Effect of surgical stress on pituitary-testicular function

Hypogonadism and urologic surgeries: a narrative review

Background and Objective

Previous studies indicated that the treatment of male hypogonadism can be beneficial for intraoperative and postsurgical outcomes. In this study, we aimed to determine the impact of male hypogonadism on urologic surgeries. We provided an overview of the key studies in the field with the focus on the outcomes of urologic surgeries in hypogonadal men with/without testosterone replacement therapy (TRT).

Methods

We performed a literature review in PubMed and Google Scholar databases for the most relevant articles pertaining to the outlined topics without placing any limitations on publication years or study designs. We included full-text English articles published in peer reviewed journals between January 1970 and March 2022.

Key Content and Findings

Androgen deficiency is a common finding after major urologic surgeries. Although guidelines recommend against TRT in men with prostate carcinoma, recent investigations showed no association between TRT and disease progression and recurrence. Indeed, recent evidence suggested that low androgen levels could be related to high grade prostate carcinoma and increased risk of upgrading from low to high grade disease. Investigations on the application of TRT in benign prostatic hyperplasia (BPH) patients also revealed contrasting results. While some studies suggested higher rates of prostate-related events in men who received TRT, others showed that TRT could alleviate urinary symptoms in hypogonadal men with BPH. Decreased testosterone level is commonly seen in bladder cancer patients. The treatment of perioperative androgen deficiency can reduce postoperative morbidities and lower the risk of recurrence in these patients. Low testosterone levels are observed in approximately half of the men who undergo artificial urinary sphincter (AUS) placement and can increase the risk of complications.

Conclusions

The role of testosterone treatment in patients with urologic diseases such as prostate carcinoma and BPH is controversial. Further investigations are needed to determine the impact of hypogonadism and TRT on the outcomes of urologic surgeries in patients with androgen deficiency.

Association Between Sex Hormone Levels and Clinical Outcomes in Patients With COVID-19 Admitted to Hospital: An Observational, Retrospective, Cohort Study

Understanding the cause of sex disparities in COVID-19 outcomes is a major challenge. We investigate sex hormone levels and their association with outcomes in COVID-19 patients, stratified by sex and age. This observational, retrospective, cohort study included 138 patients aged 18 years or older with COVID-19, hospitalized in Italy between February 1 and May 30, 2020. The association between sex hormones (testosterone, estradiol, progesterone, dehydroepiandrosterone) and outcomes (ARDS, severe COVID-19, in-hospital mortality) was explored in 120 patients aged 50 years and over. STROBE checklist was followed. The median age was 73.5 years [IQR 61, 82]; 55.8% were male. In older males, testosterone was lower if ARDS and severe COVID-19 were reported than if not (3.6 vs. 5.3 nmol/L, p =0.0378 and 3.7 vs. 8.5 nmol/L, p =0.0011, respectively). Deceased males had lower testosterone (2.4 vs. 4.8 nmol/L, p =0.0536) and higher estradiol than survivors (40 vs. 24 pg/mL, p = 0.0006). Testosterone was negatively associated with ARDS (OR 0.849 [95% CI 0.734, 0.982]), severe COVID-19 (OR 0.691 [95% CI 0.546, 0.874]), and in-hospital mortality (OR 0.742 [95% CI 0.566, 0.972]), regardless of potential confounders, though confirmed only in the regression model on males. Higher estradiol was associated with a higher probability of death (OR 1.051 [95% CI 1.018, 1.084]), confirmed in both sex models. In males, higher testosterone seems to be protective against any considered outcome. Higher estradiol was associated with a higher probability of death in both sexes.

Sepsis as a Pan-Endocrine Illness-Endocrine Disorders in Septic Patients

Sepsis is defined as "life-threatening organ dysfunction caused by a dysregulated host response to infection". One of the elements of dysregulated host response is an endocrine system disorder. Changes in its functioning in the course of sepsis affect almost all hormonal axes. In sepsis, a function disturbance of the hypothalamic-pituitary-adrenal axis has been described, in the range of which the most important seems to be hypercortisolemia in the acute phase. Imbalance in the hypothalamic-pituitary-thyroid axis is also described. The most typical manifestation is a triiodothyronine concentration decrease and reverse triiodothyronine concentration increase. In the somatotropic axis, a change in the secretion pattern of growth hormone and peripheral resistance to this hormone has been described. In the hypothalamic-pituitary-gonadal axis, the reduction in testosterone concentration in men and the stress-induced "hypothalamic amenorrhea" in women have been described. Catecholamine and β-adrenergic stimulation disorders have also been reported. Disorders in the endocrine system are part of the "dysregulated host response to infection". They may also affect other components of this dysregulated response, such as metabolism. Hormonal changes occurring in the course of sepsis require further research, not only in order to explore their potential significance in therapy, but also due to their promising prognostic value.

Characterization of perioperative androgen profiles in men with bladder cancer undergoing radical cystectomy

BACKGROUND

Prior studies have demonstrated declines in androgen levels in men with cancer and patients undergoing anesthesia and surgery. In this study, we hypothesized that decreased serum androgen levels are prevalent in male patients undergoing radical cystectomy (RC) for bladder cancer and that it persists in the postoperative period. We characterized perioperative androgen hormonal profiles and examined for associated changes indicative of sarcopenia on computed tomography scans in men undergoing RC.

METHODS

We implemented a prospective observational trial in men with newly diagnosed non-metastatic bladder cancer undergoing RC. Baseline pre-operative total testosterone (TT), free testosterone (FT), and luteinizing hormone (LH) were obtained on morning lab draws with 30 days of surgery. TT and FT were then repeated on postoperative days (POD) 2, 3, 30, and 90. The threshold for normal TT was defined as >300 ng/dl, consistent with the AUA Guidelines for Evaluation and Management of Testosterone Deficiency. We evaluated postoperative changes in weight and psoas muscle cross-sectional area using computed tomography scans to assess for sarcopenic changes.

RESULTS

Univariable statistical analysis was performed. 25 patients were enrolled. The mean patient age was 68.9 years. The mean pre-operative TT was 308 ng/dl, and 12/23 (52.5%) patients had low testosterone. Mean TT onPOD 2 and 3 were 166 ng/dl and 161 ng/dl, respectively (range 24-345). 19/20 (95%) of men who had morning lab draws had decreased TT. The mean TT at 30 days was 253 ng/dl with 37.5% of men having low TT. Mean TT at 90 days was 306 ng/dl. The mean FT levels were 43 ng/dl, 29.25 ng/dl, 28.2 ng/dl, 40.89 ng/dl, and 42.62 ng/dl at baseline, POD 2, POD 3, POD 30, and POD 90, respectively. Mean LH at baseline was 9.9 IU/L. Average weight loss at 30- and 90- days postop was -4.29 and -4.38 kilograms, respectively. Weight loss was persistent with only 3/23 (13%) returning to their presurgery weight by 90 days. Despite significant declines in weight and perioperative TT, no significant differences in psoas muscle cross-sectional area were observed (net change -92 mm², P= 0.13) CONCLUSIONS: Perioperative disruption of androgen levels is prevalent in men undergoing RC. Our trial demonstrates a pre-op, immediate postop, 30- and 90-day postoperative prevalence of low TT of 52%, 95%, 63%, and 37.5%, respectively. Significant changes in baseline weight were noted, although no significant changes in psoas muscle cross-sectional area were observed, limiting conclusions regarding a link between changes in androgens and sarcopenia in this setting.

