Cortisol and GH secretory dynamics, and their interrelationships, in healthy aged women and men

Sex differences in cortisol levels in depression: A systematic review and meta-analysis

Higher prevalence of depression in females might be associated with sex-specific cortisol levels. Evidence exists that cortisol levels differ between healthy females and males, however a sex-specific association in depression has not been systematically assessed. Thus, the current study quantifies the existing literature on different cortisol parameters, i.e., basal cortisol, hair cortisol, cortisol awakening response (CAR), and cortisol stress reactivity comparing depressed females and males as well as sex-specific comparisons with healthy controls. Following an extensive literature research, fifty original articles were included. Depressed females had significantly higher hair cortisol, higher CAR, and lower cortisol stress reactivity compared to depressed males. In comparison with sex-matched controls, female patients had significantly higher evening basal cortisol, higher CAR and lower cortisol stress reactivity, and male patients had significantly higher general, morning and evening basal cortisol. Overall, sex as a fundamental driver of cortisol levels in depression needs to be taken into account.

Interrelationships Between Pituitary Hormones as Assessed From 24-hour Serum Concentrations in Healthy Older Subjects

CONTEXT

Hormones of the hypothalamic-pituitary-target gland axes are mostly investigated separately, whereas the interplay between hormones might be as important as each separate hormonal axis.

OBJECTIVE

Our aim is to determine the interrelationships between GH, TSH, ACTH, and cortisol in healthy older individuals.

DESIGN

We made use of 24-hour hormone serum concentrations assessed with intervals of 10 minutes from 38 healthy older individuals with a mean age (SD) of 65.1 (5.1) years from the Leiden Longevity Study. Cross-correlation analyses were performed to assess the relative strength between 2 24-hour hormone serum concentration series for all possible time shifts. Cross-approximate entropy was used to assess pattern synchronicity between 2 24-hour hormone serum concentration series.

RESULTS

Within an interlinked hormonal axis, ACTH and cortisol were positively correlated with a mean (95% confidence interval) correlation coefficient of 0.78 (0.74-0.81) with cortisol following ACTH concentrations with a delay of 10 minutes. Between different hormonal axes, we observed a negative correlation coefficient between cortisol and TSH of -0.30 (-0.36 to -0.25) with TSH following cortisol concentrations with a delay of 170 minutes. Furthermore, a positive mean (95% confidence interval) correlation coefficient of 0.29 (0.22-0.37) was found between TSH and GH concentrations without any delay. Moreover, cross-approximate entropy analyses showed that GH and cortisol exhibit synchronous serum concentration patterns.

CONCLUSIONS

This study demonstrates that interrelations between hormones from interlinked as well as different hypothalamic-pituitary-target gland axes are observed in healthy older individuals. More research is needed to determine the biological meaning and clinical consequences of these observations.

Effects of growth hormone administration on luteinizing hormone secretion in healthy older men and women

The known interactions between the somatotropic and hypothalamic-pituitary-gonadal (HPG) axes have not been well delineated in older individuals. Aging-associated decline in insulin like growth factor-1 (IGF-1) levels has been proposed to play a role in reproductive senescence in animals. However, the effects of GH on LH secretion are unknown in older individuals. Our objective was to determine whether GH modulates LH secretion or levels of sex steroids (SS) in healthy older (ages 65-88 years) men (n = 24) and women (n = 24) with low-normal plasma IGF-1 levels. In a double-masked, placebo-controlled (n = 24), randomized study, we evaluated the effects of GH (n = 24, 20 μg/kg sc 3×/week) for 26 weeks on nocturnal LH secretory dynamics [(8 pm to 8 am, Q20) min sampling and analyzed by multiparameter deconvolution algorithm]. Indices of LH secretion [frequency, mass per burst, pulsatile production rate, and approximate entropy (ApEn)] and fasting serum IGF-1, SHBG, and SS (TT, fT, or E2) were measured. At baseline, all indices of LH secretion (frequency, mass per burst, pulsatile production rate) were inversely (P < 0.05) related to IGF-1, but not to mean nocturnal serum GH concentrations. GH administration for 26 weeks increased serum IGF-1, but exerted no significant effects on LH secretory dynamics, or concentrations of SSs (TT, fT, or E2) or SHBG in older women or men. These data suggest that GH-mediated increases in IGF-1 do not modulate the HPG axis in older individuals.

Pulsatile Cortisol Feedback on ACTH Secretion Is Mediated by the Glucocorticoid Receptor and Modulated by Gender

CONTEXT

Factors that regulate physiological feedback by pulses of glucocorticoids on the hypothalamic-pituitary unit are sparsely defined in humans in relation to gluco- or mineralocorticoid receptor pathways, gender, age, and the sex steroid milieu.

