Testosterone regulates 25-hydroxycholesterol production in testicular macrophages

Recently, we found that testicular macrophages produce 25-hydroxycholesterol (25-HC) and express 25-hydroxylase, the enzyme that converts cholesterol to 25-HC. In addition, 25-HC may be an important paracrine factor mediating the known interactions between macrophages and neighboring Leydig cells, because it is efficiently converted to testosterone by Leydig cells. The purpose of the present study was to determine if testosterone can regulate the production of 25-HC in rat testicular macrophages, representing a potential negative-feedback loop from Leydig cells. We found that expression of 25-hydroxylase mRNA and production of 25-HC by cultured testicular macrophages were significantly inhibited by testosterone at 10 micro g/ml. This dose of testosterone did not have an effect on cell viability and did not change the rate of mRNA degradation in the presence of actinomycin D. These studies indicate that production of 25-HC is negatively regulated by testosterone, which may be representative of a paracrine negative-feedback loop.     

Role of testicular interstitial macrophages in regulating testosterone release in hyperprolactinemia

Hyperprolactinemia-induced hypogonadism has been linked to a dysfunction of the hypothalamus-pituitary-testis axis. The direct inhibitory effects of prolactin on the testicular release of testosterone have also been demonstrated, though their mechanisms remain unclear. Incubation of rat testicular interstitial cells (TICs) with prolactin stimulated the release of testosterone. TICs from rats with anterior pituitary-grafting-induced hyperprolactinemia release lower amounts of testosterone than controls. However, Leydig cells isolated from anterior pituitary-grafted rats release a greater amount of testosterone. These paradoxical observations have remained unexplained. This study examined the roles of testicular interstitial macrophages and of their product, tumor necrosis factor-alpha (TNF-alpha), in regulating Leydig cells under condition of hyperprolactinemia. Hyperprolactinemia was induced by grafting two anterior pituitary glands of rats under the renal capsule. Control animals were grafted with rat cortex tissue. The rats were sacrificed 6 weeks later. TICs and macrophages, and Leydig cells were isolated for in vitro incubation and drugs challenge. Testosterone released by testicular interstitial or Leydig cells was measured by radioimmunoassay. TNF-alpha concentration in the medium of TICs or macrophages was measured by enzyme-linked immunosorbent assay (ELISA). A dose-dependent stimulation of TNF-alpha secretion in the medium of TICs or macrophages by the prolactin challenge was observed. Higher amounts of TNF-alpha were released by TICs in the anterior pituitary-grafted rats than in the control group. In contrast, the release of TNF-alpha by testicular interstitial macrophages isolated from the anterior pituitary- and cortex-grafted groups was quantitatively similar. Challenge with human chorionic gonadotropin did not modify the TNF-alpha release by testicular interstitial macrophages in either group. Challenge of Leydig cells with TNF-alpha inhibited their release of testosterone stimulated by human chorionic gonadotropin, but not their basal testosterone release. These different patterns of testosterone release in TICs versus Leydig cells cultures in anterior pituitary-grafted rats may be due to the influence of testicular interstitial macrophages. These observations correlate with in vivo conditions, where prolactin increases the release of TNF-alpha by testicular interstitial macrophages, which, in turn, decreases the human chorionic gonadotropin-stimulated release of testosterone by Leydig cells. In summary, hyperprolactinemia-induced hypogonadism involves a mechanism of prolactin-originated, macrophage-mediated inhibitory regulation of testosterone release by Leydig cells. TNF-alpha, one of the cytokines secreted by macrophages, may play a key role in this mechanism.     

Ultrastructure of testicular macrophages in aging mice

Testicular macrophages of aging mice were studied by TEM. Testicular macrophages retained with Leydig cells the close morphological relationships observed in the adult young animals, but digitations were not found. Lipofuscin granules like those of the Leydig cells from aging mice were observed in the cytoplasm. These organelles were generally absent in the testicular macrophages of young adult mice. Testicular macrophages did not display phagocytosis of the lipofuscin granules. In addition, the latter were not found in the intercellular spaces. These observations indicated that lipofuscin granules were formed, at least in a great part, within testicular macrophages as a consequence of metabolic changes occurring with age. Fine lamellar organization was seen in the lipofuscin granules of both Leydig cells and testicular macrophages. Frequently, lipofuscin granules originated from secondary lysosomes containing lipidic vacuoles only. Together with accumulation of the lipofuscin granules, changes of testicular macrophage fine morphology were observed. Endoplasmic reticulum and Golgi apparatus became poorly developed, and coated vesicles were rarely found. Fewer mitochondria were encountered, but their ultrastructure was not altered. These results suggest that in testicular macrophages lipofuscin accumulation is associated with a functional involution.     

