Effects of continuous and intermittent exposure of lactating mothers to Aroclor 1242 on testicular steroidogenic function in the adult male offspring

Polychlorinated biphenyls (PCBs) are worldwide pollutants and have caused h azardous effects on many animal species including humans. They have been de tected in human milk and therefore exposure of newborns to PCBs is unavoida ble if they are breast-fed. We present our findings on two experiments perf ormed to test the effects of intermittent and continuous exposure of lactat ing rats to two different doses (80 mug and 8 mug) of Aroclor 1242 (a PCB c ongener) on testicular steroidogenic function of their adult male offspring . In experiment I, three groups of lactating dams received daily subcutaneo us (SC) injections of either corn oil, 80 mug of Aroclor 1242 and 8 mug of Aroclor 1242 in corn oil, respectively. In experiment II, three groups of l actating dams received two SC injections per week of either corn oil or Aro clor 1242 (80 mug and 8 mug) in corn oil, respectively. Pups in all groups (n=8 per group) were weaned at day 21 and were raised on a normal diet unti l sacrificed at 90 days. Experiment I: Leydig cell number per testis was si gnificantly (P < 0.05) increased and the average volume of a Leydig cell wa s significantly (P < 0.05) reduced in both groups of Aroclor-exposed rats c ompared to corn oil controls. Both doses of Aroclor resulted in reduced (P < 0.05) serum testosterone levels compared to corn oil-treated controls. LH -stimulated testosterone production per testis and per Leydig cell was lowe r in Aroclor-exposed rats compared to controls. Experiment II: No changes w ere observed in Leydig cell size and number per testis among the three grou ps. Serum LH, testosterone and LH-stimulated testicular testosterone produc tion in offspring rats of Aroclor-treated darns were not significantly diff erent (P > .05) from the offspring of corn oil-treated dams. However, these parameters were lower in value in the offspring of dams treated with Arocl or 80 mug compared to the other two groups, LH-stimulated testosterone secr etory capacity per Leydig cell was significantly lower in off spring of dar ns treated with Aroclor compared to controls. Serum T-4 and T-3 levels were not significantly different among the Aroclor-exposed and control rats in both experiments. These results demonstrate that continuous exposure of lac tating mothers to 8 and 80 mug of Aroclor 1242 causes hypotrophy and malfun ctioning of Leydig cells in the adult male offspring resulting in a hypoand rogenic status.