often represent a challenging task and this is even more significant in the elderly. Diagnosis can be insidious due to the physiological changes occurring with aging that complicate the interpretation of hormonal investigations, and the need to avoid some provocative tests that carry higher risks of side effects in this population. Treatment of hypopituitarism has generally the goal to replace the hormonal deficiencies to restore a physiological balance as close as possible to that of healthy individuals but in the elderly this must be balanced with the risks of over-replacement and worsening of comorbidities. Moreover, the benefit of some hormonal replacement therapies in the elderly, including sex hormones and growth hormone, remains controversial.

The diagnosis and prevalence of hypoprolactinemia in patients with panhypopituitarism and the effects on depression and sexual functions

PURPOSE

We aimed to investigate the prevalence and the diagnostic criteria of hypoprolactinemia in patients with panhypopituitarism and the effects of hypoprolactinemia on depression and sexual functions.

MATERIALS AND METHODS

Forty-eight patients with panhypopituitarism and 20 healthy volunteers were included. Basal hormone levels were measured and a TRH stimulation test was performed. For the evaluation of sexual functions, questionnaries of Female Sexual Functional Index (FSFI) for females and International Erectile Functional Index for males were performed to the subjects. Depressive symptoms were evaluated by Beck Depression Envontory score (BDI-II).

RESULTS

The peak PRL response to TRH stimulation test at 5th percentile in the control group was 18.6 ng/ml in males and 41.6 ng/ml in females and accepted as the cut-offs for sufficient response of PRL. Prolactin was insufficient in 42(87.5%) patients. A basal PRL level of ≤ 5.7 ng/ml in males and 7.11 ng/ml in females was 100% specific in predicting an inadequate response to TRH stimulation test with 80% and 70% sensitivity respectively. A basal PRL level of ≥ 8.5 ng/dl in males was 100% specific and 76% sensitive, and in females a level of ≥ 15.2 ng/dl was 96% specific and 66% sensitive in predicting an adequate response to TRH. PRL deficient patients with panhypopituitarism had higher depression scores compared to the controls, lower sexual function scores in males.

CONCLUSION

PRL deficiency is prevalent among individuals with panhypopituitarism, with the potential to result in elevated depression scores in both sexes and impaired sexual functions in males. A basal PRL level seems to be sufficient for the diagnosis of hypoprolactinemia in routine clinical practice.

The Hypothalamic-Pituitary-Thyroid Axis in Cushing Syndrome Before and After Curative Surgery

BACKGROUND

We do not fully understand how hypercortisolism causes central hypothyroidism or what factors influence recovery of the hypothalamic-pituitary-thyroid axis. We evaluated thyroid function during and after cure of Cushing syndrome (CS).

METHODS

We performed a retrospective cohort study of adult patients with CS seen from 2005 to 2018 (cohort 1, c1, n = 68) or 1985 to 1994 (cohort 2, c2, n = 55) at a clinical research center. Urine (UFC) and diurnal serum cortisol (F: ~8 am and ~midnight [pm]), morning 3,5,3'-triiodothyronine (T3), free thyroxine (FT4), and thyrotropin (TSH) (c1) or hourly TSH from 1500 to 1900 h (day) and 2400 to 04000 h (night) (c2), were measured before and after curative surgery.

RESULTS

While hypercortisolemic, 53% of c1 had central hypothyroidism (low/low normal FT4 + unelevated TSH). Of those followed long term, 31% and 44% had initially subnormal FT4 and T3, respectively, which normalized 6 to 12 months after cure. Hypogonadism was more frequent in hypothyroid (69%) compared to euthyroid (13%) patients. Duration of symptoms, morning and midnight F, adrenocorticotropin, and UFC were inversely related to TSH, FT4, and/or T3 levels (r = -0.24 to -0.52, P < .001 to 0.02). In c2, the nocturnal surge of TSH (mIU/L) was subnormal before (day 1.00 ± 0.04 vs night 1.08 ± 0.05, P = .3) and normal at a mean of 8 months after cure (day 1.30 ± 0.14 vs night 2.17 ± 0.27, P = .01). UFC greater than or equal to 1000 μg/day was an independent adverse prognostic marker of time to thyroid hormone recovery.

