Hypothalamic derangement in traumatized patients: growth hormone (GH) and prolactin response to thyrotrophin-releasing hormone and GH-releasing hormone

Endocrine Dysfunction in Traumatic Subarachnoid Hemorrhage: A Prospective Study

Background This study has prospectively investigated pituitary function and their correlation with severity, pressure effect, and Glasgow outcome scale in the acute phase of traumatic subarachnoid hemorrhage (SAH). Most of the retrospective studies have demonstrated that traumatic SAH-mediated hypopituitarism could be more frequent than previously known.

Objectives The aim of the study is to find the prevalence of endocrine dysfunction in traumatic SAH and its correlation with severity of injury and final outcome.

Materials and Methods Eighty-four consecutive patients of traumatic SAH formed the study group. Apart from clinical assessment, noncontrast computed tomography of the head was performed on all patients on admission. The hormonal analysis (FT3, FT4, thyroid-stimulating hormone, growth hormone [GH], cortisol, prolactin, testosterone) was performed within 24 hours of traumatic brain injury and was repeated on the seventh day amongst the patients who survived.

Results Most common hormone to increase on day one was cortisol (48.78%), while on day seven follicle-stimulating hormones and cortisol (15.38%) showed increment in levels. Most common hormone to decrease on day one was FT3 (36.84%) and GH (36.26%), while on day seven testosterone (66.67%) and FT4 (30.76%) showed decreasing levels. Hormone most resistant to change was prolactin.

Conclusion Hormonal dysfunction is common in moderate to severe traumatic brain injury. There is a direct association between radiological grading (Fischer) of SAH and hormonal profile changes. Performance of hormonal analysis should be considered in patients with moderate to severe traumatic brain injury, preferably with high-grade SAH, so that appropriate hormonal replacement can be done to optimize the clinical outcome.

Pituitary dysfunction after traumatic brain injury: prevalence and screening strategies

INTRODUCTION

Pituitary gland is vulnerable to traumatic brain injury (TBI). As a result a series of neuroendocrine changes appear after head injury; in many occasions they reverse with time, while occasionally new late onset changes may develop.

AREAS COVERED

In this review, we focus on the prevalence of anterior and posterior pituitary hormonal changes in the acute and chronic post-TBI period in both children and adults. Moreover, we present evidence supporting the need for evaluating pituitary function along with the current suggestions for the most appropriate screening strategies. We attempted to identify all published literature and we conducted an online search of PubMed, from January 1970 to June 2020.

EXPERT OPINION

Adrenal insufficiency and water metabolism disorders are medical emergencies and should be promptly recognized. Awareness for long-term hormonal derangements is necessary, as they may lead to a series of chronic health issues and compromise quality of life. There is a need for well-designed prospective long-term studies that will estimate pituitary function during the acute and chronic phase after head injury.

Traumatic brain injury induced neuroendocrine changes: acute hormonal changes of anterior pituitary function

PURPOSE

It is estimated that approximately 69 million individuals worldwide will sustain a TBI each year, which accounts for substantial morbidity and mortality in both children and adults. TBI may lead to significant neuroendocrine changes, if the delicate pituitary is ruptured. In this review, we focus on the anterior pituitary hormonal changes in the acute post-TBI period and we present the evidence supporting the need for screening of anterior pituitary function in the early post-TBI time along with current suggestions regarding the endocrine assessment and management of these patients.

METHODS

Original systematic articles with prospective and/or retrospective design studies of acute TBI were included, as were review articles and case series.

RESULTS

Although TBI may motivate an acute increase of stress hormones, it may also generate a wide spectrum of anterior pituitary hormonal deficiencies. The frequency of post-traumatic anterior hypopituitarism (PTHP) varies according to the severity, the type of trauma, the time elapsed since injury, the study population, and the methodology used to diagnose pituitary hormone deficiency. Early neuroendocrine abnormalities may be transient, but additional late ones may also appear during the course of rehabilitation.

