Oviducts obtained from cycling baboons were first flushed with saline, then minced and cultured in the presence of L-[3H] leucine. The flushings, tissue culture media, and solubilized tissues were analyzed by electrophoresis for secretory products that were oviduct-specific. The fluorographs of one-dimensional 7.5% slab gels demonstrated that a macromolecule of Mr 130,000 was present in the tissue culture medium of oviducts obtained during the mid-to late follicular stages, and absent during the mid-to late luteal stages. Two-dimensional analysis revealed that the Mr 130,000 band consisted of one basic protein and two acidic proteins. The basic protein formed the major component of this band and was the protein either absent or greatly reduced in intensity during the luteal stage. A macromolecule with similar electrophoretic properties was present in silver-stained, two-dimensional gels of follicular stage flushings, and absent in both luteal stage flushings and follicular stage serum. Two other macromolecules (Mr approximately equal to 160,000 and 88,000) appeared to be secretory products that were oviduct-specific. While both were present at all stages of the menstrual cycle, the Mr 160,000 protein showed a midcycle intensification, and the Mr 88,000 protein showed a midluteal stage intensification. Thus, the synthetic ability of baboon oviduct tissue and macromolecular content of the oviduct lumen changed with the stage of the menstrual cycle. The major alteration was in the synthesis and secretion of the Mr 130,000 basic macro-molecule, which was the major protein present during the follicular stage of the cycle.(ABSTRACT TRUNCATED AT 250 WORDS)