Increase in fluid viscosity during epididymal transit and the immobilization of rat epididymal spermatozoa

Abstract

A microcapillary method was developed to measure the viscosity of small volumes of undiluted epididymal fluid. Fluid from the cauda epididymis registered 82 ± 17 centipoise which was much more viscous than fluid from the caput region (8 ± 2 centipoise). Initiation of sperm motility was strongly suppressed in the viscosity range of 7 to 150 centipoise. A significant increase in the viscosity of fluid from the caput region was observed when immobilin in the fluid binds with a lectin from Jack fruit (Artocarpus heterophyllus). Thus, it is postulated that aggregation of the immobilin induced by a lectin‐like material produced by the cauda epididymis may be a mechanism by which fluid viscosity is increased during epididymal transit. Copyright © 1986, Wiley Blackwell. All rights reserved