Changes in the concentration and size of testicular macrophages during development

Structural and functional interactions exist between Leydig cells and testicular macrophages of adult rats. Since the function of Leydig cells changes during critical periods of development and postnatal maturation, it is possible that macrophages are in part involved in regulating this process. As a first step towards gaining an understanding of the development of this paracrine phenomenon, I have undertaken a series of studies designed to determine when macrophages first become identifiable in the fetal tests and to determine whether the concentration or size of macrophages changes during important stages of testicular maturation. Macrophages were identified immunohistochemically in frozen sections of testis from rats at various prenatal and postnatal ages using commercially available monoclonal antibodies to proteins specific to rat macrophages. It was found that macrophages positive for these antigens were found only within the interstitial compartment and were commonly associated with clusters of presumptive Leydig cells that were negative for these antigens. Macrophages were first identifiable in the testis at Day 19 of fetal development. The number of macrophages/unit area of interstitium increased 15-fold between Day 20 of gestation and Day 47 postpartum. The cross-sectional area of the macrophages increased 1.7-fold between Days 13 and 47 postpartum. These results demonstrate that the number and size of testicular macrophages changes with age, suggesting a role for these cells during important times of testicular development and maturation.     

Production of 25-hydroxycholesterol by testicular macrophages and its effects on Leydig cells

Testicular macrophages secrete 25-hydroxycholesterol, which can be converted to testosterone by neighboring Leydig cells. The purposes of the present studies were to determine the mode of production of this oxysterol and its long-term effects on Leydig cells. Because oxysterols are produced both enzymatically and by auto-oxidation, we first determined if testicular macrophages possess cholesterol 25-hydroxylase mRNA and/or if macrophage-secreted products oxidize cholesterol extracellularly. Rat testicular macrophages had 25-hydroxylase mRNA and converted 14C-cholesterol to 14C-25-hydroxycholesterol; however, radiolabeled cholesterol was not converted to 25-hydroxycholesterol when incubated with medium previously exposed to testicular macrophages. Exposure of Leydig cells to 10 microg/ml of 25-hydroxycholesterol, a dose within the range known to result in high basal production of testosterone when tested from 1 to 6 h, completely abolished LH responsiveness after 2 days of treatment. Because 25-hydroxycholesterol is toxic to many cell types at 1-5 microg/ml, we also studied its influence on Leydig cells during 4 days in culture using a wide range of doses. Leydig cells were highly resistant to the cytotoxic effects of 25-hydroxycholesterol, with no cells dying at 10 microg/ml and only 50% of cells affected at 100 microg/ml after 2 days of treatment. Similar conditions resulted in 100% death of a control lymphocyte cell line. These results demonstrate that 1) testicular macrophages have mRNA for cholesterol 25-hydroxylase and can convert cholesterol into 25-hydroxycholesterol, 2) macrophage-conditioned medium is not capable of auto-oxidation of cholesterol, 3) Leydig cells are highly resistant to the cytotoxic influences of 25-hydroxycholesterol, and 4) long-term treatment with high doses of 25-hydroxycholesterol results in loss of LH responsiveness. These results support the concept that testicular macrophages enzymatically produce 25-hydroxycholesterol that not only is metabolized to testosterone by Leydig cells when present at putative physiological levels but also may exert inhibitory influences on Leydig cells when present for extended periods at very high concentrations that may occur under pathological conditions.     

