The effect of dietary wild pistachio oil on serum leptin concentration and thyroid hormones in the female rat

Background: Unsaturated fatty acids decrease serum leptin level and wild pistachio oil is rich of
them. With attention to this effect and reciprocal effects between leptin and thyroid hormones, the
aim of the present study was to investigate the impact of dietary wild pistachio oil on serum leptin
concentration and its relationship with thyroid hormones.
Materials and Methods: 28 healthy adult female rats were selected and divided randomly to four
equal groups. Group 1 as the control group and other three groups received normal diet a long
with, 5, 10 and 20% of wild pistachio oil, respectively. RIA for thyroid hormones assay (T3 and T4)
and ELISA for leptin, fT3 and fT4 measurement were used.
Results: Serum leptin level reduced with increasing wild pistachio oil concentration in the diet
after 60 days. In the control group with normal diet important alterations weren't observe. The
differences between groups were significant. Pearson correlation coefficients were calculated
between leptin and thyroid hormones in the different sampling times. Control group had not any
significant correlation. In group 2 (feeding with 5% wild pistachio oil), leptin concentration had a
positive significant correlation with fT4(r=0.87; P<0.05). There was no significant correlation
between leptin and thyroid hormones at the third stage of sampling. A positive significant
correlation between leptin concentration and T4 at the third stage of bleeding was observed in
group 4 (feeding with 20% wild pistachio oil) (r=0.95; P<0.05).
Discussion:: Wild pistachio oil has a high content of unsaturated fatty acids; therefore reducing
serum leptin level in the studied rats can be related to unsaturated fatty acids effect on serum leptin
level. Taken together oral consuming of wild pistachio oil has a positive effect on reducing leptin
and cholesterol of serum, Its association with thyroid hormones and prevention of cardiovascular
diseases.