Electronic Library of Scientific Literature - © Academic Electronic Press
Volume 35 / No. 4 / 2001
E. Demcakova, E. Sebokova, J. Ukropec, D. Gasperikova, I. Klimes
Diabetes & Nutrition Research, Institute of Experimental
Endocrinology Slovak Academy of Science, Vlαrska 3, 833 06 Bratislava, Slovak
Republic
E-mail: ueeniwar@savba.sk
Objective. We have shown previously that the impaired insulin action in
hereditary hypertriglyceridemic (hHTg) rat is accompanied by a specific
fatty acid (FA) profile in the insulin target tissues, possibly due to a desaturation
defect. Thus, the aim of this study was to measure the enzymatic activity and
gene expression of delta-6 desaturase in liver of hHTg rats and the tissue FA
composition in relation to insulin action.
Methods. Glucose, triglycerides and insulin in plasma were measured using
commercially available enzymatic sets. The hepatic delta-6 desaturase activity
in hHTg rats was determined radiometrically in a microsomal fraction using
the 1-14C-linoleic acid as substrate. delta-6 Desaturase gene
expression was measured by the Northern blot technique using a specific
cDNA probe. Tissue FA profile was determined by gas chromatography in the total
lipid fraction extracted to chloroform. The glucose turnover rate was measured
in conscious freely moving animals with the aid of euglycemic hyperinsulinic
clamp method.
Results. Tissue triglycerides showed a high accumulation in skeletal
muscle of hHTg rats. In the liver of these animals, a defect in delta-6
desaturase enzymatic activity was found, while the gene expression for delta-6
desaturase was not changed. Such decreased delta-6 desaturase activity in the
liver was linked to a decrease of delta-6 desaturase index as calculated
from the liver FA composition. Also the concentration of arachidonic acid (a
final metabolite in the biosynthesis of polyunsaturated fatty acids of the n-6
series) was significantly decreased in hHTg rat liver. These changes in FA
metabolism were accompanied by a decreased glucose infusion rate (a measure
of in vivo insulin action) required to maintain euglycemia at
hyperinsulinemia in hHTg rats, and correlated with the hepatic delta-6
desaturase activity.
Conclusions. 1. hHTg rats showed a reduced activity of the delta-6
desaturase in liver without any changes in gene expression for this enzyme; 2.
such impairment is accompanied by a lower delta-6 desaturase index
(18:2n-6/18:3n-6) found in the liver of these animals and by specific FA
profiles in the tissues, particularly regarding the amount of long-chain PUFAs
and 18:2n-6 metabolites; and (4) these alterations seem to be related to the
impaired insulin action of hHTg rats.
Key words: hHTg rat delta-6 desaturase (DS) activity DS
gene expression Tissue fatty acid spectrum Insulin action
ENDOCRINE REGULATIONS, Vol. 35, 179186, 2001
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Zdenko Pirnik, Marek Schwendt, Daniela Jezova
Institute of Experimental Endocrinology, Slovak Academy of Sciences, 833 06
Bratislava, Slovakia
E-mail: ueenpirn@savba.sk
Objective. This study was aimed to evaluate the effects of morphine on
hypothalamo-pituitary-adrenocortical (HPA) axis, namely proopiomelanocortin
(POMC) mRNA and plasma corticosterone, in relation to its influence on glutamate
receptor gene expression in central and peripheral sites related to HPA axis
regulation. As previous data on morphine action were obtained mainly in male
rats, these experiments were performed in females to see potential gender
differences.
Methods. Adult female Sprague-Dawley rats were injected with a single
dose of morphine (10 mg/kg s.c.) or vehicle. Blood and tissues were sampled 4 h
and 24 h following the treatment. In situ hybridization was used to measure
POMC mRNA concentrations, reverse transcription-polymerase chain reaction to
quantify mRNA coding for N-methyl-D-aspartic acid (NMDA) receptor subunit 1 and
radioimmunoassay to measure plasma corticosterone.
Results. Single dose of morphine was followed by a decrease in gene
expression of glutamate receptor subunit NMDAR1 in the adrenal gland.
