Histochemical Demonstration of Δ5,3β-hydroxysteroid Dehydrogenase Activity in Cultured Leydig Cells under the Influence of Gonadotropic Hormones and Testosterone

Effects of phytoestrogens on testosterone secretion by Leydig cells from Biłgoraj ganders (Anser anser)

The aim of this study was to examine ganders at different stages of the reproductive season and the effect of: (1) diets with high phytoestrogen content and (2) in vitro phytoestrogen treatment on testosterone secretion by isolated Leydig cells. Thirty-six male Biłgoraj geese were fed control diets with low phytoestrogen content (containing grass meal) and diets with high phytoestrogens (containing alfalfa meal and soy). Testes were obtained from both groups of ganders at three different times of the breeding season: peak of reproductive activity (March), second half of reproductive activity (May) and beginning of photorefractoriness (July). Isolated Leydig cells were incubated with LH as well as genistein, daidzein, equol and coumestrol and the concentration of testosterone in the medium was determined by radioimmunoassay. The mean weight of testes from ganders in May and July decreased relative to their weights in March, but no significant differences among experimental groups were noted. No differences were observed in basal and LH-stimulated testosterone secretion by Leydig cells of ganders fed the control diets and the diets with higher phytoestrogen content. In July, LH did not stimulate testosterone secretion in either group. In vitro treatment with genistein, daidzein and equol (5 and 50 microM) inhibited basal and LH-stimulated testosterone production by Leydig cells from both groups. Coumestrol (5 and 50 microM) inhibited basal testosterone secretion only in March in the control group. Dietary exposure to phytoestrogens had a slight effect on in vitro testicular secretion in ganders. In vitro treatment with phytoestrogen inhibited testosterone production by Leydig cells. Genistein showed the strongest effect and coumestrol had the weakest influence on testicular secretion.

Mouse Leydig cell culture on microcarriers

Culturing cells on microcarriers maximizes the ratio of surface area to culture medium volume. The aim of this study was to show microcarrier culture as a useful tool for improvement of steroidogenic activity in mouse Leydig cells. Freshly isolated cells were grown on Sephadex microcarriers, Cytodex 3, and gelatin beads (gelaspheres) that were uncoated, coated with collagen or coated with fibronectin. The cells were cultured in control or LH-supplemented medium. The effect of LH on testosterone and estradiol secretion was studied with appropriate radioimmunoassays. The activity of hydroxysteroid dehydrogenases (3 beta-HSD, 17 beta-HSD) was evaluated histochemically. Leydig cells growing on microcarriers formed colonies. The strongest response to luteinizing hormone stimulation was observed on gelatin beads coated with fibronectin and collagen. In cells growing on a fibronectin layer, very strong activity of 3 beta-HSD and 17 beta-HSD and an increase in steroid hormone levels were observed. Basal and LH-stimulated testosterone and estradiol secretion were all much higher in the microcarrier than in the monolayer culture system. We conclude that Leydig cells maintain differentiated functions more efficiently on collagen- and fibronectin-coated gelasperes than on Sephadex microcarriers and that uncoated gelaspheres are less efficient than coated ones. Pure gelaspheres are unsuitable for improvement of the hormonal and enzymatic activity of Leydig cells.

The effect of chronic luteinizing hormone treatment on adult rat Leydig cells

We investigated the chronic effects of luteinizing hormone (LH) treatment on adult rat Leydig cell structure and function. Two groups of sexually mature male Sprague-Dawley rats were used; controls and rats implanted subdermally with LH-filled Alzet miniosmotic pumps (delivers 24 micrograms of LH per day). After 2 weeks of LH treatment, testes of these rats were fixed by 2.5% glutaraldehyde in cacodylate buffer and processed and embedded in epon-araldite for light and electron microscopy and electron microscopic immunocytochemistry. Using light microscopic stereology, Leydig cell volume density, number of Leydig cells per testis, and the average volume of a Leydig cell were determined. Additionally, the organelle volumes per Leydig cells were quantified by electron microscopic stereology. Sterol carrier protein-2 (SCP2) and catalase in Leydig cells were immunolocalized via the Protein A gold method. Isolated and purified Leydig cells were used to determine the LH-stimulated (100 ng/ml) testosterone secretory capacity per Leydig cell in vitro and to compare the SCP2 and catalase content in equal numbers of Leydig cells using immunoblot analysis. After 2 weeks of LH-treatment, Leydig cell number per testis and the average volume showed a two-fold increase. All organelles tested, except the lipid droplets, were significantly (P < 0.05) increased two-fold in volume per Leydig cell. Testosterone secretory capacity per Leydig cell was increased approximately six-fold in the LH-treated group. Immunolabeling studies showed that the intraperoxisomal SCP2 content was significantly greater (P < 0.05) and the catalase content was significantly lower (P < 0.05) in LH-treated rats compared to to controls. Immunoblots showed that the total SCP2 content per cell is greater and the catalase content per cell is similar in Leydig cells of LH-treated rats compared to controls. In summary, chronic LH treatment produced hyperplasia, hypertrophy and increased testosterone secretory capacity in leydig cells of adult rats. However, the increase in the testosterone secretory capacity per Leydig cell exceeds the degree of Leydig cell hypertrophy, which cannot be explained by a generalized increase in volumes of all Leydig cell organelles in the LH-treated rats. These results also suggested that chronic LH treatment induces differential synthesis of peroxisomal proteins, i.e. an increase in SCP2 synthesis and no change in catalase synthesis. This resulted in peroxisomes rich in SCP2 and lower in catalase. Significance of these effects in relation to the increased steroidogenic capacity of Leydig cells remains to be determined.

