DISCREPANCIES IN ANALYSES OF DEOXYRIBONUCLEIC ACID IN RABBIT SPERMATOZOA, INVOLVING FEULGEN STAINING (FEULGENDNA) AND ULTRAVIOLET LIGHT ABSORPTION (UV-DNA) MEASUREMENTS

Abstract

The DNA content of individual ejaculated spermatozoa and of spermatozoa recovered from the epididymis and ampulla of 15 rabbits was measured by means of 2 microspectrophotometri methods: direct determination of ultra-violet (UV) light absorbed at 260 m/u by unstained spermatozoa; determination of visible light absorbed at 560 m/u by Feulgen-stained spermatozoa. The DNA determinations in UV light for ejaculated spermatozoa and for those recovered from the male ducts revealed no difference, as contrasted with the results obtained by measuring the Feulgen-stainability. The differences in Feulgen-stainability, i.e. in the quantitative response of spermatozoa to the Feulgen reagent, are attributed to an aging process in the sperm cells: ampullary spermatozoa yielded significantly lower Feulgen-DNA values than those obtained from the epididymis; ligation of the vas deferens resulted in a decrease of the Feulgen-DNA content of epididymal spermatozoa; the variable Feulgen-DNA content of individual ejaculated spermatozoa is attributed to varying percentages of older sperm cells in the ejaculates.