Jane V. DeHoog

Fish Consumption and Other Characteristics of Reproductive-Aged Michigan Anglers—a Potential Population for Studying the Effects of Consumption of Great Lakes Fish On Reproductive Health

There has been considerable interest in the benefits and risks of eating Great Lakes fish, particularly with regard to reproductive health. We report the results of a survey conducted from 1993-1995 among Michigan anglers. The survey was designed to identify a reproductive-aged cohort of persons who consume high or low levels of Great Lakes fish in order to study the impact of polyhalogenated biphenyl (PHB) compounds and other toxins on human reproduction outcomes. Using fishing license data obtained from the Michigan Department of Natural Resources, we identified anglers of early reproductive age (18-34 years) in ten Michigan counties. The screening survey ascertained demographic, behavioral, fish consumption, and reproductive history information on anglers and their partners. Over 4,000 angler households were contacted. One thousand nine hundred fifty questionnaires were returned from 1,168 households. The median age of respondents was 30 years; 58% were male and 64% reported being married. Slightly more than one-half the respondents had attended or graduated from college, and less than 10% had not completed high school. In the past year, most respondents (46%) reported having eaten sport-caught fish 1-12 times, while 20% reported having eaten no sport-caught fish; 20% had consumed 13-24 meals. More sport-caught fish was consumed in the spring and summer than in the fall and winter, and males reported eating more fish than females. About 43% of our respondents reported that they intend to have one or more children in the next five years. Of these respondents, 287 couples had no identified impairments to reproduction and therefore would be eligible to participate in the future reproductive study.

Influence of cholera toxin on the growth and development of N-methyl-N-nitrosourea-induced rat mammary carcinomas.

Daily injections of cholera toxin (2.0 micrograms/rat/day) for 4 weeks to female Sprague-Dawley rats did not significantly affect the growth of palpable N-methyl-N-nitrosourea (MNU)-induced rat mammary carcinomas. Percent increase in tumor volume was + 78.8% for control animals and +72.8% for cholera toxin treated animals. Daily treatment for 16 weeks of female Sprague-Dawley rats with cholera toxin (1.0 micrograms/rat/day), commencing 3 days after MNU treatment, resulted in a significant (P less than 0.05) increase in mean mammary carcinoma weight per rat at the termination of the study; mammary carcinoma incidence was not significantly affected by cholera toxin treatment. Retinyl acetate feeding (1.0 mM/kg diet) for 16 weeks significantly (P less than 0.05) reduced mammary carcinoma incidence and weight of mammary carcinoma per rat at the termination of study; feeding of retinyl acetate to cholera toxin treated rats blocked the stimulatory effect of cholera toxin on mammary carcinoma development. Thus, the reported striking inhibitory effect of cholera toxin on the growth of dimethylbenzanthracene (DMBA)-induced rat mammary carcinomas was not duplicated in our study, using the MNU-induced rat mammary carcinoma; indeed the toxin appeared to enhance the early developmental stage of this neoplastic process.