scholarly journals Morphometric analysis of Leydig cells in the normal rat testis.

1980 ◽  
Vol 84 (2) ◽  
pp. 340-354 ◽  
Author(s):  
H Mori ◽  
A K Christensen
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Morphometric Analysis ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Steroidogenic Enzymes ◽  
Inner Membrane ◽  
Rat Testis ◽  
Mitochondrial Inner Membrane ◽  
Testis Tissue

Leydig cells are thought to be the source of most, if not all, the testosterone produced by the testis. The goal of this study was to obtain quantitative information about rat Leydig cells and their organelles that might be correlated with pertinent physiological and biochemical data available either now or in the future. Morphometric analysis of Leydig cells in mature normal rats was carried out on tissue fixed by perfusion with buffered glutaraldehyde, and embedded in glycol methacrylate for light microscopy and in Epon for electron microscopy. In a whole testis, 82.4% of the volume was occupied by seminiferous tubules, 15.7% by the interstitial tissue, and 1.9% by the capsule. Leydig cells constituted 2.7% of testicular volume. Each cubic centimeter (contained approximatelyy 1 g) of rat testis contained about 22 million Leydig cells. An average Leydig cell had a volume of 1,210 micron3 and its plasma membrane had a surface area of 1,520 micron2. The smooth endoplasmic reticulum (SER), the most prominent organelle in Leydig cells and a major site of steroidogenic enzymes, had a surface area of approximately 10,500 micron2/cell, which is 6.9 times that of the plasma membrane and is 60% of the total membrane area of the cell. The total surface area of Leydig SER per cubic centimeter of testis tissue is approximately 2,300 cm2 or 0.23 m2. There were 3.0 mg of Leydig mitochondria in 1 g of testis tissue. The average Leydig cell contained approximately 622 mitochondria, measuring on the average 0.35 micron in diameter and 2.40 micron in length. The mitochondrial inner membrane (including cristae), another important site of steroidogenic enzymes, had a surface area of 2,920 micron2/cell, which is 1.9 times that of the plasma membrane. There were 644 cm2 of inner mitochondrial membrane/cm3 of testis tissue. These morphometric results can be correlated with published data on the rate of testosterone secretion to show that an average Leydig cell secretes approximately 0.44 pg of testosterone/d or 10,600 molecules of testosterone/s. The rate of testosterone production by each square centimeter of SER is 4.2 ng/d or 101 million molecules/s: the corresponding rate for each square centimeter of mitochondrial inner membrane is 15 ng testosterone/d or 362 million molecules/s.

Age-related changes in human Leydig cell status

2020 ◽  
Vol 35 (12) ◽  
pp. 2663-2676
Author(s):  
Valentina Mularoni ◽  
Valentina Esposito ◽  
Sara Di Persio ◽  
Elena Vicini ◽  
Gustavo Spadetta ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Sertoli Cell ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Cell Number ◽  
Organ Donors ◽  
Steroidogenic Enzymes ◽  
Age Related ◽  
Age Range

