Electronic Library of Scientific Literature
Electronic Library of Scientific Literature
Volume 32 / No. 3 / 1998
I. Klimes, E. Sebokova, D. Gasperikova, A. Mitkova, S. Kuklova, P. Bohov, J. Stanek
Diabetes and Nutrition Research Group, Institute of Experimental
Endocrinology, Slovak Academy of Sciences, 833 06 Bratislava, Slovakia;
Clinic of Gastroenterology, Institute of Postgraduate Medical Education,
Bratislava
Objective. To test the effect of new oral hypoglycemic compound
A-4166 on insulin secretion during oral glucose challenge in normal and
hereditary non-obese, hypertriglyceridemic, insulin resistant and hypertensive
rats fed either a normal or high fat diet.
Methods. The rats used were 15 weeks old males of Wistar Charles
River strain (controls) and Wistar-derived hereditary hypertriglyceridemic
(hHTg) rats of our own colony. They were fed either basal (12 cal% of fat)
or high fat diet (70 cal% fat). After 3 weeks of feeding the above diets,
the oral glucose tolerance tests (2 g/kg) were carried out in unrestrained
conscious rats kept in special metabolic cages after overnight fasting
and ten minutes after the administration of A-4166 (100 mg/kg) or placebo
by the stomach tube. Plasma glucose, triglycerides, free fatty acids and
insulin levels were measured by routine analytical methods.
Results. High fat diet feeding resulted in an increase in fasting
plasma insulin in both rat strains, while fasting plasma glucose in high
fat diet fed animals remained unchanged as compared to those fed basal
diet. No differences in the fasting FFA levels were found. The glucose
area under curve (AUC) did not differ between the two strains used and
high fat diet resulted in a higher glucose AUC in both strains. The administration
of A-4166 improved the glucose tolerance in all animals, namely in those
fed the basal diet. Insulin AUC showed very similar pattern in both rat
strains proving the stimulatory effect of A-4166 on insulin secretion during
an oral glucose challenge. High fat feeding resulted in an impairment of
insulin action, but the administration of A-4166 restored the antilipolysis
in both strains to the normal range.
Conclusions. The previously reported hypoglycemic action of A-4166
resulting from the increased insulin secretion was confirmed. Moreover,
some beneficial action of A-4166 on antilipolysis in vivo was demonstrated.
Key words: Insulin - OGTT - Glucose - FFA - Hereditary insulin
resistant rats - Hypoglycemic drug A-4166 -High fat diet
Endocrine regulations, Vol. 32, 115 - 123, 1998
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B. Simic, J. Kniewald, Z. Kniewald
Faculty of Food Technology and Biotechnology, University of Zagreb, 10000 Zagreb, Croatia
Objective. To give more insight in the progesterone metabolism
in rat after the treatment with the progestin ethynodiol diacetate.
Methods. Urinary excretion of the metabolites of subcutaneously
administred (4-14C)-progesterone was studied in female rats.
After an acid hydrolysis and extraction of urine the metabolites were analysed
by thin layer chromatography and by gas chromatography-mass spectrometry.
Results. The most of radioactivity was excreted during the first
24 h, and total of 8.36 % has been recovered within four days. The excreted
metabolites in urine were found as glucuronides and free steroids (80.72
%), and 19.28 % were determined as sulphates. Among detected metabolites,
5alpha-pregnane-3,20-dione, 3alpha-hydroxy-5alpha-pregnan-20-one and A-homo-3-oxa-5alpha-pregnane-4,20-dione
were determined in the urinary extracts. The last one has not yet been
identified before in rat urine.
Conclusions. Consecutive injections of progestin ethynodiol diacetate
(6 mg/kg b.w. daily) to adult female rats during 10 days (short-term treatment),
or during 70 days (long-term treatment), starting on the 21st day of life,
caused significant differences in the amounts of excreted 3alpha-hydroxy-5alpha-pregnan-20-one
and A-homo-3-oxa-5alpha-pregnane-4,20-dione. Significant increase in the
weights of pituitary, liver and kidneys were noted in rats treated with
ethynodiol diacetate. The short-term treatment caused an increase, while
after the long-term treatment a decrease of the ovarian weight was observed.