OBJECTIVE

The objective of the study was to test (the clinical hypothesis) that glucocorticoid (GR) and mineralocorticoid (MR) receptor-selective mechanisms differentially govern pulsatile cortisol-dependent negative feedback on ACTH output (by the hypothalamo-pituitary unit) in men and women studied under experimentally defined T and estradiol depletion and repletion, respectively.

SETTING

The study was conducted at the Mayo Center for Translational Science Activities.

SUBJECTS

Healthy middle-aged men (n = 16) and women (n = 25) participated in the study.

INTERVENTIONS

This was a randomized, prospective, double-blind, placebo- and saline-controlled study of pulsatile cortisol infusions in low cortisol-clamped volunteers with and without eplerenone (MR blocker) and mifepristone (GR blocker) administration under a low and normal T and estradiol clamp. During frequent sampling, a bolus of CRH-arginine vasopressin was infused to assess corticotrope responsiveness. Analytical Methods and Outcomes: Deconvolution and approximate entropy of ACTH profiles were measured.

RESULTS

Infusion of cortisol (but not saline) pulses diminished ACTH secretion. The GR antagonist, mifepristone, interfered with negative feedback on both ACTH burst mass and secretion regularity. Eplerenone, an MR antagonist, exerted no detectable effect on the same parameters. Despite feedback imposition, CRH-arginine vasopressin-stimulated ACTH secretion was also increased by mifepristone and not by eplerenone. Withdrawal vs addback of sex steroids had no effect on ACTH secretion parameters. Nonetheless, ACTH secretion was greater (P = .006) and more regular (P = .004) in men than women.

CONCLUSION

Pulsatile cortisol feedback on ACTH secretion in this paradigm is mediated by the glucocorticoid receptor, in part acting at the level of the pituitary, and influenced by sex.

Reflections on the interaction of psychogenic stress systems in humans: the stress coherence/compensation model

Although stress simultaneously affects and causes changes in central nervous system systems together with the sympathetic nervous system and the hypothalamus-pituitary-adrenal axis, this interaction and its behavioral consequences are rarely assessed. The current paper first describes the different systems involved in the perception and processing of stressful stimuli on an anatomical and functional level, and the available measures to assess changes in these systems. It then explores, based on theoretical and empirical grounds, the interaction of the systems. This is followed by a review of previous stress models, and how these attempted to integrate the interaction of these systems. Then, it complements previous models by suggesting a complementary regulation of the stress systems, and discusses potential behavioral consequences. Finally, based on the three-system approach to assess stress it is argued that psychological measures, together with physiological and endocrine measures are indispensable. However, the lack of consensus on how to best assess the central and sympathetic nervous system components of stress make it more difficult to include measures of all systems routinely in future stress studies. Thus, the paper closes by giving some recommendations on how to include a minimum of feasible stress measures for all systems involved in stress processing and regulation.

Crosstalk between the circadian clock circuitry and the immune system

Various features, components, and functions of the immune system present daily variations. Immunocompetent cell counts and cytokine levels present variations according to the time of day and the sleep-wake cycle. Moreover, different immune cell types, such as macrophages, natural killer cells, and lymphocytes, contain a circadian molecular clockwork. The biological clocks intrinsic to immune cells and lymphoid organs, together with inputs from the central pacemaker of the suprachiasmatic nuclei via humoral and neural pathways, regulate the function of cells of the immune system, including their response to signals and their effector functions. Consequences of this include, for example, the daily variation in the response to an immune challenge (e.g., bacterial endotoxin injection) and the circadian control of allergic reactions. The circadian-immune connection is bidirectional, because in addition to this circadian control of immune functions, immune challenges and immune mediators (e.g., cytokines) were shown to have strong effects on circadian rhythms at the molecular, cellular, and behavioral levels. This tight crosstalk between the circadian and immune systems has wide-ranging implications for disease, as shown by the higher incidence of cancer and the exacerbation of autoimmune symptoms upon circadian disruption.