Abstract STUDY QUESTION What are the consequences of ageing on human Leydig cell number and hormonal function? SUMMARY ANSWER Leydig cell number significantly decreases in parallel with INSL3 expression and Sertoli cell number in aged men, yet the in vitro Leydig cell androgenic potential does not appear to be compromised by advancing age. WHAT IS KNOWN ALREADY There is extensive evidence that ageing is accompanied by decline in serum testosterone levels, a general involution of testis morphology and reduced spermatogenic function. A few studies have previously addressed single features of the human aged testis phenotype one at a time, but mostly in tissue from patients with prostate cancer. STUDY DESIGN, SIZE, DURATION This comprehensive study examined testis morphology, Leydig cell and Sertoli cell number, steroidogenic enzyme expression, INSL3 expression and androgen secretion by testicular fragments in vitro. The majority of these endpoints were concomitantly evaluated in the same individuals that all displayed complete spermatogenesis. PARTICIPANTS/MATERIALS, SETTING, METHODS Testis biopsies were obtained from 15 heart beating organ donors (age range: 19–85 years) and 24 patients (age range: 19–45 years) with complete spermatogenesis. Leydig cells and Sertoli cells were counted following identification by immunohistochemical staining of specific cell markers. Gene expression analysis of INSL3 and steroidogenic enzymes was carried out by qRT-PCR. Secretion of 17-OH-progesterone, dehydroepiandrosterone, androstenedione and testosterone by in vitro cultured testis fragments was measured by LC-MS/MS. All endpoints were analysed in relation to age. MAIN RESULTS AND THE ROLE OF CHANCE Increasing age was negatively associated with Leydig cell number (R = −0.49; P < 0.01) and concomitantly with the Sertoli cell population size (R= −0.55; P < 0.001). A positive correlation (R = 0.57; P < 0.001) between Sertoli cell and Leydig cell numbers was detected at all ages, indicating that somatic cell attrition is a relevant cellular manifestation of human testis status during ageing. INSL3 mRNA expression (R= −0.52; P < 0.05) changed in parallel with Leydig cell number and age. Importantly, steroidogenic capacity of Leydig cells in cultured testis tissue fragments from young and old donors did not differ. Consistently, age did not influence the mRNA expression of steroidogenic enzymes. The described changes in Leydig cell phenotype with ageing are strengthened by the fact that the different age-related effects were mostly evaluated in tissue from the same men. LIMITATIONS, REASONS FOR CAUTION In vitro androgen production analysis could not be correlated with in vivo hormone values of the organ donors. In addition, the number of samples was relatively small and there was scarce information about the concomitant presence of potential confounding variables. WIDER IMPLICATIONS OF THE FINDINGS This study provides a novel insight into the effects of ageing on human Leydig cell status. The correlation between Leydig cell number and Sertoli cell number at any age implies a connection between these two cell types, which may be of particular relevance in understanding male reproductive disorders in the elderly. However aged Leydig cells do not lose their in vitro ability to produce androgens. Our data have implications in the understanding of the physiological role and regulation of intratesticular sex steroid levels during the complex process of ageing in humans. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by grants from Prin 2010 and 2017. The authors have no conflicts of interest. TRIAL REGISTRATION NUMBER N/A.

scholarly journals Specific protein synthesis in isolated rat testis leydig cells. Influence of luteinizing hormone and cycloheximide

1977 ◽  
Vol 162 (2) ◽  
pp. 341-346 ◽  
Author(s):  
F H A Janszen ◽  
B A Cooke ◽  
H J van der Molen
Keyword(s):  
Protein Synthesis ◽  
Luteinizing Hormone ◽  
Leydig Cell ◽  
Half Life ◽  
Leydig Cells ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Protein Band ◽  
Specific Protein ◽  
Rat Testis

The effect of luteinizing hormone (luteotropin) and cycloheximide on specific protein synthesis in rat testis Leydig cells has been investigated. Proteins were labelled with either I114C]leucine, [3H]leucine or [35S]methionine during incubation with Leydig-cell suspensions in vitro. Total protein was extracted from the cells and separated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. No detectable increase in the synthesis of specific proteins could be observed after incubation of Leydig cells with luteinizing hormone for up to 1 h. However, after a 2h incubation period, an increase in [35S]methionine incorporation was observed in a protein with an apparent mol.wt. of 21000 (referred to as ‘protein 21’). When, after labelling of this protein with [35S]-methionine, Leydig cells were incubated for another 30min with cycloheximide, no decrease in radioactivity of this protein band was observed, indicating that it does not have a short half-life. However, another protein band was detected, which after incubation with cycloheximide disappeared rapidly, the reaction following first-order kinetics, with a half-life of about 11 min. This protein, with an apparent mol.wt. of 33000 (referred to as “protein 33”), was found to be located in the particulate fraction of the Leydig cell, and could not be demonstrated in other rat testis-cell types or blood cells. No effect of luteinizing hormone on molecular weight, subcellular localization or half-life of protein 33 was observed. A possible role for protein 33 and protein 21 in the mechanism of action of luteinizing hormone on testosterone production of Leydig cells is discussed.

