Mouse Leydig Cells Processed by Freeze-Substitution, with Particular Reference to the Lamellar Arrangement of the Smooth Endoplasmic Reticulum

1987 ◽  
Keyword(s):  
Endoplasmic Reticulum ◽  
Leydig Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Freeze Substitution

Smooth endoplasmic reticulum in perfusion and immersion-fixed Leydig cells

1990 ◽  
Vol 48 (3) ◽  
pp. 82-83
Author(s):  
R.T.F. Bernard ◽  
R.H.M. Cross
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Steroid Hormones ◽  
Transmission Electron Microscope ◽  
Leydig Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Random Mixture ◽  
Transmission Electron

Smooth endoplasmic reticulum (SER) is involved in the biosynthesis of steroid hormones, and changes in the organisation and abundance of this organelle are regularly used as indicators of changes in the level of steroidogenesis. SER is typically arranged as a meshwork of anastomosing tubules which, with the transmission electron microscope, appear as a random mixture of cross, oblique and longitudinal sections. Less commonly the SER appears as swollen vesicles and it is generally suggested that this is an artefact caused during immersion fixation or during immersion of poorly-perfused tissue.During a previous study of the Leydig cells of a seasonally reproducing bat, in which tissue was fixed by immersion, we noted that tubular SER and vesicular SER often occured in adjacent cells and sometimes in the same cell, and that the abundance of the two types of SER changed seasonally. We came to doubt the widelyheld dogma that vesicular SER was an artefact of immersion fixation and set out to test the hypothesis that the method of fixation does not modify the ultrastructure of the SER.

scholarly journals Polarized compartmentalization of organelles in growth cones from developing optic tectum.

1985 ◽  
Vol 101 (4) ◽  
pp. 1473-1480 ◽  
Author(s):  
T P Cheng ◽  
T S Reese
Keyword(s):  
Endoplasmic Reticulum ◽  
Growth Cone ◽  
Smooth Endoplasmic Reticulum ◽  
Freeze Substitution ◽  
Growth Cones ◽  
Distal Segment ◽  
Computer Assisted ◽  
Chemical Fixation ◽  
Coated Pits ◽  
Membrane Bound

We have used computer-assisted reconstructions of continuous serial sections to study the cytoplasmic organization of growth cones in vivo. Optic tecta from 6.25-6.5-d-old chicken embryos were quick-frozen and then freeze-substituted in acetone-osmium tetroxide or, for comparison, prepared by conventional fixation. Images of eight freeze-substituted and two conventionally fixed growth cones were reconstructed from aligned serial micrographs. After freeze-substitution, numerous lumenless membrane-bound sacs arrayed in multilamellar stacks appear to replace the abundant smooth endoplasmic reticulum found after chemical fixation. Microtubule fascicles progressively diverge from their typical fascicular organization in the initial segment of the growth cone and are absent in the varicosity and the more distal segment. Mitochondria, in contrast, are concentrated in the proximal segment of the varicosity; multilamellar stacks and endosome-like vacuoles are in the distal segment; and coated pits and vesicles are concentrated near the terminal filopodium, which is the most distal and organelle-poor domain of the growth cone. These observations suggest that dilation and fusion of the lumenless, membrane-bound sacs that occurs during chemical fixation give rise to the network of smooth endoplasmic reticulum. The three-dimensional reconstructions show that the cytoplasmic components of growth cones, including the membrane-bound sacs and multilamellar stacks revealed by freeze substitution, are polarized along the axis of these growth cones, which suggests that they have a role in recycling of membrane during elongation of the growth cone.

Localization of various phosphatase activities within the golgi apparatus and lysosomes of rat leydig cells

1986 ◽  
Vol 44 ◽  
pp. 294-295
Author(s):  
M. F. Lalli ◽  
V. Lacroix ◽  
L. Hermo ◽  
Y. Clermont ◽  
C. E. Smith
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Leydig Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Fluid Phase ◽  
Multivesicular Bodies ◽  
Golgi Stack ◽  
Dense Membrane ◽  
Membrane Bound ◽  
Adsorptive Endocytosis

The testosterone-secreting Leydig cells contain an abundance of smooth endoplasmic reticulum, peroxisomes, mitochondria as well as a large, spheroidal, juxtanuclear Golgi apparatus composed of interconnected stacks of saccules (Figs. 1,2). Each Golgi stack appears to be composed of between 5 to 7 saccules or sacculo-tubular elements (Figs.1,2). These cells also possess pale and dense multivesicular bodies and dense membrane-bound bodies identified assecondary lysosomes, all of which have been shown to be involved in fluid phase and adsorptive endocytosis as well as in receptor mediated endocytosis. The purpose of the present study was to characterize the reactivity of Golgi saccules, multivesicular bodies and lysosomes of Leydig cells for different phosphatases.