Preemptive light sedation in intensive care unit may reduce pulmonary complications in geriatrics receiving pancreaticoduodenectomy

BACKGROUND

Patients undergoing pancreaticoduodenectomy (PD) for periampullary lesions are usually elderly with a high risk of postoperative morbidity and mortality. This retrospective cohort study investigated whether postoperative preemptive light sedation aids in recovery of elderly patients following PD.

METHODS

Ninety-nine geriatric patients undergoing PD at one hospital were enrolled from 2009 to 2018. Patients in the sedation group received mechanical ventilation support and preemptively light sedation with fentanyl and propofol or dexmedetomidine in the first 5 days postoperatively in the intensive care unit (ICU). Patients in the control group underwent early extubation and received morphine for pain control but no postoperative sedatives in the ordinary ward. Patients in the two groups were matched 1:1 using propensity scoring. The postoperative complication rate, surgical mortality, and postoperative hospital length of stay (LOS) were recorded. We also tested inflammation in an immortal human bronchial epithelial cell line.

RESULTS

After 1:1 matching, 40 patients in the sedation group were compared with 40 patients in the control group. The sedation group had a significantly lower pulmonary complication rate and fewer patients with postoperative gastroparesis. Both groups had similar postoperative hospital LOS and identical surgical mortality rates. Patients in the sedation group had significantly better postoperative quality of life, including less pain and less heartbeat variation. In vitro cell experiments supported the above clinical observations, showing that adequate use of sedatives could significantly elevate the cell viability rate, protect cells from damage, decrease interleukin-6 production, and reduce inflammation.

CONCLUSION

Postoperative preemptive light sedation in the ICU in geriatric patients following PD may not only reduce the rates of postoperative pulmonary complications and gastroparesis but also improve postoperative quality of life without prolonging the postoperative hospital LOS.

Compromised Activation of Vitamin D After Elective Surgery: A Prospective Pilot Study

Surgical stress reduces concentrations of most proteins in serum and necessitates a rapid adjustment of hormones dependent on protein binding. Activation of vitamin D by renal 1α-hydroxylation is dependent on protein binding because 1,25-dihydroxyvitamin D (1,25(OH)₂D₃) is formed after megalin-mediated reabsorption of 25-hydroxyvitamin D (25OHD) bound to vitamin D binding protein (DBP). Postoperative alterations in serum concentrations of DBP and albumin may therefore impair 1,25(OH)₂D₃ production. Our objective was to determine sex-specific changes in serum concentrations of vitamin D metabolites and sex steroids 2, 6, 24, and 48 hours and 3 weeks postoperatively. Fourteen women and eleven men aged 45 to 77 years without severe comorbidities undergoing unilateral total knee arthroplasty participated in this prospective study in a tertiary center for arthroplasty (trial ID: NCT02336932). The main outcome measures were total and free serum concentrations of 25OHD, 1,25(OH)₂D₃, 24,25-dihydroxyvitamin-D, DBP, albumin, sex hormone binding globulin (SHBG), calcium, and parathyroid hormone (PTH). Serum albumin and SHBG decreased postoperatively (Δalbumin_48h -18% [-22%; -14%]). Unexpectedly, concentrations of DBP and 25OHD remained unaltered, but 1,25(OH)₂D₃ declined postoperatively. 1,25(OH)₂D₃ was 3 weeks after surgery -24% (-40%; -8%) lower than preoperative levels, whereas 24,25-dihydroxyvitamin-D remained unchanged in postmenopausal women. The calculated conversion rate of 25OHD to 1,25(OH)₂D₃ was strongly associated with serum 25-OHD and PTH preoperatively, whereas serum calcium was most predictive postoperatively. In conclusion, surgery had no effect on serum concentrations of DBP, 25OHD, and PTH, whereas production of 1,25(OH)₂D₃ was markedly reduced. Further studies are needed to determine duration and putative outcome effects of this postoperative 1,25(OH)₂D₃ deficit in women, which in part may be due to discordance in CYP27B1 and CYP24A1 activity.

Low Testosterone Levels are Frequent in Patients with Acute Respiratory Failure and are Associated with Poor Outcomes

OBJECTIVE

Low testosterone level is a common finding in critically ill patients with trauma, shock, and sepsis. However, its prevalence and outcomes in patients with primary acute respiratory failure is unknown; low testosterone could contribute to respiratory muscle weakness and further compromise ventilation in these patients.

METHODS

We aimed to determine the prevalence, severity, and effects of hypotestosteronemia in patients with acute respiratory failure in a 16-bed single academic center medical intensive care unit (ICU). We studied 30 men who required mechanical ventilation for ≥24 hours for a primary diagnosis of acute respiratory failure. Blood samples were drawn on ICU day 1 and day 3 to measure serum levels of total and free testosterone.

RESULTS

Hypotestosteronemia (level below the lower reference limit) was present on day 1 in 93.1% (total testosterone) and 76.7% (free testosterone) of patients and on day 3 in 94.4% (total testosterone) and 100% (free testosterone) of patients. Sex hormone-binding globulin, dehydroepiandrosterone sulfate, follicle-stimulating hormone, luteinizing hormone, and thyroid function levels were all within stated reference ranges. Total and free testosterone levels correlated inversely with ventilator days and ICU length of stay.

CONCLUSION

Hypotestosteronemia is common in mechanically ventilated patients with primary acute respiratory failure and may contribute to longer ICU stay. Further studies are needed to determine the effect of testosterone replacement on short- and long-term outcomes in these patients.

Hypothalamic-pituitary hormones during critical illness: a dynamic neuroendocrine response

Independent of the underlying condition, critical illness is characterized by a uniform dysregulation of the hypothalamic-pituitary-peripheral axes. In most axes a clear biphasic pattern can be distinguished. The acute phase of critical illness is characterized by low peripheral effector hormone levels such as T3, IGF-1 and testosterone, despite an actively secreting pituitary. The adrenal axis with high cortisol levels in the presence of low ACTH levels is a noteworthy exception. In the prolonged phase of critical illness, low peripheral effector hormone levels coincide with a uniform suppression of the neuroendocrine axes, predominantly of hypothalamic origin. The severity of the alterations in the different neuroendocrine axes is associated with a high risk of morbidity and mortality, but it remains unknown whether the observed changes are cause or consequence of adverse outcome. Several studies have identified therapeutic potential of hypothalamic releasing factors, but clinical outcome remains to be investigated with sufficiently powered randomized controlled trials.

The effect of toxoplasmosis on the level of some sex hormones in males blood donors in Baghdad

Toxoplasma gondii is a unique intracellular parasite, which infect a large proportion of the world population, but uncommonly causes clinically significant disease. The present study was performed to estimate the prevalence of toxoplasmosis in 400 apparently healthy blood donor males, their ages were between 18 and 57 years using enzyme linked immunosorbent assay, and to examine the effects of infection on total testosterone, free testosterone and follicle stimulating hormone (FSH) levels in their sera. Seroprevalence showed 10 (2.5 %) and 121 (30 %) of them had IgM and IgG antibodies respectively. Both acute and chronic toxoplasmosis in males recorded higher significant (P < 0.05) mean concentration for total and free testosterone hormone, they were 12.188 ± 0.73, 7.837 ± 0.52 ng/ml and 44.121 ± 1.76, 27.984 ± 0.94 pg/ml respectively. The mean concentration of FSH revealed non-significant (P < 0.05) differences in both disease activities, they were 6.41 ± 0.47 and 6.515 ± 0.51 IU/ml respectively.