CONCLUSIONS

Acute hypocortisolism should be diagnosed and managed promptly, as it can be life-threatening, but currently there is no evidence to support treatment of acute GH, thyroid hormones or gonadotropins deficiencies. However, a more comprehensive assessment of anterior pituitary function should be undertaken both in the early and in the post-acute phase, since ongoing hormone deficiencies may adversely affect the recovery and quality of life of these patients.

Pituitary dysfunction after aneurysmal subarachnoid hemorrhage in Japanese patients

To elucidate the pituitary function of Japanese patients after aneurysmal subarachnoid hemorrhage (aSAH) and implicative factors related to growth hormone deficiency (GHD) after aSAH. We evaluated basal pituitary hormone levels among 59 consecutive aSAH patients with a modified Rankin Scale (mRS) ⩽4 at 3months after aSAH onset. Patients with low insulin-like growth factor 1 (IGF-1) SD score (SDS) or who seemed to develop pituitary dysfunction underwent provocative endocrine testing during a period of 3-36months after SAH onset. The relationship between IGF-1 SDS and clinical factors of the patients such as severity of SAH, aneurysm location, and treatment modalities, were assessed. Six patients (10.2%) demonstrated their IGF-1 SDS less than -2. Multiple logistic regression analyses revealed that patients who underwent surgical clipping had a significantly lower IGF-1 SDS (<-1SD) than patients who underwent endovascular embolization with an odds ratio of 5.83 (p=0.032). Thirty-three patients took provocative tests and five (15.6%) patients were identified as having GHD. The mean IGF-1 SDS of these five GHD patients was 0.08 SD. The aneurysms in all GHD patients were located in internal carotid artery (ICA) or anterior cerebral artery (ACA). To the best of our knowledge, this is the first report describing the prevalence of GHD in Japanese patients after aSAH, and it was not as high as that of previous European studies. We recommend that screening pituitary dysfunction for aSAH survivors with their aneurysms located in ICA or ACA.

Pituitary and/or hypothalamic dysfunction following moderate to severe traumatic brain injury: Current perspectives

There is an increasing deliberation regarding hypopituitarism following traumatic brain injury (TBI) and recent data have suggested that pituitary dysfunction is very common among survivors of patients having moderate-severe TBI which may evolve or resolve over time. Due to high prevalence of pituitary dysfunction after moderate-severe TBI and its association with increased morbidity and poor recovery and the fact that it can be easily treated with hormone replacement, it has been suggested that early detection and treatment is necessary to prevent long-term neurological consequences. The cause of pituitary dysfunction after TBI is still not well understood, but evidence suggests few possible primary and secondary causes. Results of recent studies focusing on the incidence of hypopituitarism in the acute and chronic phases after TBI are varied in terms of severity and time of occurrence. Although the literature available does not show consistent values and there is difference in study parameters and diagnostic tests used, it is clear that pituitary dysfunction is very common after moderate to severe TBI and patients should be carefully monitored. The exact timing of development cannot be predicted but has suggested regular assessment of pituitary function up to 1 year after TBI. In this narrative review, we aim to explore the current evidence available regarding the incidence of pituitary dysfunction in acute and chronic phase post-TBI and recommendations for screening and follow-up in these patients. We will also focus light over areas in this field worthy of further investigation.

Assessment of endocrine abnormalities in severe traumatic brain injury: a prospective study

OBJECTIVE

The frequency and pattern of endocrine abnormalities among patients with traumatic brain injury have been the subject matter of very few studies. This study was intended to assess the pattern of endocrine dysfunction following severe head injury.

METHODS

Severe head injury patients admitted to the Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, from January to December in 1 year formed the study group. Apart from clinical assessment, NCCT of the head was performed on all patients on admission. A complete anterior pituitary hormone analysis was performed within 24 h of injury and was repeated at 2 weeks, 3 months and 6 months amongst patients who survived.

RESULTS

A total of 99 patients were included in the study. Forty of our patients succumbed in the hospital. Rest of the patients were followed up for 6 months. Elevations of cortisol followed by prolactin were the most common hormonal derangements at admission. Midline shift on CT scans was inversely related to cortisol elevation and directly related to GH elevation. Infarct on CT scans was inversely related to cortisol and LH elevation. A significant alteration was found in the decreasing trend of the mean T4 values and normalisation or a decreasing trend from initially elevated mean cortisol and GH levels during follow-up (p < 0.05).