scholarly journals Comparison of cell types in the rat Leydig cell lineage after ethane dimethanesulfonate treatment

Reproduction ◽  
2013 ◽  
Vol 145 (4) ◽  
pp. 371-380 ◽  
Author(s):  
Jingjing Guo ◽  
Hongyu Zhou ◽  
Zhijian Su ◽  
Bingbing Chen ◽  
Guimin Wang ◽  
...  
Keyword(s):  
Leydig Cell ◽  
Leydig Cells ◽  
Pubertal Development ◽  
Cell Lineage ◽  
Hydroxysteroid Dehydrogenase ◽  
Mrna Levels ◽  
Steroidogenic Enzymes ◽  
Isolated Cells ◽  
Adult Leydig Cells

The objective of this study was to purify cells in the Leydig cell lineage following regeneration after ethane dimethanesulfonate (EDS) treatment and compare their steroidogenic capacity. Regenerated progenitor (RPLCs), immature (RILCs), and adult Leydig cells (RALCs) were isolated from testes 21, 28 and 56 days after EDS treatment respectively. Production rates for androgens including androsterone and 5α-androstane-17β, 3α-diol (DIOL), testosterone and androstenedione were measured in RPLCs, RILCs and RALCs in media after 3-h in vitro culture with 100 ng/ml LH. Steady-state mRNA levels of steroidogenic enzymes and their activities were measured in freshly isolated cells. Compared to adult Leydig cells (ALCs) isolated from normal 90-day-old rat testes, which primarily produce testosterone (69.73%), RPLCs and RILCs primarily produced androsterone (70.21%) and DIOL (69.79%) respectively. Leydig cells isolated from testes 56 days post-EDS showed equivalent capacity of steroidogenesis to ALCs and primarily produced testosterone (72.90%). RPLCs had cholesterol side-chain cleavage enzyme, 3β-hydroxysteroid dehydrogenase 1 and 17α-hydroxylase but had almost no detectable 17β-hydroxysteroid dehydrogenase 3 and 11β-hydroxysteroid dehydrogenase 1 activities, while RILCs had increased 17β-hydroxysteroid dehydrogenase 3 and 11β-hydroxysteroid dehydrogenase 1 activities. Because RPLCs and RILCs had higher 5α-reductase 1 and 3α-hydroxysteroid dehydrogenase activities they produced mainly 5α-reduced androgens. Real-time PCR confirmed the similar trends for the expressions of these steroidogenic enzymes. In conclusion, the purified RPLCs, RILCs and RALCs are similar to those of their counterparts during rat pubertal development.

scholarly journals 11beta-hydroxysteroid dehydrogenase is a predominant reductase in intact rat Leydig cells

1998 ◽  
Vol 159 (2) ◽  
pp. 233-238 ◽  
Author(s):  
CM Leckie ◽  
LA Welberg ◽  
Keyword(s):  
Leydig Cell ◽  
Leydig Cells ◽  
Reductase Activity ◽  
Primary Cultures ◽  
Intact Cells ◽  
Rat Testis ◽  
Testosterone Production ◽  
Tissue Homogenates