Immunodetection of inhibin in the human testis and epididymis during normal development and in non-tumoural testicular lesions

Plasma concentrations of inhibin are correlated with spermatogenetic function. Inhibin is secreted mainly by the Sertoli and Leydig cells of the testis. In the human epididymis, the location and function of inhibin are contentious. Thus, the aim of the present study was to determine the location of inhibin in the human epididymis. Investigations were performed in samples with normal testicular function at different stages of development, as well as in samples in which testicular function or the testicular–epididymal connection were altered. In fetal, newborn and infant testes, Sertoli and Leydig cells stained positive for inhibin, whereas no such staining was detected in the epididymides. Inhibin was located in both the Sertoli and Leydig cells, as well as in the epididymis, in the apical pole of mainly secretory cells in the efferent ducts. This staining pattern was not correlated with the staining pattern for macrophages. The main duct of the epididymis was negative for inhibin staining. In ischaemic atrophic testes, the few tubules in which Sertoli cells were present stained positive for inhibin, whereas the epididymides stained negative. In paediatric cryptorchidism, Sertoli and Leydig cells stained positive for inhibin, whereas the epididymides were negative. In adult cryptorchidism, Sertoli and Leydig cells stained positive for inhibin, even in tubules containing Sertoli cells only. Interestingly, inhibin was absent from the efferent ducts. In three cases undergoing hormonal treatment prior to subsequent gender change, Sertoli and Leydig cells stained positive for inhibin. In contrast, the efferent ducts were negative or only faintly positive in cases of shorter hormonal treatment. In all cases studied, the presence of inhibin in the efferent ducts was associated with its production in the testis, suggesting that the epididymis is not responsible for the production of inhibin in men. The pattern of inhibin staining does not correlate with that of macrophages, suggesting that inhibin is not degraded in the human epididymis. The data suggest that, in humans, inhibin is secreted by Sertoli cells into the seminiferous tubules and then travels towards the efferent ducts, where it is reabsorbed into the bloodstream.

Gonadal status and body mass index jointly determine growth hormone (GH)-releasing hormone/GH-releasing peptide synergy in healthy men

CONTEXT

Sex steroid hormones potentiate whereas increased body mass index (BMI) represses GH secretion. Whether sex steroids modify the negative effect of BMI on secretagogue-induced GH secretion in men is not known. The issue is important in designing GH-stimulation regimens that are relatively insensitive to both gonadal status and adiposity.

OBJECTIVE

Our objective was to compare the relationships between BMI and peptide-stimulated GH secretion in men with normal and reduced testosterone and estradiol availability.

SETTING

The study was performed at an academic medical center.

SUBJECTS

Healthy young men were included in the study.

INTERVENTIONS

Randomized separate-day iv infusion of saline and/or maximally effective doses of L-arginine/GHRH, L-arginine/GH-releasing peptide (GHRP)-2, and GHRH/GHRP-2 in eugonadal (n=12) and experimentally hypogonadal (n=10) men was performed.

OUTCOMES

Regression of paired secretagogue-induced GH responses on BMI was determined.

RESULTS

In eugonadal men, peak GH concentrations correlated negatively with BMI. In particular, BMI accounted for only 38% of the response variability after L-arginine/GHRH (P=0.0165), but 62% after GHRH/GHRP-2 (P=0.0012) and 65% after L-arginine/GHRP-2 (P=0.00075). In contrast, in hypogonadal men, GH responses were uncorrelated with BMI. The negative effects of BMI on peak GH responses in eugonadal and hypogonadal states differed most markedly after stimulation with GHRH/GHRP-2 (P=0.0019). This contrast was corroborated using integrated GH responses (P=0.0007).

CONCLUSIONS

Short-term experimental gonadal sex hormone depletion attenuates dual secretagogue-stimulated GH secretion in lean young men. The inhibitory effect of relative adiposity on GH secretion appears to predominate over that of acute sex steroid withdrawal.

Infection, immunity, and hormones/endocrine interactions

Infections and stress, immune responses, and hormones are interconnected, ensuring immune competence to deal with immediate threat of overwhelming infection and metabolic collapse. Emergence of cytokines as key signal mediators and appreciation of autocrine-paracrine influences of hormones have helped explain how signals are transmitted and responses evoked. This has led to possibilities of creating therapies that might be used to enhance protective signals and dampen signals emanating from host and invading organism interaction that might otherwise be detrimental. Correcting certain metabolic abnormalities, such as hyperglycemia and metabolic acidosis, benefits the host by decreasing morbidity and mortality.

Male hypogonadism in systemic disease

Hypogonadism is often observed in the presence of common acute and chronic illnesses in men. Low testosterone levels in these patients can be associated with loss of lean body mass and bone mass density, decline in mood, loss of energy, and sexual dysfunction. The mechanisms explaining hypogonadism and various systemic diseases are not completely understood, but these conditions are likely caused by a combination of stress, nonspecific weight loss, inflammation, and medication. Testosterone replacement can be considered in this population to improve lean body mass, bone mass density, and quality of life. More information is needed regarding the risk benefits of testosterone treatment on health outcomes in men who have systemic illness.

Endocrine modifications and interventions during critical illness

The ongoing hypermetabolic response in patients with prolonged critical illness leads to the loss of lean tissue mass. Since the cachexia of prolonged illness is usually associated with low concentrations of anabolic hormones, hormonal intervention has been thought to be beneficial. However, most interventions have been shown to be ineffective and their indiscriminate use even causes harm. Before considering endocrine intervention in these frail patients, a detailed understanding of the neuroendocrinology of the stress response is warranted. It is now clear that the acute phase and the later phase of critical illness behave differently from an endocrinological point of view. The acute stress reponse consists primarily of an actively-secreting pituitary in the presence of low circulating peripheral anabolic hormones, suggesting resistance of the peripheral tissues to the effects of anterior pituitary hormones. However, when the disease process becomes prolonged, there is a uniformly-reduced pulsatile secretion of anterior pituitary hormones with proportionally reduced concentrations of peripheral anabolic hormones. The origin of this suppressed pituitary secretion is located in the hypothalamus, as hypothalamic secretagogues can reactivate the anterior pituitary and restore pulsatile secretion. The reactivated pituitary secretion is accompanied by an increase in peripheral target hormones, indicating at least partial sensitivity of these tissues to anterior pituitary hormones in this chronic phase of illness. Thus, endocrine intervention with a combination of hypothalamic secretagogues that more completely reactivate the anterior pituitary could be a more physiological and effective strategy for inducing anabolism in patients with prolonged critical illness.

The inflammatory response to surgery and trauma

PURPOSE OF REVIEW

The inflammatory or stress response to injury has evolved to ensure survival. This review will examine this response in otherwise healthy patients. Additionally, the impact of several common comorbid conditions on the inflammatory response will be considered. What will become evident is that the stress response may be exaggerated in some conditions and suppressed in others. Rapid identification of both an abnormal response and its cause will allow clinicians to maximize a patient's healing potential.