A new version of the Ag-NOR technique. A combination with DAPI staining

The Ag-NOR staining technique is widely used for visualizing nucleolar organizer regions (NORs) in various plant and animal tissues. We describe a simple and time-saving combination of Ag-NOR staining with DNA detection by fluorescence microscopy. This modification was tested on cultured cells and semi-thin sections of plastic-embedded tissues. Of the different fixatives and embedding media used in our studies, the best results (i.e., high selectivity of staining, and lack of or very low background precipitation) were obtained with fixation in methanol-acetone at-20 degrees C for cultured cells, and fixation in 4% formaldehyde followed by embedding in Histocryl resin for tissue sections. The optimal time of Ag-NOR staining was determined experimentally for all materials tested. The specificity of the staining was checked at the electron microscopical level. Especially good results were obtained by mixing epifluorescence with standard bright-field illumination. In such a combination, Ag-NOR-positive nucleoli, or their fibrillar centres and dense fibrillar components, were clearly visible against a bright background of nuclear DNA.

Immunocytochemical demonstration of androgen receptors in Leydig cells of the bank vole (Clethrionomys glareolus, Schreber): an in vitro study

Androgen receptors of the bank vole Leydig cells in vitro were immunostained using a polyclonal antibody against androgen receptors followed by streptavidine-peroxidase complex or rhodamine-labelled goat anti-rabbit IgG visualization. The immunocytochemical studies revealed localization of androgen receptors in the whole cytoplasm or in the perinuclear area of the cells. Addition of dehydroepiandrosterone into the culture medium resulted in nuclear localization of the androgen receptors. Long (18L : 6D) and short (6L : 18D) photoperiods as well as the age of animals were taken into account. The concentration of androgen receptors was changed dependent on age and status of reproduction.

Visualization of the cytoskeleton in Leydig cells in vitro. Effect of luteinizing hormone and cytoskeletal disrupting drugs

Effect of LH, vinblastine and cytochalasin B on the cytoskeleton of cultured Leydig cells was investigated using monoclonal antibodies and fluorescence microscopy. After LH addition and treatment with cytoskeletal disrupting drugs, three main effects were observed: 1) increase of androgen level secreted by cultured mouse Leydig cells, 2) changes of cell-shape towards regular and rounded, 3) increase of delta 5,3 beta-HSD activity. The results are discussed in respect to possible involvement of cytoskeleton in the regulation of steroidogenesis.

The effect of estradiol on enzymatic activity and androgen secretion in Leydig cells in vitro

The effect of estradiol-17 beta (E2) on cultured Leydig cells isolated from mice testes was studied histochemically and radioimmunologically. Both analyses showed low activity of the enzymes studied and a decrease of the androgen level in E2 treated cultures. When the dose of estradiol preceded LH addition the androgen response to LH was attenuated. These results suggest direct inhibition of Leydig cell function by exogenous estradiol.

Regulation of steroidogenesis in rat Leydig cells in culture: effect of human chorionic gonadotropin and dibutyryl cyclic AMP on the synthesis of cholesterol side chain cleavage cytochrome P-450 and adrenodoxin

Rat Leydig cells in primary culture were used as a model system to investigate the effects of human chorionic gonadotropin (hCG) and dibutyryl cyclic AMP (Bt2cAMP) on the synthesis of cholesterol side chain cleavage cytochrome P-450 (cytochrome P-450scc) and the iron-sulfur protein, adrenodoxin. Leydig cells isolated from the testes of mature rats were placed in monolayer culture in the absence of stimulatory factors for 8 days. HCG (10 mIU/ml) or Bt2cAMP (1 mM) were then added to some of the cultures and the incubations were continued for up to 48 h. Testosterone production was increased markedly in cells incubated with hCG or Bt2cAMP. A significant accumulation of pregnenolone in the medium of cells treated with Bt2cAMP was also observed. Both hCG and Bt2cAMP increased the rates of synthesis of cytochrome P-450scc and adrenodoxin. In hCG-treated cells the apparent rate of synthesis of cytochrome P-450scc was increased 13-fold over that of controls after 48 h of incubation; the rate of adrenodoxin synthesis was increased 4-fold by hCG treatment. In Bt2cAMP-treated cells the rate of synthesis of cytochrome P-450scc was 37-fold greater than that of control cells after 48 h of incubation; adrenodoxin synthesis was increased 36-fold over controls. In hCG- and Bt2cAMP-treated cells, the concentration of immunoreactive cytochrome P-450scc and adrenodoxin increased with increasing time of incubation, and were correlated with the stimulatory effects of these agents on cytochrome P-450scc activity and on total steroid production. The results of this study are indicative that the maintenance by LH/hCG of elevated levels of testosterone synthesis by the Leydig cell is mediated, in part, by induction of the synthesis of cytochrome P-450scc and its associated protein, adrenodoxin. Since Bt2cAMP had effects similar to those observed with hCG, it is suggested that the stimulatory effects of hCG on the synthesis of cytochrome P-450scc and adrenodoxin are mediated by increased cyclic AMP formation.

Effect of fixation on the ultrastructural localization of delta 53 beta-hydroxysteroid dehydrogenase in adrenocortical and Leydig cells of the rat

A comparison of the effects of perfusion and immersion fixation on localization of delta 53 beta-HSD in adrenocortical and testicular Leydig cells has been made. The results demonstrated that regardless of the mode of fixation, localization of the enzyme (smooth endoplasmic reticulum) and variability in staining intensity were similar in both tissues. Also noted was the uneven distribution of the staining reaction product within the cells. This finding was interpreted as an expression of regional disparity in metabolic activity rather than artefactual since this phenomenon was noted in both perfusion and immersion fixed tissue.