3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
P94 DISTRIbuTION OF DIAZINON IN
VARIOuS TISSuES AND ITS EFFECT ON
SERuM ChOLINESTERASE AFTER AN
INTRAPERITONEAL ADMINISTRATION
BRAnISLAV ŠIŠKA, JOZEF GOLIAn, ROBERT
TOMAn and AnDREA KRAJČíROVá
Department of Food Hygiene and Safety, Faculty of Biotechnology
and Food Sciences, Slovak Agricultural University in
Nitra,Trieda A. Hlinku 2, 949 76 Nitra,
branislav.siska@gmail.com
Introduction
Diazinon (O,O-diethyl O-2-isopropyl-6-methylpyrimidin-4-yl
phosphorothioate) belongs to the group of organophosphate
insecticides used to control cockroaches, fleas and
ants. It is also used to control a wide variety of sucking and
leaf eating insects and it has also veterinary use 1 .
Diazinon has toxic effect on nervous system. This effect
is achieved through the inhibition of acetylcholinesterase
2 . This enzyme has a key role in process for controlling of
nervous signal transfer. Lack of acetylcholinesterase causes
accumulation of acetylcholine. Accumulation of this neurotransmitter
on the connections between nerves and muscles
causes uncontrolled muscular contraction and algospasmus,
between nerves and glands causes continual secretion of
these glands, while acetylcholine cumulation between certain
nerve cells in a brain causes sensory behavior disorders 3 .
Diazinon is also able to cause oxidative stress of the
organism through the forming of free radicals that are formed
during the increased overextension of the organism by pesticides
4,5 .
LD 50 (letal dose for 50 % of tested animals) for diazinon
is very different depending up to the species of used
laboratory animal. For rats, this value was established to be
1250 mg kg –1 after peroral administration and for laboratory
mice 80–135 mg kg –1 of diazinon after peroral administration.
ADI value (acceptable daily intake) was established on
0.002 mg kg –1 of diazinon per day 3,6 . Typical symptoms of
poisoning are weakness, headaches, tightness in the chest,
blurred vision, nonreactive pinpoint pupils, salivation, sweating,
nausea, vomiting, diarrhea, abdominal cramps, and slurred
speech. Some researches pointed out that diazinon has
also mutagenic effect, however current evidence is inconclusive
3,7 . When it comes for a carcinogenic effect, diazinon is
not considered to be a carcinogenic compound 7 .
Metabolism and excretion rates for diazinon are rapid.
The half-life of diazinon in animals is about 12 hours. The
product is passed out of the body through urine and in the
feces. The metabolites account for about 70 % of the total
amount excreted. Diazinon does not belong to the group of
chemicals that is characteristic with the long-lasting cumulation
in human or animal tissues. However, in some cases
could be diazinon detected in the samples of fat tisse, because
this tissue has certain ability to cumulate organophosphate
insecticides for relatively short period of time.Cattle exposed
s789
to diazinon may store the compound in their fat over the short
term 8 .
In this assay, we studied the effect of diazinon intraperitoneal
administration on rat serum cholinesterase catalytic
activity and the distribution of diazinon in various tissues of
organs of experimental animals.
Experimental
Laboratory rats in the age of 135 days were randomly
divided into 2 groups. Each group consisted of 10 males.
Animals in the first group were administrated with diazinon
(Sigma, USA) 20 mg kg –1 b.w. intraperitoneally in physiological
solution. The second group served as a control group
and was administrated only with the physiological solution.
24 hours after the administration of tested substance, animals
were sacrificed, blood samples were taken from hearts and
samples of livers, kidneys, muscles and fat tissue were taken
during the autopsy.
Catalytic activity of cholinesterase was determined with
using of Bio-La-Test ® . The amount of diazinon in tissues
was determined with using of gas chromatography with mass
spectrometry.
Basic statistical characteristics – arithmetic mean, standard
deviation and variation coefficient were calculated for
cholinesterase catalytic activity and for amount of diazinon
in each group. Obtained data were then processed in order
to determinate statistical significance of the results. The
Student’s t-test was finally used for establishment of statistical
significance.
Results
no deaths were observed in any of groups of experimental
animals. However, animals from diazinon treted group
approximately 12 hours after the administration of diazinon
showed symptoms connected with depression of cholinesterase
activity and did not react on external stimuli. Results of
the determination of cholinesterase activity are presented in
Table I.
Table I
Cholinesterase activity (μkat dm –3 ) in different groups
Cholinesterase activity Variation
Group of animals activity coefficient
(X ± SD) [%]
Dizinon group 1.81 ± 0.79 * 44
Control group 3.69 ± 0.51 14
X – arithmetic mean, SD – standard deviation,
* p-value < 0.05
Changes of cholinesterase catalytic activity were observed
in diazinon treated animals. We observed significant decrease
of cholinesterase catalytic activity from 3.69 µkat dm –3 in
control group to 1.81 µkat dm –3 in experimental group. Muscular
weakness, confuse and lethargy were typical symptoms
that were observed on experimental animals in our assay.