RECENT FINDINGS

Recent work has shown that an altered inflammatory response has marked effects on both immune competence and the endocrine system. Investigations are ongoing to delineate the mechanism of lymphocyte dysfunction. With regard to critical care endocrinopathies, the effects of insulin and hyperglycemia on inflammation and wound healing are being investigated.

SUMMARY

An understanding of the stress response will aid the clinician in preparing for expected responses, recognizing and perhaps correcting deviations from the norm and accounting for potential complications that arise in the face of preexisting disease. Deviations from the normal time course may represent the effects of preexisting medical illness, treatment or postoperative/injury complications.

The dynamic neuroendocrine response to critical illness

The severity of striking alterations in the hypothalamic-anterior pituitary-peripheral hormone axes, which are the hallmark of severity of critical illness, is associated with a high risk for morbidity and mortality. Most attempts to correct the hormone balance are ineffective or harmful because of lack of pathophysiologic understanding. Extensive research has provided more insight in the biphasic neuroendocrine response to critical illness: the acute phase is characterized by an actively secreting pituitary but low peripheral effector hormone levels. In contrast, in prolonged critical illness, uniform suppression of the neuroendocrine axes, predominantly of hypothalamic origin, contributes to low serum levels of the respective target-organ hormones.

Endocrine aspects of acute and prolonged critical illness

Critical illness is characterized by striking alterations in the hypothalamic-anterior-pituitary-peripheral-hormone axes, the severity of which is associated with a high risk of morbidity and mortality. Most attempts to correct hormone balance have been shown ineffective or even harmful because of a lack of pathophysiologic insight. There is a biphasic (neuro)endocrine response to critical illness. The acute phase is characterized by an actively secreting pituitary, but the concentrations of most peripheral effector hormones are low, partly due to the development of target-organ resistance. In contrast, in prolonged critical illness, uniform (predominantly hypothalamic) suppression of the (neuro)endocrine axes contributes to the low serum levels of the respective target-organ hormones. The adaptations in the acute phase are considered to be beneficial for short-term survival. In the chronic phase, however, the observed (neuro)endocrine alterations appear to contribute to the general wasting syndrome. With the exception of intensive insulin therapy, and perhaps hydrocortisone administration for a subgroup of patients, no hormonal intervention has proven to beneficially affect outcome. The combined administration of hypothalamic releasing factors does, however, hold promise as a safe therapy to reverse the (neuro)endocrine and metabolic abnormalities of prolonged critical illness by concomitant reactivation of the different anterior-pituitary axes.

Androgens, aging, and Alzheimer's disease

Testosterone depletion is a normal consequence of aging in men that is associated with senescent effects in androgen- responsive tissues. We discuss new evidence that one consequence of testosterone depletion in men is an increased risk for the development of Alzheimer's disease (AD). Furthermore, we discuss two candidate mechanisms by which testosterone may affect AD pathogenesis. First, testosterone has been identified as an endogenous regulator of beta-amyloid, a protein that abnormally accumulates in AD brain and is implicated as a causal factor in the disease. Second, findings from several different paradigms indicate that testosterone has both neurotrophic and neuroprotective functions. These new findings support the clinical evaluation of androgen-based therapies for the prevention and treatment of AD.

The Neuroendocrine Response to Critical Illness is a Dynamic Process

Striking alterations in the hypothalamic-anterior pituitary-peripheral hormone axes hallmark the state of critical illness, their severity being associated with high risk for morbidity and mortality. Early endocrine intervention strategies aimed to correct the hormone balance have been shown ineffective or even harmful because of lack of thorough pathophysiologic understanding of these neuroendocrine changes. Extensive research, however, has provided crucial insights, with the demonstration of the biphasic response of the anterior pituitary to the severe stress of critical illness.

Effects of Experimental Cryptorchidism on Sperm Motility and Testicular Endocrinology in Adult Male Rats

The effect of induced cryptorchidism on testicular function and sperm motility was investigated. Bilateral cryptorchidism was created surgically in adult male rats (treated group), and sham-operated rats were used as a control group. Five rats from each group were sacrificed on days 1, 3, 5, and 7 after surgery. The percentage of motile spermatozoa began to decrease 1 day after the operation, followed by an abrupt decline 3 and 5 days later in cryptorchid rats. Furthermore, there were significant decreases in the other sperm motility parameters 5 days after inducement of cryptorchidism. In cryptorchid rats, plasma concentrations of LH, FSH, testosterone, and inhibin B were significantly lower than in the control group 1 day after the operation. Thereafter, plasma concentrations of LH, FSH, and testosterone gradually increased in the cryptorchid rats. On the other hand, plasma concentrations of inhibin B showed a further decline from day 3 after the operation onward. Concentrations of immunoreactive (ir)-inhibin, but not testosterone, in testicular interstitial fluid were remarkably increased until 3 days after surgery in the cryptorchid rats, and declined thereafter. Testicular response to human chorionic gonadotropin (hCG) for testosterone release was decreased in the cryptorchid rats compared with the control rats, indicating that heat stress to testes resulted in a reduction of the activity of Leydig cells and Sertoli cells. These results clearly indicate that heat stress to the testes resulted in a significant reduction of sperm activity within 3 days, and this was followed by changes in testicular endocrine function.

Free Androgen Index Is Superior to Total Testosterone for Short-Term Assessment of the Gonadal Axis after Renal Transplantation

OBJECTIVE

Recent studies have assessed gonadal function in association with different immunosuppressive drugs in transplanted patients mainly relying on the measurement of total testosterone. It is the aim of this study to assess the short-term changes of the hypothalamic-pituitary-gonadal axis following renal transplantation using the free androgen index (FAI).

PATIENTS AND METHODS

The sequential changes in total testosterone, sex hormone-binding globulin (SHBG), gonadotropin and prolactin concentrations were measured in 22 male patients before and after 1-3 days, and 1, 2 and 3 weeks following renal transplantation.

RESULTS

Total testosterone and SHBG concentrations dropped significantly after transplantation (total testosterone: baseline: 15.2 +/- 1.6 nmol/l vs. 1 week: 7.9 +/- 0.8 nmol/l vs. 2 weeks: 9.8 +/- 0.9 nmol/l, SHBG: baseline: 29.9 +/- 3.2 nmol/l vs. 1 week: 19.9 +/- 2.1 nmol/l, 2 weeks: 18.9 +/- 2.4 nmol/l, p < 0.01). FAI decreased significantly after day 1-3 returning to values near baseline thereafter (baseline: 60 +/- 9% vs. day 1-3: 38 +/- 6%, 2 weeks: 61 +/- 7%; p < 0.01). There was a significant positive correlation between FAI and renal function.

CONCLUSION

Measurement of the free androgen index is superior to total testosterone for assessment of the pituitary-gonadal axis in the first weeks after renal transplantation.

