Effect of incubation conditions, inhibitors and seminal plasma on protein synthesis in ram spermatozoa.

Abstract

The effects of incubation time (15 min-4 h), rate of semen to buffer dilution (1/10-1/40), and concentration of glucose (5.5-22 mM) on the rate of protein synthesis by ejaculated washed ram spermatozoa were determined. The rate of protein synthesis increased linearly as incubation time, dilution rate, and the glucose concentration increased. Denaturation of sperm protein with 1% HgCl2 caused an almost complete inhibition of amino acid incorporation. Protein synthesis over a period of 4 h was also inhibited by chloramphenicol but was not affected by cycloheximide. Protein synthesis and uptake of [14C]cAMP by washed ram spermatozoa was also significantly inhibited by the inclusion of 2-8% seminal plasma in the buffer. The present results indicate that the authentic protein synthesis by mature ram spermatozoa is mainly of mitochondrial origin. The data also suggest a role for intracellular cAMP in the regulation of sperm protein synthetic activity.