Hormone and cytokine circadian alteration in non-small cell lung cancer patients

Alterations in hormone secretion and cytokine levels have been evidenced in many neoplastic diseases. In this study we have evaluated the circadian profile of growth hormone (GH), insulin-like growth factor-1 (IGF-1), interleukin-2 (IL2), melatonin (MEL) and cortisol (COR) serum levels in non-small cell lung cancer patients. Blood was sampled every 4 h for 24 h in 11 healthy (H) men (ages 35-53 years) and 9 men with stage 2, 3 or 4 non-small cell lung cancer (C) (ages 43-63 years). Serum GH, total IGF1, IL2, MEL and COR were measured and examined for group differences, trends, and rhythm characteristics. 24-h means were significantly higher in C234 vs H for GH, GH/IGF1, IL2 and COR, and lower for IGF1, but IL2 and COR were not different for C23 vs H. A linear regression across 4 groups (H, C2, C3, C4) found a positive trend for COR, GH, GH/IGF1 and IL2, and a negative trend for IGF1. A linear regression run between the 24-h mean levels of GH, IGF1, COR, MEL and IL2 in healthy subjects evidenced a statistically significant positive trend between MEL and GH (R = 0.281, p = 0.022) and in cancer patients showed a statistically significant negative trend between GH and IGF1 (R = 0.332, p = 0.01), COR and IGF1 (R=0.430, p=0.001), and a statistically significant positive trend between the 24-h mean of COR and GH (R = 0.304, p = 0.02). Rhythms in MEL and COR (peaks near 01:00h and 08:00h, respectively) indicated identical synchronization to the light-dark cycle for both groups. A circadian rhythm was detected in GH and GH/IGF1 for C23 and H, with IGF1 and IL2 non-rhythmic in any group. In conclusion, an increasing trend and progressive loss of circadian rhythmicity in GH and GH/IGF1, an increasing trend in cortisol and IL2, and a decreasing trend in IGF1 in C, reflect a complex chain of events that could be involved in progression of neoplastic disease. A therapeutic strategy needs to take into account circadian patterns and complex interactions of the multiple functions that characterize the hormone and cytokine levels in the frame cancer progression.

The assessment of cortisol in human hair: associations with sociodemographic variables and potential confounders

To inform the future use of hair cortisol measurement, we have investigated influences of potential confounding variables (natural hair colour, frequency of hair washes, age, sex, oral contraceptive (OC) use and smoking status) on hair cortisol levels. The main study sample comprised 360 participants (172 women) covering a wide range of ages (1-91 years; mean = 25.95). In addition, to more closely examine influences of natural hair colour and young age on hair cortisol levels, two additional samples comprising 69 participants with natural blond or dark brown hair (hair colour sample) as well as 28 young children and 34 adults (young age sample) were recruited. Results revealed a lack of an effect for natural hair colour, OC use, and smoking status on hair cortisol levels (all p's >0.10). No influence of frequency of hair washes was seen for proximal hair segments (p = 0.335) but for the third hair segment indicating lower cortisol content (p = 0.008). We found elevated hair cortisol levels in young children and older adults (p < 0.001). Finally, men showed higher hair cortisol levels than women (p = 0.002). The present data indicate that hair cortisol measurement provides a useful tool in stress-related psychobiological research when applied with the consideration of possible confounders including age and sex.

The hormonal response of older men to sub-maximum aerobic exercise: the effect of training and detraining

The hormonal response of 32 older men (70-80years) to a bout of sub-maximum aerobic exercise was examined before, after 16weeks of resistance or aerobic training and again after 4weeks of detraining. Blood samples were obtained at rest and immediately post sub-maximum exercise (30min @ 70% VO(2) max) to determine the concentrations of growth hormone (GH), insulin-like growth factor-1 (IGF-1), testosterone (Test), sex hormone-binding globulin (SHBG) and the calculation of free testosterone (FT). Both training groups had significant increases in leg strength and VO(2) max after 16weeks training but leg strength and VO(2) max returned to pre-training levels in the aerobic training and resistance training groups, respectively. During the 20week study there was no change in resting concentrations of any hormones among the three groups. There was no increase in GH, IGF-1 or SHBG immediately post sub-maximum exercise in any of the groups before training, after 16weeks training or after 4weeks detraining. Testosterone and FT increased immediately post sub-maximum exercise within all groups before training, after 16weeks training and after 4weeks detraining with the increase in Test and FT higher after 16weeks of resistance training compared to before training and after 4weeks detraining within the resistance training group. The increased responsiveness of Test and FT after 16weeks of resistance training was lost after 4weeks of detraining. Our results indicate that some physiological and hormonal adaptations gained after 16weeks training are lost after only 4weeks detraining.