The decline of androgen levels in elderly men and its clinical and therapeutic implications

Aging in men is accompanied by a progressive, but individually variable decline of serum testosterone production, more than 20% of healthy men over 60 yr of age presenting with serum levels below the range for young men. Albeit the clinical picture of aging in men is reminiscent of that of hypogonadism in young men and decreased testosterone production appears to play a role in part of these clinical changes in at least some elderly men, the clinical relevancy of the age-related decline in sex steroid levels in men has not been unequivocally established. In fact, minimal androgen requirements for elderly men remain poorly defined and are likely to vary between individuals. Consequently, borderline androgen deficiency cannot be reliably diagnosed in the elderly, and strict differentiation between "substitutive" and "pharmacological" androgen administration is not possible. To date, only a few hundred elderly men have received androgen therapy in the setting of a randomized, controlled study, and many of these men were not androgen deficient. Most consistent effects of treatment have been on body composition, but to date there is no evidence-based documentation of clinical benefits of androgen administration to elderly men with normal or moderately low serum testosterone in terms of diminished morbidity or of improved survival or quality of life. Until the long-term risk-benefit ratio for androgen administration to elderly is established in adequately powered trials of longer duration, androgen administration to elderly men should be reserved for the minority of elderly men who have both clear clinical symptoms of hypogonadism and frankly low serum testosterone levels.

Endocrine evaluation of patients with critical illness

Prolonged critical illness has a high morbidity and mortality. The acute and chronic phases of critical illness are associated with distinct endocrine alterations. The acute neuroendocrine response to critical illness involves an activated anterior pituitary function. In prolonged critical illness, however, a reduced pulsatile secretion of anterior pituitary hormones and the so-called "wasting syndrome" occur. The impaired pulsatile secretion of GH, thyrotropin and gonadotropin can be re-amplified by relevant combinations of releasing factors, which also substantially increase circulating levels of IGF-1, GH-dependent IGFBPs, thyroxin, tri-iodothyronine and testosterone. Anabolism is clearly re-initiated at the time GH secretagogues, thyrotropin-releasing hormone and gonadotropin-releasing hormone are coadministered but the effect on survival remains unknown. A lethal outcome of critical illness is predicted by a high serum concentration of IGFBP-1, pointing to impaired insulin effect rather than pituitary function, and survival was recently shown to be dramatically improved by strict normalization of glycemia with exogenous insulin. In addition to the illness-induced endocrine alterations, patients may have pre-existing central or peripheral endocrine diseases, either previously diagnosed or unknown. Hence, endocrine function testing in a critically ill patient represents a major challenge and the issue of treatment remains controversial. The recent progress in knowledge of the neuroendocrine response to critical illness and its interrelation with peripheral hormonal and metabolic alterations during stress, allows for potential new therapeutic perspectives to safely reverse the wasting syndrome and improve survival.

Dynamic neuroendocrine responses to critical illness

Prolonged critical illness has high morbidity and mortality. The acute neuroendocrine response to critical illness involves an activated anterior pituitary function. In prolonged critical illness, however, a reduced pulsatile secretion of anterior pituitary hormones and the so-called 'wasting syndrome' occur. The impaired pulsatile secretion of growth hormone (GH), thyrotropin and gonadotropin can be re-amplified by relevant combinations of releasing factors, which also substantially increase circulating levels of insulin-like growth factor (IGF)-I, GH-dependent IGF-binding proteins, thyroxine, tri-iodothyronine, and testosterone. Anabolism is clearly re-initiated when GH secretagogues, thyrotropin-releasing and gonadotropin-releasing hormones are co-administered but the effect on survival remains unknown. A lethal outcome of critical illness is predicted by a high serum concentration of IGF-binding protein 1, pointing to impaired insulin effect rather than pituitary function, and survival was recently shown to be dramatically improved by strict normalization of glycemia with exogenous insulin. The recent progress in the knowledge of the neuroendocrine response to critical illness and its interrelation with peripheral hormonal and metabolic alterations during stress allows for potential new therapeutic perspectives to safely reverse the wasting syndrome and improve survival. These novel insights will be reviewed herein.

Endocrine and metabolic issues in the management of the chronically critically ill patient

The metabolic syndrome of chronic critical illness (CCI) consists of multisystem organ dysfunction resulting from the initial acute injury and chronic immune-neuroendocrine axis activation, adult kwashiorkor-like malnutrition, and prolonged immobilization with suppression of the PTH-vitamin D axis and hyper-resorptive metabolic bone disease. CCI patients can also present unique challenges in the management of diabetes mellitus, thyroid and adrenal diseases, electrolyte abnormalities and hypogonadism.

Neuroendocrine pathobiology of chronic critical illness

The neuroendocrine stress response is a dynamic process involving multiple hormonal alterations with distinct features in the acute and chronic phase of critical illness. In the initial response to an acute stress event, the anterior pituitary actively releases its hormones into the circulation while in the periphery, anabolic target organ hormones are inactivated. This response is thought to be beneficial and adaptive. When critical illness becomes prolonged, pulsatile secretion of anterior pituitary hormones becomes uniformly reduced due to reduced (hypothalamic) stimulation, and this underlies reduced activity of the respective target tissues and impaired anabolism. This difference in the acute and chronic stress response may not be trivial. It was the (inappropriate) assumption that acute stress responses, such as GH resistance, persist throughout the course of critical illness, which had formed the (inappropriate) justification to administer high doses of GH to long-stay intensive care patients to induce anabolism [102]. The concomitant endocrine changes in chronic critical illness may have predisposed to severe side effects of high doses of GH. In view of the significant benefits of strict glycemic control using exogenous insulin recently demonstrated in ICU patients [101], GH-induced insulin resistance and hyperglycemia may have played a role. It remains to be studied whether endocrine intervention with releasing factors such as TRH and GHRP in prolonged critical illness will accelerate recovery of patients who have entered the vicious circle of prolonged intensive care dependency.

Protein turnover, lipolysis, and endogenous hormonal secretion in critically ill children

OBJECTIVES

The catabolic state is a major contributor to morbidity and mortality of critical illness and may be related to endocrine changes. We studied whether protein and lipid turnover correlate with insulin and growth and thyroid hormone plasma levels in critically ill infants.

DESIGN

Prospective clinical study.

SETTING

Pediatric intensive care unit.

PATIENTS

Twelve critically ill children and ten age-matched controls.

MEASUREMENTS

We measured lipolysis and protein turnover by infusing albumin-bound uniformly 13C palmitic acid and 2H3-leucine for 3 hrs and 2H5-glycerol for 5 hrs to critically ill infants. Simultaneously, we measured serum growth hormones, insulin, C-peptide, thyroid-stimulating hormone, T4, T3, albumin, retinol binding protein (RBP), and prealbumin. Hormone and serum protein levels were also measured in six children when recovered from critical illness. Ten healthy age-matched children served as controls for hormone serum levels comparison.

RESULTS

Palmitic acid and glycerol turnover were 5.6 +/- 2.2 micromol/kg/min and 12.2 +/- 7.3 micromol/kg/min, respectively, whereas alpha-ketoisocaproic turnover was 4.9 +/- 2.8 micromol/kg/min. Alpha-ketoisocaproic turnover positively correlated (R = 0.7, p = .03) with duration of pediatric intensive care unit admission and with prealbumin and RBP serum levels (R = 0.9, p = .001). Insulin-like growth factor binding protein (IGFBP)-2 was significantly higher and IGFBP-3 was significantly lower in critically ill children (p = .03 and p = .04 vs. recovery phase, respectively). No other hormonal differences were found. Serum albumin was significantly lower in sick children. We found a significant correlation between prealbumin and RBP and IGFBP-3 (R = 0.6, p = 0.03 and R = 0.6, p = .04, respectively). Alpha-ketoisocaproic turnover positively correlated with IGFBP-1 (R = 0.79, p = .01) and did not correlate with insulin-like growth factor I (R = -0.5, p = .15 [not significant]) No other correlations were found. Lipid turnover measurements did not correlate with any endogenous hormone levels or with duration of critical illness.