CONCLUSIONS

This study reveals that abnormalities in hormonal profiles appear to be relatively common in severe traumatic brain injury and fluctuate significantly over at least 6 months; there is a correlation with age and radiological findings. Performance of hormonal analysis evaluation should be considered in patients with severe brain injury so that appropriate hormonal replacement can be done to optimise the clinical outcome.

Managing patients with hypopituitarism after traumatic brain injury

PURPOSE OF REVIEW

To highlight how traumatic brain injury as well as subarachnoid hemorrhage and primary brain tumors of the central nervous system can induce hypopituitarism - an underdiagnosed clinical problem. Then, further information of the problem is likely to stimulate appropriate screening programs for patients with brain injuries, at high risk of developing an unrecognized hypopituitarism.

RECENT FINDINGS

Recent papers have alerted endocrinologists about brain injury-induced hypopituitarism. Both retrospective and prospective studies recommended that patients with more severe forms of head injury and, in particular, those with fractures of the base of the skull or early diabetes insipidus be closely monitored for signs and symptoms of endocrine dysfunction, and appropriate dynamic pituitary function tests performed.

SUMMARY

We hope this review will stimulate further interest in the endocrine community about the pathophysiology and management (diagnosis and treatment) of different kinds and degrees of pituitary insufficiency due to traumatic brain injury. Further studies will be crucial to raise awareness and remind physicians of the prevalence of hypopituitarism in patients with traumatic brain injury, and elucidate any incremental benefits these patients may receive from hormone replacement.

The Rotating Ring-Disk Electrochemistry of the Copper(II) Complex of Thyrotropin-releasing Hormone

Thyrotropin-releasing Hormone (TRH) forms an electroactive Cu(II) complex in aqueous solution. Rotating ring-disk electrochemistry reveals oxidation at the disk electrode and reduction at the ring electrode. The plot of limiting current vs. square root of rotation frequency deviates from the Levich equation, indicating both preceding and following chemical reactions. The reaction following the oxidation is a multiple-electron ECE-type of process that has been seen before in Cu(II)-peptide electrochemistry. The preceding reaction is unusual. The deviation from diffusion-controlled behavior is more pronounced at higher initial concentration of Cu(II) and peptide. We propose that a non-electroactive dimer, Cu(II)(2)-TRH(2), is in a slow equilibrium with the electroactive Cu(II)-TRH. Simulation of the RRDE behavior of the postulated Cu(II)-TRH system has succeeded in matching experimental data. Capillary electrophoresis indicates that there is a negative charge on the dimer. It is suggested that a hydroxo-bridge may link the two Cu(II) centers. Calculations verify that bi-nuclear Cu(II)(2)-TRH(2) complexes are possible.

Residual pituitary function after brain injury-induced hypopituitarism: a prospective 12-month study

CONTEXT

Traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) are conditions at high risk for the development of hypopituitarism.

OBJECTIVE

The objective of the study was to clarify whether pituitary deficiencies and normal pituitary function recorded at 3 months would improve or worsen at 12 months after the brain injury.

DESIGN AND PATIENTS

Pituitary function was tested at 3 and 12 months in patients who had TBI (n = 70) or SAH (n = 32).

RESULTS

In TBI, the 3-month evaluation had shown hypopituitarism (H) in 32.8%. Panhypopituitarism (PH), multiple (MH), and isolated (IH) hypopituitarism had been demonstrated in 5.7, 5.7, and 21.4%, respectively. The retesting demonstrated some degree of H in 22.7%. PH, MH, and IH were present in 5.7, 4.2, and 12.8%, respectively. PH was always confirmed at 12 months, whereas MH and IH were confirmed in 25% only. In 5.5% of TBI with no deficit at 3 months, IH was recorded at retesting. In 13.3% of TBI with IH at 3 months, MH was demonstrated at 12-month retesting. In SAH, the 3-month evaluation had shown H in 46.8%. MH and IH had been demonstrated in 6.2 and 40.6%, respectively. The retesting demonstrated H in 37.5%. MH and IH were present in 6.2 and 31.3%, respectively. Although no MH was confirmed at 12 months, two patients with IH at 3 months showed MH at retesting; 30.7% of SAH with IH at 3 months displayed normal pituitary function at retesting. In SAH, normal pituitary function was always confirmed. In TBI and SAH, the most common deficit was always severe GH deficiency.