11beta-Hydroxysteroid dehydrogenases (11beta-HSDs) interconvert active corticosterone and inert 11-dehydrocorticosterone. In tissue homogenates, 11beta-HSD type 1 (11beta-HSD-1) exhibits both 11beta-dehydrogenase (corticosterone inactivating) and 11beta-reductase (corticosterone regenerating) activities, whereas 11beta-HSD type 2 (11beta-HSD-2) is an exclusive dehydrogenase. In the rat testis, 11beta-HSD has been proposed to reduce glucocorticoid inhibition of testosterone production, promoting puberty and fertility. This hypothesis presupposes dehydrogenation predominates. 11beta-HSD-1 immunoreactivity has been localised to Leydig cells. However, recent studies suggest that 11beta-HSD-1 is predominantly an 11beta-reductase in many intact cells. We therefore examined the expression and reaction direction of 11beta-HSD isozymes in cultures of intact rat Leydig cells. Reverse transcriptase PCR demonstrated expression of 11beta-HSD-1, but not 11beta-HSD-2 mRNA in rat testis. Primary cultures of intact rat Leydig cells showed predominant 11beta-reductase activity, activating 50-70% of 11-dehydrocorticosterone to corticosterone over 3 h, whereas 11beta-dehydrogenation was <5%. Although both dexamethasone (10 nM) and corticosterone (1 microM) modestly inhibited LH-stimulated testosterone production by Leydig cells, inert 11-dehydrocorticosterone (1 microM) had similar effects, suggesting 11beta-reductase is functionally important. Carbenoxolone (10(-5) M) inhibited 11beta-reduction in intact Leydig cells. However, although carbenoxolone reduced Leydig cell testosterone production, this also occurred in the absence of glucocorticoids, suggesting effects distinct from modulation of corticosteroid access to Leydig cells. In conclusion, rat Leydig cell 11beta-HSD-1 is unlikely to reduce glucocorticoid access to testicular receptors. More likely, 11beta-reductase amplifies glucocorticoid action, perhaps to maintain Leydig cell metabolic and endocrine functions.

scholarly journals Protein-dependent membrane remodeling in mitochondrial morphology and clathrin-mediated endocytosis

2021 ◽  
Author(s):  
Daryna Tarasenko ◽  
Michael Meinecke
Keyword(s):  
Plasma Membrane ◽  
Molecular Mechanisms ◽  
Membrane Receptors ◽  
Coated Vesicle ◽  
Mitochondrial Outer Membrane ◽  
Mitochondrial Morphology ◽  
Membrane Remodeling ◽  
Inner Membrane ◽  
Membrane Morphology ◽  
Mitochondrial Inner Membrane

AbstractCellular membranes can adopt a plethora of complex and beautiful shapes, most of which are believed to have evolved for a particular physiological reason. The closely entangled relationship between membrane morphology and cellular physiology is strikingly seen in membrane trafficking pathways. During clathrin-mediated endocytosis, for example, over the course of a minute, a patch of the more or less flat plasma membrane is remodeled into a highly curved clathrin-coated vesicle. Such vesicles are internalized by the cell to degrade or recycle plasma membrane receptors or to take up extracellular ligands. Other, steadier, membrane morphologies can be observed in organellar membranes like the endoplasmic reticulum or mitochondria. In the case of mitochondria, which are double membrane-bound, ubiquitous organelles of eukaryotic cells, especially the mitochondrial inner membrane displays an intricated ultrastructure. It is highly folded and consequently has a much larger surface than the mitochondrial outer membrane. It can adopt different shapes in response to cellular demands and changes of the inner membrane morphology often accompany severe diseases, including neurodegenerative- and metabolic diseases and cancer. In recent years, progress was made in the identification of molecules that are important for the aforementioned membrane remodeling events. In this review, we will sum up recent results and discuss the main players of membrane remodeling processes that lead to the mitochondrial inner membrane ultrastructure and in clathrin-mediated endocytosis. We will compare differences and similarities between the molecular mechanisms that peripheral and integral membrane proteins use to deform membranes.

scholarly journals Relationship between the density distribution of intramembrane particles and electron transfer in the mitochondrial inner membrane as revealed by cholesterol incorporation.