25-hydroxycholesterol is produced by testicular macrophages during the early postnatal period and influences differentiation of Leydig cells in vitro

Leydig cells develop inappropriately in animals lacking testicular macrophages. We have recently found that macrophages from adult animals produce 25-hydroxycholesterol, an oxysterol involved in the differentiation of hepatocytes and keratinocytes. Therefore, we hypothesized that testicular macrophages also produce 25-hydroxycholesterol during the early postnatal period and that this oxysterol plays a role in the differentiation of Leydig cells. We assessed the production of 25-hydroxycholesterol and 25-hydroxylase mRNA by cultured testicular macrophages from rats at 10, 20, and 40 days of age. We also tested the long-term effects of 25-hydroxycholesterol on basal and LH-stimulated testosterone production, and 3beta-hydroxysteroid dehydrogenase activity as end points of Leydig cell differentiation in vitro. We found that testicular macrophages from animals at all ages produced both 25-hydroxycholesterol and 25-hydroxylase mRNA, with macrophages from 10-day-old animals having the highest steady-state levels of message. We also found that chronic exposure of Leydig cells to 25-hydroxycholesterol increased basal production of testosterone but decreased LH-stimulated steroidogenesis at all ages. Finally, 25-hydroxycholesterol increased 3beta-hydroxysteroid dehydrogenase activity in both progenitor and immature Leydig cells. These findings support the hypothesis that testicular macrophages play an important role in the differentiation of Leydig cells through the secretion of 25-hydroxycholesterol.     

Localization of immunoreactive beta-endorphin and adrenocorticotropic hormone and pro-opiomelanocortin mRNA to rat testicular interstitial tissue macrophages.

Pro-opiomelanocortin (POMC) gene expression and POMC peptides have been demonstrated in the Leydig cells of the testis, although selective removal of the Leydig cells with the cytotoxic drug ethane dimethane sulfonate did not significantly reduce levels of testicular POMC mRNA or peptides in adult rats. Since macrophages in the rat spleen synthesize POMC peptides, we investigated whether isolated macrophages from the adult rat testis may be an additional source of POMC-derived peptides. Testicular macrophages were isolated by collagenase treatment of adult rat testes and adherence to siliconized glass coverslips; the biological, cytochemical and immunological characteristics of the attached cells were compared with those of Leydig cells purified by Percoll gradient centrifugation. Macrophages in the cell preparations were identified by positive esterase cytochemical staining, latex bead ingestion, and immunocytochemical staining with ED2 (a macrophage-specific monoclonal antibody), and an absence of 3 beta-hydroxysteroid dehydrogenase cytochemical staining. Leydig cells in the purified preparations were positive for 3 beta-hydroxysteroid dehydrogenase and esterase staining but negative with ED2, and were not phagocytic. Based on these criteria, the purities of the macrophage and Leydig cell preparations employed in this study were estimated to be 87 +/- 4% and 91 +/- 3%, respectively. Cytoplasmic beta-endorphin (beta EP) immunoreactivity (ir) was present in 62 +/- 9% of cells in the purified Leydig cell preparations--confirming these cells as a source of POMC-derived peptides. In addition, ir-beta EP and ir-ACTH were localized to the cytoplasm of a similar proportion of cells (beta EP, 62.5 +/- 5%; ACTH, 64 +/- 5%) in macrophage preparations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mitosis of resident macrophages in the adult rat testis

Resident macrophages are maintained at a comparatively high, yet stable, tissue concentration in the adult rat testis. After destruction of Leydig cells by ethane dimethane sulphonate treatment, the number of resident macrophages increases briefly and then decreases to below normal values, but returns to normal after the reappearance of Leydig cells. The mechanisms by which the adult testicular macrophage population is maintained, either by monocyte recruitment or by mitosis of the resident macrophages, have not been examined. An immunohistochemical dual labelling approach using a specific monoclonal antibody for resident macrophages, ED2, and markers of mitotic activity (bromodeoxyuridine incorporation and expression of the proliferating cell nuclear antigen) was used to investigate resident macrophage proliferation in Bouin's-fixed paraffin wax-embedded adult rat testes. Detection of the normally fixation sensitive antigen recognized by ED2 was achieved by using a decreased fixation time and antigen retrieval. Peaks of resident macrophage mitotic activity were observed during the phases of macrophage proliferation immediately after ethane dimethane sulphonate treatment and during the recovery phase associated with Leydig cell restoration. These data demonstrate that resident macrophages have the capacity to proliferate within the adult rat testis and, thus, this population of resident macrophages is maintained, at least in part, by mitotic division in situ.     

