Epididymal influence on acquisition of sperm motility in the gekkonid lizard Hemidactylus flaviviridis

Seasonal changes in the protein profile and enzyme activity of the epididymal luminal fluid in the lizard, Eutropis carinata (Schneider, 1801)

The epididymis of the male reproductive system is known to be involved in sperm maturation via the production of polypeptides, glycoproteins, surface proteins, enzymes and other factors. During the annual reproductive cycle, the epididymis of the lizard Eutropis carinata undergoes dramatic changes, both morphologically and biochemically, that occur in a well-organized sequence. The present study reveals the sequential changes that occur in the production and concentration of proteins in the epididymal luminal fluid throughout the annual reproductive cycle. A one-dimensional electrophoretic profile of the epididymal luminal proteins revealed a total of 18 bands in the regenerative phase, 22 bands during breeding and 17 bands in the post-breeding as well as regressed phases of the reproductive cycle. By two-dimensional electrophoresis, the protein complexes that are unique to the breeding phase were further resolved based on their pI and the molecular weight of each protein of the protein complex was determined. This is the first study to observe that proteins that are present during the reproductively inactive phase disappear during the reproductively active phase. The Periodic Acid Schiff (PAS) test for protein profiles revealed the presence of proteins with a carbohydrate moiety. Certain enzymes, such as acid phosphatase, alkaline phosphatase, and α-glucosidase, are highly sensitive to seasonal changes and their activity parallels the production of the epididymal proteins. This study provides evidence for androgen-dependent cyclical changes in the pattern of protein profiles and enzyme activity of the epididymal lumen in the lizard E. carinata.

Light and electron microscopic observations of fabrication, release, and fate of biphasic secretion granules produced by epididymal epithelial principal cells of the fan-throated lizardSitana ponticeriana cuvier

The epididymis of the fan-throated lizard Sitana ponticeriana was examined with light and transmission electron microscopy to understand the cellular mechanisms of fabrication of secretion granules in epithelial principal cells, granule release into the lumen, and the fate of the dense structured granules after reaching the lumen. Principal cells of the ductus epididymis, except at the cauda, secrete electron-dense biphasic granules copiously, which decrease in abundance from the initial segment to corpus. The principal cell possesses a prominent Golgi apparatus and all versions of endoplasmic reticulum (ER), rough, smooth, and sparsely granulated. The material of the dense portion of the secretion granules, after processing at the Golgi apparatus, appears to accumulate in large ER cisternae in the supranuclear cytoplasm. It undergoes condensation when the cisternae become condensing vacuoles. Mitochondria appear to play a role in dense granule formation. The condensing vacuoles are displaced toward the apical cytoplasm when the material of the less dense portion is added to the condensing vacuoles at the Golgi area. Thus, the less dense and dense portions of the secretion granules are secreted and added to the condensing vacuoles separately. The composite granules are released into the lumen by exocytosis when the less dense portion merges with the luminal content, whereas the dense portion maintains its structured identity. The latter, initially measuring 1-2 microm in diameter, increases in size several times. It is inferred that these granules release their content gradually, resulting in the appearance of vacuoles, and suggesting that the granules have an insoluble matrix in which there is a sparingly soluble material. The substance leaching out of the granules appears to contribute to keeping the sperm quiescent and alive during storage in the male reproductive tract.

Morphology of the male reproductive duct system of Caiman crocodilus (Crocodylia, Alligatoridae)

The male reproductive duct system of Caiman crocodilus in different reproductive stages was studied using light and electron microscopy, to determine whether shared morphological features exist between Crocodylia and Aves, in concurrence with the Archosauria hypothesis. The sexual duct system of Caiman crocodilus is constituted of the rete testis, ductuli efferentes, ductuli epididymides, ductus epididymidis, and ductus deferens. The morphology and histochemical properties of these ducts suggest their involvement in seminal fluid production and/or its modification. Three types of non-ciliated cells were identified along the duct system. 1. The noncliated cells of the ductuli efferentes contain electron dense worm-like structures and coated vesicles, both related to absorptive processes, as has been suggested in Aves. 2. The non-ciliated cells of the ductuli epididymides have apical electron dense granules suggesting a secretory role, and 3. The non-ciliated cells of the ductus epididymidis and ductus deferens did not exhibit conspicuous storage of secretory material, but have a prominent rough endoplasmic reticulum content indicating active protein production. The occurrence of abundant secretory granules in the epithelial cells of the distal ductus deferens during non-reproductive stages suggests its participation in the removal of luminal debris when the reproductive season ends. Additional ducts were observed running along the ductus deferens; they shared morphological characteristics with the ductuli epididymides. The maximum diameter and therefore the greatest sperm accumulation of the excurrent ducts were observed during the initial testicular regression. The comparative analysis suggests that the male reproductive system of the Crocodylia exhibits structural characteristics nearer to those of Aves than to Lepidosauria, Testudines, and Mammalia, additional data that support an Aves and Crocodylia sister group relationship.