CONCLUSIONS

Abnormal thyroid function, likely mediated by subnormal nocturnal TSH, is prevalent in Cushing syndrome and is reversible after cure.

Copeptin response to hypoglycemic stress is linked to prolactin activation in children

PURPOSE

The physiological role of arginine vasopressin (AVP) in the acute stress response in humans and especially in children is unclear. The aim of this study was to explore the interaction between copeptin, a well-established surrogate marker of AVP release, and anterior pituitary hormone activation in response to acute hypoglycemic stress in children and adolescents.

METHODS

We conducted an exploratory single center study involving 77 children and adolescents undergoing insulin-induced hypoglycemia. Blood levels of copeptin, ACTH, cortisol, GH, prolactin, interleukin-6 (IL-6), adrenaline and noradrenaline were determined at baseline and after insulin-induced hypoglycemia.

RESULTS

Basal plasma levels of copeptin (median: 5.2 pmol/L) increased significantly after hypoglycemia (median 9.7 pmol/L; P < 0.0001). Subjects with insufficient HPA axis response or severe GH deficiency had lower hypoglycemia-induced copeptin increase (median: 2.3 pmol/L) compared with individuals with intact pituitary response (median: 5.2 pmol/L, P = 0.02). Copeptin increase correlated significantly with the maximal increase of ACTH (r_s = 0.30; P = 0.010), cortisol (r_s = 0.33; P = 0.003), prolactin (r_s = 0.25; P = 0.03), IL-6 (r_s = 0.35; P = 0.008) and with BMI-SDS (r_s = - 0.28, P = 0.01). In multivariate regression analysis, prolactin increase was the only independent variable associated with copeptin increase (P = 0.0004).

CONCLUSION

Our data indicate that: (1) hypoglycemic stress elicits a marked copeptin response in children and adolescents, pointing out its role as an acute stress marker in this population; (2) stress-induced AVP/copeptin release is associated with anterior pituitary activation, mainly a prolactin response.

UNDERSTANDING PROLACTIN REGULATION AND DETERMINING THE EFFICACY OF CABERGOLINE AND DOMPERIDONE TO MITIGATE PROLACTIN-ASSOCIATED OVARIAN CYCLE PROBLEMS IN ZOO AFRICAN ELEPHANTS (LOXODONTA AFRICANA )

Perturbations in serum prolactin secretion, both over- and underproduction, are observed in zoo African elephants (Loxodonta africana) that exhibit abnormal ovarian cycles. Similar prolactin problems are associated with infertility in other species. Pituitary prolactin is held under constant inhibition by a hypothalamic-derived neurotransmitter, dopamine; thus, regulation by exogenous treatment with agonists or antagonists may be capable of reinitiating normal ovarian cycles. This study tested the efficacy of oral administration of cabergoline (agonist) and domperidone (antagonist) as possible treatments for hyperprolactinemia or chronic low prolactin, respectively. Hyperprolactinemic (overall mean prolactin, >30 ng/ml), acyclic elephants were administered oral cabergoline (2 mg, n = 4) or placebo (dextrose capsule, n = 4) twice weekly. Overall mean prolactin concentration decreased in treated females compared with controls (32.22 ± 14.75 vs 77.53 ± 0.96 ng/ml; P = 0.01). Interestingly, overall mean progestagen concentrations also increased slightly (P < 0.05) in treated females (0.15 ± 0.01 ng/ml) compared with controls (0.07 ± 0.01 ng/ml), but no reinitation of normal cyclic patterns was observed. Chronic low prolactin (overall mean prolactin, <10 ng/ml), acyclic females were orally administered domperidone (2 g/day, n = 4) or placebo (dextrose capsule, n = 4) for 4 wk, followed by 8 wk of no treatment (four cycles) to simulate the prolactin pattern observed in normal cycling elephants. Overall mean prolactin concentrations increased (P = 0.005) during domperidone treatment (21.77 ± 3.69 ng/ml) compared with controls (5.77 ± 0.46 ng/ml), but progestagen concentrations were unaltered. Prolactin regulation by dopamine was confirmed by expected responses to dopamine agonist and antagonist treatment. Although prolactin concentrations were successfully reduced by cabergoline, and domperidone initiated the expected cyclic prolactin pattern, neither treatment induced normal ovarian activity.