Endocytosis and the lysosomal apparatus of rat Leydig cells

1984 ◽  
Vol 42 ◽  
pp. 708-709
Author(s):  
M.F. Lalli ◽  
L. Hermo ◽  
Y. Clermont
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Cell Surface ◽  
Leydig Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Extracellular Fluid ◽  
Multivesicular Bodies ◽  
Rat Testis ◽  
Endocytic Activity

The Leydig cells of the rat testis which are involved in testosterone production contain an abundance of smooth endoplasmic reticulum and mitochondria (Figs. 2,6). These cells also possess many peroxisomes, lysosomes and multivesicular bodies (MVB's). On the cell surface, the plasma membrane contains numerous short microvilli, small invaginations and large plasmalemmal folds which appear to engulf extracellular fluid. There are also many large dilated vacuoles adjacent to the cell surface. The purpose of the present study is to determine if these cells show endocytic activity and to differentiate by various cytochemical means lysosomal elements from peroxisomes.To identify lysosomes, tissue chopper sections of 2% glutaraldehyde-fixed testes (containing 2.5% dextran) were incubated in media containing thiamine monophosphate as a substrate (Lalli, 1983) to demonstrate the presence of acid phosphatase or in media containing P-nitrocatechol sulfate for the demonstration of arylsulfatase (Hopsu-Havu et al., 1967).

scholarly journals Macroautophagy Involved in Testosterone Synthesis in Leydig Cells of Male Dairy Goats (Capra Hircus)

2021 ◽  
Author(s):  
Hong Chen ◽  
Kexin Chen ◽  
Fange Zhao ◽  
Yihan Guo ◽  
Yue Liang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Leydig Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Capra Hircus ◽  
Dairy Goats ◽  
Serum Luteinizing Hormone ◽  
Ultrastructural Characteristics ◽  
Autophagy Activity ◽  
Testosterone Synthesis

Abstract Background Testosterone is an important steroid hormone that is indispensable for male sexual development and the reproductive system. Leydig cells (LCs), where autophagy extremely active, reside in the testicular interstitium and are the major sites of testosterone production. However, the ultrastructural characteristics and the functional role of autophagy in LCs of livestock remain unknown. This study was to investigate the role of autophagy in LCs testosterone synthesis of dairy goats at juvenile, pubertal, and adult stages. Results In the present study, morphological results showed that the steroidogenic activity and ultrastructure of the LCs were altered with increasing age. Serum luteinizing hormone and testosterone levels were significantly elevated with sexual maturation. Organelles involved in testosterone synthesis, e.g., smooth endoplasmic reticulum, mitochondria, and lipid droplets, were abundantly distributed within the cytoplasm of LCs in adult testes. However, further studies demonstrated that selective autophagy (including lipophagy and mitophagy) did not participate in the synthesis of testosterone in LCs. In contrast, the autophagy activity was enhanced in the testes at puberty and adulthood compared to that at the juvenile stage. Moreover, a number of different autophagosomes, including phagophores and autolysosomes, were observed within the cytoplasm of LCs. Conclusions Together, our results reveal that macroautophagy is involved in testosterone synthesis mainly through degrading mitochondria and endoplasmic reticulum in the LCs of dairy goats.

In Vitro Induction of Crystals of MT Protein by Vinblastine-Colcemid in Mouse Spermatids

1974 ◽  
Vol 32 ◽  
pp. 132-133
Author(s):  
John J. Wolosewick ◽  
John H. D. Bryan
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Nuclear Ring ◽  
Rough Er ◽  
Distal Direction ◽  
In Vitro Induction

Early in spermiogenesis the manchette is rapidly assembled in a distal direction from the nuclear-ring-densities. The association of vesicles of smooth endoplasmic reticulum (SER) and the manchette microtubules (MTS) has been reported. In the mouse, osmophilic densities at the distal ends of the manchette are the organizing centers (MTOCS), and are associated with the SER. Rapid MT assembly and the lack of rough ER suggests that there is an existing pool of MT protein. Colcemid potentiates the reaction of vinblastine with tubulin and was used in this investigation to detect this protein.

Hepatic Ultrastructure Changes Induced by Lithocholic Acid

1967 ◽  
Vol 25 ◽  
pp. 162-163 ◽  
Author(s):  
F. G. Zaki
Keyword(s):  
Endoplasmic Reticulum ◽  
Lithocholic Acid ◽  
Smooth Endoplasmic Reticulum ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Electron Microscopic ◽  
Hydropic Degeneration ◽  
Hepatic Cells ◽  
Low Protein ◽  
Microscopic Studies

Addition of lithocholic acid (LCA), a naturally occurring bile acid in mammals, to a low protein diet fed to rats induced marked inflammatory reaction in the hepatic cells followed by hydropic degeneration and ductular cell proliferation. These changes were accompanied by dilatation and hyperplasia of the common bile duct and formation of “gallstones”. All these changes were reversible when LCA was withdrawn from the low protein diet except for the hardened gallstones which persisted.Electron microscopic studies revealed marked alterations in the hepatic cells. Early changes included disorganization, fragmentation of the rough endoplasmic reticulum and detachment of its ribosomes. Free ribosomes, either singly or arranged in small clusters were frequently seen in most of the hepatic cells. Vesiculation of the smooth endoplasmic reticulum was often encountered as early as one week after the administration of LCA (Fig. 1).

Ultrastructural Changes of Smoooth Endoplasmic Reticulum in the Retinal Pigment Epithelium by Choline Chloride

1972 ◽  
Vol 30 ◽  
pp. 58-59
Author(s):  
Kazushige Hirosawa ◽  
Eichi Yamada
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cell ◽  
Smooth Endoplasmic Reticulum ◽  
Pigment Epithelium ◽  
Choline Chloride ◽  
Retinal Pigment ◽  
Ultrastructural Changes ◽  
Lower Vertebrate ◽  
Visual Cells ◽  
Pigment Epithelial

The pigment epithelium is located between the choriocapillary and the visual cells. The pigment epithelial cell is characterized by a large amount of the smooth endoplasmic reticulum (SER) in its cytoplasm. In addition, the pigment epithelial cell of some lower vertebrate has myeloid body as a specialized form of the SER. Generally, SER is supposed to work in the lipid metabolism. However, the functions of abundant SER and myeloid body in the pigment epithelial cell are still in question. This paper reports an attempt, to depict the functions of these organelles in the frog retina by administering one of phospholipid precursors.

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