Abdominal adiposity rather than age and sex predicts mass and regularity of GH secretion in healthy adults

1997 ◽  
Vol 272 (6) ◽  
pp. E1108-E1116 ◽  
Author(s):  
N. Vahl ◽  
J. O. Jorgensen ◽  
C. Skjaerbaek ◽  
J. D. Veldhuis ◽  
H. Orskov ◽  
...  
Keyword(s):  
Linear Regression Analysis ◽  
Maximal Oxygen Consumption ◽  
Approximate Entropy ◽  
Multiple Linear Regression Analysis ◽  
Abdominal Fat ◽  
Deconvolution Analysis ◽  
Gh Secretion ◽  
Major Predictor ◽  
Underlying Mechanisms ◽  
Age Range

We tested the hypothesis that body composition is the major predictor of growth hormone (GH) secretion in nonobese adults. We measured lean and fat tissue distribution (computerized tomography and dual-energy X-ray absorptiometry scan) and physical fitness [maximal oxygen consumption (Vo2max)] in 42 healthy nonobese adults (22 women and 20 men, age range 27-59 yr, mean +/- SE body mass index = 24 +/- 0.5 kg/m2). Deconvolution analysis was used to estimate specific features of 24-h GH secretion and clearance. Approximate entropy was used to quantify the regularity of GH release. Older subjects exhibited decreased estimates of GH secretion compared with younger subjects. Females had higher estimates of GH secretion, a longer GH half-life, and displayed more irregularity in GH release than males. Mean 24-h serum GH concentrations correlated inversely with intra-abdominal fat and waist-to-hip ratio and positively with Vo2max. Multiple linear regression analysis revealed intra-abdominal fat as the dominant determinant of estimates of GH secretion. Vo2max was more important than sex and age in predicting GH secretion. We conclude that abdominal fat is the major determinant of GH secretion in healthy nonobese adults. Although the underlying mechanisms remain elusive, our findings extend the clinical implications of visceral adiposity to include hyposomatotropism.

scholarly journals Increased Pulsatility, Process Irregularity, and Nocturnal Trough Concentrations of Growth Hormone in Amenorrheic Compared to Eumenorrheic Athletes1

2001 ◽  
Vol 86 (3) ◽  
pp. 1013-1019
Author(s):  
Debra L. Waters ◽  
Clifford R. Qualls ◽  
Richard Dorin ◽  
Johannes D. Veldhuis ◽  
Richard N. Baumgartner
Keyword(s):  
Oxygen Consumption ◽  
Hospital Admissions ◽  
Maximal Oxygen Consumption ◽  
Exercise Bout ◽  
Approximate Entropy ◽  
Sampling Period ◽  
Igf Binding Proteins ◽  
Deconvolution Analysis ◽  
Gh Secretion ◽  
Igf I

Amenorrheic athletes exhibit a spectrum of neuroendocrine disturbances, including alterations in the GH-insulin-like growth factor I (IGF-I) axis. Whether these changes are due to exercise or amenorrhea is incompletely characterized. The present study investigates spontaneous (overnight) and exercise-stimulated GH secretion and associated IGF-binding proteins (IGFBPs) in amenorrheic (AA; n = 5), and eumenorrheic athletes ( n = 5) matched for age, percent body fat (dual energy x-ray absorptiometry), training history, and maximal oxygen consumption. Each volunteer participated in two hospital admissions consisting of a 50-min submaximal exercise bout (70% maximal oxygen consumption) and an 8-h nocturnal sampling period. Deconvolution analysis of serum GH concentration time series revealed increases in the half-life of GH (60%) and the number of secretory bursts (85%) as well as a decrease in their half-duration (50%) and the mass of GH secreted per pulse (300%) in the AA cohort. Time occupancy at elevated trough GH concentrations was significantly increased, and GH pulsatility (approximate entropy) was more irregular in the AA group. During exercise, AA exhibited a reversal of the normal relationship between IGF-I and GH, and a 4- to 5-fold blunting of stimulated peak and integrated GH secretion. Fasting levels of plasma IGF-I, IGFBP-3, and IGFBP-1 appeared to be unaffected by menstrual status. In ensemble, this phenotype of GH release in amenorrheic athletes suggests disrupted neuroregulation of episodic GH secretion, possibly reflecting decreased somatostinergic inhibition basally, and reduced GHRH output in response to exercise compared with eumenorrheic athletes. Accordingly, we postulate that the amenorrheic state, beyond the exercise experience per se, alters the neuroendocrine control of GH output in amenorrheic athletes.

