Abstract:
This study was initiated to investigate the possible.
effects on the sexual competence of male rats followin,g short
term exposure to hexavalent chromium (sodium chromate) and
the antigestational effects of hexavalent chromium and
trivalent chromium (chromium chloride) on the pregnancy
outcome of rats. Concentrations tested in the males were
1mg/kg/day and 4mgjkg/day, given intraperitoneally (IP) for
five consecutive days. The pregnant female rats were treated
IP using the same dose levels in addition to a higher dose
level of 8mgjkgjday during days 1-7 and 7-14 of pregnancy.
In an another set, hexavalent chromium was administered
subcutaneously during days 14-21 of pregnancy at a dose level
of 4mg/kg/day.
The higher dose of hexavalent chromium caused severe
impairment of libido in male rats. However, at successful
matings the fertility remained unaltered. The number of
animals attempting mounting, intromission and achieving
ejaculation were significantly reduced respectively by 43%,
43% and 72% and so was t,he mount frequency (treatment vs
controls: 6.0 I 2.8 vs 18.5I 1.9) and intromittent frequency
(5.8 I 2.8 vs 16.1 I 2.0). Intercopulatory interval was
enhanced (423.6 I 169.0 vs 37.8 I 3.0 sec.). In contrast,
time up to ejaculation and copulatory efficiency remained
unaltered.
The investigations on the pregnancy outcome of rats
showed that there was a significant interruption in pregnancy
with pre-natal exposure of hexavalent chromium, in contrast
to trivalent chromium. The intermediate dose (4mg/kg/day) of
hexavalent chromium administered during day 7-14 of pregnancy
caused a significant reduction in the number of uterine
implants (by 50%) and a significant increase in postimplantation losses by 33%. Irrespective of the time of
treatment (day 1-7 or day 7-14 of pregnancy) this dose caused
a significant reduction of foetal size. Furthermore,
significant impairment of the number of pups born was
observed with this dose, when administered from day 14-21 of
pregnancy.
The only significant effect observed with trivalent
chromium administration was a marked dimunition of foetal
size during day 7-14 of pregnancy.
Approximate LD50 values for sodium chromate were greater
than 20mg/kg and lower than 200mg/kg while those for chromium
chloride were greater than 200mg/kg and lower than 2000mg/kg.
These results demonstrate that hexavalent chromium is
hazardous to both male and female reproduction in rats. The
antireproductive effects of trivalent chromium were minimal
compared to hexavalent form