CONCLUSION

Protein turnover but not lipolysis correlated with a persisting critically ill condition, serum prealbumin, RBP, and plasma IGFBP-1.

Altered gonadal steroidogenesis in critical illness: is treatment with anabolic steroids indicated?

The physiology of the reproductive system changes dramatically with the onset of major illness. The serum testosterone concentrations fall to pre-pubertal levels secondary to a decreased secretion of gonadotropins and a decreased Leydig cell response to luteinizing hormone. At the same time, the serum oestrogen concentration rises as the result of an increased rate of peripheral aromatization. The clinical consequences of these marked changes are not yet well understood. One line of evidence argues for the administration of anabolic steroids (derivatives of testosterone) to critically ill patients to improve their catabolic state. Another line of evidence in animal models suggests that testosterone may suppress the immune system and myocardial function in critical illness. No clinical trials of oestrogen administration to critically ill patients have been reported, although two animal studies suggest that oestrogen may have a positive effect on survival. This chapter reviews changes in the physiology of the reproductive system in major illness as well as current evidence regarding the clinical effects of androgens and oestrogens in critical illness and their potential therapeutic roles.

The neuroendocrine response to stress is a dynamic process

The initial neuroendocrine response to critical illness illness consists primarily of activated anterior pituitary function, the peripheral anabolic pathways being inactivated. This response presumably provides metabolic substrates, establishes the host's defences and is thus considered to be adaptive and beneficial. It was previously assumed that the acute stress response persisted throughout the course of critical illness, but this assumption has now been disproved. Indeed, a uniformly reduced pulsatile secretion of growth hormone, thyroid-stimulating hormone, prolactin and luteinizing hormone has been observed in protracted critical illness, impairing the function of target organs. A reduced availability of thyrotropin-releasing hormone, gonadotropin-releasing hormone, the endogenous ligand of the growth hormone-releasing peptide receptor (possibly ghrelin) and, in very long-stay critically ill men, also growth hormone-releasing hormone seems to be involved. The pulsatile secretion of growth hormone, thyroid-stimulating hormone, prolactin and luteinizing hormone can be re-established by relevant combinations of releasing factors, which also substantially increase the circulating levels of insulin-like growth factor-1, growth hormone dependent binding proteins, thyroxine, tri-iodothyronine and testosterone. Active feedback inhibition loops prevent the target organs being overstimulated. The metabolism is altered in a beneficial way when growth hormone-secretagogues, thyrotropin-releasing hormone and gonadotropin-releasing hormone are administered together, whereas the effect of single-hormone treatment is minor and accompanied by side-effects. This new concept of a selectively reduced stimulation of pituitary function in the chronic phase of critical illness unveils new therapeutic perspectives to reverse the paradoxical wasting syndrome' and intensive care dependency.

Andropausa: insuficiência androgênica parcial do homem idoso. Uma revisão

Andropausa é uma designação inapropriada para o quadro clínico resultante do declínio progressivo da produção androgênica encontrado em pelo menos 20% dos homens com idade entre 60 e 70 anos, e que algumas vezes se inicia a partir dos 50 anos. Uma designação mais adequada é insuficiência androgênica parcial do homem idoso. Como a produção de testosterona diminui regularmente, em homens de 75 anos os níveis médios de testosterona são somente 65% daqueles dos adultos jovens, sendo que pelo menos 25% destes idosos apresentam níveis subnormais de testosterona biodisponível. A etiologia deste declínio da testosterona dependente da idade é multifatorial e envolve alterações testiculares primárias, disfunção da regulação neuroendócrina das gonadotropinas, elevação das concentrações séricas de globulina ligadora de hormônios sexuais e redução da sensibilidade dos receptores androgênicos. A senescência é acompanhada de uma série de sinais e sintomas, muitos deles bastante semelhantes aos observados em hipogonádicos jovens. Este quadro clínico complexo pode se dever aos efeitos conjuntos do próprio processo de senescência e de doenças intercorrentes. No entanto, existem evidências que o declínio dos níveis de testosterona próprio da idade é, pelo menos em parte, codeterminante deste quadro clínico, visto que a reposição androgênica tem mostrado efeitos favoráveis em mais de 30% destes idosos sintomáticos. No momento, esta reposição hormonal deveria somente ser considerada em presença de níveis séricos de testosterona abaixo dos limites normais mínimos para adultos jovens, acompanhada de sinais inequívocos de insuficiência androgênica, na ausência de outras causas reversíveis de hipoandrogenismo e após a exclusão de contra-indicações.

Declining gonadal function in elderly men

Ageing in men is accompanied by a progressive decline of gonadal function with, in particular, a decline of total and free testosterone (T) plasma levels resulting in a significant proportion of elderly men over age 60 years presenting with subnormal T levels compared with the levels in young adults. A great interindividual variation in T levels is observed in elderly men, a variability explained in part by physiological variables and differences in life style, while associated acute or chronic diseases may accentuate the age-related decline of T levels. The progressive decrease of plasma T levels has been shown to result from both primary testicular changes and altered neuroendocrine regulation of Leydig cell function. At present, little is known about the clinical relevance of the relative hypoandrogenism of elderly men and there is an urgent need for more longitudinal studies, which may clarify a possible role of decreased T levels in the modulation of the clinical consequences of ageing in men. In view of the lack of relevant controlled clinical trials having careful assessment of the risks and benefits of androgen replacement therapy in elderly men, this treatment should be reserved for selected patients with clinically and biochemically manifest hypogonadism, after careful screening for contraindications.

Anterior pituitary function during critical illness and dopamine treatment

OBJECTIVE

To summarize the available data on anterior pituitary function in critical illness and to focus on the endocrine effects of dopamine infusion. The analogy with anterior pituitary function in the elderly is highlighted, and the potential importance of these observations for recovery from critical illness is discussed.

DATA SOURCES

Computerized search of published research and reference list review.

STUDY SELECTION

Review of 178 citations. Included are seven original studies on the effect of dopamine on pituitary function in adult and pediatric critical illness performed by the authors.

DATA EXTRACTION

Studies on the endocrinology of illness, chronic stress, aging, and dopamine, or on the clinical importance of endocrine changes.

DATA SYNTHESIS

The different pituitary axes are important determinants of normal anabolism and immune function. Continuously increased serum cortisol concentrations, insulin resistance, blunted prolactin release, and attenuated pulsatility of growth hormone and luteinizing hormone secretory patterns, as well as multiple anomalies in the thyroid axis, characterize the endocrine profile of prolonged critical illness. Dopamine, a natural catecholamine with hypophysiotropic properties, which has been used for more than two decades as an inotropic and vasoactive drug in intensive care, suppresses the circulating concentrations of all anterior pituitary-dependent hormones, except for cortisol. Available evidence suggests that the major effect of dopamine administration on the endocrine system is unlikely to be beneficial for the threatened metabolic and immunologic homeostasis of the severely ill patient. This pattern of hypopituitarism induced by chronic, severe illness and exogenous dopamine administration is reminiscent of the hormonal profiles obtained in experimental models of chronic stress, suggesting that endogenous dopamine may play a role in the endocrine and metabolic response to critical illness.