Concentrations of mRNAs coding for NMDAR1 in the hippocampus and for POMC in the
anterior pituitary remained unaffected. However, plasma corticosterone levels,
which were measured at 4 and 24 h after the treatment with morphine,
showed a disturbed daily variation in corticosterone release. The efficacy
of morphine was confirmed by Straub tail response, one of the classical effect
of this drug, in mice.
Conclusions. Present data obtained in females allow to suggest that
morphine exerts some of its effects on HPA axis by POMC unrelated mechanisms
seemingly in a gender specific manner. Decrease in glutamate
receptor gene expression in adrenals induced by a single dose of morphine
may result in a modulation of adrenal function in response to subsequent
exposure to opioids and contribute to some alterations occurring during opioid
drug abuse.
Key words: Morphine Gene expression POMC NMDA
receptor Corticosterone Adrenal gland
ENDOCRINE REGULATIONS, Vol. 35, 187193, 2001
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Lucia Micutkova , Alexander Kiss, Maxim Filipenko, Natasha Rychkova, Olga Krizanova , Miklos Palkovits, Richard Kvetnansky
Institute of Experimental Endocrinology, Slovak Academy of Sciences, Vlαrska
3, 833 06 Bratislava, Slovak Republic;
Institute of Bioorganic Chemistry, Russian Academy of Sciences, Novosibirsk,
Russia and
Laboratory of Neuromorphology, Semmelweis University, Budapest, Hungary
E-mail: ueenmicu@savba.sk
Objective. The A5 group of noradrenergic neurons plays a key role in
autonomic mechanisms like cardiovascular regulation, nociception and
respiration. The aim of this work was to detect the gene expression of
catecholamine synthesizing enzymes in A5 brain nuclei.
Methods. The gene expression of. tyrosine hydroxylase (TH),
dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyl-transferase
(PNMT) in A5 brain nuclei was estimated. We also investigated various time
intervals after the end of the single two-hour immobilization, as well as the
effect of short-term repeated immobilization (120 min daily for 7 days) on
tyrosine hydroxylase gene expression, the rate-limiting enzymes in
catecholamines biosynthesis, in the A5 cell group. For all experiments, reverse
transcription with subsequent polymerase chain reaction (RT-PCR) was used.
Results. As expected, we detected a clear signal for TH and DBH mRNA but
no signal for PNMT mRNA. Both, single and repeated immobilization stress
exposure increased significantly the gene expression of TH in A5 area. Maximal
elevation in TH mRNA levels occurred after single immobilization for two hours
and subsequent decapitation 24 hours later.
Conclusions. In this study we detected for the first time the presence of
DBH mRNA in micro dissected A5 cell group. We also showed how the gene
expression of tyrosine hydroxylase changed with the function of time after the
single immobilization exposure. Thus, TH mRNA in A5 cell group is modulated by
immobilization stress in a time-dependent manner.
Key words: tyrosine hydroxylase A5 cell group immobilization
stress gene expression
ENDOCRINE REGULATIONS, Vol. 35, 195200, 2001
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Danuta Chlebna-Sokol, Agnieszka Rusinska
Department of Paediatric Propedeutics, Institute of Paediatry, Medical University of Lodz, 91-738 Lodz, Poland
Objective. To determine whether the serum concentration of insulin-like
growth factor I (IGF-I) correlates with the occurrence of idiopathic
osteoporosis in children, and whether serum levels of IGF-I correlate with
selected bone metabolism markers in patients with osteoporosis.
Methods. The study comprised 24 patients aged 7-18 years, including 12
with idiopathic osteoporosis and 12 control children. Bone mineralisation
disorders were diagnosed on the basis of complex clinical, densitometric and
biochemical evaluation. In all children serum concentration of IGF-I was
estimated by radioimmunoassay and the third fraction of IGF binding proteins
(IGFBP3) by immunoradiometry.. In children with osteoporosis the indices of bone
metabolism were also assessed, e.g. serum levels of osteocalcin and activity of
bone isoenzyme of alkaline phosphatase (bone formation markers) and urine
concentration of pyridinoline and deoxypyridinoline and collagen type I crosslinked
C-telopeptyde (resorption markers).
