Introduction Impact of in utero exposure to nicotine, on
the structure of the thyroid-pituitary axis and the parathyroid
glands have been examined in 1-month-old rats and
compared with that of thiocyanate.
Materials and Methods Three pregnant female groups
were used; control, nicotine and thiocyanate. Treatment
started from gestation day (4–20) and the specimens were
harvested from the male offspring of all groups at the age
of 1 month and processed for light, electronmicroscopic
and immunohistochemical examination. Total triiodothyronine
(tT3), total thyroxine (tT4) and total thyrotropin
(TSH) were quantitatively determined in serum.
Results Both nicotine and thiocyanate activated the thyroid
follicular cells, with an increase in height (about
30 %) and a negative feedback on the pituitary thyrotrophs
which revealed a reduction in the number of cytoplasmic
secretory granules, particularly the thiocyanate group.
However, in thiocyanate group there was signs of impaired
secretory activity of the thyroid gland. The arbitrary area of
parathyroid chief cells, increased (about 45 %) particularly
in nicotine group, with signs of reduced activity and a
positive feedback on the parafollicular cells which revealed
hypertrophy, proliferation (25 %) and increased intensity
of positive immunohistochemical reaction for calcitonin.
Conclusion Nicotine impaired chief parathyroid cells
activity and consequently activated parafollicular cells.
Thiocyanate reduced pituitary thyrotrophs activity whereas both nicotine and thiocyanate increased thyroid
follicular cells activity. This impact of in utero exposure
persisted for 1-month postnatal.