CONCLUSION

There is high risk for H in TBI and SAH patients. Early diagnosis of PH is always confirmed in the long term. Pituitary function in brain-injured patients may improve over time but, although rarely, may also worsen. Thus, brain-injured patients must undergo neuroendocrine follow-up over time.

Endocrine dysfunction following traumatic brain injury: mechanisms, pathophysiology and clinical correlations

Despite growing recognition among those who provide care for traumatic brain injury patients, endocrine dysfunction following brain injury is an often under-recognized phenomenon. From historical reports one would conclude that endocrine dysfunctions hardly ever occurs following trauma to the head. However, recent studies suggest that a significant proportion of patients suffer some degree of hypopituitarism. To date, there are no clear predicting factors identifying patients at risk for developing hormonal disturbances and thus no parameters exist for screening. Several retrospective analyses and literature reviews, and more recently, a few longitudinal studies of brain injured patients have been performed.

Hypopituitarism after traumatic brain injury

Traumatic brain injury (TBI) is one of the main causes of death and disability in young adults, with consequences ranging from physical disabilities to long-term cognitive, behavioural, psychological and social defects. Post-traumatic hypopituitarism (PTHP) was recognized more than 80 years ago, but it was thought to be a rare occurrence. Recently, clinical evidence has demonstrated that TBI may frequently cause hypothalamic-pituitary dysfunction, probably contributing to a delayed or hampered recovery from TBI. Changes in pituitary hormone secretion may be observed during the acute phase post-TBI, representing part of the acute adaptive response to the injury. Moreover, diminished pituitary hormone secretion, caused by damage to the pituitary and/or hypothalamus, may occur at any time after TBI. PTHP is observed in about 40% of patients with a history of TBI, presenting as an isolated deficiency in most cases, and more rarely as complete pituitary failure. The most common alterations appear to be gonadotropin and somatotropin deficiency, followed by corticotropin and thyrotropin deficiency. Hyper- or hypoprolactinemia may also be present. Diabetes insipidus may be frequent in the early, acute phase post-TBI, but it is rarely permanent. Severity of TBI seems to be an important risk factor for developing PTHP; however, PTHP can also manifest after mild TBI. Accurate evaluation and long-term follow-up of all TBI patients are necessary in order to detect the occurrence of PTHP, regardless of clinical evidence for pituitary dysfunction. In order to improve outcome and quality of life of TBI patients, an adequate replacement therapy is of paramount importance.

Online preconcentration of thyrotropin-releasing hormone (TRH) by SDS-modified reversed phase column for microbore and capillary high-performance liquid chromatography (HPLC)

Thyrotropin-releasing hormone (TRH, pGlu-His-Pro-amide) is an important tripeptide existing in biological systems at low concentrations. It is a fairly hydrophilic peptide, cationic in acidic solutions. Preconcentration online before reversed phase chromatography separation can enhance concentration detection limits of hydrophobic, but not hydrophilic species. The hydrophilic TRH can be preconcentrated using a reversed phase precolumn charged with sodium dodecyl sulfate (SDS). The separation also uses SDS. The preconcentration is effective for a microbore system, achieving detection limit of 250 pM for a sample size of 500 microl with electrochemical detection of the biuret complex formed post column. Preconcentration using an online precolumn is also effective in packed capillary high-performance liquid chromatography (HPLC) with a detection limit of 3 nM in 24 microl.

Plasma insulin growth factor-1 and incident delirium in older people

BACKGROUND

A variety of demographic and clinical variables are acknowledged as risk factors for delirium; a syndrome thought to be mediated by abnormalities in a wide range of neurotransmitters. However, little research has been conducted in this field and the role of neuro-immunological factors as a mechanism of medication has received very little attention.