Results. It was found that in children with osteoporosis IGF-I concentration
was significantly lower than in the control group (mean values were 583 and 850
ng/ml, respectively; P<0.05). These differences were independent on
biological age of the studied children and were present in all adolescence
stages. Concentrations of IGFBP3 did not differ significantly between groups
(3593 vs. 3955 ng/ml), while that of IFG-I correlated positively with total and
spinal bone mineral density (R=0.85 and R=0.80, respectively; P<0.00001). In
children with osteoporosis there was also a significant relationship
between IGF-I concentration and elimination of pyridinoline and
deoxypyridinoline with urine (R=0.64 and R=0.65, respectively; P<0.05). There
was no significant correlation between the concentration of IGF-I and IGFBP3 and
other studied bone metabolism markers.
Conclusions. The conducted study revealed that lower IFG-I concentrations
correlate with higher bone resorption markers values and decreased
mineralisation. These results suggest the importance of insulin-like growth
factor in the ethiopathogenesis of idiopathic osteoporosis, which needs to be
confirmed in further studies.
Key words. Idiopathic osteoporosis Children Insulin-like
growth factor I Bone metabolism markers
ENDOCRINE REGULATIONS, Vol. 35, 201208, 2001
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Mariana Bakalska, N. Atanassova, P. Angelova, I. Koeva, B. Nikolov, M. Davidoff
Institute of Experimental Morphology and Anthropology, Bulgarian Academy of
Sciences, Sofia, Bulgaria;
Higher Medical Institute, Department of Histology and Embryology, Plovdiv,
Bulgaria
Institute of Anatomy, University of Hamburg, Hamburg, Germany
E-mail: mbakalska@dir.bg
Objective. To investigate degeneration and restoration patterns of
spermatogenesis in relation to the changes in Leydig cells (LCs) after treatment
with ethane dimethanesulfonate (EDS).
Materials and methods. Adult Wistar male rats were treated with EDS at a dose
75 mg/kg body weight and the testes were sampled at 7, 14, 21, 35 and 49 days
after treatment for histological and ultrastructural studies.
Results. During the first two weeks after treatment stage dependent loss
of germ cells was found within seminiferous tubules that led to a profound
disturbance of spermatogenesis. The restoration of seminiferous epithelium
followed also in stage specific manner and in relation to development of a new
LC population (third week). The development of new LCs after EDS treatment
repeats the normal dynamics of postnatal LC development within a similar
time range.
Conclusion. EDS treatment of rats causes a temporary germ cell
degeneration in the testis. The kinetics of disappearance of germ cells and
their regeneration broadly follows the changes in LC population.
Key words: Spermatogenesis - Germ cells - Leydig cells Testis
Rats Ethane dimethanesulfonate
ENDOCRINE REGULATIONS, Vol. 35, 209215, 2001
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B. Kos-Kudla, Z. Ostrowska, B. Marek, N. Ciesielska-Kopacz, M. Kudla, D. Kajdaniuk, L. Siemidska, J. Strzelczyk
Department of Pathophysiology and Endocrinology,
Department of Clinical Biochemistry,
Clinic of Internal and Allergic Diseases,
III Clinic of Obstetrics and Gynaecology. Silesian Medical University, Katowice,
Poland
E-mail: beatakos@ka.onet.pl
Objective. To assess mean 24-h serum concentrations of
dehydroepianrosterone (DHEAS) in postmenopausal women with asthma before and
after hormone replacement therapy (HRT).
Methods. Studies were performed in 55 asthmatic and 20 healthy
postmenopausal women aged 48-60 before HRT and after 6 months of
transdermal 17b-estradiol (E2) and medroxyprogesterone acetate
treatment (cyclical method). Serum DHEAS concentrations were assessed with the
use of RIA method.
Results. In the group of postmenopausal asthmatic women treated with
glucocorticoids the mean 24 h DHEAS serum levels were lower than in a similar
group not treated with glucocorticoids and a control group of healthy
postmenopausal women. However, in both groups of asthmatic women (e.g.
glucocorticoid treated and untreated) a significant increase of mean daily
DHEAS levels after 6 months of HRT was observed. The hormone concentrations
did not change in control group.
