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Volume 36 / No. 2 / 2002
(Monte A. and Peggy Greer)
Ioannis Ilias, Alexandros N Vgontzas, Astero Provata, George Mastorakos
Endocrine Unit, «Evgenidion» Hospital, University of Athens, Athens,
Greece;
Sleep Research and Treatment Center, Department of Psychiatry, College of
Medicine, Pennsylvania State University, Hershey Pennsylvania, USA;
Institute of Physical Chemistry, National Research Center «Demokritos»,
Athens, Greece
E-mail: lliaslo@mail.nih.gov
Objective. The circadian secretory profiles of cortisol and growth
hormone (hGH) in normal subjects are interrelated. Slight alterations in
cortisol secretion are paralleled by similar ones of hGH secretion. Under
physiological conditions an inhibitory effect of glucocorticoids on hGH
secretion is more potent than a stimulatory one, while in normal young
subjects the nychtohemeral cortisol and hGH levels are lower and higher,
respectively, post 24 hours total sleep-deprivation, compared to baseline
values. The aim of the present work was to further assess the qualitative
characteristics of the 24-hour secretory patterns of these two hormones before
and after 24 hours total sleep deprivation, by studying their non-linear
profiles using fractal analysis.
Methods. Cortisol and hGH were measured in 24-hour samples drawn from 10
healthy men (mean age±SD: 24±1 yr, mean BMI±SD: 25±1 kg/m2)
before and after 24 hours total sleep deprivation. Twenty-four hour blood
sampling was performed serially every 30 min the day before and the day after
total sleep deprivation. The 24-hour hormone profiles were analyzed by Fourier
spectrum, in order to verify periodicities; the corresponding attractors were
drawn and their respective fractal dimensions were calculated using the box
counting method.
Results. Diurnal cortisol levels before sleep deprivation gave rise to a fractal
attractor with a D0 fractal dimension of 2.65±0.03, which
decreased, post-sleep deprivation, to D0: 2.18±0.04. Growth hormone
before sleep deprivation gave rise to a fractal attractor with a D0
dimension of 1.96±0.60, which increased to 2.24±0.60 post-sleep deprivation.
These post-sleep deprivation changes of the fractal dimensions of cortisol and
hGH, suggest that sleep deprivation leads to a more regular secretory
profile of cortisol, while it tends to render hGH secretory profile less
regular. Additionally, these changes of the fractal dimensions parallell the
previously described quantitative overall changes of these hormones.
Conclusions. The post-sleep deprivation decrease of cortisol fluctuation
might reflect the mechanism by which sleep deprivation temporarily improves mood
in melancholic depression, a condition associated with hyperactivity of the
hypothalamic-pituitary-adrenal axis.
Key words: Cortisol – growth hormone – human – sleep
deprivation – non-linear analysis
ENDOCRINE REGULATIONS, Vol. 36, 63–72, 2002
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Zofia Cervenakova, Lucia Ksinantova, Juraj Koska
Institute of Experimental Endocrinology, Slovak Academy of Sciences,
Bratislava, Slovak Republic
E-mail: ueencerv@savba.sk
Objective. Several indices have been published to quantify insulin
sensitivity from fasting plasma glucose and fasting plasma insulin levels as
well as from the data obtained by the oral glucose tolerance test (oGTT).
Obesity represents the main risk factor associated with development of insulin
resistance and Type 2 diabetes mellitus. The aim of this study was to
evaluate the influence of body composition on various indices of insulin
sensitivity and secretion in subjects with normal glucose tolerance.
Methods. A total of 33 male subjects (aged 26-51 years, BMI
19.7-30.9 kg/m2) underwent a standard oral glucose tolerance
test (oGTT). Thereafter the cut-off value of BMI= 25 kg/m2 was set to
divide the group into normal subjects and subjects with overweight. Indices of
insulin sensitivity and secretion were calculated from plasma glucose and
insulin concentrations using the formulas proposed by Matthews et al. (1985),
Cederholm and Wibell (1990), Matsuda and DeFronzo (1999) and Stumvoll et al.
(2000).
Results. All subjects had a normal glucose tolerance according to
standard diagnostic criteria. No difference was found in the course of glycemia,
while overweight subjects displayed an enhanced insulin response (P<0.01).
BMI correlated closely with all indices. The correlation coefficient was highest
in ISIMatsuda, followed by ISICederholm and ISIStumvoll.
The indices of insulin sensitivity all significantly increased in the overweight
group. The groups did not differ in the values of index SecrHOMA.
Conclusions. The easiest way to predict the insulin sensitivity and to
control the development of insulin resistance in a subject with yet normal
glucose tolerance, but at high risk of development of overt Type 2 diabetes
is to calculate an index from glucose and insulin concentrations during an oGTT.
