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Y Clermont

Publications and source records attributed to Y Clermont.

At least 37 records · Page 2Linked to original sources
PubMed1992

Formation of secretory granules in the Golgi apparatus of prolactin cells in the rat pituitary gland: a stereoscopic study.

The mode of secretory granule formation in prolactin cells was analyzed in thin or thick sections of pituitary glands from non-lactating or lactating female as well as from male rats. In all these animals, the Golgi apparatus of prolacting cells consists of a continuous twisted ribbon-like structure that branches and anastomoses to form a hollow sphere located in the juxtanuclear area. The early signs of secretory granule formation are observed along the trans-aspect of the Golgi ribbon where progranules appear as focal distensions simultaneously occurring anywhere in the last trans thiamine pyrophosphatase (TPPase)-containing Golgi element. In the transmost Golgi saccule, such dilatations usually contain several nodular masses of electron opaque material which are separated from each other and from the saccular membrane by a less intensely stained material. While this transmost saccule becomes more fenestrated, its focal polynodular distensions seemingly yield polynodular tubular progranules which are initially closely apposed and usually parallel to the trans face of the Golgi ribbon. Subsequently, these progranules, which frequently show small membranous tubules or tubular networks attached to them, are seen some distance from the Golgi stacks and progressively transform into the more compact polymorphous granules characteristic of prolactin cells. These observations suggest that the polynodular tubular progranules arise by fragmentation of portions of the trans-Golgi elements rather than by fusion of small uninodular granules budding from the edges of a trans-Golgi saccule. Once the progranules have been liberated, the rest of the transmost Golgi element appears to break down into small residual networks, tubules, and vesicles. Thus, in prolactin cells as in other glandular cells, the whole transmost Golgi element would fragment during formation of prosecretory granules.

Animals↗
PubMed1992

Segregation of secretory material in all elements of the Golgi apparatus in principal epithelial cells of the rat seminal vesicle.

At the apex of the epithelial principal cells of the seminal vesicle, there appears to be two types of mature secretory granules, i.e., large and small. Both types of secretory granules showed an eccentric electron-dense spherical body with one pole attached to the delimiting membrane. The remainder of the large granule surrounding the eccentric body showed a granulofilamentous texture, whereas that of the small granule was electron lucent. The formation of these two types of granules was traced back to the various elements of the Golgi stacks. In the case of the large granules, the earliest stage of segregation of the precursor of the eccentric dense body was observed in distensions of the cis-element. Within distensions of all subjacent saccules, the dense bodies continued to be present but progressively increased in size while remaining attached to the saccular membrane. Following separation from the trans-face of the stack, the large prosecretory granules continued to increase in size by fusing with each other. The very large prosecretory granules, as they migrated toward the cell apex to become mature secretory granules, reduced in size prior to exocytosis. The small granules formed exclusively on the trans-aspect of the Golgi stacks and did not appear to fuse with each other. Observations on the formation of the large prosecretory granules within the Golgi apparatus and of the eccentric body in particular, which may be taken as a marker of the saccular membrane, were suggestive of a cis-trans migration and renewal of Golgi saccules.

Animals↗
PubMed1991

Golgi apparatus of epithelial principal cells of the epididymal initial segment of the rat: structure, relationship with endoplasmic reticulum, and role in the formation of secretory vesicles.