Suprasellar extension independently predicts preoperative pituitary hormone deficiencies in patients with nonfunctioning pituitary macroadenomas: a single-center experience

PURPOSE

Nonfunctioning pituitary adenomas (NFPAs) are among the commonest benign tumors of the pituitary. Hypopituitarism is frequently present at the time of diagnosis, and this has been attributed to stalk portal vessel compression and/or destruction of normal anterior pituitary cells. The aim of our study was to examine possible factors at diagnosis associated with the presence of hypopituitarism.

METHODS

We retrospectively evaluated the records of patients with nonfunctioning pituitary macroadenomas from the database of our department. The inclusion criterion was the availability of imaging data regarding the extension of the lesion.

RESULTS

A total of 148 patients (89 men, 60.1%) with nonfunctioning macroadenomas and available imaging data were identified. Mean age at diagnosis was 56.0 ± 14.5 years, and hypopituitarism was found in 66.2%. The maximum diameter of the adenoma, the patient's age at diagnosis, and compression of the optic chiasm were significant factors predicting the presence of hypopituitarism (OR 1.077, p = 0.006; OR 1.025, p = 0.045; and OR 2.893, p = 0.042, respectively). Suprasellar adenomas with extension to adjacent sinuses, although larger than those with only suprasellar extension, did not differ as to the degree of hypopituitarism. Moreover, in suprasellar adenomas, prolactin levels, albeit not independently, were also related to hypopituitarism (OR 1.035, p = 0.045).

CONCLUSIONS

In patients with NFPAs, prognostic factors related to increased risk of hypopituitarism are age at diagnosis, size of the adenoma, and most importantly the presence of suprasellar extension. These data accentuate the necessity for surgical decompression in case of suprasellar extension, in order, apart from saving visual acuity, to possibly avoid or reverse hypopituitarism.

Suspected Testosterone-Producing Tumor in a Patient Taking Biotin Supplements

A perimenopausal woman presented with palpitations, hirsutism, and inability to lose weight. Laboratory tests revealed an unusual endocrine hormonal profile including pituitary hormones (TSH, ACTH, and prolactin) below reference intervals and gonadal (testosterone) and adrenal (cortisol) hormones above reference intervals. Ultimately, after a comprehensive workup including a scheduled surgical procedure, abnormal laboratories were determined due to biotin interference. Biotin (vitamin B7) is a water-soluble vitamin and essential cofactor for the metabolism of fatty acids, glucose, and amino acids. The recommended daily intake of biotin for adults is 30 µg/d. Many over-the-counter products, particularly those marketed for hair, skin, and nail growth, contain biotin 100-fold of recommended daily intake. This case is unique due to the abnormalities observed not only in the well-described TSH "sandwich" immunoassay, but also in tests for gonadal steroids, adrenal, and pituitary hormones. Falsely high as well as falsely low results can be ascribed to biotin. Competitive immunoassays (Fig. 1A)- in this case, tests used initially for serum cortisol and testosterone- can demonstrate falsely high results. Interference falsely lowers the immunometric "sandwich" immunoassay (Fig. 1B)-in this case, TSH. Biotin effect on our patient's endocrine testing led to decidedly abnormal findings, unnecessary medical referrals and diagnostic studies, and comprehensible psychological distress. Interference with one immunoassay, TSH, persisted a full 2 weeks after discontinuation of biotin; indeed, some tests demonstrate sensitivity to lesser quantities of biotin. Improved communication between patients, health care providers, and laboratory professionals is required concerning the likelihood of biotin interference with immunoassays.

Pituitary Hypoplasia

This article summarizes pituitary development and function as well as specific mutations of genes encoding the following transcription factors: HESX1, LHX3, LHX4, POU1F1, PROP1, and OTX2. Although several additional genetic defects related to hypopituitarism have been identified, this article focuses on these selected factors, as they have been well described in the literature in terms of clinical characterization of affected patients and molecular mechanisms of action, and therefore, are very relevant to clinical practice.

A relationship between a level of hemoglobin after delivery and exclusive breastfeeding initiation at a baby friendly hospital in Japan

BACKGROUND

The recent National Nutrition Survey of 2013 demonstrated that 16.7% of women in childbearing age are underweight, and 5.0-10.0% of these women manifested a Hemoglobin (Hb) level less than 11.0 g/dl. The purpose of this study was to investigate if such maternal nutritional status affects success of exclusive breastfeeding (EBF) practice.