scholarly journals Proximate Factors Determining Age and Mass at Fledging in Rhinoceros Auklets (Cerorhinca Monocerata): Intra- and Interyear Variations

The Auk ◽  
2004 ◽  
Vol 121 (2) ◽  
pp. 452-462 ◽  
Author(s):  
Tomohiro Deguchi ◽  
Akinori Takahashi ◽  
Yutaka Watanuki
Keyword(s):  
Growth Rate ◽  
Wing Length ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Major Effect ◽  
Timing Of Breeding ◽  
Hatching Date ◽  
Cerorhinca Monocerata ◽  
Parental Provisioning ◽  
Underlying Mechanisms

Abstract In alcids, growth rate and hatching date of chicks appear to affect fledging age and mass. Underlying mechanisms are hypothesized to be (1) critical wing length at fledging for postfledging survival, (2) synchronization of fledging to dilute predation risk, and (3) variable parental provisioning according to timing of breeding. To elucidate the effects of growth rate and hatching date on fledging age and mass, and to test those mechanistic hypotheses, we measured chick growth and fledging periods in Rhinoceros Auklets (Cerorhinca monocerata) at Teuri Island from 1995 to 2000. The multiple-linear regression analysis showed that intrayear variations of fledging age and mass were explained by growth rate or hatching date in five out of six years. Faster-growing chicks fledged younger and heavier, and earlier-hatched chicks fledged older and heavier. Consequently, no apparent correlation between fledging age and mass was observed in five out of six years. Analysis of interyear variation showed a negative correlation between fledging age and mass, which indicates that growth rates rather than hatching dates had a major effect. Wing length at fledging was independent of growth in mass. More than 80% of chicks fledged when they attained a narrow range of wing length (130–150 mm), presumably because they remained in their nests until they attained the critical wing length. In five out of six years, the chicks did not synchronize timing of fledging relative to timing of hatching. Later-hatched chicks attained lighter peak masses and at younger ages, which may indicate that their parents decreased provisioning rates when the chicks were still young. We suggest that (1) critical wing length at fledging and (2) variable parental provisioning according to timing of breeding could be underlying mechanisms determining these relationships between fledging age and mass.

Somatostatin infusion suppresses GH secretory burst frequency and mass in normal men

1996 ◽  
Vol 270 (6) ◽  
pp. E975-E979 ◽  
Author(s):  
E. Calabresi ◽  
E. Ishikawa ◽  
L. Bartolini ◽  
G. Delitala ◽  
G. Fanciulli ◽  
...  
Keyword(s):  
Cluster Method ◽  
Computer Assisted ◽  
Adult Males ◽  
Burst Frequency ◽  
Deconvolution Analysis ◽  
Gh Secretion ◽  
Detection Program ◽  
Neuroendocrine Mechanisms ◽  
Normal Men ◽  
Age Range

In attempting to elucidate the neuroendocrine mechanisms that regulate pulsatile growth hormone (GH) secretion, we measured serum GH concentrations by an ultrasensitive immunofluorometric method in blood collected every 10 min for 8 h in 11 young healthy male volunteers (age range 21-31 yr) before and during somatostatin (SS) administration (an iv bolus dose of 350 micrograms followed by a continuous infusion at the rate of 6 micrograms.kg-1.h-1, which increases the circulating SS levels to approximately 570 pg/ml). Pulsatile GH secretion was analyzed using the computer-assisted pulse detection program cluster method and deconvolution analysis. The area and frequency of GH peaks were significantly reduced during SS infusion compared with basal values, but detectable pulsatile episodes were still present. These data suggest that, in adult males, SS controls pulsatile GH secretion and can decrease the mass and frequency of GH secretory bursts.

scholarly journals Estradiol Supplementation in Postmenopausal Women Attenuates Suppression of Pulsatile Growth Hormone Secretion by Recombinant Human Insulin-like Growth Factor Type I

2008 ◽  
Vol 93 (11) ◽  
pp. 4471-4478 ◽  
Author(s):  
Johannes D. Veldhuis ◽  
Daniel M. Keenan ◽  
Joy N. Bailey ◽  
Adenborduin Adeniji ◽  
John M. Miles ◽  
...  
Keyword(s):  
Postmenopausal Women ◽  
Negative Feedback ◽  
Academic Medical Center ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Approximate Entropy ◽  
Type I ◽  
Deconvolution Analysis ◽  
Gh Secretion ◽  
Igf I

