Polyamines in Ejaculated Ram Spermatozoa and Their Relationship with Sperm Motility

Abstract

ABSTRACT: Intracellular polyamine levels in ejaculated spermatozoa and seminal fluid from rams were determined by fluorescent spectroscopy of their dansyl derivatives. Relationships between the sperm polyamine content and sperm motility of six mature and eight pubescent rams were studied. Samples were collected from both groups once a month from August through October. Mature rams had a greater percentage of motile sperm cells than lambs (94% versus 73% in September and 92% versus 78% in October); higher spermidine content (36 versus 9 pmol/108 cells in September and 162 versus 55 pmol/108 cells in October); higher spermine content (984 versus 205 pmol/108 cells in September and 1,229 versus 414 pmol/108 cells in October); and higher total sperm polyamine content (1,021 versus 216 pmol/108 cells in September and 2,258 versus 973 pmol/108 cells in October). In the lambs, spermidine content increased (55 versus 9 pmol/108 cells); spermine content increased (414 versus 205 pmol/108 cells); and total sperm polyamine content increased (973 versus 215 pmol/108 cells) in October compared to September. Ejaculates with sperm motility higher than 85% had greater spermine (848 versus 234 pmol/108 cells in September and 1064 versus 449 pmol/108 cells in October), and total sperm polyamine content (882 versus 244 pmol/108 cells in September and 2,015 versus 1,008 pmol/108 cells in October) than ejaculates with less than 85% motility. Sperm motility in ejaculates with less than 450 pmol total sperm polyamines/108 cells was 68% ± 6% compared to 90% ± 4% in cells with greater than 450 pmol (average for all ejaculates) total sperm polyamines/108 cells. These data suggest a positive relationship between sperm polyamine content and sperm motility. Sperm‐free seminal plasma from mature rams contained 7.5 and 0.28 nmol/ml of spermine and spermidine, respectively. Seminal fluids from pre‐pubertal rams also contained similar amounts of polyamines.