METHODS

This cross-sectional study investigated 1532 dyads of mothers and infants with full-term singleton pregnancies delivered during 2011 at a perinatal center in Tokyo. Outcome is EBF initiation defined as the successful practice at discharge and 1 month after discharge. A logistic regression model was applied to investigate the impact of Hb levels (<9.0, 9.0-10.9, and ≥11.0 g/dl) measured within 2-3 days after delivery on successful EBF initiation adjusting for covariates including bleeding at delivery.

RESULTS

Mean age was 34 years, 23.0% were underweight and 63.0% were nulliparous. The success rate for EBF initiation at discharge and at 1 month after discharge was 72.7 and 63.0% for a Hb level <9.0 g/dl, 81.9 and 68.9% for a Hb level of 9.0-10.9 g/dl, and 85.7 and 75.9% for a Hb level ≥11.0 g/dl, respectively. A logistic regression model showed that risk factors of unsuccessful EBF practice at discharge and 1 month after discharge included lower level Hb categories (P < 0.001 and P < 0.001), postpartum hemorrhage > 500 ml (P = 0.089 and P = 0.011), maternal age (P < 0.001 and P < 0.001), nulliparity (P < 0.0001 and P < 0.001), pregnancy-induced hypertension (P = 0.002 and P = 0.012), gestational week (P = 0.006 and P = 0.002), Low Birth Weight (LBW) (P < 0.001 and P < 0.001), and immediate separation (P < 0.001 and P = 0.020). After adjusting for the covariates, compared with a Hb level ≥11.0 g/dl, a Hb level <9.0 g/dl was significantly associated with unsuccessful EBF initiation at discharge [odds ratio (OR): 2.15; 95% confidence interval (CI): 1.37-3.39] and at 1 month after discharge (OR: 1.63; 95% CI: 1.10-2.42), and a Hb level of 9.0-10.9 g/dl also was significant at 1 month after discharge (OR: 1.35; 95% CI: 1.04-1.75). Pre-pregnancy underweight was not associated with success of EBF practice both at hospital discharge and 1 month after discharge.

CONCLUSION

Maternal severe anemia after delivery was associated with the risk of unsuccessful initiation of EBF even after adjusting for bleeding at delivery, suggesting the importance of dietary management especially in the later trimester.

Hypopituitarism

Hypopituitarism refers to deficiency of one or more hormones produced by the anterior pituitary or released from the posterior pituitary. Hypopituitarism is associated with excess mortality, a key risk factor being cortisol deficiency due to adrenocorticotropic hormone (ACTH) deficiency. Onset can be acute or insidious, and the most common cause in adulthood is a pituitary adenoma, or treatment with pituitary surgery or radiotherapy. Hypopituitarism is diagnosed based on baseline blood sampling for thyroid stimulating hormone, gonadotropin, and prolactin deficiencies, whereas for ACTH, growth hormone, and antidiuretic hormone deficiency dynamic stimulation tests are usually needed. Repeated pituitary function assessment at regular intervals is needed for diagnosis of the predictable but slowly evolving forms of hypopituitarism. Replacement treatment exists in the form of thyroxine, hydrocortisone, sex steroids, growth hormone, and desmopressin. If onset is acute, cortisol deficiency should be replaced first. Modifications in replacement treatment are needed during the transition from paediatric to adult endocrine care, and during pregnancy.

Prolactin insufficiency but normal thyroid hormone levels after cranial radiotherapy in long-term survivors of childhood leukaemia

BACKGROUND

Acute lymphoblastic leukaemia (ALL) patients treated with cranial radiotherapy (CRT) have an increased risk of GH deficiency (GHD). Little is known about insufficiencies of prolactin (PRL) and TSH, but also lactation failure has been reported in this population.

OBJECTIVE

To study the long-term outcome of CRT on PRL and thyroid hormone levels in GHD ALL patients and the prevalence of lactation failure.

DESIGN

Case-control study.

PATIENTS

We examined 40 GHD and 4 GH insufficient ALL patients, in median 20 years (range: 8-27) after ALL diagnosis and 44 matched population controls.