Background: Why pulsatile GH secretion declines in estrogen-deficient postmenopausal individuals remains unknown. One possibility is that estrogen not only enhances stimulation by secretagogues but also attenuates negative feedback by systemic IGF-I. Site: The study took place at an academic medical center. Subjects: Subjects were healthy postmenopausal women (n = 25). Methods: The study included randomized assignment to estradiol (n = 13) or placebo (n = 12) administration for 16 d and randomly ordered administration of 0, 1.0, 1.5, and 2.0 mg/m2 recombinant human IGF-I sc on separate days fasting. Analysis: Deconvolution analysis of pulsatile and basal GH secretion and approximate entropy (pattern-regularity) analysis were done to quantify feedback effects of IGF-I. Outcomes: Recombinant human IGF-I injections increased mean and peak serum IGF-I concentrations dose dependently (P < 0.001) and suppressed mean GH concentrations (P < 0.001), pulsatile GH secretion (P = 0.001), and approximate entropy (P < 0.001). Decreased GH secretion was due to reduced secretory-burst mass (P = 0.005) and frequency (P < 0.001) but not basal GH release (P = 0.52). Estradiol supplementation lowered endogenous, but did not alter infused, IGF-I concentrations while elevating mean GH concentrations (P = 0.012) and stimulating pulsatile (P = 0.008) and basal (P < 0.001) GH secretion. Estrogen attenuated IGF-I’s inhibition of pulsatile GH secretion (P = 0.042) but was unable to restore physiological GH pulse frequency or normalize approximate entropy. Conclusion: Short-term estrogen replacement in postmenopausal women selectively mutes IGF-I-mediated feedback on pulsatile GH secretion. Disinhibition of negative feedback thus confers a novel mechanism by which estrogen may obviate hyposomatotropism.

scholarly journals GH secretory pattern in young adults who discontinued GH treatment for GH deficiency and decreased longitudinal growth in childhood

2006 ◽  
Vol 155 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Johan Svensson ◽  
Gudmundur Johannsson ◽  
Ali Iranmanesh ◽  
Kerstin Albertsson-Wikland ◽  
Johannes D Veldhuis ◽  
...  
Keyword(s):  
Young Adults ◽  
Gh Deficiency ◽  
Adult Life ◽  
Approximate Entropy ◽  
Longitudinal Growth ◽  
Lower Percentage ◽  
Healthy Controls ◽  
Gh Treatment ◽  
Deconvolution Analysis ◽  
Gh Secretion

Objective: Some adolescents who discontinue GH treatment due to GH deficiency (GHD) and short stature in childhood do not have classical GHD at retesting in adult life. It is unknown whether there is a neuroendocrine disturbance in the spontaneous pattern of GH release in these patients. Design/patients/methods: Thirty-seven adolescents, who had received treatment with GH due to impaired longitudinal growth, were included. The adolescents were divided into two groups; one (GHD; n = 19) with classical GHD in adult life and another (GH sufficient (GHS); n = 18) without classical adult GHD. One year after GH discontinuation, 24-h GH profiles were performed with blood sampling every 30 min. Sixteen matched healthy controls were also studied. All blood samples were analysed using an ultrasensitive GH assay and then, approximate entropy (ApEn) and deconvolution analysis were performed. Results: The GHD group had higher mean ApEn level than the healthy controls (P < 0.05). As measured by deconvolution analysis, they had lower basal GH secretion (P < 0.01), increased number of GH peaks (P < 0.001), but lower burst mass (P < 0.001), lower percentage pulsatile GH secretion (P < 0.001) and lower total GH secretion (P < 0.001), compared with control subjects. Adolescents in the GHS group had a pattern of 24-h GH release similar to that in healthy controls. Conclusion: Young adults with childhood-onset severe GHD have a high-frequency, low-amplitude GH secretion with decreased orderliness. The adolescents without classical GHD in adult life maintain a pattern of spontaneous GH release that is not statistically different from that in the healthy controls.

scholarly journals Pengaruh Persepsi Stigma Sosial Dan Dukungan Sosial Terhadap Kesejahteraan Psikologis Pada Narapidana

2018 ◽  
Vol 3 (2) ◽  
pp. 183-207 ◽  
Author(s):  
Wahyu Utami
Keyword(s):  
Social Support ◽  
Social Stigma ◽  
Linear Regression Analysis ◽  
Sampling Technique ◽  
Well Being ◽  
Multiple Linear Regression Analysis ◽  
Psychological Well Being ◽  
Dependent Variables ◽  
The Subject ◽  
Age Range