Key words: Progesterone metabolites - Rat - Urine - Ethynodiol
diacetate - Gas chromatography - Mass spectrometry
Endocrine regulations, Vol. 32, 125 - 131, 1998
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V. Kristova, M. Kriska, P. Babal, D. Jezova
Department of Pharmacology and
Department of Pathology, Faculty of Medicine, Comenius University, 811
08 Bratislava, Slovakia;
Institute of Experimental Endocrinology, Slovak Academy of Sciences, 833
06 Bratislava, Slovakia
Objectives. To evaluate possible alterations of vascular responsiveness
to vasoactive hormones in the vessel preparations from adult rats treated
neonatally with high doses of glutamate.
Methods. The responses to noradrenaline and serotonin in perfused
hindlimb vascular bed and isolated renal artery were measured in MSG-treated
(2 and 4 mg/g BW) and control groups of adult rats at the age of 10 weeks.
Acetylcholine test was used to assess the endothelium-dependent relaxation
of the hindlimb vascular preparation. The vessel specimens from this vascular
bed were evaluated histologically.
Results. Vasoconstrictory responses to noradrenaline and serotonin
were significantly reduced in the hindlimb vascular bed in MSG-treated
rats. In the renal artery, a significant decrease of the responses to noradrenaline
was found without significant changes in the responses to serotonin. The
observed changes were more pronounced in groups treated with a high dose
of MSG. Comparison of relaxing responses to acetylcholine in the hindlimb
preparation did not show any statistically significant differences in control
and MSG treated groups. Histological evaluation of this preparations did
not reveal any endothelial damage or morphological changes of vessel wall.
Conclusions. The obtained results showed reduced vascular responsiveness
to vasoconstrictory agents in adult rats neonatally treated with MSG suggesting
that early postnatal administration of glutamate may result in irreversible
changes in cardiovascular function.
Key words: Noradrenaline - Serotonin - Glutamate (MSG) - Neurotoxic
damage - Blood vessels - Vascular responsiveness - Maturation processes
Endocrine regulations, Vol. 32, 133 - 139, 1998
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T. Mitsuma, J. Takagi, K. Otake, M. Kayama, Y. Mori, K. Adachi, T. Nogimori, J. Sakai, Y. Hirooka
Forth Department of Internal Medicine,
Department of Laboratory medicine and
First Department of Physiology, Aichi Medical University, Nagakute, Aichi,
Aichi 480-1195, Japan and
Department of Internal Medicine, Konanshowa Hospital, Konan, Aichi, Japan
Objective. To develop radioimmunoassay for aquaporin-2 (AQP-2).
Methods. Anti-AQP-2 antiserum has been raised in New Zealand white
rabbits immunized with a conjugate of synthetic AQP-2 peptide (257-271)
with bovine serum albumin. Radioiodination of synthetic peptide (tyrosine-AQP2
(257-271) was performed by chloramine T method, followed by purification
of radioiodinated material on Sephadex G-25 column.
Results. The obtained antibody did not crossreact with vasopressin,
pituitary hormones, hypothalamic hormones and neuropeptides. The assay
was performed with a double antibody system. The values are expressed as
an equivalent of synthetic AQP-2 peptide (257-271). The dilution curve
of high AQP-2 urine in radioimmunoassay system was parallel to the standard
curve. The recovery percentage of AQP-2 added to urine was about 100 %
in this assay system. Intra-assay and inter-assay variation was 4.5 % and
7.2 %, respectively. Mean urinary excretion of AQP-2 was 1.16 ng equivalent
of AQP-2 (257-271)/mg creatine and was lower in patients with diabetes
insipidus.
Conclusion. These data suggest that his assay system is a suitable
to measure AQP-2 in urine.
Key words: Aquaporin-2 - Immunohistochemistry - Rat
Endocrine regulations, Vol. 32, 141 - 144, 1998
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B. Jakubowska-Naziemblo, B. Dziedzic, A. Walczewska, E. Potargowicz, W. Z. Traczyk
Department of Physiology, Institute of Physiology and Biochemistry. Medical University of Lodz, 90-131 Lodz, Poland
Objective. To evaluate whether orchidectomy (ORCX) and sex steroid
hormones can modify the release of gonadotropin releasing hormone (Gn-RH)
and substance P (SP) are released into the cerebral ventricular fluid (CSF).
Methods. The perfusions of lateral ventriculo-cerebello-medullary
cistern were performed in anesthesised (urethane with chloralose) rats,
three 30 min samples of perfusion fluid being collected in each animal.
Four weeks prior to this experiment adult male rats (except INTACT group)
were bilaterally orchidectomized and implanted s.c. either with empty silastic
capsules (ORCX) or with these containing 17ß-estradiol (ORCX+E2)
or testosterone propionate (ORCX+T). This procedure was performed in two
series of experiments: first one for Gn-RH and second one for SP estimation
by RIA. In some animals the unconjugated fraction of E2 and
T was estimated in blood samples collected at the end of experiment.