Comparison of circadian characteristics for cytotoxic lymphocyte subsets in non-small cell lung cancer patients versus controls

Lymphocyte subsets are major cellular components of the adaptive immune response and in most cases show 24-h (circadian) variations in health. In order to determine overall levels and circadian characteristics of cytotoxic natural killer (NK) and T and B lymphocyte subsets, blood samples were collected every 4 h for 24 h from eleven male controls (C) without neoplastic disease and nine men with untreated non-small cell lung cancer (NSCLC) and analyzed for 3 hormones (melatonin, cortisol, and interleukin 2 [IL2]) and for 11 lymphocyte subpopulations classified by cell surface clusters of differentiation (CD) and antigen receptors. Circadian rhythmicity for each variable was evaluated by ANOVA and 24 h cosine fitting and groups compared. Rhythms in melatonin and cortisol (peaks near 01:30 and 08:00 h) indicated identical synchronization to the light-dark schedule and probable persistent entrainment of rhythms for both groups in metabolism or proliferation of healthy tissues normally tightly coupled to the sleep-wake cycle. Twenty-four hours means were significantly higher in NSCLC for CD16, CD25, cortisol, and IL2 and lower for CD8, CD8bright, and γδTCR. A significant circadian rhythm was found in C with daytime peaks for CD8, CD8dim, CD16, Vδ2TCR, and cortisol and nighttime peaks for CD3, CD4, CD20, and melatonin, and in NSCLC, with daytime peaks for CD16, γδTCR, Vδ2TCR and cortisol, and nighttime peaks for CD4, CD25, and melatonin. Thus, NSCLC was associated with significant increases or decreases in proportions for several lymphocyte subsets that may reflect disease development, but peak times were nevertheless similar between C and NSCLC for each variable, suggesting that timed circadian administration (chronotherapy) of immunotherapy and other cancer treatments may improve efficacy due to persistent circadian entrainment of healthy tissues.

The impact of frailty in the elderly on the outcome of surgery in the aged

As the population continues to age, we will continue to encounter issues involving aging and the elderly. Despite these issues, knowledge is expanding and evolving with new solutions to ongoing problems. Mechanistically, frailty at its root is a symptom of growing old, with cascades and circuitous feedback between organ systems at all levels. Clinically, frailty is as equally dynamic and its multifactorial nature represents a unique challenge to the surgical community and warrants the integration of geriatric assessment into clinical practice. Integration within clinical practice includes using an interdisciplinary approach, where surgeons work with anesthesiologists, geriatricians, nursing, rehabilitation, nutritionists, and other support staff to provide holistic assessment, efficient delivery, and higher quality of care. This in hand, recognition of frailty can occur in a timely fashion to initiate treatment, decreasing the risk of morbidity and mortality for improved surgical outcomes.

WITHDRAWN: Neuroendocrine axes function in healthy aging: Evaluation of predictive and manipulable blood serum indexes

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.biomag.2010.09.002. The duplicate article has therefore been withdrawn.

Intraocular and systemic pharmacokinetics of triamcinolone acetonide after a single 40-mg posterior subtenon application

PURPOSE

To characterize the pharmacokinetics of triamcinolone acetonide (TA) in aqueous, vitreous, and systemic circulation after a single subtenon injection.

DESIGN

Prospective interventional case series.

PARTICIPANTS

Thirty-six patients (36 eyes) who received a single posterior subtenon injection of TA (40 mg in 0.4 ml).

METHODS

Aqueous, vitreous, and blood samples were obtained at 1-hour, 1-day, 3-day, 5-day, 10-day, 14-day, 21-day, and 28-day time points after the posterior subtenon TA injection. At each time point, there were 3 to 6 eyes (patients). The concentrations of TA in the aqueous, vitreous, and plasma were analyzed using ultra-performance liquid chromatography coupled with tandem mass spectrometry.

MAIN OUTCOME MEASURES

Triamcinolone acetonide concentration in the samples was measured, and pharmacokinetic parameters were calculated.

RESULTS

The TA concentration-time profile in aqueous consisted of a fast distribution phase during the first 24 hours and a slow elimination phase thereafter. In contrast, the TA concentration-time profile in vitreous consisted of an absorption phase during the first 24 hours followed by a slow elimination phase. The TA in plasma followed a mono-exponential elimination during the study course. The TA concentration peak time for aqueous and plasma was at 1 hour and 24 hours, for vitreous after subtenon injection. The terminal elimination half-life in aqueous, vitreous, and plasma was 11.8, 17.1, and 25 days, respectively. The integral of the area under the concentration time curve (AUC(0-∞)) was 862 ng/day/ml for aqueous, 1262 ng/day/ml for vitreous, and 17.4 ng/day/ml for plasma. The total TA exposure to vitreous was 46% more than total TA exposure to the aqueous. The TA concentration in vitreous was 70- to 98-fold higher than that in plasma.

CONCLUSIONS

Posterior subtenon TA application can provide a sustained high local ocular TA level while also resulting in a very low systemic TA level, which may be well below the normal glucocorticoid level in humans.