The initial segment of the epididymis of rats, fixed with glutaraldehyde, was postfixed with reduced osmium, a technique that clearly delineates the membranes of cisternae of the endoplasmic reticulum (ER) and the various elements of the Golgi apparatus, or with tannic acid to enhance the coats of vesicles and ribosomes on ER cisternae. The material was also treated to demonstrate various phosphatase activities (NADPase, TPPase, CMPase, G-6-Pase) or impregnated with osmium tetroxide. In osmium-impregnated material, the Golgi apparatus of the epithelial principal cells of the initial segment appeared in the light microscope as a branching, anastomosing ribbon forming a large network in the supranuclear region. In the electron microscope, ER were of two types: the heavily granulated, flattened, rough ER seen in the infranuclear and juxtanuclear regions and the distended, tubular, sparsely granulated ER, showing only few ribosomes, seen interlaced with the Golgi ribbon in the supranuclear region and at the apical pole of the cell. Of particular interest in this cell was the fact that the sparsely granulated ER approximated the Golgi stack on both its cis- and trans-faces. On the cis-face of the Golgi stack, the sparsely granulated ER cisternae showed the usual finger- or bud-like protrusions directed toward the cis element of the Golgi stack and around which numerous small 80 nm vesicles or membranous tubules were clustered. The Golgi stack consisted of the following elements in a cis-trans axis: the cis osmiophilic element, a first saccule slightly dilated, saccules two to four (S2-S4), which were NADPase-positive, and saccules five to seven and the eight Golgi element, which were TPPase-positive. On the trans-aspect of the Golgi stacks, several (up to four) CMPase-positive trans-Golgi networks were observed often in close apposition to the sparsely granulated ER cisternae. One of the trans-Golgi networks showed a "peeling-off" configuration, i.e. part of it was closely apposed to the overlying Golgi element of the stack, whereas the remaining part was separated from the stack by a space occupied by a cisterna of sparsely granulated ER. The other trans-Golgi networks were completely separated from the stack and were often seen sandwiched between sparsely granulated ER cisternae. Thus, ER cisternae showed extensive areas of close apposition but no continuity with the trans-Golgi networks. Although the saccules of the Golgi stacks showed NADPase and/or TPPase activity, the trans-Golgi networks displayed CMPase activity, thus facilitating their identification from the closely associated unreactive sparsely granulated ER cisternae.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Origin and distribution of perforatorial proteins during spermatogenesis of the rat: an immunocytochemical study.

The perforatorium is the subacrosomal portion of the perinuclear theca that encapsulates the nucleus of spermatozoa. In the rat, the perforatorium is a curved pointed structure, which in cross section is triangular in outline over the apical half and beyond the tip of the nucleus. The perforatorium, composed of several proteins, appears as a distinct structural entity only at the very end of spermiogenesis. In this study, polyclonal antibodies prepared against the entire isolated perforatorial fraction and against the major 16 and 34 kDa perforatorial polypeptides were used to determine the distribution of perforatorial proteins in germinal cells at various steps of differentiation. Immunoperoxidase staining at the LM level and quantitative immunogold labeling at the EM level were used. The labeling patterns with all three antibody preparations were identical. The immunolabeling first appeared in early pachytene spermatocytes and increased progressively, with a statistically significant upward trend, in both the nuclei and cytoplasm of spermatocytes and spermatids until step 9 of spermiogenesis. Up to this step the labeling concentration was significantly higher over the nucleus than over the cytoplasm. During nuclear condensation in steps 9 and 12 spermatids, there was a progressive loss of all the labeling over the nucleus and a corresponding increase of labeling over the cytoplasm. During steps 16-18, the early signs of condensation of perforatorial proteins occurred next to the inner acrosomal membrane. Then during step 19 there was a sudden condensation of perforatorial proteins into a definitive perforatorium. Thus proteins destined to form this cytoskeletal structure reside in both the nucleus and cytoplasm of spermatocytes and spermatids until nuclear condensation of the latter. Thereafter, they are restricted to the spermatid's cytoplasm and finally condense around the elongated nucleus at the end of spermiogenesis.

Acrosome↗
PubMed1991

Glucose-6-phosphatase activity of endoplasmic reticulum and Golgi apparatus in spermatocytes and spermatids of the rat: an electron microscopic cytochemical study.

The glucose-6-phosphatase (G6Pase) activity of cytoplasmic components of spermatocytes and spermatids of the rat was examined by electron microscope cytochemistry using cerium chloride as a capture agent. G6Pase activity, a recognized ER-resident enzyme, was present in all ER cisternae of spermatocytes. In spermatids, while some ER cisternae were G6Pase-reactive, others were negative or only slightly reactive, indicating an unequal distribution of the enzymatic activity throughout the network of ER cisternae in these cells. In spermatocytes, the cis- and trans-elements of the stacks of Golgi saccules were slightly but significantly reactive for G6Pase. In the Golgi apparatus of spermatids, the cis-element, 4 or 5 underlying saccules, as well as one or two thick trans Golgi elements were G6Pase reactive. The G6Pase activity of the various Golgi elements, like that of the ER cisternae was not affected by the pH of the medium and was completely inhibited by Na-vanadate, a known G6Pase inhibitor. Sertoli and Leydig cells, submitted to the same cytochemical conditions, showed complete G6Pase reactivity of their ER; however in Sertoli cells, all Golgi components were consistently negative while in Leydig cells the cis- and trans-elements of the Golgi stacks were slightly reactive, as in spermatocytes. Thus, the G6Pase reactivity of Golgi elements, appeared variable from one cell type to another. The compact juxtanuclear Golgi apparatuses of spermatocytes and spermatids were both associated with numerous G6Pase reactive ER cisternae; some were present at their surface, others crossed their cortices between Golgi stacks and formed elaborate networks in their cores.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Effects of low temperature on the formation of secretion granules in the Golgi apparatus of granular cells of the frog urinary bladder.