Results. In all groups Gn-RH and SP were continuously released into
the perfusion fluid. The mean Gn-RH concentration was higher than that
of SP in the collected samples. A long-term modification of sex steroid
hormone level in blood resulted in significant decrease of Gn-RH concentration
only in ORCX as compared to INTACT rats, while Gn-RH and SP levels in the
perfusion fluid were found relatively unchanged by a high concentration
of 17ß-estradiol or testosterone in the peripheral circulation.
Key words: Gonadotropin releasing hormone (Gn-RH) - Substance
P - Cerebrospinal Fluid - Sex steroids - Orchidectomy
Endocrine regulations, Vol. 32, 145 - 153, 1998
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A.I. Russinova, N.N. Atanassova, M.L. Paskaleva, L.S. Kancheva
Institute of Experimental Morphology and Anthropology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
Objective. To characterize immunocytochemically the antigen recognized
which appears at specific stages of germ cell development and acrosomal
biogenesis by the novel monoclonal antibody (Mab 3C2).
Methods. The novel monoclonal antibody (Mab 3C2) raised against
testicular Sertoli and germ cells.
Results. The immunoreactivity of this Mab in testicular sections
from immature 20-day-old rats was confined to the pachytene spermatocytes.
In adult testis the Mab 3C2, besides meiotic cells, recognized also acrosomal
component of round spermatids. The immune reaction was observed in Golgi
and cap phases of acrosomal development until the stage VIII of the cycle
of the seminiferous epithelium. Immunostaining was absent in acrosome of
elongating and mature spermatids and indicated that some modifications
in acrosomal protein may exist in subsequent stages of acrosomal development.
Conclusions. Novel Mab 3C2 shares a common antigen in pachytene
spermatocytes and round spermatids. Therefore, it may be a marker of meiotic
and postmeiotic germ cells.
Key words: Immunocytochemistry - Novel monoclonal antibody -
Spermatogenesis - Acrosome - Spermatocytes - Round Spermatids
Endocrine regulations, Vol. 32, 155 - 159, 1998
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J. Jurcovicova, M. Dobrakovova, S. Zorad
Institute of Experimental Endocrinology, Slovak Academy of Sciences, 833 06 Bratislava, Slovakia
Objective. To evaluate the impact of repeated neonatal mother
deprivation (RMD) of male rats on the behavioral parameters and response
of prolactin to mild stress stimuli in the adulthood.
Methods. Afer birth, the pups of Wistar Porton Olac rats were crossfostered
and their number was adjusted to 8 per litter (4 males and 4 females).
They were removed from the dam for 6 hours daily on postnatal day 6, 7,
8 and for 12 hours daily on postnatal day 12, 13, 15, 16 and placed to
another cage lined with cotton wool at controlled temperature 37 °C. Body
weight was estimated repeatedly from postnatal day 9 to 97. At 14 weeks
of life the behavioral activity was measured in an open field on 2 occasions,
2 days apart. One week later the rats were exposed to 15 min novelty stress
or to 3 min handling and decapitated 15 min after the initiation of both.
Trunk blood was collected and plasma prolactin (PRL) was measured by radioimmunoassay.
Results. On postnatal day 15 the eye opening was found in 75 % of
control pups and 73 % of pups with RMD. In the rats after RMD the body
weight gain was significantly decreased from day 21 until the day 97. Vertical
behavioral activity (rearing) was enhanced in RMD rats when measured on
the first occasion. Horizontal behavioral activity did not significantly
differ from the control group. Stress of novel environment elicited the
activation of PRL secretion in untreated animals (19.3 1±4.6 ng/ml vs.
7.17±1.03 ng/ml, P<0.05), while no change was found in the rats after
RMD (8.15±2.0 ng/ml vs. 4.35±0.48 ng/ml).
Conclusions. In the rats exposed to neonatal mother deprivation
the lower emotionality was found. Significantly decreased body weight gain
in these animals was probably due to the nutritional deprivation during
the postnatal separation from the mother. The nonresponsiveness of lactotrophs
to mild stressor in adult rats after RMD may have a negative impact on
defense mechanisms to immune challenges.
Key words: Rats - Neonatal mother deprivation - Open field -
Stress - Prolactin
Endocrine regulations, Vol. 32, 161 - 165, 1998
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