Effects of testosterone administration on nocturnal cortisol secretion in healthy older men

In animal studies, testosterone decreases, whereas estrogen increases, cortisol production. In one clinical study, short-term testosterone replacement attenuated corticotrophin-releasing hormone-stimulated cortisol secretion during leuprolide-induced hypogonadism in young men. The effects of longer term testosterone treatment on spontaneous cortisol secretion in younger or older men are unknown. In a randomized, double-masked placebo-controlled study, we assessed the effects of testosterone supplementation (100 mg intramuscular every 2 week) for 26 weeks on nocturnal cortisol secretory dynamics in healthy older men. Testosterone administration increased early morning serum concentrations of free testosterone by 34%, decreased sex hormone-binding globulin by 20%, and did not alter early morning concentrations of cortisol-binding globulin or cortisol compared with placebo treatment. Testosterone did not significantly alter nocturnal mean and integrated cortisol concentrations, cortisol burst frequency, mass/burst, basal secretion, pulsatile cortisol production rate, pattern regularity, or approximate entropy. We conclude that low-dose testosterone supplementation for 26 weeks does not affect spontaneous nocturnal cortisol secretion in healthy older men.

Systemic absorption of triamcinolone acetonide after posterior sub-Tenon injection

PURPOSE

To study systemic absorption of triamcinolone acetonide (TA) after posterior sub-Tenon injection.

DESIGN

Prospective, interventional case series.

METHODS

The study was conducted in a tertiary care teaching hospital on 35 eyes in which posterior sub-Tenon injection of 40 mg TA was administered after conventional extracapsular cataract extraction. Patients who had received any systemic steroid over 6 weeks preceding the period of study or had inflammatory ocular conditions were excluded. Serum TA levels were estimated by high-performance liquid chromatography at 1, 2, 3, 24, and 48 hours and 1, 2, and 6 weeks after injection.

RESULTS

Significant levels of the drug were detected in 45.71% of samples (mean serum levels, 6.94 +/- 8.98 ng/ml; P < .001) at 1 hour after sub-Tenon injection, in 85.71% of samples (mean serum levels, 21.83 +/- 12.92 ng/ml; P < .001) at 2 hours after injection, in 100% of samples (mean serum levels, 47.14 +/- 12.20 ng/ml; P < .001) at 3 hours after injection, in 100% of samples (mean serum levels, 35.49 +/- 13.79 ng/ml; P < .001) at 24 hours after injection, in 62.86% of samples (mean serum levels, 10.46 +/- 10.69 ng/ml; P < .001) at 48 hours after injection, and in 28.57% of samples (mean serum levels, 3.74 +/- 6.45 ng/ml; P = .002) at 1 week after injection. The drug was not detected in any of the samples obtained 2 weeks and 6 weeks later.

CONCLUSIONS

Posterior sub-Tenon injection of 40 mg TA adds statistically significant quantities to physiologic concentration of corticosteroids in peripheral blood. This may be detrimental for patients having certain metabolic diseases like diabetes and preferably should be avoided or administered with caution.

Relationships among plasma dehydroepiandrosterone and dehydroepiandrosterone sulfate, cortisol, symptoms of dissociation, and objective performance in humans exposed to underwater navigation stress

BACKGROUND

A growing body of research has provided evidence that dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) are involved in an organism's response to stress and that it may provide beneficial behavioral and neurotrophic effects.

METHODS

This study investigated plasma DHEA and DHEAS, cortisol, psychological symptoms of dissociation, and military performance in 41 healthy active duty subjects enrolled in the military Combat Diver Qualification Course (CDQC).

RESULTS

Baseline values of DHEA and DHEAS were significantly and positively predictive of superior performance in the underwater navigation exam; in addition, DHEA and DHEAS were significantly and negatively related to stress-induced symptoms of dissociation during performance of the task. Similarly, participants who reported fewer symptoms of dissociation exhibited superior military performance and increased levels of DHEA after the test.

CONCLUSIONS

These data provide prospective, empiric evidence that DHEA and DHEAS are associated with superior stress tolerance, fewer symptoms of dissociation, and superior, objectively assessed, military performance.

Salivary cortisol differs with age and sex and shows inverse associations with WHR in Swedish women: a cross-sectional study

BACKGROUND

Most studies on cortisol have focused on smaller, selected samples. We therefore aimed to sex-specifically study the diurnal cortisol pattern and explore its association with abdominal obesity in a large unselected population.

METHODS

In 2001-2004, 1811 men and women (30-75 years) were randomly selected from the Vara population, south-western Sweden (81% participation rate). Of these, 1671 subjects with full information on basal morning and evening salivary cortisol and anthropometric measurements were included in this cross-sectional study. Differences between groups were examined by general linear model and by logistic and linear regression analyses.