The formation of secretion granules has been studied in the Golgi apparatus of granular epithelial cells of frog urinary bladders maintained at room temperature or cooled at 4 degrees C for various lengths of time. In control animals, the Golgi apparatus was composed of the following stacked elements: subjacent to the cis-element made up of anastomosed tubules, two elements in the mid-compartment consisted of flattened saccules interconnected by tubules. On the trans-face, two or three sacculo-tubular elements were slightly dilated by an electron dense granular material. In the trans-Golgi elements, this material was segregated into dilatations of various sizes and shapes which are continuous with flattened portions devoid of stained material. In the trans-Golgi region, free irregular progranules, seemingly formed by rupture of the trans-most Golgi elements. In granular cells examined after 4 h at 4 degrees C, all Golgi compartments were affected by the low temperature. The cis-half portion of the Golgi apparatus consisted mainly of anastomosed membranous tubules and the cis-element was no longer recognizable. The trans-compartment was reduced to a few flattened saccules with progranules hardly visible on their trans-aspect. At later time intervals, there was a progressive reconstitution of the cis-zone while saccular elements started to pile up in the trans-compartment. At 24 h, the trans-compartment comprised six to eight saccular elements which showed irregular dilatations filled with granular material separated by large flattened portions. These various observations were interpreted as indicating that the trans-compartment was a dynamic structure undergoing continuous renewal.

Animals↗
PubMed1991

Biogenesis of specialized cytoskeletal elements of rat spermatozoa.

Our results on the formation of the ODF and perforatorium are diagrammatically summarized in Figures 30 and 31. The developmental expression of proteins making up these two cytoskeletal elements differs in timing, duration and intracellular localization. The ODF proteins are synthesized exclusively during the latter part of spermiogenesis, well after transcriptional activity in the haploid germ cell nucleus has ended. This implies that these major integral proteins of the tail are translationally regulated and that mechanisms must exist for the storage and eventual release of the mRNAs encoding these proteins. The perforatorial proteins, on the other hand, begin to be synthesized during the meiotic prophase reaching a peak of production in early spermiogenesis just before the initiation of the condensation of the spermatid's nucleus, at which time RNA synthesis stops. Another major difference between ODF and perforatorial protein production is that there seems to be a coordinated activity between the synthesis and the assembly of the ODF proteins, whereas there appears to be an almost 25 day delay between the initial meiotic synthesis and final condensation of perforatorial proteins in the subacrosomal space at the end of spermiogenesis. As for the intracellular localization of ODF and perforatorial proteins both have unprecedented distributions. The ODF proteins appear to be concentrated in a particular type of granular body which is especially abundant in the elongated spermatid at the time of peak ODF assembly. The perforatorial proteins, on the other hand, appear to be concentrated in the nuclei of pachytene spermatocytes and round spermatids until their displacement into the cytoplasm during nuclear condensation. Both forms of localization suggest a storage role for these proteins uniquely adapted by the spermatid to regulate the assemblies of the respective cytoskeletal elements.

Animals↗
PubMed1990

Role of spermatogonia in the stage-synchronization of the seminiferous epithelium in vitamin-A-deficient rats.

