EPIDIDYMAL GLYCOPROTEIN INVOLVED IN RAT SPERM ASSOCIATION

Recently, a new head-to-head sperm association was described in the ra t during epididymal transit. This association was called a rosette and a filamentous and PAS-positive material was also described joining th e sperm heads. The begining of rosette formation in the epididymis and the linking material between heads have remained unclear. Epididymide s of adult rats were fixed by vascular perfussion and thin sections of the principal regions were studied by transmission electron microscop y (TEM). The first evidence of rosette formation was observed in the d istal corpus. Rosettes were isolated from the distal corpus and proces sed for immunogold and immunofluorescence microscopy to detect an epid idymal glycoprotein called DE. This glycoprotein is secreted by the co rpus epididymis and appears to be involved in sperm maturation. Colloi dal gold marks and fluorescence were observed in the linking material between the sperm heads. The results presented here show that rosettes begin to appear following the sites of DE secretion and permit us to postulate that DE is involved in rosette formation and constitutes ano ther example of gamete-epididymal interaction. (C) 1994 Wiley-Liss, In c.