However, the assessment of appropriate cut-off values is necessary for
introducing the indices in clinical practice.
Key words: Glucose – Insulin – Diabetes – Insulin
resistance
ENDOCRINE REGULATIONS, Vol. 36, 73–77, 2002
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Michal Pohanka, Richard Hampl, Ivan Šterzl, Luboslav Stárka
Institute of Endocrinology, Národní 8, 116 94 Praha 1, Czech Republic
E-mail: rhampl@endo.cz
Objective. In addition to many components, seminal fluid contains also
hormonal steroids. So far, the studies were focused mostly to androgens, their
precursors, estrogens and also cortisol, in most instances in relation to sperm
abnormalities. Our group detected for the first time in the ejaculate
7-hydroxylated metabolites of dehydroepiandrosterone, believed to function as
immunomodulatory and immunoprotective agents. Occurrence of steroids in seminal
fluid and their possible role is reviewed in the first part of the article.
Methods. In a group of 34 men (age 21-46 years) with various
problems of fertility the presence of 7-hydroxydehydroepiandrosterone
isomers and dehydroepiandrosterone in seminal fluid was found.. The
concentrations of steroids in seminal fluid and plasma were determined by
recently developed radioimmunoassay. In brief, the ejaculate was extracted twice
with diethyl ether and the water phase was separated by freezing in solid carbon
dioxide and evaporating the solvent to dryness. The dry residue was dissolved in
methanol:water:light petroleum ether (1.3:1.0:0.3 ml) and mixed. After
separation the water-methanolic phase was evaporated, the dry residue was
re-dissolved in phosphate buffer and aliquots were used for RIA. The results
were corrected for losses by counting the residual radioactivity of [3H]
testosterone added initially to the sample of seminal fluid.
Results. The concentrations of 7-hydroxydehydroepiandrosterone varied
from 1.08 to as much as 15.7 nmol/l, while those of dehydroepiandrosterone were
about five times higher. The concentrations of both
7-hydroxydehydroepiandrosterone isomers were close to or even higher than
recently reported levels of these substances in blood serum.
Conclusion. The presence of steroids derived from dehydroepiandrosterone
by 7-hydroxylation with recently reported immunomodulatory activity was for the
first time demonstrated in seminal fluid of normal men.
Key words: Seminal fluid – Steroid hormones – 7-Hydroxydehydroepiandrosterone
– Dehydroepiandrosterone –Immunomodulatory activity
ENDOCRINE REGULATIONS, Vol. 36, 79–86, 2002
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Maria Fickova
Institute of Experimental Endocrinology, Slovak Academy of Sciences, 833 06
Bratislava, Slovakia
E-mail: ueenfick@savba.sk
Key words: EGF receptor – structure – activation
ENDOCRINE REGULATIONS, Vol. 36, 87–93, 2002
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Richard Imrich
Institute of Experimental Endocrinology, Slovak Academy of Sciences, Vlarska
3, 833 06 Bratislava, Slovak Republic
E-mail: ueenmri@savba.sk
Interactions between the neuroendocrine and immune system play an important
role in maintaining and restoring homeostasis. In susceptible individuals a dysfunction
of the neuroendocrine system may be one of the risk factors involved in the
pathogenesis of rheumatic diseases. Specific causes of altered neuroendocrine
function are still not fully elucidated. Accumulation of genetical,
environmental, behavioral and other risk factors during long preclinical period
may result in chronic imbalances in homeostatic mechanisms maintained by
neuroendocrine, microvascular and immune systems. Chronic inflammatory stress
mediated by humoral and neural signals during active stages of the disease and
autoantibodies against the structures of the neuroendocrine system may further
participate in the neuroendocrine dysfunction. In a subset of patients with
rheumatoid arthritis (RA), an assumed defect of the
hypothalamic-pituitary-adrenocortical axis may be implicated in the
pathogenesis. Results of some studies support the concept of adrenal dysfunction
in women with premenopausal onset of the RA. Significantly lower levels of
dehydroepiandrosterone sulfate (DHEAS) plasma levels of women who subsequently
developed RA indicate that neuroendocrine dysfunction may be present already in
preclinical period and thus are not only secondary due to ongoing inflammatory
process. These findings are sketching the new prospects of possible primary
prevention of RA in the future. The role of some other hormones including
prolactin, growth hormone, sex hormones and involvement of autonomic nervous
system in relation with the rheumatic diseases is also reviewed in the paper.
Further research concerning their role in the pathogenesis of other rheumatic
diseases will possibly provide new prospects in optimizing their therapy.
Keywords: Rheumatoid arthritis – Systemic lupus erythematosus – Sjoegren’s
syndrome – HPA axis – Prolactin – Growth hormone – Autonomic
nervous system – HPG axis
ENDOCRINE REGULATIONS, Vol. 36, 95–106, 2002
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