Benchmark doses for lead induced spermatoxicity in rabbits.
Moorman-WJ; Skaggs-SR; Krieg-EF; Turner-TW; Dankovic-D; Schrader-SM
J Androl 1998 Jan-Feb; 19(Suppl 1):49
The dose-response relationships for elevated blood lead and semen quality have been developed in the rabbit model. The Benchmark Dose (BMD) has been proposed to replace the no-observed-adverse-effect-level (NOAEL) and to overcome the limitations recognized in establishing a Reference Dose (RfD). Benchmark doses that were associated with a 5% and 10% response (BMDL 5% 10%) for the principal endpoints of semen analysis were determined. Eight treatments were used producing target blood lead levels from 0 to 110 ug/dl. A 5 week pre-exposure period was followed by a 15 week exposure testing period. Semen analysis revealed that increased blood lead levels resulted in adverse changes in sperm count, volume, motility, and morphology. This report provides a basis for determining the blood lead levels that result in a 5% or 10% impairment in the principal variables of semen analysis. For the 5% response, an average (of sperm count, volume, motion, and morphology) BMDL 5% is 19.9 ug/dl and for a 10% response an average BMDL 10% is 44.5 ug/dl. RfDs were calculated for elevated blood lead level effects on semen quality. A 5% adverse response divided by an uncertainty factor of 10 results in a RfD for blood lead of 1.9 ug/dl (19.9/10=1.9; likewise a 10% adverse response would result in a RfD of 4.45 ug/dl (44.5/10=4.45).
Laboratory-animals; Animals; Animal-studies; Lead-compounds; Dose-response; Models; Exposure-levels; Exposure-assessment; Heavy-metals; Reproductive-effects; Reproductive-hazards
Abstract; Conference/Symposia Proceedings
Journal of Andrology