After 20-day-old rats are placed on a vitamin-A-deficient diet (VAD) for a period of 10 weeks, the seminiferous tubules are found to contain only Sertoli cells and a small number of spermatogonia and spermatocytes. Retinol administration to VAD rats reinitiates spermatogenesis, but a stage-synchronization of the seminiferous epithelium throughout the testis of these rats is observed. In order to determine which cell type is responsible for this synchronization, the germ cell population has been analyzed in whole mounts of seminiferous tubules dissected from the testes of rats submitted to the following treatments. Twenty-day-old rats received a VAD diet for 10 weeks and then were divided into three groups of six rats. In group 1, all animals were sacrificed immediately; in group 2, the rats were injected once with retinol and sacrificed 3 hr later; in group 3, the rats were injected once with retinol, placed on a retinol-containing diet for 7 days and 3 hr, and then sacrificed. Three rats from each group had one testis injected with 3H-thymidine 3 hr (groups 1 and 2) or 7 days and 3 hr (group 3) before sacrifice. Three normal adult rats (approximately 100 days old) served as controls. Labeled and unlabeled germinal cells were mapped and scored in isolated seminiferous tubules. In group 1, type A1 and type A0 spermatogonia as well as some preleptotene spermatocytes were present; type A2, A3, A4, In, and B spermatogonia were completely eliminated from the testis. Neither type A1 mitotic figures nor 3H-thymidine-labeled-type A1 nuclei were seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Regional differences in composition of the perforatorium and outer periacrosomal layer of the rat spermatozoon as revealed by immunocytochemistry.

The rat perforatorium is the part of the perinuclear theca that underlies the acrosomic system. It appears to be composed of several polypeptides. The main objective of this study was to determine the distribution of seven of these perforatorial polypeptides in the head of the rat spermatozoon. For this purpose, polyclonal antibodies were affinity purified from these polypeptides and tested 1) for their distribution on electron-microscope sections of late spermatids and spermatozoa by immunogold labeling and 2) for their specificity on Western blots of denatured perforatorial polypeptides by immunoblotting. Immunoblotting showed that all seven of the prominent perforatorial polypeptides had epitopes in common. Immunogold labeling of spermatozoa showed that antibodies against the 13, 13.4, and 16 kDa polypeptides were restricted in their localization to the thicker apical portion of the perforatorium and to the inner zone of the ventral spur. However, antibodies against the 34, 43, 57, and 63 kDa polypeptides reacted with the entire perforatorium but, in addition, reacted with the inner part of the ventral spur and with a portion of the "outer periacrosomal layer" lying between the plasma membrane and the outer acrosomal membrane. These results suggest 1) that there are regional differences in protein composition of the perforatorium, of the outer periacrosomal layer, and of the postacrosomal dense lamina; and 2) that perforatorial polypeptides may not necessarily be restricted to the subacrosomal region, but may also compose portions of the outer periacrosomal layer and postacrosomal dense lamina. Based on both immunoblotting and immunocytochemical results, using an antiactin monoclonal antibody that recognizes all known isoforms of actin, actin was not detected in the perforatorium of step 19 spermatids or spermatozoa. Actin, however, together with the seven perforatorial polypeptides tested, was present in the subacrosomal space of elongating spermatids before the process of condensation of the perforatorium takes place.

Actins↗
PubMed1990

Immunocytochemical localization of proteins utilized in the formation of outer dense fibers and fibrous sheath in rat spermatids: an electron microscope study.

Affinity purified antibodies prepared against proteins isolated from fibrous sheath (FS) and outer dense fibers (ODF) were utilized in an immunocytochemical study of spermatids at various steps of spermiogenesis. This study, using the immunogold technique, was performed on sections of Epon or Lowicryl embedded tissues examined with the electron microscope. In the case of FS antibodies there was a selective immunoreactivity of the FS itself from step 10 onwards, but no reactivity over the plasma membrane associated FS anlagen. In addition there was a diffuse immunoreaction over the cytoplasmic matrix from step 9 until step 18 of spermiogenesis but no reactivity over the various types of dense bodies (e.g., granulated bodies, reticulated body, etc.) seen in the cytoplasm of these spermatids. In the case of ODF antibodies the ODF were immunolabeled throughout their development from step 11 onward. In addition to a diffuse immunoreactivity of the cytoplasmic matrix of spermatids from step 9 until step 18 of spermiogenesis, there was an immunolabeling of "granulated bodies." These bodies appeared in relation to ER cisternae during steps 10-14, increased in number and size during steps 15-17 and decreased in number thereafter leaving only a few coarsely granulated bodies in the residual cytoplasm which detached from late step 19 spermatids. No other cytoplasmic structures were labeled with the ODF antibody-gold complexes. Thus the granulated bodies appeared to serve as a transitory storage site for some proteins destined to form ODF, a major cytoskeletal element of the tail of rat spermatozoa.

Acrosome↗
PubMed1989

Formation of secretion granules in the Golgi apparatus of plasma cells in the rat.