This study aims to determine the effect of social stigma perception and social support on psychological wellbeing on prisoners. perceptions of social stigma and social support as independent variables and psychological well-being of dependent variables. Subjects were 140 prisoners who underwent half of prisoners in prisons class II A kediri with age range 20 to 37 years. The random sampling technique is used as the subject taking method. Data analysis used multiple linear regression analysis and data collection using scale psychological well being scale (PWBS), perceived social stigmatization (STS) and Multidimensional scale of perceived social support (MSPSS). The results showed that social stigma perception with psychological well-being had negative and significant influence with value (? = -.514, p = 0,000), social support gave influence to psychological welfare with value (? = 0.422, P = 0.000), perception social stigma and social support together have an influence on psychological well-being with value (F = 54,339, P = 0,000)

scholarly journals Overtrained horses alter their resting pulsatile growth hormone secretion

2009 ◽  
Vol 297 (2) ◽  
pp. R403-R411 ◽  
Author(s):  
E. de Graaf-Roelfsema ◽  
P. P. Veldhuis ◽  
H. A. Keizer ◽  
M. M. E. van Ginneken ◽  
K. G. van Dam ◽  
...  
Keyword(s):  
Growth Hormone ◽  
High Speed ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Approximate Entropy ◽  
Underlying Mechanism ◽  
Deconvolution Analysis ◽  
Gh Secretion ◽  
Pulsatility Pattern ◽  
It Training

The influence of intensified and reduced training on nocturnal growth hormone (GH) secretion and elimination dynamics was studied in young (1.5 yr) Standardbred geldings to detect potential markers indicative for early overtraining. Ten horses trained on a treadmill for 32 wk in age-, breed-, and gender-matched fixed pairs. Training was divided into four phases (4, 18, 6, and 4 wk, respectively): 1) habituation to high-speed treadmill trotting, 2) normal training, in which speed and duration of training sessions were gradually increased, 3) in this phase, the horses were divided into 2 groups: control (C) and intensified trained (IT) group. In IT, training intensity, duration, and frequency were further increased, whereas in control these remained unaltered, and 4) reduced training (RT). At the end of phases 2, 3, and 4, blood was sampled overnight every 5 min for 8 h for assessment of GH secretory dynamics using pulse detection, deconvolution analysis, and approximate entropy (ApEn). Intensified training induced overtraining (performance decreased by 19% compared with C), which was associated with an increase in concentration peaks number (3.6 vs. 2.0, respectively), a smaller peak secretion pattern with a prolonged half-life (15.2 vs. 7.3 min, respectively), and an increased ApEn (0.89 vs. 0.49, respectively). RT did not lead to full recovery for the overtrained horses. The increased irregularity of nocturnal GH pulsatility pattern is indicative of a loss of coordinated control of GH regulation. Longer phases of somatostatin withdrawal are hypothesized to be the underlying mechanism for the observed changes in GH pulsatility pattern.

scholarly journals Impact of two or three daily subcutaneous injections of hexarelin, a synthetic growth hormone (GH) secretagogue, on 24-h GH, prolactin, adrenocorticotropin and cortisol secretion in humans

2002 ◽  
pp. 310-318 ◽  
Author(s):  
M Maccario ◽  
JD Veldhuis ◽  
F Broglio ◽  
LD Vito ◽  
E Arvat ◽  
...  
Keyword(s):  
Approximate Entropy ◽  
Sampling Period ◽  
Significant Rise ◽  
Cortisol Secretion ◽  
Burst Frequency ◽  
Deconvolution Analysis ◽  
Gh Secretion ◽  
Igf I ◽  
Cortisol Release ◽  
The Impact

OBJECTIVE: To extend the insights on the action of GH secretagogues (GHS) on pituitary function, we studied the impact of intermittent daily s.c. administration of a peptidyl GHS, hexarelin (HEX), on 24-h GH, PRL, ACTH and cortisol release in healthy volunteers. DESIGN: We investigated the impact of two or three times daily s.c. administration of a short-acting peptidyl GHS, the hexapeptide HEX (1.5 microg/kg) on 24-h GH, PRL, ACTH and cortisol secretion (sampling every 20 min) in six normal young men. To monitor possible down-regulation, the effect of 1 microg/kg i.v. HEX at the end of each 24-h sampling period was studied. METHODS: Multi-parameter deconvolution analysis was used to quantitate pulsatile GH, PRL, ACTH and cortisol secretion and estimate the corresponding hormone half-lives. Complementary to deconvolution analysis, approximate entropy was used as a scale- and model-independent statistic to quantify the serial orderliness or pattern regularity of hormone measurements. RESULTS: Mean and integrated (24-h) serum GH concentrations were increased from baseline values to the same extent by two and three HEX injections. Both HEX schedules equally increased GH secretory burst mass (but not burst frequency), mean daily GH production rate, GH half-life and irregularity of GH release patterns. No change occurred in the secretion of IGF-I, PRL, ACTH and cortisol. Intravenous HEX at the end of each spontaneous 24-h profile induced a significant rise in GH, PRL, ACTH and cortisol. Prior HEX administration blunted the GH response, abolished that of ACTH and cortisol and did not modify the PRL increase. CONCLUSIONS: The study showed that two or three daily s.c. injections of HEX augmented 24-h GH secretion equally, amplifying selectively GH secretory pulse mass without altering lactotroph and corticotroph secretion. IGF-I levels were not modified by these 1-day HEX treatment schedules.