MEASUREMENTS

PRL secretion (area under the curve; AUC) after GHRH-arginine test in all patients and matched controls, and PRL and TSH AUC after a TRH-test in 13 patients and 13 controls. And basal PRL and thyroid hormone levels after 5 years with GH therapy and 8 years without GH therapy.

RESULTS

Compared with controls, ALL patients had significantly lower basal and AUC PRL after GHRH-Arginine (P = 0·03, P = 0·02), and AUC PRL after TRH (P = 0·001). After 5 and 8 years, PRL levels decreased further (P = 0·01, P = 0·03), but thyroid hormones remained normal at baseline and at follow-up. PRL insufficiency was significantly associated with increased levels of BMI and insulin. Six out of seven pregnant ALL women reported lactation failure.

CONCLUSIONS

Long-term ALL survivors treated with CRT have GHD and PRL insufficiency, and a high prevalence of lactation failure, but thyroid hormones remained normal. PRL insufficiency was associated with cardiovascular risk.

Failure of antibody response to polysaccharide antigen in treated panhypopituitary adults

Although pituitary hormones are known to affect immune function, treated hypopituitarism is not a recognized cause of immune deficiency in humans. We set out to assess integrity of baseline and stimulated immune function in severely hypopituitary adults. Twenty-one panhypopituitary adults (group 1), on stable pituitary replacement including growth hormone, and 12 healthy volunteers (group 2) were studied. Lymphocyte subsets, pneumococcal antibody levels pre- and 1 month after polysaccharide vaccination, T cell numbers and in-vitro interferon (IFN)-gamma response were studied. There were no significant differences in T cell numbers or IFN-gamma secretion. B cell numbers were lower in group 1, especially those with low prolactin levels. Independent of this finding, nine of 21 patients in this group had low antibody response to polysaccharide antigen. This was most striking in those with low insulin-like growth factor 1 levels and appeared to be independent of the use of anti-convulsants or corticosteroid replacement. Significant humoral immune deficiency is seen in panhypopituitarism and may contribute to morbidity.

Hypopituitarism: clinical features, diagnosis, and management

Hypopituitarism is characterized by loss of function of the anterior pituitary gland. It is a rare condition that can present at any age and is caused by pathology of the hypothalamic-pituitary axis or one of many gene mutations. The symptoms and signs of hypopituitarism may evolve over several years and be nonspecific or related to the effects of the underlying disease process or to hormone deficiencies. Investigation of patients requires a combination of basal hormone levels and dynamic function tests; management requires regular monitoring. The goal of physicians managing patients who have hypopituitarism is to improve their health and long-term outcome.

Preoperative assessment for pituitary surgery

Evaluation of pituitary function is essential before pituitary surgery. In hyperprolactinaemic patients with a pituitary macrolesion, tumoral secretion of prolactin must be distinguished from 'disconnection' hyperprolactinaemia; serum prolactin >200 mcg/l is virtually diagnostic of a macroprolactinoma whereas levels <80 mcg/l usually indicate 'disconnection'. The prolactin 'hook effect' should be excluded. A minimum set of pre-operative endocrine tests should include serum electrolytes, cortisol (at 08.00-09.00 h), free-T4, TSH, prolactin, oestradiol/testosterone, LH, FSH and IGF-1. Some clinicians will choose to perform pre-operative Synacthen or insulin tolerance testing to further define ACTH reserve. If basal cortisol, Synacthen or insulin tolerance test results are abnormal, steroid supplementation is indicated for at least the first 48 h after surgery. If pre-operative basal cortisol is <100 nmol/l, replacement steroids should be continued until the time of post-operative pituitary function testing (6-8 weeks after surgery). In patients with pre-operative basal cortisol >450 nmol/l, peri-operative glucocorticoid replacement is unnecessary and further cortisol levels should be checked a few days after surgery. Most clinicians defer detailed evaluation of growth hormone reserve until after surgery. Diabetes insipidus is rarely a problem before surgery in patients with pituitary adenomas but may occur post-operatively. Close co-operation between anesthetic, endocrine and surgical teams is strongly recommended.