1982 ◽  
Vol 94 (2) ◽  
pp. 387-393 ◽  
Author(s):  
H Schneider ◽  
M Höchli ◽  
C R Hackenbrock
Keyword(s):  
Electron Transfer ◽  
Surface Area ◽  
Lipid Bilayer ◽  
Average Distance ◽  
Membrane Lipid ◽  
Membrane Bilayer ◽  
Inner Membrane ◽  
Intramembrane Particles ◽  
Mitochondrial Inner Membrane ◽  
Membrane Lipid Bilayer

A low pH method of liposome-membrane fusion (Schneider et al., 1980, Proc. Natl. Acad. Sci. U. S. A. 77:442) was used to enrich the mitochondrial inner membrane lipid bilayer 30-700% with exogenous phospholipid and cholesterol. By varying the phospholipid-to-cholesterol ratio of the liposomes it was possible to incorporate specific amounts of cholesterol (up to 44 mol %) into the inner membrane bilayer in a controlled fashion. The membrane surface area increased proportionally to the increase in total membrane bilayer lipid. Inner membrane enriched with phospholipid only, or with phospholipid plus cholesterol up to 20 mol %, showed randomly distributed intramembrane particles (integral proteins) in the membrane plane, and the average distance between intramembrane particles increased proportionally to the amount of newly incorporated lipid. Membranes containing between 20 and 27 mol % cholesterol exhibited small clusters of intramembrane particles while cholesterol contents above 27 mol % resulted in larger aggregations of intramembrane particles. In phospholipid-enriched membranes with randomly dispersed intramembrane particles, electron transfer activities from NADH- and succinate-dehydrogenase to cytochrome c decreased proportionally to the increase in distance between the particles. In contrast, these electron-transfer activities increased with decreasing distances between intramembrane particles brought about by cholesterol incorporation. These results indicate that (a) catalytically interacting redox components in the mitochondrial inner membrane such as the dehydrogenase complexes, ubiquinone, and heme proteins are independent, laterally diffusible components; (b) the average distance between these redox components is effected by the available surface area of the membrane lipid bilayer; and (c) the distance over which redox components diffuse before collision and electron transfer mediates the rate of such transfer.

scholarly journals Monocyte Chemoattractant Protein-1 stimulates the differentiation of rat stem and progenitor Leydig cells during regeneration

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Xiangcheng Zhan ◽  
Jingwei Zhang ◽  
Saiyang Li ◽  
Xiaolu Zhang ◽  
Linchao Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Serum Testosterone ◽  
Monocyte Chemoattractant Protein 1 ◽  
Rat Testis ◽  
Monocyte Chemoattractant ◽  
Monocyte Chemoattractant Protein

Abstract Background Monocyte chemoattractant protein-1(MCP-1) is a chemokine secreted by Leydig cells and peritubular myoid cells in the rat testis. Its role in regulating the development of Leydig cells via autocrine and paracrine is still unclear. The objective of the current study was to investigate the effects of MCP-1 on Leydig cell regeneration from stem cells in vivo and on Leydig cell development in vitro. Results Intratesticular injection of MCP-1(10 ng/testis) into Leydig cell-depleted rat testis from post-EDS day 14 to 28 significantly increased serum testosterone and luteinizing hormone levels, up-regulated the expression of Leydig cell proteins, LHCGR, SCARB1, CYP11A1, HSD3B1, CYP17A1, and HSD17B3 without affecting progenitor Leydig cell proliferation, as well as increased ERK1/2 phosphorylation. MCP-1 (100 ng/ml) significantly increased medium testosterone levels and up-regulated LHCGR, CYP11A1, and HSD3B1 expression without affecting EdU incorporation into stem cells after in vitro culture for 7 days. RS102895, a CCR2 inhibitor, reversed MCP-1-mediated increase of testosterone level after culture in combination with MCP-1. Conclusion MCP-1 stimulates the differentiation of stem and progenitor Leydig cells without affecting their proliferation.

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