RESULTS

Morning and Delta-cortisol (morning - evening cortisol) were significantly higher in women than men. In both genders older age was significantly associated with higher levels of all cortisol measures, however, most consistently with evening cortisol. In women only, age-adjusted means of WHR were significantly lower in the highest compared to the lowest quartile of morning cortisol (p = 0.036) and Delta-cortisol (p < 0.001), respectively. Furthermore, when comparing WHR above and below the mean, the age-adjusted OR in women for the lowest quartile of cortisol compared to the highest was 1.5 (1.0-2.2, p = 0.058) for morning cortisol and 1.9 (1.3-2.8) for Delta-cortisol. All findings for Delta-cortisol remained after adjustments for multiple covariates and were also seen in a linear regression analysis (p = 0.003).

CONCLUSION

In summary, our findings of generally higher cortisol levels in women than men of all ages are novel and the stronger results seen for Delta-cortisol as opposed to morning cortisol in the association with WHR emphasise the need of studying cortisol variation intra-individually. To our knowledge, the associations in this study have never before been investigated in such a large population sample of both men and women. Our results therefore offer important knowledge on the descriptive characteristics of cortisol in relation to age and gender, and on the impact that associations previously seen between cortisol and abdominal obesity in smaller, selected samples have on a population level.

Hormonal status of cortisol and dehydroepiandrosterone sulfate in an elderly Tunisian population

Adrenal function and aging have been the object of intense interest recently, especially as regards dehydroepiandrosterone sulfate (DHEA-S), which is of major importance, since it is distinct from cortisol and aldosterone in declining with age. In a group of healthy old Tunisians, we investigated the association between cortisol and DHEA-S, on the one hand, and age, sex, lifestyle, physical health, including the body mass index (BMI), physical activity, and smoking indicators, on the other hand. We observed that cortisol concentrations did not change with aging, while DHEA-S concentrations decrease with age in both sexes. Cortisol/DHEA-S ratio, however, increases with aging. Our results revealed that DHEA-S levels are affected neither by physical activity nor by weight. It appears also that current smoking could not affect the level of DHEA-S. Relationships were found between DHEA-S concentrations and BMI, then between DHEA-S levels and serum cholesterol, triglycerides and calcium. No modification in the morning serum cortisol was found to be associated with aging. Decrease in DHEA-S levels is, however, clearly associated with this phenomenon. High cortisol/DHEA-S ratio accelerates the occurrence of some adult diseases, such as diabetes mellitus, atherosclerosis, dementia, and osteoporosis. Generally, the adrenal insufficiency marked by a cognitive impairment, immune disorders, sexual dysfunction, and scores for depression and anxiety can be corrected by a replacement of deficient DHEA-S.

Long-term testosterone supplementation augments overnight growth hormone secretion in healthy older men

Circulating testosterone (T) and GH/IGF-I are diminished in healthy aging men. Short-term administration of high doses of T augments GH secretion in older men. However, effects of long-term, low-dose T supplementation on GH secretion are unknown. Our objective was to evaluate effects of long-term, low-dose T administration on nocturnal GH secretory dynamics and AM concentrations of IGF-I and IGFBP-3 in healthy older men (65-88 yr, n = 34) with low-normal T and IGF-I. In a double-masked, placebo-controlled, randomized study we assessed effects of low-dose T supplementation (100 mg im every 2 wk) for 26 wk on nocturnal GH secretory dynamics [8 PM to 8 AM, Q(20) min sampling, analyzed by multiparameter deconvolution and approximate entropy (ApEn) algorithms]. The results were that T administration increased serum total T by 33% (P = 0.004) and E(2) by 31% (P = 0.009) and decreased SHBG by 17% (P = 0.002) vs. placebo. T supplementation increased nocturnal integrated GH concentrations by 60% (P = 0.02) and pulsatile GH secretion by 79% (P = 0.05), primarily due to a twofold increase in GH secretory burst mass (P = 0.02) and a 1.9-fold increase in basal GH secretion rate (P = 0.05) vs. placebo. There were no significant changes in GH burst frequency or orderliness of GH release (ApEn). IGF-I levels increased by 22% (P = 0.02), with no significant change in IGFBP-3 levels after T vs. placebo. We conclude that low-dose T supplementation for 26 wk increases spontaneous nocturnal GH secretion and morning serum IGF-I concentrations in healthy older men.

Hypothalamic-pituitary-adrenal axis suppression in asthmatic children on inhaled corticosteroids: part 1. Which test should be used?

