Synthesis of seminal ribonuclease in isolated lobules of bull seminal vesicles.

A procedure is described for preparing and maintaining in culture isolated lobules of bovine seminal vesicles, consisting of glandular acini, surrounded by little connective tissue and with free access to the external medium, in which secreted material can be collected. After 48 h in culture, the isolated lobules appeared indistinguishable, by morphological and biochemical criteria, from freshly isolated lobules. After much longer culture times about one third of the glandular cells were still capable of effective protein synthesis. Studying the biosynthesis of seminal ribonuclease with preparations of isolated lobules we found that the enzyme was synthesized and secreted; only the fully amidated isoenzyme was synthesized and secreted, indicating that production of the selectively deamidated isoenzymic forms occurred after secretion, newly synthesized protein was rapidly exported, indicating that the high levels of enzyme previously reported for the seminal vesicle tissue were essentially due to its content of stored secretion.