PARENT SESSION
REPRODUCTIVE TOXICOLOGY
Harborside C
7:30 AM-10:00 AM

(291) NEONATAL ESTROGEN EXPOSURE OF MALE RATS ALTERS REPRODUCTIVE FUNCTIONS AT ADULTHOOD.

Robateau, Ayana¹, Tarleton, Becky¹, Braden, Tim², Williams, Carol¹, Ali, Kamaleldin¹, Srivastava, Kunwar¹, Goyal, Hari¹, ¹ Dept of Biomedical Sciences, Tuskegee, AL² Dept of Physiology, Auburn, AL

ABSTRACT- This study evaluated effects of neonatal exposure to different doses of diethylstilbestrol (DES) on reproductive functions of male rats at 83-91 days of age. Neonatal Sprague-Dawley rats (5-10/group) received sc injections of 25 l olive oil containing DES at a rate of 10, 1, 0.1, 0.01, 0.001, or 0 (control) g/rat on alternate days from day 2-12. Reproductive parameters, including i) daily sperm production (DSP)/testis, ii) absolute and relative weights of the testis, epididymis (EP), and seminal vesicle, and iii) sperm numbers in both regions of the EP, declined significantly in a dose-dependent manner in the 10- and 1-g groups. In addition, sperm motility patterns and sperm morphology were adversely affected in the 10-g group. Conversely, in the ⩽1-g groups, none of these parameters (except DSP/testis and weight of the EP in the 0.1-g group) was different from controls. Generally, plasma testosterone level decreased, but FSH and prolactin levels increased in the 10- and 1-g groups. LH was unaltered. In a fertility study, four, 70-80-day-old, male rats each from the 10-g, 1-g, 0.1-g, and control groups were cohabited with untreated, 60-70-day-old females (1:1) for 12 days. While each male in the 1-g, 0.1-g, and control groups produced a copulatory plug and impregnated a female, none could do so in the 10-g group. The mean number of pups per litter was reduced to 8 in the 1-g group, in contrast to 15 in the 0.1-g group and 16 in controls. In conclusion, exposure of neonatal rats to DES not only reduced weights of reproductive organs, DSP/testis, and sperm numbers in the EP, but also altered sperm motility patterns, sperm fertility (as evident from reduced number of pups in the 1-g group), and sexual behavior (as evident from absence of copulatory plugs in the 10-g group). Whether these reductions/alterations persist in older rats (4-6 months of age) is under investigation. Supported by NIH/MBRS-5-S06-GM-08091.

KEY WORDS: estrogen, epididymis, testis, sperm