Acquired prolactin deficiency in patients with disorders of the hypothalamic-pituitary axis

Acquired PRL deficiency occurs when the anterior pituitary is functionally destroyed, and it usually accompanies other pituitary hormone deficiencies. We retrospectively investigated in an outpatient endocrine clinic of a major tertiary medical center the prevalence and clinical characteristics of acquired PRL deficiency in patients with diseases of the hypothalamic-pituitary axis. The study included 100 consecutive patients, 61 men and 39 women, aged 4-79 yr at diagnosis. Patients were divided by PRL level to normal (>5 ng/ml), mild (3-5 ng/ml), and severe deficiency (<3 ng/ml). Twenty-seven patients (27%) had PRL deficiency, 13 mild deficiency and 14 severe deficiency. Patients with severe PRL deficiency tend to be younger at diagnosis (mean age, 37.5+/-21.8 yr) than patients with normal PRL (46+/-18.5 yr; ns). Underlying diseases including pituitary apoplexy, non-functioning pituitary adenoma, craniopharyngioma, and idiopathic hypogonadotropic hypogonadism were associated with PRL deficiency. The incidence of severe PRL deficiency rose with an increase in the number of other pituitary hormone deficits (ACTH, TSH, gonadotropin, vasopressin), from 0 in patients with no other deficits to 38% in patients with 4 deficits (p=0.006). Patients with severe deficiency had a mean of 3 hormone deficits compared to 1.8 in the other groups (p=0.006). PRL deficiency was significantly associated with TSH, ACTH and GH deficiency.

CONCLUSIONS

PRL deficiency is common in patients with hypothalamic-pituitary disorders, especially pituitary apoplexy and craniopharyngioma. Acquired severe PRL deficiency can be considered a marker for extensive pituitary damage and a more severe degree of hypopituitarism.

Attenuated pulse size, disorderly growth hormone and prolactin secretion with preserved nyctohemeral rhythm distinguish irradiated from surgically treated acromegaly patients

BACKGROUND

Radiation induces time-dependent loss of anterior pituitary function, attributed to damage of the pituitary gland and hypothalamic centres. The development of growth hormone deficiency (GHD) in irradiated acromegaly patients is not well defined.

OBJECTIVE

Detailed analysis of spontaneous 24-h GH and prolactin (PRL) secretion in relation to other pituitary functions and serum IGF-I concentrations in an attempt to find criteria for GHD in acromegalic patients with a GH response < 3 microg/l during the insulin tolerance test (ITT).

DESIGN

Plasma hormone profiles obtained by 10 min sampling for 24 h in postoperatively irradiated acromegalic patients, compared with patients cured by surgery only and matched healthy controls.

SETTING/PARTICIPANTS

University setting. Fifteen subjects in each group.

OUTCOME MEASURES

GH and PRL secretory parameters quantified by deconvolution, cluster, cosinor and approximate entropy (ApEn) analyses, IGF-I concentrations.

RESULTS

Irradiation attenuated pulsatile secretion of GH and PRL, but total PRL secretion was unchanged. GH and PRL secretory regularity were diminished. Circadian timing remained intact. Pulsatile GH secretion and IGF-I were correlated (R = 0.30, P = 0.04). Criteria of pulsatile GH secretion = 12 microg/l/24 h and ApEn = 0.800 separated 12 of 15 irradiated patients from all others.

CONCLUSION

Irradiated acromegaly patients with a subnormal GH response to ITT have very limited spontaneous GH secretion, with specific attenuation of the size of GH bursts and a highly irregular pattern, but with retained diurnal properties. These patients are thus likely GH-deficient and might benefit from GH replacement.

Aetiology, diagnosis, and management of hypopituitarism in adult life

Hypopituitarism is a complex medical condition associated with increased morbidity and mortality, requires complicated treatment regimens, and necessitates lifelong follow up by the endocrinologist. The causes, clinical features, and the management of hypopituitarism including endocrine replacement therapy are considered in this review article.