AIMS

To determine if low base line (on admission) IGF-1 levels (a protective cytokine released by brain cells in response to insult) is a risk factor for incident delirium in patients aged 75 and over admitted to an acute medical ward.

METHOD

Base line demographic and clinical variables and serum IGF-1 levels were measured in a consecutive series of 100 non-delirious subjects on inpatient admission. Subjects were assessed daily regarding the development of delirium during the inpatient episode.

RESULTS

Twelve patients developed incident delirium. IGF-1 (OR: 0.822, CI: 0.69, 0.97, p = 0.027), pre-admission cognitive deterioration (assessed by IQCODE) (OR; 3.26, CI: 1.18, 9.04, p = 0.023) and depression (GDS four item: cut-off score > or = 3) (OR; 8.99, CI 1.59,50.76, p = 0.013) were identified as risk factors for developing subsequent delirium.

CONCLUSIONS

Despite the small size of this study our findings suggest that low, pre-morbid IGF-1 is a risk factor for subsequent delirium in this population, emphasizing the potential protective role of this anabolic cytokine and the need for replication of these findings.

Variations of pituitary function over time after brain injuries: the lesson from a prospective study

Traumatic Brain Injury (TBI) and Subarachnoid Haemorrhage (SAH) are conditions at high risk to develop hypopituitarism as pointed out by many papers in scientific literature. But most of the papers were referred to retrospective evaluations, not considering the possible evolution of the pituitary function over time. Aim of our studies was to clarify whether pituitary deficiencies and normal pituitary function recorded at short term follow-up (3 months), would improve or worsen, respectively, at long term (12 months after the brain injury). In a multicenter study protocol, in patients who suffered TBI (n = 70; 50 Males, 20 Females; age 39.31 +/- 2.4 years; BMI 23.8 +/- 0.4 kg/m(2)) or SAH (n = 32; 12M, 20F; age: 51.9 +/- 2.2 year; BMI: 24.7 +/- 0.6 kg/m(2)) we tested 3 and 12 months after the pathological events the pituitary function. In TBI patients, the 3 month evaluation had shown some degree of hypopituitarism in 32.8% and the 12 months retesting demonstrated some degree of hypopituitarism in 22.7%. Total hypopituitarism was always confirmed at 12 months while Multiple and Isolated deficits recorded at 3 months was confirmed in nearly 25% only of the patients. On the other hand, in 5.5% of TBI with normal pituitary function at 3 months Isolated deficits were recorded at 12 months testing. Moreover, in 13.3% of TBI with Isolated deficit at 3 months Multiple hypopituitarism was demonstrated at 12 months retesting. In SAH patients, the 3 months evaluation had shown some degree of hypopituitarism in 46.8% and the 12 month retesting demonstrated some degree of hypopituitarism in 37.5%. No multiple hypopituitarism recorded at 3 months was confirmed at 12 months, but 2 patients with isolated deficits at 3 months showed multiple hypopituitarism at 12 month retesting. At 12 as well as at 3 months, both in TBI and SAH patients, the most common deficit was severe GHD (>20%) followed by secondary hypogonadism and then hypoadrenalism and hypothyroidism. In all, in patients who experienced TBI or SAH the risk to develop hypopituitarism is very high; early diagnosis of total hypopituitarism is always confirmed at the long term follow-up; however pituitary function in brain injured patients may improve over time, because, isolated and even multiple pituitary insufficiencies recorded at short term can be transient; on the other hand normal pituitary function recorder at short term may, become impaired 12 months after the injury. Thus, brain injured patients must undergo neuroendocrine follow-up over time in order to monitoring pituitary function and eventually providing appropriate placement.

Traumatic brain injury and subarachnoid haemorrhage are conditions at high risk for hypopituitarism: screening study at 3 months after the brain injury

OBJECTIVE

Acquired hypopituitarism in adults is obviously suspected in patients with primary hypothalamic-pituitary diseases, particularly after neurosurgery and/or radiotherapy. That brain injuries (BI) can cause hypopituitarism is commonly stated and has been recently emphasized but the management of BI patients does not routinely include neuroendocrine evaluations.

AIM

To clarify the occurrence of hypopituitarism in patients after traumatic brain injury (TBI) or subarachnoid haemorrhage (SAH) 3 months after the BI.