The three-dimensional structure of the components of the Golgi apparatus was analyzed in plasma cells of rat duodenum. The spheroidal juxtanuclear Golgi apparatus was formed by a continuous ribbonlike structure composed of the following stacked elements. On the cis-face of the Golgi stack, there was a tubular membranous network referred to as the cis-element and/or a slightly dilated saccule perforated with small pores. The two or three subjacent saccules, which showed few pores, were slightly dilated and contained a fluffy granulofilamentous material. They were also perforated in register by cavities or wells containing 80-nm vesicles. The next one or two underlying elements were fenestrated saccules showing flattened portions as well as distended portions containing a homogeneous material denser than that seen in the overlying saccules. The last two or three elements of the stack showed a partially separated or "peeling off" configuration. These last elements consisted of prosecretory granules attached to flattened, empty-looking saccules showing buds at their surface; detached, more-or-less fenestrated, flattened saccules; and shrivelled residual trans-tubular networks. In the trans-region of the stack, in addition to numerous small vesicles, short membranous tubules, detached prosecretory granules, and denser fully formed secretion granules were also seen. These images were interpreted to indicate that secretory material present in the trans-saccules flows toward the dilated portions which become prosecretory granules. The trans-most elements seemingly peel off the stack to yield prosecretory granules and fragmenting trans-tubular networks.

Animals↗
PubMed1989

Granule formation and polarity of the Golgi apparatus in neutrophil granulocytes of the rat.

The formation of granules in neutrophil (heterophil) progenitor cells was examined with the electron microscope in sections of rat bone marrow fixed in 2% glutaraldehyde and postfixed with reduced osmium (Karnovsky: Proceedings of the 11th Meeting, American Society of Cell Biologists, Abstr. 284, p. 146, 1971). The cells were also osmicated in 2% osmium tetroxide for 36 hours at 37 degrees C to outline the osmiophilic element usually observed on the cis-face of the stacks of saccules of the Golgi apparatus of various cell types. In myeloblasts, which do not produce granules, the cis-osmiophilic element (CE) was found on the concave face of the C-shaped Golgi stacks. In promyelocytes the CE was present on the convex aspect of the C-shaped stacks, while the primary (azurophilic) granules formed in relation to elements on the concave aspects of the stacks. In myelocytes, the situation was reversed: the CE was found on the concave face of the Golgi stacks, while the secondary (specific) granules were seen forming in relation to elements on the convex aspect of the stacks. Finally, in metamyelocytes and mature neutrophils in which no granule formation took place, the appearance on Golgi stacks varied: they were either flat or C-shaped. The CE was indiscriminately found on one face or the other of the flat Golgi stacks of metamyetocytes and on the convex or concave faces of the C-shaped Golgi stacks of mature neutrophils. Using the cis-osmiophilic-element as a marker of the cis-face of the stacked Golgi elements, it thus appeared that despite marked changes in the configuration and orientation of the stacks of the cis-trans polarity of the stacked elements was maintained throughout granulopoiesis. In addition the primary and secondary granules that appeared sequentially in promyelocytes and myelocytes were both seen to form in relation to trans-elements of the Golgi apparatus.

Animals↗
PubMed1989

Light microscopic immunocytochemical study of fibrous sheath and outer dense fiber formation in the rat spermatid.

The formation of the fibrous sheath (FS) and outer dense fibers (ODF), two major cytoskeletal components of the tail of spermatozoa, was analyzed in the seminiferous epithelium by immunoperoxidase techniques applied to paraffin-embedded testicular sections. Antibodies were prepared from purified FS and ODF fractions and from major 75 and 14.4 kDa FS polypeptides and major 32-26 14.4 kDa ODF polypeptides. The immunostaining results showed that the production of FS and ODF proteins appeared to be exclusive to step 9-19 spermatids and lasted over the duration of a full cycle of the seminiferous epithelium, or 12.8 days. During this period there was seemingly an initial lag of short duration between the synthesis and assembly of FS and ODF proteins followed by a long process of coordinated activity. Peak cytoplasmic immunoreactivity was reached in step 15 for FS proteins and midstep 16 for ODF proteins and remained elevated thereafter for approximately 80 hr for both FS and ODF proteins. The immunoreactivity was more uniform and diffused for FS proteins and granulated or clumpy for ODF proteins. Assembly of FS proteins along the axoneme proceeded in a distal to proximal direction while for ODF proteins assembly proceeded in a proximal to distal direction. The main route of elimination of residual cytoplasmic FS and ODF proteins appeared to take place through the cytoplasmic droplets and residual bodies, respectively. There appeared to be no variation in step reactivity between the major ODF polypeptides tested and only minor variation in step reactivity between the major FS polypeptides tested. However, although the 14.4 kDa polypeptides of FS and ODF share antigenic determinants, they do not appear to be identical, because they presented different immunolocalizations during spermiogenesis and different directions of assembly along the axoneme.

