Role of ascorbic acid in metabolism of rat testis and epididymis in relation to the onset of puberty

The metabolism of ascorbic acid, cholesterol, serum testosterone level and activities of 3Β and 17Β hydroxysteroid dehydrogenases were studied in testis and Cauda epididymis of prepubertal, pubertal and postpubertal (5, 15, 30, 45, 55 and 60 day old) rats. The data showed that serum testosterone levels and 3Β and 17Β hydroxysteroid dehydrogenases were increased with the age. The ascorbic acid metabolism was found to be stabilized in testis at day 30 being comparable with the adult, whereas a spurt in its metabolism occurred by day 45 and a significant depletion in ascorbic acid content in relation to the passage of the first wave of spermatozoa through cauda epididymis. The results of this study clearly elucidate that ascorbic acid is involved in metabolism of testis and epididymis in developing postnatal rats, in relation to the increasing demands for attaining a stable hormonal milieu, and the onset of puberty and the passage of the first wave of spermatozoa,via the formation of its free radical monodehydroascorbic acid and charge transfer complex mechanism     

Relationship of scrotal circumference and testicular volume to age and body weight in the swamp buffalo (Bubalus bubalis)

Scrotal circumference (SC) and testicular volume (TV) were measured in 65 swamp buffalo bulls ranging in age from 7 to 60 months and weighing 130 kg to 560 kg. Ages and body weight (BW) were recorded for each male at the time of measurement to find out if they correlated with SC and TV. SC and TV increased linearly and correlated significantly with age and BW (SC vs age: r = 0.74, p<0.01; SC vs BW: r = 0.88, p<0.01; TV vs BW: r = 0.82, p<0.01). SC measurements ranged from 15.1 +/- 1.1 cm to 24.0 +/- 0.4 cm for ages ranging from 10.0 +/- 0.6 to 48.5 +/- 6.3 months, revealing that testicular size in swamp buffaloes was very much smaller than domestic cattle. The SC norms distributed with age would be useful in the evaluation of swamp buffalo males for breeding soundness.     

Structural components of sea urchin sperm nuclei

The sea urchin sperm nucleus rapidly loses its conoid morphology and becomes more voluminous and spherical upon its entry into the egg cytoplasm during fertilization. This investigation has attempted to determine what are the structural constraints placed upon the sperm nucleus, so that further investigations might determine the egg cytoplasmic factors that are responsible for modifying nuclear morphology. Isolated sperm nuclei were subjected to various extraction procedures in order to remove the majority of the proteins (histones) and also the DNA; subsequently, the residual structures were processed for and examined by electron microscopy. The data presented in this investigation demonstrate the removal of the sperm nuclear histones plus other nonhistone proteins has no effect on the conoid morphology of the sperm nucleus, yet this protein removal has a profound effect on the structure of the nuclear chromatin. It is also shown that removal of the majority of the nuclear DNA has no effect on the shape of the sperm nucleus. These results indicate that there are other components (possibly a nuclear matrix) associated with the sperm nucleus that are responsible for maintaining its conoid morphology.     

The transport of morphologically abnormal sperm in the female reproductive tract of mice

Mice of the PL/J strain exhibit a high percentage of morphologically abnormal sperm and provide a model for studying the function of abnormal sperm. The ability of such sperm to reach the site of fertilization within the female reproductive tract has been investigated. We have found a decrease in the percentage of structurally abnormal sperm within the population that reaches the oviduct. This observation suggests either that there is an active selection against abnormal sperm or that they are physiologically disadvantaged in reaching the site of fertilization.     

Influence of the concentration of sperm on the percentage of eggs fertilized for three strains of mice

This study was conducted to determine the optimal concentration of sperm to use for the insemination of females to detect differences among strains of mice in the percentage of eggs fertilized. Female ICR mice were inseminated with sperm of concentrations ranging from 0.25 to 8 × 10⁶/50 μl from males of either DBA/2N, CF1, or C57BL/6N strains. Differences among strains were detected only when approximately 50% of the eggs were fertilized but not when each of the strains fertilized either a high or low percentage of eggs. The optimal concentration of sperm therefore was the concentration that gave approximately 50% fertilized eggs.     

The onset and maintenance of hyperactivated motility of spermatozoa from the mouse

Estimates were made of the proportion of freely motile mouse spermatozoa displaying hyperactivated motility by an objective photographic method employing stroboscopic illumination under dark-field conditions and examining displacements of the sperm head and bend angles of the sperm tail. In media known to support in vitro fertilisation hyperactivation gradually appeared reaching about 40% by 6 hr incubation, and it was not promoted by 2 mM caffeine or 0.1 mM Bt₂ cAMP or washing the cells free of epididymal fluid. Raising the osmolarity of the medium to 400 mOSM with electrolytes, but not nonelectrolytes, did promote hyperactivation (60% by 2 hr) suggesting that the ionic strength of the medium was important. Hyperactivation in high ionic strength media could be prevented by removing or chelating Ca²⁺, or replacing Ca²⁺ with Ba²⁺ or Mg²⁺, when nonhyperactivated motility was maintained, but Sr²⁺, like Ca²⁺, permitted hyperactivated motility. Hyperactivation in low ionic strength medium could be promoted by the ionophore A23187, suggesting that Ca²⁺ movement into the cells is important. Of a range of glycolytic substrates tested supporting nonhyperactivated motility in the presence of lactate, only glucose supported hyperactivation. Addition to glucose— or Ca²⁺ — free, high ionic strength media after 2 hr increased hyperactivation immediately (glucose) or after a lag of 2 hr (Ca²⁺) suggesting that glucose acts on a Ca²⁺ — primed system. Removal from high ionic strength medium, chelation of Ca²⁺ or inhibition of glucose metabolism did not prevent hyperactivation continuing once it had been initiated, indicating different requirements for initiation and maintenance of this form of motility.     