SUBJECTS AND METHODS

The occurrence of hypopituitarism in conscious patients after traumatic brain injury [TBI, n = 100, 31 women, 69 men; age 37.1 +/- 1.8 years; body mass index (BMI) 23.7 +/- 0.4 kg/m(2); Glasgow Coma Scale (GCS) 3-15] or subarachnoid haemorrhage [SAH, n = 40, 14 men, 26 wpmen, 51.0 +/- 2.0 years; 25.0 +/- 0.6 kg/m(2); Fisher's scale 1-4] was studied in a multicentre study 3 months after the BI. All patients underwent wide basal hormonal evaluation; the GH/IGF-I axis was evaluated by GHRH + arginine test and IGF-I measurement.

RESULTS

In TBI patients, some degree of hypopituitarism was shown in 35%. Total, multiple and isolated deficits were present in 4, 6 and 25%, respectively. Diabetes insipidus was present in 4%. Secondary adrenal, thyroid and gonadal deficit was present in 8, 5 and 17%, respectively. Severe GH deficiency (GHD) was the most frequent pituitary defect (25%). In SAH patients, some degree of hypopituitarism was shown in 37.5%. Despite no total hypopituitarism, multiple and isolated deficits were present in 10 and 27.5%, respectively. Diabetes insipidus was present in 7.5%. Secondary adrenal, thyroid and gonadal deficit was present in 2.5, 7.5 and 12.5%, respectively. Severe GHD was the most frequent defect (25%).

CONCLUSIONS

TBI and SAH are conditions associated with high risk of acquired hypopituitarism. The pituitary defect is often multiple and severe GHD is the most frequent defect. Thus neuroendocrine evaluations are always mandatory in patients after brain injuries.

Occurrence of Pituitary Dysfunction following Traumatic Brain Injury

Traumatic brain injury (TBI) may be associated with impairment of pituitary hormone secretion, which may contribute to long-term physical, cognitive, and psychological disability. We studied the occurrence and risk factors of pituitary dysfunction, including growth hormone deficiency (GHD) in 50 patients (mean age 37.6 +/- 2.4 years; 40 males, age 20-60 years; 10 females, age 23-87 years) with TBI over 5 years. Cranial or facial fractures were documented in 12 patients, and neurosurgery was performed in 14. According to the Glasgow Coma Scale (GCS), 16 patients had suffered from mild, 7 moderate, and 27 severe TBI. Glasgow Outcome Scale (GOS) indicated severe disability in 5, moderate disability in 11, and good recovery in 34 cases. Basal pituitary hormone evaluation, performed once at times variable from 12 to 64 months after TBI, showed hypogonadotrophic hypogonadism in 7 (14%), central hypothyroidism in 5 (10%), low prolactin (PRL) levels in 4 (8%), and high PRL levels in 4 (8%) cases. All subjects had normal corticotrophic and posterior pituitary function. Seven patients showed low insulin-like growth factor-I (IGF-I) levels for age and sex. Results of GHRH plus arginine testing indicated partial GHD in 10 (20%) and severe GHD in 4 (8%) cases. Patients with GHD were older (p <0.05) than patients with normal GH secretion. Magnetic resonance imaging demonstrated pituitary abnormalities in 2 patients; altogether pituitary dysfunction was observed in 27 (54%) patients. Six patients (12%) showed a combination of multiple abnormalities. Occurrence of pituitary dysfunction was 37.5%, 57.1%, and 59.3% in the patients with mild, moderate, and severe TBI, respectively. GCS scores were significantly (p <0.02) lower in patients with pituitary dysfunction compared to those with normal pituitary function (8.3 +/- 0.5 vs. 10.2 +/- 0.6). No relationship was detected between pituitary dysfunction and years since TBI, type of injury, and outcome from TBI. In conclusion, subjects with a history of TBI frequently develop pituitary dysfunction, especially GHD. Therefore, evaluation of pituitary hormone secretion, including GH, should be included in the long-term follow-up of all TBI patients so that adequate hormone replacement therapy may be administered.