Animals↗
PubMed1989

Tridimensional analysis of the formation of secretory vesicles in the Golgi apparatus of absorptive columnar cells of the mouse colon.

The tridimensional structure of the Golgi apparatus has been studied in the absorptive cells of the mouse colon by means of reduced osmium postfixation and phosphatase cytochemistry. In thick sections of tissue impregnated with osmium tetroxide or treated with a technique to demonstrate TPPase activity, the Golgi formed a continuous ribbon-like structure capping the upper pole of the nucleus. Along the longitudinal axis of this ribbon, compact zones made up of superposed flattened saccules alternated with less compact zones which consisted of highly perforated saccules or bridging anastomosed tubules. In the cis-trans axis, the following elements were observed: (1) a cis element consisting of a continuous osmiophilic tubular network; (2) two or three subjacent elements selectively perforated by wells; (3) a trans compartment made up of two or three TPPase-reactive sacculotubular elements, some showing a "peeling-off" configuration. In some regions, the first flattened saccule of this trans compartment displayed discrete ovoid dilatations, located in compact zones and containing a dense granulofibrillar material; in the subjacent elements this material was seen concentrated in nodular swellings, at the intersection of the meshes of anastomosed membranous tubules. 100-300 nm vesicles containing a similar dense granulofilamentous material were observed in the trans Golgi zone and interspersed in the supranuclear cytoplasm between the Golgi zone and the apical surface of the cell. Smaller vesicles 80-100 nm in diameter containing a fine dusty material were also seen in proximity. These morphological observations suggested that at least two kinds of material were segregated in the saccules of the trans compartment and packaged in vesicles of two class sizes that detached from the Golgi stack on its trans aspect.

Animals↗
PubMed1988

Formation of secretion granules in the Golgi apparatus of pancreatic acinar cells of the rat.

The three-dimensional structure of the Golgi apparatus and its components has been analyzed in sections of pancreatic acinar cells by using stereopairs of electron microscope photographs. Pancreatic tissue fixed in glutaraldehyde was postfixed in reduced osmium, and the sections were stained with lead citrate. Tissues were also treated to demonstrate phosphatase activity (i.e., nicotinamide adenine dinucleotide phosphatase, NADPase; thiamine pyrophosphatase, TPPase; cytidine monophosphatase, CMPase). The following stacked components were observed along the branching, anastomotic, continuous, ribbonlike Golgi apparatus. 1) On the cis-face of the Golgi stack there was a tubular membranous network known to be osmiophilic and referred to as the cis-osmiophilic tubular network or cis-element. 2) A first, poorly fenestrated saccule, unreactive for the phosphatases tested, was slightly distended in places and contained a fluffy granulofilamentous material. 3) The subjacent three or four saccules, reactive for NADPase and/or TPPase, showed dilated portions containing a granulofilamentous secretory material similar to that filling the rest of the saccule. They also showed nondilated portions perforated with large fenestrations, some of which were in register and formed wells containing 80-nm vesicles. The dilated portions of these saccules were present at random along the length of the saccules and were not located exclusively at their edges. 4) The remaining one or two elements of the stack, CMPase positive, showed dilated spheroidal portions or prosecretory granules containing a homogeneous secretory material and flattened fenestrated regions free of secretory material and having the appearance of networks of narrow membranous tubules. 5) Lastly on the trans-aspect of the stack there were detached prosecretory granules reactive for CMPase and surrounded by a corona of small vesicles, and smooth-surfaced spherical CMPase-negative granules having a denser content that were identified as fully formed secretion granules; there were also occasional free trans-tubular networks strongly reactive for CMPase that appeared to undergo fragmentation and numerous small vesicles free from acid-phosphatase activity. These various images were interpreted as indicating that prosecretory granules formed in relation to two or three fenestrated saccules on the trans-side of the stack. Such granules, following their detachment from the trans-face of the stack, their separation from trans-tubular networks, and condensation of their content, yielded mature secretion granules.

Animals↗