GENITAL LESIONS FOLLOWING LONG-TERM ADMINISTRATION OF CLENBUTEROL IN FEMALE PIGS

Pathologic findings, lectin histochemistry, and nuclear estrogen recep tors were studied in the reproductive organs of gilts treated with cle nbuterol. A ration containing 1 ppm of clenbuterol was fed for 40 days to four Landrace x Large white, 9-month-old gilts, weighing 134 to 17 2 kg at slaughter (gilt Nos. 5-8). Four gilts (Nos. 1-4) served as con trols. Treated animals had macroscopic lesions characterized by microc ystic ovaries and uterine atrophy. Histopathologic lesions included at retic degeneration of many ovarian follicles, complete absence of func tional corpora lutea, a reduction in the number of endometrial glands, and a decrease in cytoplasmic volume of endometrial and glandular epi thelial cells. In ovaries, uterus, and vagina lectin histochemistry, p erformed with thirteen different biotinylated lectins, revealed a diff erent staining distribution between control and treated gilts. The bin ding pattern of Ricinus communis agglutinin-I (RCA-I) and -II (RCA-II) in the ovaries of control gilts, displayed labeling of cytoplasm in t heca interna cells of Graafian follicles. There was no labeling of the same cells in treated gilts. Labeling patterns with Griffonia simplic ifolia agglutinin-I (GS-I), Phaseolus vulgaris agglutinin (PHA), RCA-I and RCA-II documented a difference in the vascularity of the theca in terna between Graafian follicles of control and treated gilts. The GS- I and Ulex europaeus agglutinin-I (UEA-I) binding patterns in uterus a nd vagina of treated gilts when compared to control gilts suggested th at there was a block of the cycling activity in the proliferative stag e. Immunohistochemical staining for estrogen receptors in the endometr ium was positive in all but one treated gilts, and negative to weakly positive in control gilts. Serum progesterone concentrations were decr eased in treated animals when compared to control; estradiol concentra tions were similar in both group of gilts. Cystic ovaries, uterine atr ophy, and reduction in progesterone concentrations suggested that clen buterol changed ovarian hormonal activity in treated animals.