Upregulation of iNOS expression and phosphorylation of eIF-2alpha are paralleled by suppression of protein synthesis in rat hypothalamus in a closed head trauma model

When the inducible form of nitric oxide synthase (iNOS) is expressed after challenge to the nervous system, it results in abnormally high concentrations of nitric oxide (NO). Under such conditions, NO could phosphorylate the eukaryotic translation initiation factor (eIF)-2alpha, thus suppressing protein synthesis in neurons that play a role in endocrine and autonomic functions. Using the Marmarou model of traumatic brain injury (TBI), we observed a rapid increase (at 4 h after TBI) of iNOS mRNA in magno- and parvocellular supraoptic and paraventricular neurons, declining gradually by approximately 30% at 24 h and by approximately 80% at 48 h. Western analysis indicated a trend towards increased iNOS protein synthesis at 4 h, which peaked at 8 h, and tended to decrease at the later time points. At the same time points, we detected immunocytochemically the phosphorylated form of eIF-2alpha (eIF-2alpha[P]) as cytoplasmic and more often as nuclear labeling. The incidence of double-labeled [iNOS and eIF-2alpha(P)] neuronal profiles, particularly at 24 h and 48 h after TBI, was high. De novo protein synthesis assessed quantitatively after infusion of 35S methionine/cysteine was reduced by approximately 20% at 4 h, remained depressed at 24 h, and did not return to control levels up to 48 h following the trauma. The results suggest that iNOS may trigger phosphorylation of eIF-2alpha, which in turn interferes with protein synthesis at the translational (ribosomal complex) and transcriptional (chromatin) levels. The depression in protein synthesis may include downregulation of iNOS itself, which could be an autoregulatory inhibitory feedback mechanism for NO synthesis. Excessive amounts of NO may also participate in dysfunction of hypothalamic circuits that underlie endocrine and autonomic alterations following TBI.

NMDA receptor mediated changes in IGF-II gene expression in the rat brain after injury and the possible role of nitric oxide

This study was undertaken in order to investigate the role of insulin-like growth factor (IGF)-II, c-fos, N-methyl-D-aspartate (NMDA) receptors, and nNOS in the cellular processes following a penetrating brain injury. IGF-II mRNA levels, as determined by Northern analysis, were decreased at 4, 8, and 24 h after brain injury, in the lesioned, compared to the contralateral intact hemisphere. Forty-eight and 72 h after the injury, there was no difference between the lesioned and the contralateral intact hemisphere in IGF-II mRNA levels. c-fos mRNA levels followed a parallel, but opposite course: They were increased at 4, 8 and 24 h after the injury, while at 48 and 72 h c-fos mRNA levels in the lesioned hemisphere did not differ from those in the intact. Administration of MK-801 reversed the injury-induced decrease in IGF-II mRNA levels. Administration of MK-801 resulted in an increase in IGF-II mRNA in both the intact and the lesioned hemispheres. Brain injury resulted in an increase in nNOS immunopositive cells in the hippocampal formation, which was detectable at 4 and 12, but not 48 h after the injury. These results suggest that IGF-II, c-fos, NMDA receptors and nNOS are involved in the cellular responses to brain injury.

Hypopituitarism following closed head injury

We describe four young patients (age 19-34 years) with hypopituitarism following closed head injury. The diagnosis was made by demonstration of low basal pituitary hormone levels and dynamic tests showing low pituitary reserve. The time interval between the injury and diagnosis of hypopituitarism was between three weeks and two months demonstrating the difficulty and complexity of making this diagnosis. Three of our patients (all patients suffering from anterior pituitary hormone deficiency) had ACTH deficiency, a condition which may be life threatening if left undiagnosed; these patients also demonstrated central hypothyroidism. Hypogonadotrophic hypogonadism occurred in three of the patients and was treated with hormonal replacement. Diabetes insipidus was the only insult in one of our patients, accompanied other hormonal deficits in two, and did not appear at all in another patient. Information about skull damage was available for three of the patients, and included skull base and facial bone fractures, probably reflecting the extent of injury necessary to cause hypopituitarism. All patients regained normal lives with adequate hormonal replacement therapy.