This study was carried out to investigate the effects of nicotinic acid
(NA) on lipid profile , glucose and insulin levels in normal and streptozotocin
(572) induced diabetic rats.6 groups of albino rats ( each consists of
10 rats) were used in this study. Group ( I) & (2) were done to detect the
effects of NA in normal rats .Group (1) served as control group without
any medication. Group (2) received daily intraperitoneal. ( IP) injection of
NA . After 4 weeks, rats were fasted overnight and blood samples were
collected by intracardiac puncture and the following parameters were estimated
: Fasting blood glucose. insulin, cholesterol, triglycerides , HDL
and LDL . Our results showed that NA resulted in a significant decease
in levels of glucose insulin , cholesterol triglycerides and LDL but
caused a significant increase in HDL level. Groups (3) & (4) were planned
to study the protective effect of NA added to diet on development of STZ
diabetic rats. The rats of group (3) were given a normal diet while group
(4) were given a diet supplemented with NA for 4 weeks , then both
groups were given a single IP injection of S 12 for 4 weeks. Blood
samples were collected by the same method used with groups (1)& (2)
and the same parameters were estimated. We found that addition of
NA in diet caused a significant reduction in fasting blood glucose, cholesterol,
triglycerides and LDL while caused a significant increase in
serum insulin and HDL levels . Groups (5) &(6) were carried out to
study the possible curative effect of NA in S77 induced diabetic rats .
Rats of group (5) were given a single IP injection of STZ while rats of
group (6) were given a single IP injection of 577 then received daily IP
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Ashraf Bela! and Rizk A. Sanad
injection of NA. After 4 weeks blood samples were collected by the
same method mentioned previously and sera were estimated for the
same parameters as we did with the former 4 groups. We found marked
significant reduction in fasting blood glucose. cholesterol, triglycerides
and LDL with marked significant increase in serum insulin and HDL in
group(6) compared to group (5) .
In conclusion: NA administration resulted in a significant increase in
HDL and a significant decrease in levels of fasting blood glucose, cholesterol.
triglycerides and LDL in normal and STZ induced diabetic rats.
The can se of glucose decreasing effect may be inhibition of gluconeogensis
and improving insulin sensitivity. As regards insulin level
NA showed controversy effect. It caused a decrease in insulin level
in normal rats while in SlZ induced diabetic rats it increased insulin
level. The mechanism in diabetic rats may be the protective effect of
NA in the form of returning of fl-cell of pancreas to its normal morphology
. In normal rats this effect negligible and overcome by insulin lowering
effect of decreased PTA occurred after NA administration. It could
be concluded that NA proves efficiency in diabetic prevention and
management. |