Adenylate cyclase activity of membrane fractions isolated from sea urchin sperm

The adenylate cyclase activity of sperm membrane fragments isolated from Lytechinus pictus sperm according to Cross [20] has been studied. Two distinct fractions preferentially coming from the flagellar plasma membrane are obtained. Surface I¹²⁵-labeling experiments performed by Cross [20] indicate that these membranes are representative of the entire sperm plasma membrane. Both fractions are enriched in their adenylate cyclase activity: the specific activity of the top membranes is eightfold higher than in whole sperm, whereas that of the middle membranes is 15-fold higher. The cyclase seems to be associated with the membranes. Lytechinus pictus egg jelly has no effect or slightly inhibits the adenylate cyclase activity of the isolated sperm plasma membrane fragments. Mg⁺⁺ and Na⁺ stimulated their cyclase activity about sevenfold at 2.5 mM Mn⁺⁺ and 3.2 mM ATP. At this ATP to Mn⁺⁺ ratio, high concentrations of Ca⁺⁺ have a small stimulatory effect.     

Normal levels of zinc and sulfhydryls in morphologically abnormal populations of spermatozoa from moderately zinc-deficient rats

Zinc is required for spermatogenesis in mammals and is concentrated in the dense outer fibers of the sperm tail, where it is associated with cysteine-rich protein. To investigate the effects of marginal zinc deficiency upon dense fiber formation and upon sperm quality in general, weanling Sprague-Dawley rats were administered a commercial low-zinc diet, supplemented with phytate, for approximately 60 days, and were compared with controls fed the same diet plus 50 ppm zinc in their drinking water. The following characteristics of the zinc-deficient rats were significantly lower than in the controls: body weight, testis weight, epididymis weight, seminal vesicle weight, sperm content of the cauda epididy-midis, sperm motility, testis zinc, and hair zinc. By contrast, the levels of sperm zinc and sperm sulfhydryls were the same in the zinc-deficient and control rats. The zinc-deficient rats displayed a highly variable spectrum of sperm defects, which included decapitation, disorganized and redundant tail elements, and superfluous cytoplasm. However, abortive dense fiber development was only rarely observed. Apparently, even when availability of zinc is limited and reduced sperm production ensues, elaboration of dense fibers rich in zinc and sulfhydryls continues to be obligatory for the completion of spermiogenesis.     

A phosphorus NMR study of the reaction products of cis-diamminedichloroplatinum (II) with a double-helical oligonucleotide and with DNA

The structural distortion of oligonucleotides upon cis-PtCl2(NH3)2[d(T-C-T-C-G-G-T-C-T-C)-N7(5), N7(6)] reveals shifting of 4 phosphorus resonances due to platination. 3 Resonances could be assigned by selective 31P-irradiation, showing P(6) (P between the two Gs) to be shifted 1.5 ppm to low field. In the concomitant double strands P(6) is shifted 0.9 ppm to lower field. A similar peak has been observed in platinated salmon sperm DNA (37 degrees C), indicating that Pt-binding to GpG-fragments in DNA is similar to that found for the decanucleotide, so the distortion of DNA might be comparable.     

Diisopropylfluorophosphate-interacting proteinases of nuclei of rat testis cells

Nuclei and chromatin of seminiferous epithelial cells of rat testis contain acid-extractable and non-extractable proteins which interact readily with [³H]DFP (diisopropylfluorophosphate). Proteinase activity is closely associated with these DFP-interacting proteins, and the proteinase activities are inhibited by DFP and PMSF. DFP-interacting proteins of testis chromatin increase greatly in amount at 26–32 days after birth when spermatids are appearing in increasing numbers. In nuclei separated by zonal centrifugation on sucrose gradients, the DFP-labeled proteins are highest in activity in the elongated spermatids at the stage in spermiogenesis at which histones are being replaced by testis-specific proteins and protamines. Electrophoresis in SDS-polyacrylamide gels reveals the presence of three species of DFP-interacting proteins in nuclei of seminiferous epithelial cells of the testis. The chromatin of epididymal spermatozoa of the rat contains three or four species of DFP-interacting proteins by SDS-polyacrylamide electrophoresis and some of these labeled proteins co-migrate with two of the three basic proteins which are observed during electrophoresis on polyacrylamide gels in Triton-urea.