Burden of informal carers in northwest Ireland: A pilot study of factors that influence burden

2016 ◽  
Vol 33 (S1) ◽  
pp. S188-S188
Author(s):  
G. McCarthy ◽  
I. Gresswell ◽  
D. Adamis
Keyword(s):  
Support Services ◽  
Demographic Data ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Behavioural Problems ◽  
Carer Burden ◽  
Care Giving ◽  
Competing Interest ◽  
Informal Carers ◽  
Age Range

IntroductionResearch has shown that approximately 67% of carers experience extreme mental tiredness, a decrease in their quality of life and a deterioration in their physical health since taking on a care-giving role.Aims and objectivesThis study aims to identify factors that influence carer burden and in doing so, identify the sub-populations of carers who are most susceptible to burden.MethodsIn northwest Ireland, 53 informal carers referred to the Carers Association, Sligo were contacted and met for a face-to-face interview. Measurements used included demographic data, the Neuropsychiatric Inventory, Zarit Burden Interview, Social Network Index and Brown's Locus of Control Scale.ResultsOf the 53 carers, 43 were females and 10 males (age range: 32–81 years, mean age of 64.5 years). Of the corresponding 53 patients, 21 were females and 32 males (age range: 17–92 years, mean age of 72.1 years). Multiple linear regression analysis showed that sex of carer, marital status and the patient's behavioural problems were statistically significant independent factors, which influenced carer burden (p < 0.01). Female sex and greater patient behavioural problems increased susceptibility to burden and being married increased resilience towards burden.ConclusionsThe ability to predict which carers are more susceptible to burden allows physicians to more quickly identify “higher risk” carers, facilitating routine check-ups by physicians and carer support services. Further research should explore why female and unmarried carers are more susceptible to burden and whether it is possible to tailor support services to their individual needs.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Enhanced endothelial vasoreactivity in endurance-trained older men

1999 ◽  
Vol 87 (6) ◽  
pp. 2136-2142 ◽  
Author(s):  
Tomasz M. Rywik ◽  
Marc R. Blackman ◽  
Alberto R. Yataco ◽  
Peter V. Vaitkevicius ◽  
Richard C. Zink ◽  
...  
Keyword(s):  
Treadmill Exercise ◽  
Regression Coefficient ◽  
Linear Regression Analysis ◽  
Maximal Oxygen Consumption ◽  
Limb Ischemia ◽  
Older Men ◽  
Multiple Linear Regression Analysis ◽  
Endurance Athletes ◽  
Brachial Artery Diameter ◽  
Vascular Ultrasound

Using external vascular ultrasound, we measured brachial artery diameter (Diam) at rest, after release of 4 min of limb ischemia, i.e., endothelium-dependent dilation (EDD), and after sublingual nitroglycerin, i.e., non-endothelium-dependent dilation (NonEDD), in 35 healthy men aged 61–83 yr: 12 endurance athletes (A) and 23 controls (C). As anticipated, treadmill exercise maximal oxygen consumption (V˙o 2 max) was significantly higher in A than in C (40.2 ± 6.6 vs. 27.9 ± 3.8 ml ⋅ kg−1 ⋅ min−1; respectively, P < 0.0001). With regard to arterial physiology, A had greater EDD (8.9 ± 4.2 vs. 5.7 ± 3.5%; P = 0.02) and a tendency for higher NonEDD (13.9 ± 6.7 vs. 9.7 ± 4.2%; P = 0.07) compared with C. By multiple linear regression analysis in the combined sample of older men, only baseline Diam (β = −2.0, where β is the regression coefficient; P = 0.005) andV˙o 2 max (β = 0.23; P = 0.003) were independent predictors of EDD; similarly, only Diam (β = −4.0; P = 0.003) andV˙o 2 max (β = 0.27; P = 0.01) predicted NonEDD. Thus endurance-trained older men demonstrate both augmented EDD and NonEDD, consistent with a generalized enhanced vasodilator responsiveness, compared with their sedentary age peers.

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