The effect of inhaled corticosteroids (ICS) on the hypothalamic-pituitary-adrenal axis (HPA) has been regarded as a 'benign physiological response'. A recent survey suggests that adrenal crisis might be more common in asthmatic children on ICS than previously thought. The clinical features of adrenal insufficiency are non-specific and can easily be missed. Accurate biochemical assessment of the axis is therefore mandatory. A review of the literature determined that all basal adrenal function tests, including plasma cortisol profiles, cannot identify which children can respond to stress. There is no evidence to suggests that the degree of the physiological adjustment of the HPA to ICS predicts clinically significant HPA suppression. Only gold standard adrenal function tests can assess the integrity of the whole axis. Of the two available tests, the correctly performed overnight metyrapone test (with ACTH levels) is safe and better by far. The use of cortisol profiles should only be used to demonstrate differences in systemic activity of various ICS and delivery devices. Regulatory bodies should insist on trials that evaluate the HPA with a gold standard adrenal function test before it is declared safe and allowed to be marketed. A re-analysis of studies that have utilized gold standard adrenal function tests only might identify the lowest safe dose and duration of ICS.

Analysis of bidirectional pattern synchrony of concentration-secretion pairs: implementation in the human testicular and adrenal axes

The hypothalamo-pituitary-testicular and hypothalamo-pituitary-adrenal axes are prototypical coupled neuroendocrine systems. In the present study, we contrasted in vivo linkages within and between these two axes using methods without linearity assumptions. We examined 11 young (21–31 yr) and 8 older (62–74 yr) men who underwent frequent (every 2.5 min) blood sampling overnight for paired measurement of LH and testosterone and 35 adults (17 women and 18 men; 26–77 yr old) who underwent adrenocorticotropic hormone (ACTH) and cortisol measurements every 10 min for 24 h. To mirror physiological interactions, hormone secretion was first deconvolved from serial concentrations with a waveform-independent biexponential elimination model. Feedforward synchrony, feedback synchrony, and the difference in feedforward-feedback synchrony were quantified by the cross-approximate entropy (X-ApEn) statistic. These were applied in a forward (LH concentration template, examining pattern recurrence in testosterone secretion), reverse (testosterone concentration template, examining pattern recurrence in LH secretion), and differential (forward minus reverse) manner, respectively. Analogous concentration-secretion X-ApEn estimates were calculated from ACTH-cortisol pairs. X-ApEn, a scale- and model-independent measure of pattern reproducibility, disclosed 1) greater testosterone-LH feedback coordination than LH-testosterone feedforward synchrony in healthy men and significant and symmetric erosion of both feedforward and feedback linkages with aging; 2) more synchronous ACTH concentration-dependent feedforward than feedback drive of cortisol secretion, independent of gender and age; and 3) enhanced detection of bidirectional physiological regulation by in vivo pairwise concentration-secretion compared with concentration-concentration analyses. The linking of relevant biological input to output signals and vice versa should be useful in the dissection of the reciprocal control of neuroendocrine systems or even in the analysis of other nonendocrine networks.

Serum levels of triamcinolone acetonide after intravitreal injection

PURPOSE

To evaluate serum levels of triamcinolone acetonide after intravitreal high-dose injection.

DESIGN

Prospective, interventional case series study.

METHODS

For 20 consecutive patients, venous blood samples were taken before and 13 +/- 19 days (range 4 to 92) after an intravitreal injection of 20 to 25 mg triamcinolone acetonide as treatment of edematous macular diseases.

RESULTS

Serum levels of triamcinolone acetonide did not differ significantly (P =.174; t test for paired matches) preoperatively (0 microg/l) and postoperatively (0.065 microg/l +/- 0.21 microg/l). In 18 eyes (90%), triamcinolone acetonide could not be detected in serum samples. For two patients (10%), serum samples taken 5 days and 7 days after the injection, respectively, contained 0.5 microg/l triamcinolone acetonide and 0.8 microg/l triamcinolone acetonide, respectively.

CONCLUSION

After an intravitreal high-dose injection of 20 to 25 mg triamcinolone acetonide, triamcinolone acetonide is not, or only marginally, detectable in serum samples obtained within 4 to 92 days after the injection.

