Animal Reproduction Science, 23 ( 1990 ) 213-222 213 Elsevier Science Publishers B.V., Amsterdam Proteolytic and antiproteolytic activities in goat antral follicles A.M. Rosales b, O. Hernandez-Perez a, R. Dominguez a, E. Mercado a and A. Rosado c aLaboratorio de Biologia Molecular, Unidad de Investtgacion Biomedica, I.M.S.S., Mexico, D.F. 03020, Mexico bDepartamento de Produccion Agricola y Animal, Universidad Autonoma Metropolitana, Unidad Xochimilco, Calzada del Hueso 1100, Mexico, D.F. 0496 O, Mexico (for correspondence ) cUniversidad Autonoma Metropolitana, Unidad lztapalapa, Mexico, D.F., Mexico (Accepted 20 February 1990) ABSTRACT Rosales, A.M., Hernandez-Perez, O., Dominguez, R., Mercado, E. and Rosado, A., 1990. Proteolytic and antiproteolytic activities in goat antral follicles. Anita. Reprod. Sci., 23: 213-222. Goat antral follicles were dissected and classified initially by size into three groups: < 3 mm, be- tween 3 and 6 ram, and > 6 ram. Follicles less than 3 mm diameter were studied without any further classification. All others were classified according to their gross stereoscopic microscope appearance into four sub-groups. Histological observation showed that sub-group 1 consisted mainly of non-atretic follicles, sub-group 2 of follicles in the early stages of atresia, while sub-groups 3a and 3b were tbrmed by secondary and tertiary atretic follicles. Tryptic and anti-trypic activites were measured in follicular fluid, homogenized follicular cells and empty follicular sacs, using a fluorometric procedure. Anti- tryptic activity in follicular fluid was found to be directly correlated with progress of atresia and in- versely with follicular growth, being smallest in big ( > 6 mm), non-atretic follicles and consistently higher in small ( < 3 mm) and in atretic follicles. No differences were detected between sub-group 3 follicles of different sizes. After elimination of anti-trypic activity by gel filtration, trypsin-like activity in cell-free follicular fluid was found only on > 6 mm non-atretic follicles. High trypsin-like activity was found in the cell walls of non-atretic or early atretic follicles. This activity was significantly lower in sub-group 3a follicles and was almost absent in tertiary atretic follicles (sub-group 3b). In contrast, trypsin-like activity in granulosa cells recovered by centrifugation of follicular fluid was twice as high in sub-group 3a as in sub-groups 1 and 2 and almost five times higher than in sub-group 3b. INTRODUCTION Changes in follicular fluid steroid concentrations have been consistently used as predictors of follicular maturation and atresia (Moor et al., 1978; Yoshimura and Wallach, 1987). However, steroid hormones are, generally, only intermediaries in the regulation of basic biochemical processes. There- fore it would be of major interest to study other biochemical parameters of 0378-4320/90/$03.50 © 1990 -- Elsevier Science Publishers B.V.