CONCLUSIONS

The dopamine-induced or aggravated pituitary dysfunction in critical illness warrants caution with prolonged infusion of this catecholamine as a so-called supportive agent, particularly in early life. The potential of combined hormonal therapy to improve the metabolic and immune status of the critically ill patient deserves thorough investigation.

Luteinizing hormone secretion and hypoandrogenaemia in critically ill men: effect of dopamine

OBJECTIVE

Critical illness has been associated with decreased LH secretion and lowering of testosterone. Dopamine is often used for vasoactive support in these patients. We therefore aimed to investigate LH secretion during severe illness and particularly the effect exerted by dopamine on LH in such patients.

PATIENTS AND DESIGN

In a randomized, controlled study of critically ill adult male polytrauma patients (n = 9), we evaluated the effect of prolonged (83-296 hours) dopamine infusion (5 micrograms/kg/min i.v.) on the dynamics of LH secretion and on serum testosterone concentrations. The effect of brief (15-21 hours) dopamine administration was documented in an additional randomized, controlled, cross-over study involving 6 patients.

MEASUREMENTS

Serum LH concentrations were measured by IRMA. The LH profiles, obtained by blood sampling every 20 minutes for 9 hours during two consecutive nights, were examined by deconvolution analysis. Serum testosterone concentrations were measured by RIA once per study night.

RESULTS

We found that before dopamine initiation and within 24 hours of dopamine withdrawal, the mean serum LH concentrations, the LH secretory amplitude, the amount of LH secreted per burst, the mean LH secretion rate and the number of LH pulses were higher than during dopamine infusion, being increased by a median of 161% (P = 0.006), 98% (P = 0.03), 106% (P = 0.03), 164% (P = 0.01) and 25% (P = 0.008) respectively. However, without dopamine administration the amplitude and mass of the LH secretory bursts still appeared to be low, whereas the pulse frequency remained elevated. After dopamine withdrawal, LH secretion increased significantly within 3 hours. Serum testosterone levels were very low and dopamine infusion appeared not to affect them within 24 hours.

CONCLUSION

We documented decreased LH secretory pulse amplitude and mass with increased pulse frequency, as well as very low serum testosterone concentrations in critically ill men. Dopamine infusion further suppressed LH release by decreasing secretory burst amplitude, mass and frequency, possibly through an inhibitory action at both the pituitary and the hypothalamic level.

Male pituitary-gonadal dysfunction following severe traumatic brain injury

A prospective study was conducted to evaluate pituitary-gonadal function and correlated parameters in 21 adult males with severe traumatic brain injury during acute inpatient rehabilitation. Serum concentrations of testosterone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were measured within 1 week after the patient was transferred to the rehabilitation unit. Fourteen of 21 patients (67%) had abnormally low testosterone levels. One of 21 patients had a subnormal FSH level and one had a supranormal level. Three of 21 patients had subnormal LH levels and two had supranormal levels. There was no correlation between the severity of brain injury and the levels of testosterone, FSH or LH. The presence of increased intracranial pressure, hypoxia, skull fracture or abnormal CT findings had no significant influence on the levels of testosterone, FSH or LH. The high incidence of hypotestosteronaemia in survivors of severe traumatic brain injury is seemingly more related to accompanying physiological stressors rather than structural or neurochemical disruption of the hypothalamic-pituitary-gonadal axis. Early identification is important relative to the potential neuromedical and rehabilitative consequences of prolonged hypotestosteronaemia in this patient population.

Effects of tumor necrosis factor on the hypothalamic-pituitary-testicular axis in healthy men

Tumor necrosis factor (TNF) has been implicated as a mediator of many diseases associated with alterations in hypothalamic-pituitary-testicular (HPT) function. To assess the effects of TNF on the HPT axis, we performed a saline-controlled cross-over study in six healthy men, sequentially measuring serum concentrations of gonadotropins, testosterone, and sex hormone-binding globulin (SHBG) after a bolus intravenous injection of recombinant human TNF (50 micrograms/m2). TNF induced an early and transient increase in serum luteinizing hormone (LH) levels from 6.0 +/- 1.0 to a maximum of 8.0 +/- 1.0 U/L after 30 minutes (P < .005), whereas the concentrations of follicle-stimulating hormone (FSH) remained unchanged. The increase in LH concentrations was followed by a transient decrease in serum testosterone levels from 18.2 +/- 0.3 to 9.1 +/- 1.2 nmol/L after 4 hours (P < .0001). Remarkably, LH levels had returned to control values when the testosterone level reached its nadir. SHBG levels were not affected by TNF. Our results suggest that TNF affects the HPT axis at multiple levels and may be involved either directly or indirectly in the decrease in circulating testosterone concentrations in systemic illnesses.

Secretion by the human testis of epitestosterone, with its sulfoconjugate and precursor androgen 5-androstene-3 beta,17 alpha-diol

Epitestosterone (ET) and testosterone (T), free and sulfoconjugated, as well as 5-androstene-3 beta,17 alpha-diol (5AD3 beta 17 alpha) and its 17 beta-epimer have been analyzed, by gas chromatography-mass spectrometry with stable isotope dilution, in peripheral and spermatic venous plasma of patients with left varicocele. All these androgens are secreted by the testis as evidenced by the significant concentration gradients between peripheral and spermatic venous plasma. Half of the daily ET production is ascribed to the testis, while 95% of T sulfate and roughly 70% of ET sulfate are also of testicular origin. Significant correlations between ET and 5AD3 beta 17 alpha are an indication that the 5-ene pathway is also operative for ET biosynthesis. High ratios of spermatic to peripheral venous plasma levels of ET and 5AD3 beta 17 alpha are also related to the high clearance rates of 17 alpha-hydroxy-androgens.

The effects of partial hepatectomy on serum sex steroids in humans

In both rats and humans, partial hepatectomy results in a substantial increase in serum estradiol concentrations. Because mammalian liver of both sexes contains estrogen receptor, it has been suggested that this surge in serum estrogen concentration may initiate or facilitate liver regeneration. We have reexamined the potential role of sex steroids in human liver regeneration by measuring serum estradiol and testosterone concentrations in men and postmenopausal women before and after hepatic resection. The results were compared with those obtained in patients subjected to other forms of major surgery. In both men and postmenopausal women, serum estradiol levels increased after partial hepatectomy. However, the magnitude of increase was not related to the amount of liver removed. Moreover, similar increases occurred in patients undergoing other major surgical procedures not involving the liver. Serum testosterone concentrations decreased in men and increased in postmenopausal women undergoing all forms of surgery. It is concluded that effects of partial hepatectomy on serum sex steroid levels are nonspecific and probably related to stress. These observations diminish the likelihood that such changes are an important factor in the control of liver regeneration in humans.

Circulating immunoreactive inhibin and testosterone levels in men with critical illness

OBJECTIVE

We aimed to concurrently characterize serial changes in circulating immunoreactive inhibin (irINH) and testosterone (T) as reflections of Sertoli and Leydig cell responses to acute critical illness in man.

DESIGN

Blood samples were drawn within 24 hours of admission to an Intensive Care Unit and at weekly intervals thereafter for up to 4 weeks while the patient remained in Intensive Care Unit or after discharge to a general ward.

