In the present study the effects of organochlorine pesticides: o,p'-DDT, p,p''-DDT, methoxychlor, and lindane on ATPase activities of microsomal fractions of bovine oviductal and endometrial cells were investigated. We were not able to characterize a Ca2+ stimulated ATPase, whereas 57 and 15% of the total ATPase activity were sensitive to Mg2+ in the oviductal and endometrial fractions, respectively. After 10 min preincubation with the four organochlorines, a significant inhibition was found only with o,p''-DDT at 32 microM (27.9%) and 64 microM (35.6%) in the oviductal microsomal fraction and at 64 microM (32.2%) in that of the endometrium. Increasing the preincubation time to 30 min, the Mg2+ ATPase in the endometrial fraction was significantly inhibited by all four pesticides at 64 microM, but in the oviductal fraction only at 64 microM o,p''-DDT. It is suggested that organochlorine pesticides can have an influence on cells responsible for reproduction.