title: Effect of preincubation of human spermatozoa in milk on penetration of zona-free hamster oocytes: comparison to TEST yolk.
abstract: OBJECTIVE
  To investigate the effect of preincubation of human sperm in milk on their ability to penetrate zona-free hamster oocytes, 27 ejaculates were studied. Each ejaculate was divided into two portions and incubated in either milk or TEST yolk (TESTY) for 22-24 hr at 5 degrees C prior to processing for the sperm penetration assay.
  
  
  RESULTS
  Spermatozoa preincubated in milk penetrated a significantly (P < 0.05) higher percentage of oocytes (mean +/- SE; 74.4 +/- 6.3) than spermatozoa preincubated in TESTY (66.8 +/- 6.6). Statistically, no significant differences were noted for penetration index or postincubation sperm motility between the two media.
  
  
  CONCLUSIONS
  Preincubation of sperm in milk therefore appears to enhance their ability to penetrate zona-free hamster oocytes, compared to TESTY preincubation. Since milk is natural, simple, inexpensive, readily available, and can be easily processed, it should be the medium of choice for sperm preincubation.
authors: Department of Obstetrics and Gynecology, Prentice Women's Hospital, Northwestern University Medical School, Chicago, Illinois 60611.
authors: M J
authors: MJ
authors: Scobey
authors: W J
authors: WJ
authors: Holmgren
authors: R S
authors: RS
authors: Jeyendran
mesh_terms: D000818:Animals; D006224:Cricetinae; D003470:Culture Media; D005260:Female; D006801:Humans; D008297:Male; D008892:Milk; D009865:Oocytes; D013084:Sperm-Ovum Interactions
chemical_list: D003470:Culture Media