Major Contribution of Epididymis to α-Glucosidase Content of Ram Seminal Plasma1

Abstract

Acid alpha-glucosidase and L-carnitine (a well-known epididymal marker) were measured in rete testis and epididymal fluids of adult male rams. These fluids were collected by selective catheterization or by a micropuncture technique, respectively. Both parameters remained at a low and constant level in rete testis and all along caput and corpus epididymidis. Then they increased at equivalent rates in cauda epididymidis to much higher levels than those in seminal plasma (5 mU/mg protein and 10 mM, respectively). An optimum pH study of alpha-glucosidase activity in these fluids showed two well-separated peaks in rete testis and caput epididymal fluids around pH 4 and 7, respectively, but only a single peak at pH 4 in cauda epididymidis that was comparable to the one in seminal plasma. Sucrose density gradient fractions analyzed for their enzyme content in the absence or presence of sodium dodecyl sulfate (1% w/v), a selective inhibitor of acid alpha-glucosidase activity, allowed the demonstration of two enzyme forms at pH 6.8 in rete testis fluid sedimenting in the 7S and 4S regions of the gradient, while a unique 4S form was encountered in cauda epididymidis and in seminal plasma. Although the fate of the minor 7S component of the rete testis fluid in its epididymal transit is presently unknown, similarities between the enzyme in cauda epididymidis and seminal plasma are strong enough to support the hypothesis that epididymis contributes primarily to the acid alpha-glucosidase content of ram seminal plasma.

The distribution of carnitine and acetylcarnitine in the epididymis and epididymal spermatozoa of the boar

“…Indeed, whereas the carnitine levels began to increase in the fluid in the distal caput epididymidis (regions 3-4), the carnitine content of spermatozoa did not rise until the cells had reached the distal corpus (regions 6-7). An increase in the carnitine amount of the epididymal fluid has already been demon¬ strated in different species (Hinton et al, 1979;Besançon et al, 1985). Our results relative to the caudal epididymal fluid of the boar as expressed in µ /ml (Table 1) are similar to those obtained by Hinton et al (1979) for the same region (15-20mM), although we found a higher carnitine concentration gradient.…”

“…After the first rise, the carnitine concentration shows only slight gradual increase along the epididymis in the hamster, rabbit and boar (Hinton et al, 1979), but a 3-fold increase has been found in the rat (Hinton et al, 1979), and an 8-fold increase in the ram (Besançon et al, 1985). The origin of acetylcarnitine in the epididymal fluid is unclear.…”

Alpha‐glucosidase activity in the rat epididymis under different physiological conditions

“…It is interesting to note that alpha-glucosidase activity is absent from the mice and hamster epididymis, whilst in monkey semen enzyme activity is barely detectable. In contrast, there is high activity of alpha-glucosidase in the epididymis of the rat and ram (Besancon et al, 1985a;Yeung et al, 1990). Because the distribution of rat epididymal alpha-glucosidase is close to that of the human, this animal may be a suitable model in which to study the role of epididymal secretions, such as alpha-glucosidase, on the metabolic activity and fertilizing ability of spermatozoa.…”

Alpha-1,4-Glucosidase Activity in Ram Seminal Plasma Is Inversely Related to Serum Testosterone

“…It was therefore of interest to ascertain whether ram epididymal a-l,4-glucosidase was under androgenic control, be cause of our initial observations indicating a net increase of the enzyme in the seminal plasma of lambs progressing to sexual matu rity [4], We postulated that the optimal physiological condition to observe this puta tive hormonal influence was to determine the enzyme activity in relationship with the In 1985, Besançon et al [1] observed that the enzyme a-l,4-glucosidase was localized mainly in the caput epididymis of adult rams. This observation corroborated pre vious results from this laboratory indicating the presence of a-l,4-glucosidase in the cauda epididymis of men [2] and rats [3].…”

“…The role of this enzyme in the reproductive tract of mammals has been a matter of inter est for our group as mammalian spermato zoa are exposed to various epithelial secre tions of the seminiferous tubule and of the epididymal duct during their development. Among the variety of minor epididymal a-Glucosidase-Specific Activity and Testosterone Concentrations Seminal plasma a-glucosidase-specific activity and blood plasma testosterone concentration were measured according to the methods previously de scribed by Besançon et al [1,4], The inter-assay coef ficient of variation of the method for the a-glucosidase assay was 2 % after dozens of determinations in duplicate at weekly intervals. serum testosterone variations which exhibit typical seasonal variations in two breeds of rams.…”