Sensitivity of anterior pituitary hormones to irradiation

Cranial irradiation is used in the management of a diverse group of intracranial pathologies. However, if any part of the hypothalamic-pituitary axis is included in the radiation field, there is a risk of developing neuroendocrine dysfunction. Growth hormone is the most radiosensitive of the anterior pituitary hormones, followed by the gonadotropins, adrenocorticotropic hormone and thyroid-stimulating hormone. A number of factors determine both the occurrence and severity of hypothalamic-pituitary dysfunction, including: the dose of radiation received by the hypothalamic-pituitary axis (determined by a number of factors including total dose and fractionation schedule and ultimately expressed as the biological effective dose); length of time since cranial irradiation; age of the patient at the time of cranial irradiation; type of radiotherapy administered; and the different inherent radiosensitivities of the anterior pituitary hormones. These neuroendocrine abnormalities usually develop a number of years after the initial insult and, therefore, patients who have received cranial irradiation should receive annual endocrine assessments. The establishment of endocrine late-effect clinics for the survivors of childhood cancers have gone some way to addressing this problem; however, other groups of patients, particularly those receiving cranial irradiation in adult life, may not have systematic endocrine assessment.

Acquired prolactin deficiency (APD) after treatment for Cushing's disease is a reliable marker of irreversible severe GHD but does not reflect disease status

OBJECTIVE

We have previously reported that acquired prolactin deficiency (APD) is a marker for severe hypopituitarism and observed a high prevalence of APD in patients treated for Cushing's disease. Recovery of GH secretion is recognized to occur in a proportion of patients treated for Cushing's disease after the effects of glucocorticoid excess on GH secretion have subsided. The aim of this study was to investigate further the association between APD, treated Cushing's disease and, in particular, to determine whether recovery of GH secretion may occur in these patients.

METHODS

Fifty-seven patients (42 female), in remission after treatment for Cushing's disease, were studied. The cohort comprised 13 patients with, and 44 without APD. APD was defined as a serum prolactin persistently below the detection limit of the assay. Severe GH deficiency was defined as a peak GH response of less than 9 mU/l during a GH stimulation test. Age and gender did not significantly differ between subgroups.

RESULTS

Of the 13 patients with APD, a macroadenoma was present in one patient, a microadenoma was present in 10, no lesion was detected in one, and in one patient (treated with an yttrium implant) the size of the tumour was unknown. Of the 28 patients who did not have APD, who were treated with primary surgery a microadenoma was present in 23 and a macroadenoma was present in five. Detailed pituitary imaging was not available in 16 patients who did not have APD, who were treated with primary external XRT. Deficiencies of GH, TSH, LH/FSH (P < 0.0001) and ADH (P = 0.006) status, by conventional testing, were present more frequently in the APD subgroup. In contrast, the prevalence of ACTH deficiency after treatment was not different between the APD and non-APD groups. However, the requirement for additional therapy, targeting the pituitary or adrenal gland, after primary treatment, in those patients not rendered ACTH-deficient, was significantly greater in the APD compared with the non-APD groups (P = 0.003). After pituitary surgery, a significant correlation between peak GH response and interval since remission of Cushing's syndrome was found in the subgroup without APD (r = 0.4, P = 0.04). Four patients who did not have APD, who had documented severe GHD in the immediate postoperative period displayed normalization of GH secretion, when re-tested after a mean interval of 27.2 months. In contrast, no patient with APD after pituitary surgery demonstrated a detectable GH response after up to 132 months of follow-up. No patient with APD showed recovery of prolactin secretion by the time of the most recent measurement (mean 57 months). All 10 patients who developed APD immediately after pituitary surgery had undergone a radical procedure (either a subtotal or total hypophysectomy). In contrast, of 28 patients with Cushing's disease who did not develop APD, only four underwent radical surgery (P < 0.0001). Seven of 14 patients (50%) who underwent a radical operation and two of 20 treated by selective adenomectomy (10%) required additional treatment to achieve control of Cushing's syndrome (P = 0.04).

CONCLUSION

In the presence of APD, patients with Cushing's disease do not experience recovery of GH secretion after treatment, even after the effects of glucocorticoid excess subside. In the absence of APD, GH status may normalize after successful surgical treatment. Although a marker for severe hypopituitarism, APD does not indicate success of treatment of Cushing's disease and may be associated with detectable ACTH secretion from residual corticotroph adenoma activity. APD after pituitary surgery for Cushing's disease occurs only after a radical operation. When a selective adenomectomy is not possible, control of Cushing's disease by operation is less frequent and when achieved, is more often at the cost of hypopituitarism. The optimal management of such patients requires further study.