This study was carried out to investigate the effects of nicotinic acid
(NA) on lipid profile, glucose and insulin levels in normal and streptozotocin
(514 inclt icrd diabetic rats.6 groups of albino rats ( each consists of
10 rats) were used in this study. Group (1) & (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 (II') 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 decrease
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 STZ 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 carded out to
study the possible curative effect of NA in 522 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 STZ then received daily IP 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 cause 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 b/Z 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 )3-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. |