Development of cytoplasmic digitations between Leydig cells and testicular macrophages of the rat

Summary Testicular macrophages and Leydig cells from adult animals are known to be functionally coupled. For example, secreted products from macrophages stimulate testosterone secretion by Leydig cells. In adult rat testes, structural coupling also exists between these cells. This coupling consists of cytoplasmic projections from Leydig cells located within cytoplasmic invaginations of macrophages. Although macrophages are known to exist in the testis in immature animals, it is not known when these digitations develop. The purpose of the present study was to determine whether the time of their development coincides with known maturational events that occur in Leydig cells, particularly during the peripubertal period. Testes from rats at 20, 30 and 40-days-of-age as well as testes from mature rats weighing more than 500 gm were prepared for ultrastructural analysis. It was found that digitations form between 20 and 30-days-of-age. These structures varied from simple tubular projections to complicated branched structures, suggesting that digitations are more than simple invaginations of microvilli into coated vesicles as previously described. Subplasmalemmal linear densities were also observed within macrophages juxtaposed to Leydig cells. Collagen was commonly observed between macrophages and Leydig cells in animals 20 days old. These studies demonstrate that although macrophages are present in the testis in maximal numbers at 20 days-of-age, they do not form junctions with Leydig cells until day 30. This is just prior to the major increase in secretory activity of rat Leydig cells that occurs during puberty.     

The response of testicular leukocytes to lipopolysaccharide-induced inflammation: further evidence for heterogeneity of the testicular macrophage population

The majority of macrophages in the rat testis can be identified by the tissue-resident macrophage marker ED2. A smaller population of intratesticular macrophages do not express the ED2 antigen but are positive for the monocyte/macrophage marker ED1. Treatment of adult rats with the inflammatory stimulus lipopolysaccharide (LPS) had no effect on the number of testicular resident (ED2(+)) macrophages but caused a transient increase in ED1(+)ED2(-) monocyte-like macrophages (an average three-fold increase 12 h later). In both control and LPS-treated rat testes, a majority of macrophages that expressed ED1 and all Leydig cells were immuno-positive for the inducible isoform of nitric oxide synthase (iNOS). However, less than 6% of ED2(+) macrophages showed any iNOS expression, even after LPS treatment. This deficiency was confirmed by the finding that isolated ED2(+) testicular macrophages (>98% pure) stimulated with LPS did not produce NO in vitro. In contrast, resident macrophages from the peritoneum showed the expected NO response, and purified Leydig cells produced significant NO regardless of the presence or absence of LPS. Collectively, these data indicate the presence of at least two macrophage subsets in the adult rat testis: (1) the ED2(+) resident macrophages, which do not alter following LPS-treatment and mostly do not express iNOS or produce NO in response to an inflammatory stimulus, and (2) the ED1(+)ED2(-) monocyte-like macrophages, which increase in number after LPS-treatment and express iNOS even in the absence of exogenous inflammatory stimulation. It is highly probable that these different subsets have different functional roles within the testis.     

Physiologic interactions between macrophages and Leydig cells

The purpose of this minireview is to present information concerning the morphologic and functional relationship between testicular macrophages and Leydig cells. Although data concerning the negative influence of macrophage-derived products on testicular Leydig cells exist, this review is focused on the stimulatory influences thought to be involved in the physiologic interactions between these two diverse cell types.     

Ultrastructural immunoperoxidase investigations of HCG binding to isolated testicular intertubular cells.

The binding and processing of human chorionic gonadotrophin (HCG) on isolated rat testicular intertubular cells was investigated using an ultrastructural immunoperoxidase technique. Following incubation of isolated cells with HCG at a range of temperatures and time intervals, cells were fixed and the presence of HCG demonstrated using monoclonal and polyclonal antibodies to HCG and its alpha and beta subunits. Results indicated that HCG binds to the surface of the Leydig cells where it is rapidly split into its component subunits. Internalization of the HCG molecule was not demonstrated. The testicular macrophages also bound HCG. In contrast to the Leydig cells they were able to internalize the molecule into lysosomes in the cytoplasm. The complete molecule and the alpha and beta subunits were found within the cells. The study suggests that results of previous studies using mixed populations of isolated cells may be due to the combined effects of the different mechanisms present in the two cell types. It is postulated that Leydig cells bind HCG on the surface and cyclic AMP is activated prior to breakdown and loss of the hormone from the surface of the cells. It is postulated that the macrophages play a role in the breakdown of excess trophic hormone and act in concert with the Leydig cells in the local control of testicular function.     

