Serum levels of insulin-like growth factor-I in relation to organochlorine pesticides exposure.

CONTEXT: Insulin-like growth factor 1 (IGF-I) and organochlorine pesticides (OCs) have been involved in the pathogenesis of several diseases like cancer, diabetes and growth disorders. OBJECTIVE AND DESIGN: The potential relationship between the serum levels of various OCs and serum IGF-I was investigated in adults (176 men and 247 women) from a representative sample of the general population of the Canary Islands (Spain). RESULTS: After adjustment for potential confounders, which include body mass index, age, and IGF-binding protein-3 (IGFBP-3), IGF-I levels were significantly lower in the 247 women who showed detectable levels of p,p'-DDD (a DDT-metabolite) than in women who presented non-detectable levels of this pesticide (p=0.030), specially in 36-50 years old women. A similar negative relationship was also found between IGF-I and aldrin (a non-DDT-derivative) in women (p=0.049). In the group of 176 men, aldrin seemed to exert a similar negative effect on IGF-I (p=0.046) and this effect was clearly significant in the oldest group (51-65 years) (p=0.009). A non-linear dose-response curve was observed between Total Cyclodienes Body Burden (Total Cyclodienes; sum of aldrin, dieldrin and endrin) and IGF-I in men (p=0.024). These findings suggest that OCs could modulate the IGF-system in a way that is highly influenced by gender, age and by chemical or combination of chemicals implicated. Such circumstances may contribute to the development of a number of diseases related to IGF-I and should be taken into account in public health decisions.

Elimination of endrin by mallard ducks.

Endrin is very toxic to birds and has been implicated in the deaths of birds in nature. However, it is not known how rapidly birds eliminate endrin, a factor important in determining how much is accumulated in tissues. In this study, the loss rate of endrin was followed for 64 days in mallard (Anas platyrhynchos) drakes that had been fed 20 ppm endrin for 13 days. The loss from carcass and blood was described by the equation Y = a e b square root of x where Y = the concentration of endrin in ppm, a = the concentration at day 0, e = the base of natural logarithms, b = the first order rate constant for the elimination process, and x = the number of days after cessation of endrin treatment. Endrin was lost rapidly at first; concentrations in carcasses on a wet-weight basis decreased by 50% in the first 3 days. Thereafter, endrin was eliminated more slowly; elimination of 50% of the remainder required 8.9 days, and it took 32.9 days to lose 90% of the original amount.