PATIENTS

We studied 13 male subjects with critical illness requiring intensive therapy.

MEASUREMENTS

Plasma levels of irINH, T, LH, FSH and sex hormone binding globulin (SHBG) were analysed in relation to (i) the severity of illness as indicated by a sepsis score, acute physiology and chronic health evaluation score, and reverse triiodothyronine (rT3) levels and (ii) the outcome of illness as determined by discharge from Intensive Care Unit and the two-month mortality.

RESULTS

Overall irINH levels remained normal and correlated negatively with rT3 (r = -0.63, P = 0.001) but not with sepsis, acute physiology and chronic health evaluation score, or gonadotrophin levels. Neither admission nor serial irINH levels significantly distinguished between the different clinical outcomes. In contrast, T levels were depressed and inversely correlated with both sepsis and acute physiology and chronic health evaluation scores (P less than 0.02), and positively with gonadotrophins (P less than 0.01), but not rT3 levels. Men eventually discharged from the Intensive Care Unit showed a rise, while those remaining showed a fall, in T levels (P = 0.02, time-course interaction). Similarly, T levels were lower in patients who died than in survivors, despite the comparable T levels on admission (P = 0.02, time-course interaction). Despite the fall in T levels, gonadotrophin levels remained inappropriately in the eugonadal range but higher in men who were discharged from Intensive Care Unit (P = 0.02, time-course interaction). FSH but not LH levels were correlated with sepsis score (P = 0.02) but not acute physiology and chronic health evaluation score or rT3.

CONCLUSIONS

Sertoli cell function as judged by circulating irINH levels is much less affected by acute critical illness than is Leydig cell function as judged by circulating T levels. The suppressive effect of acute critical illness on Leydig cell function is consistent with a hypothalamic-pituitary lesion.

Stress induced changes in testis function

The mechanism through which chronic stress inhibits the hypothalamic-pituitary-testicular axis has been investigated. Chronic restraint stress decreases testosterone secretion, an effect that is associated with a decrease in plasma gonadotropin levels. In chronically stressed rats there was a decrease in hypothalamic luteinizing hormone-releasing hormone (LHRH) content and the response on plasma gonadotropins to LHRH administration was enhanced. Thus the inhibitory effect of chronic stress on plasma LH and FSH levels seems not to be due to a reduction in pituitary responsiveness to LHRH, but rather to a modification in LHRH secretion. It has been suggested that beta-endorphin might interfere with hypothalamic LHRH secretion during stress. Chronic immobilization did not modify hypothalamic beta-endorphin, while an increase in pituitary beta-endorphin secretion was observed. Since we cannot exclude that changes in beta-endorphin secreted by the pituitary or other opioids may play some role in the stress-induced decrease in LHRH secretion, the effect of naltrexone administration on plasma gonadotropin was studied in chronically stressed rats. Naltrexone treatment did not modify the decrease in plasma concentrations of LH or FSH. These findings suggest that the inhibitory effect of restraint on the testicular axis is exerted at hypothalamic level by some mechanism other than opioids.

Effect of restraint stress on gonadal proopiomelanocortin peptides and the pituitary-testicular axis in rats

We examined the effect of restraint on testicular interstitial fluid (TIF) concentrations of ACTH, beta-endorphin-lipotropin (beta-E-LI) and testosterone and correlated those changes with plasma concentrations of ACTH, beta-E-LI, corticosterone, LH and testosterone in adult rats. Animals were subjected to 1, 2, or 3 h of restraint and were killed immediately following the stress period. Plasma values of ACTH and beta-E-LI were elevated above control values after 1 and 2 h, but not after 3 h of restraint. Plasma corticosterone showed a similar response to restraint except that concentrations were also elevated after 3 h. Plasma testosterone concentrations were elevated after 1 h of restraint, but after 3 h of restraint had fallen below control values. Restraint reduced plasma testosterone concentrations without altering plasma LH concentrations. The decline in plasma testosterone during restraint was associated with a parallel decrease in testosterone in the TIF. Concentrations of ACTH and beta-E-LI were 6- and 3-fold greater in TIF than in the plasma. While 1 or 2 h of restraint did not affect ACTH and beta-E-LI in TIF, values of these hormones were elevated in rats exposed to 3 h of restraint. These data, coupled with recent reports that testicular proopiomelanocortin (POMC)-derived peptides may modulate testicular steroidogenesis, suggest that these factors may play an autocrine or paracrine role in mediating stressor-induced changes in testicular function.

Neuroendocrine aspects of primary endogenous depression VIII. Pituitary-gonadal axis activity in male patients and matched control subjects

To determine the extent of hypothalamo-pituitary-gonadal (HPG) axis dysfunction in endogenous depressed men, we measured nocturnal and diurnal serum luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), and estradiol (E2) concentrations, and their responses to gonadotropin releasing hormone (LHRH) and dexamethasone administration, in 16 Research Diagnostic Criteria primary, definite endogenous male depressives and 16 individually matched male normal controls. Compared to their controls, the patients showed no differences in basal nocturnal or diurnal gonadotropin or gonadal steroid hormone concentrations, and no differences in hormone concentrations either post-LHRH or post-dexamethasone. Age was negatively correlated with baseline serum T in the patients but not in the controls, and it was modestly positively correlated with baseline serum LH in both groups of subjects. In the patients, the presence of DSM-III melancholia was modestly negatively correlated with baseline and post-LHRH concentrations of both LH and FSH and was positively correlated with baseline serum T, but it bore no relation to serum E2. None of the other subject characteristics or specific dimensions of depressive symptomatology were significantly related to the HPG axis measures. The HPG axis measures also were unrelated to pre- and post-dexamethasone cortisol concentrations in both groups of subjects. The results of this study suggest that, in contrast to the hypothalamo-pituitary-adrenal cortical and thyroid axis abnormalities frequently found in endogenous depressives, HPG axis function in male depressives is relatively normal.

Hypothalamic hypogonadism following major head injury

Endocrine studies, using the four hypothalamic releasing hormones, gonadotrophin releasing hormone, thyrotrophin releasing hormone, corticotrophin releasing hormone and growth hormone releasing hormone, were performed in 33 males after admission with a major head injury. The test was repeated 7 days later in all 33 patients and after 3-6 months in 21 patients. All patients had a period of unconsciousness followed by post-traumatic amnesia of greater than 24 h. The results obtained from investigating the gonadal axis are reported in this paper. The levels of total and free testosterone, basal FSH and basal LH fell significantly during the first 3 days after injury, when the LH and FSH responses to GnRH achieved their highest peak levels. This hormone pattern has not previously been reported in the gonadal axis and may be a consequence of hypothalamic dysfunction. The severity of the injury was negatively correlated to the testosterone concentration on admission and to the basal and peak FSH concentrations 1 week later. Persistent hypogonadism was found in five of the 21 patients retested after 3-6 months, with low testosterone concentrations and three continued to have an exaggerated LH response to GnRH. Thus major head injury frequently results in hypogonadism shortly after injury, with an increased gonadotrophin response to GnRH. In addition, a substantial minority of patients continue to be hypogonadal after 3-6 months. In view of these findings we strongly suggest that all patients should be endocrinologically assessed at intervals following severe head injury.