Frailty in the elderly: contributions of sarcopenia and visceral protein depletion

In any given population of free-living individuals 65 years of age and older, a substantial proportion (in the range of 6% to 25%) suffers from many of the elements of the syndrome of frailty. Although the syndrome is complex and still lacks a standard definition, there is a growing consensus about the signs and symptoms as well as the pattern of biological correlates that characterize this disorder. Patients who are afflicted with frailty typically exhibit loss of muscle strength, fatigue easily, are physically inactive, and have a slow-and often unsteady-gait, with an increased risk (and fear) of falling. They are likely to have a poor appetite and to have undergone a recent, unintentional loss of weight. Frail individuals are more likely than the nonfrail to experience impaired cognition and depression. They die sooner. Frailty, of course, is frequently complicated by a variety of coexistent illnesses. Among the biological correlates of frailty are sarcopenia (now readily measurable by dual-energy x-ray absorptiometry [DXA]), osteopenia (with an increased susceptibility to fracture), and activation of the inflammatory and coagulation systems, with a rise in inflammatory cytokines and several markers of coagulopathy. Age-dependent changes in a number of hormones also appear to promote the development of frailty in the elderly, particularly via their effects on muscle mass and strength, bone density, and by contributing to activation of the catabolic cytokines. In particular, serum levels of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) decline progressively during aging, and an association between reduction in the levels of these hormones and the involution of advancing age has been proposed. It is not yet known whether, in comparison with their nonfrail counterparts, frail individuals consistently manifest larger reductions in GH and IGF-1 (and other anabolic hormones). More research is needed before it will be known whether the benefits of administering GH to the frail elderly will outweigh the disadvantages. The poor appetite and weight loss that occur in many frail individuals are likely to be accompanied by a degree of visceral protein depletion (with its attendant morbidity), which can be estimated by making serial measurements of indicators of visceral protein status such as transthyretin (TTR), retinol-binding protein (RBP), and albumin. One characteristic of the frailty syndrome that distinguishes it from the effects of aging per se is the potential reversibility of many of its features. Progressive resistance training is feasible for many elderly individuals-even the oldest old-and, by increasing muscle mass and strength, can ameliorate or reverse important aspects of physical frailty. To the extent that visceral protein depletion has been caused by an inadequate intake of calories and protein, consumption of a more adequate diet can result in betterment of the frail patient's nutritional status, as determined by clinical improvement and favorable changes in TTR, RBP, and albumin.

Cortisol secretion in the elderly. Influence of age, sex and cardiovascular disease in a Chinese population

Adrenal function and aging have been the object of intense interest in recent years. In this study we analyzed morning (08:00 h) serum cortisol concentrations from a sample of Chinese subjects aged from 31 to 110 years. These levels differed according to age, health status and sex, although the sex difference was confirmed only among the healthy elderly. These results suggest that age (older than 60 years), disease and male sex are associated with increased morning serum cortisol levels in a Chinese population.

Growth hormone release during acute and chronic aerobic and resistance exercise: recent findings

Exercise is a potent physiological stimulus for growth hormone (GH) secretion, and both aerobic and resistance exercise result in significant, acute increases in GH secretion. Contrary to previous suggestions that exercise-induced GH release requires that a "threshold" intensity be attained, recent research from our laboratory has shown that regardless of age or gender, there is a linear relationship between the magnitude of the acute increase in GH release and exercise intensity. The magnitude of GH release is greater in young women than in young men and is reduced by 4-7-fold in older individuals compared with younger individuals. Following the increase in GH secretion associated with a bout of aerobic exercise, GH release transiently decreases. As a result, 24-hour integrated GH concentrations are not usually elevated by a single bout of exercise. However, repeated bouts of aerobic exercise within a 24-hour period result in increased 24-hour integrated GH concentrations. Because the GH response to acute resistance exercise is dependent on the work-rest interval and the load and frequency of the resistance exercise used, the ability to equate intensity across different resistance exercise protocols is desirable. This has proved to be a difficult task. Problems with maintaining patent intravenous catheters have resulted in a lack of studies investigating alterations in acute and 24-hour GH pulsatile secretion in response to resistance exercise. However, research using varied resistance protocols and sampling techniques has reported acute increases in GH release similar to those observed with aerobic exercise. In young women, chronic aerobic training at an intensity greater than the lactate threshold resulted in a 2-fold increase in 24-hour GH release. The time line of adaptation and the mechanism(s) by which this training effect occurs are still elusive. Unfortunately, there are few studies investigating the effects of chronic resistance training on 24-hour GH release. The decrease in GH secretion observed in individuals who are older or have obesity is associated with many deleterious health effects, although a cause and effect relationship has not been established. While exercise interventions may not restore GH secretion to levels observed in young, healthy individuals, exercise is a robust stimulus of GH secretion. The combination of exercise and administration of oral GH secretagogues may result in greater GH secretion than exercise alone in individuals who are older or have obesity. Whether such interventions would result in favourable clinical outcomes remains to be established.