Limited research in young adults ansi immature animals suggests a detriment
al effect of tobacco on bone during growth. This study investigated the eff
ects of nicotine, the major alkaloid component of tobacco, on calciotropic
hormone concentrations and bone status in growing female rats. One-month-ol
d animals received either saline (n = 10), nicotine at 3.0 mg/kg/day (n = 1
0), or nicotine at 4.5 mg/kg/day (n = 10) administered subcutaneously via o
smotic minipumps for either 2 or 3 months. Sera, femora, tibiae. and lumbar
vertebrae (3-5) were collected at necropsy. The concentrations of serum ca
lcium, phosphorus, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, parathyroi
d hormone, calcitonin, and insulin-like growth factor-I were determined. Bo
ne variables evaluated included mineral content and density (vertebrae and
femora), cancellous and cortical histomorphometry (tibiae), and bone streng
th (vertebrae and femora). Statistically significant differences in serum m
ineral and hormone concentrations were not associated with nicotine dose or
exposure time. No significant nicotine treatment effects were detected for
bone mineral content and density, bone histomorphometry, or bone strength.
We conclude that nicotine treatment for 2 or 3 months at serum concentrati
ons in the upper range of those found in smokers has no detrimental effect
on bone mass, volume. or strength in the growing rat.