Conclusions. Postmenopausal asthmatic women show diminished circadian
dehydroepiandrosterone sulphate serum concentrations irrespective whether they
were treated with glucocorticoids or not. However, after 6 months of
hormonal replacement therapy in these groups increased levels of DHEA were
found.
Key words: Dehydroepiandrosterone sulphate - Bronchial asthma - Hormone
replacement therapy
ENDOCRINE REGULATIONS, Vol. 35, 217222, 2001
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Anna K. Wojtowicz, Erik Ropstad, Ewa L. Gregoraszczuk
Laboratory of Physiology and Toxicology of Reproduction, Department of Animal
Physiology, Institute of Zoology, Jagiellonian University, Ingardena 6, 30-060
Krakσw, Poland.
Department of Reproduction and Forensic Medicine, Norwegian School of Veterinary
Science, Oslo, Norway.
E-mail: greg@zuk.iz.uj.edu.pl
Objective. To characterize PCB 153 action on the ovary, the direct effect
of PCB153 was investigated in vitro using a co-culture of pig granulosa and
theca cells collected during different stages of follicular development.
Methods. The cells were cultured in the absence or presence of 5, 10, 50
or 100 ng/ml of PCB 153. Media were changed after 48, 96 and 144 h and
frozen until further estradiol (E2), progesterone (P4) and testosterone (T)
analysis.
Results. 48 hrs exposure of follicular cells collected from small-size
follicles to all the investigated doses of PCB 153 caused statistically
significant decrease in progesterone (P4) secretion and at doses of 50 ng and
100 ng/ml in testosterone (T) secretion. No effect on estradiol (E2) secretion
was observed. After 96h and 144h exposure to PCB an increase in P4 secretion
with concomitant drastic decrease in T secretion and a tendency to
decrease in E2 secretion was observed. Similarly as in the case of small
follicles, the action of PCB on steroid secretion by cells collected from medium
follicles depended on time of exposure. The increase in T secretion and no
influence on P4 and E2 secretion was observed after 2 days of exposure to
PCB. Antiestrogenic action of PCB was noted after 4 and 6 days of
exposure to PCB. In large, preovulatory follicles 2 days exposure to PCB
had no effect on steroids secretion while longer exposition to this congener
caused statistically significant antiestrogenic action.
Conclusion. The presented paper suggests various actions of PCB 153 as an
endocrine disrupter on estradiol, progesterone and testosterone secretion from
ovarian cells in vitro which were dependent on both exposure length and
stage of the follicular development.
Key words: PCB 153 Ovarian follicles Estradiol Progesterone
Testosterone - Steroid secretion Estrous cycle
ENDOCRINE REGULATIONS, Vol. 35, 223228, 2001
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Anna Goraca
Department of Experimental and Clinical Physiology, Institute of Physiology and Biochemistry, Medical University of Lodz. 92-215 Lodz, Poland
In past several years the in vivo blood microdialysis technique has
been widely used for a variety of pharmacological and physiological
applications to study, monitor and analyze endogenous substances, such as
neurohormones, and exogenous substances such as therapeutic drugs and their
metabolites. The technique is being desctribed in detail and discussed, in which
microdialysis probes were implanted into the jugular vein, blood was flowing
freely around the dialysis membrane. The probe was perfused at a very low
flow rate (~ 1-2 ΅L/min)with the solution resembling closely the composition of
body fluid. In this laboratory (Department of Experimental and Clinical
Physiology, Institute of Physiology and Biochemistry, Medical University of
Lodz) the technique of in vivo blood minidialysis was worked out in small
laboratory animals (rat, guinea-pig, hamster) and used to demonstrate that
neurohypophysial hormones can be released into the blood outflowing from the
region of the sella turcica and blood dialysate from the femoral vein.
Key words: Microdialysis Cavernous sinus Brain blood
Small animals Minireview
ENDOCRINE REGULATIONS, Vol. 35, 229236, 2001
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ENDOCRINE REGULATIONS, Vol. 35, 237240, 2001
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