Bactericidal activity of testicular macrophages

The purpose of these studies was to determine if testicular macrophages are capable of bactericidal activity. Testicular macrophages were isolated from adult Wistar rats and studied in vitro. Studies were designed to determine if these cells could kill pathogenic gram-negative organisms and if these cells secreted lysozyme, an enzyme involved with the lysis of the cell wall of gram-positive bacteria. The regulation of lysozyme secretion by hormones and lipopolysaccharide was also studied. The secretion of this enzyme by testicular macrophages was also compared to enzyme secretion by macrophages isolated from other tissues. We also studied the secretion of superoxide anion, which is known to be involved in cytotoxic reactions. It was found that testicular macrophages were capable of killing up to approximately 38% of a virulent encapsulated strain of Klebsiella pneumoniae within 1 h. This process was in part dependent upon the presence of immune serum generated against these organisms but could not be mimicked by control serum or immune serum tested in the absence of macrophages. Testicular macrophages secreted lysozyme in culture for at least 8 days; however, macrophages from the peritoneal cavity and lung secreted significantly more lysozyme under the same conditions. Lipopolysaccharide suppressed lysozyme secretion in a dose-dependent manner, whereas neither follicle-stimulating hormone, testosterone, nor leuteininzing hormone had an effect on lysozyme secretion. Finally, testicular macrophages secreted superoxide anion in a manner similar to peritoneal macrophages. These studies indicate that testicular macrophages have the capability to mount an appropriate defense against pathogenic bacteria by opsonization-dependent phagocytosis, the secretion of lysozyme, and the production of super oxide anion.     

The role of tumor necrosis factor-alpha and interleukin-1 in the mammalian testis and their involvement in testicular torsion and autoimmune orchitis

This review will focus the roles of TNF-alpha, IL-1 alpha, and IL-1 beta in the mammalian testis and in two testicular pathologies, testicular torsion and orchitis. TNF alpha in the testis is produced by round spermatids, pachytene spermatocytes, and testicular macrophages. The type 1 TNF receptor has been found on Sertoli and Leydig cells and numerous studies suggest a paracrine mode of action for TNF alpha in the normal testis. IL-1 alpha has been reported to be produced by Sertoli cells, testicular macrophages, and possibly postmeiotic germ cells. IL-1 receptors have been reported on Sertoli cells, Leydig cells, testicular macrophages, and germ cells suggesting both autocrine and paracrine functions. While these proinflammatory cytokines have important roles in normal testicular homeostasis, an elevation of their expression can lead to testicular dysfunctions. Testicular torsion is a clinical pathology with results in testicular ischemia and surgical intervention is often required for reperfusion. A pivotal role for IL-1beta in the pathology of testicular torsion has been recently described whereby an increase in IL-1beta production after reperfusion of the testis is correlated with the activation of the stress-related kinase, c-jun N-terminal kinase, and ultimately resulting in neutrophil recruitment to the testis and germ cell apoptosis. In autoimmune orchitis, on the other hand, TNF alpha produced by T-lymphocytes and macrophages of the testis has been implicated in the development and progression of the disease. Thus, both proinflammatory cytokines, TNF alpha and IL-1, have significant roles in normal testicular functions as well as in certain testicular pathologies.     

Autoradiographical localization of luteinizing hormone releasing hormone (LHRH) receptors on rat testicular intertubular cells fractionated on Percoll density gradients

The specific binding of 125I-labelled [D-Ser(tBu)6,des-GlyNH2(10)] LHRH ethylamide (LHRH-A) to testicular intertubular cells fractionated on Percoll density gradients was investigated. The greatest binding per cell occurred in the density region which contained the largest proportion of Leydig cells (sp. gr. 1.0820-1.0585). Autoradiographs of the cells from this region confirmed that silver stains were predominantly located over the Leydig cell, significantly (P less than 0.01) more grains were observed over this cell type in the total binding fractions than in the non-specific binding fractions. However, 5.9% of cells other than Leydig cells (testicular macrophages and indeterminate connective tissue cells) from this region also displayed significant displaceable binding (P less than 0.01). The location of [125I]LHRH-A binding to cells in other density regions, which did not contain identifiable Leydig cells, could not be established by autoradiography. These results confirm that the Leydig cell possesses LHRH receptors, but also indicate that other testicular cells have specific, high-affinity binding sites for LHRH-A, and may either be responsive to direct stimulation by LHRH, or may partially mediate the effects of LHRH and its agonists on Leydig cell function.     

Spontaneous testicular neoplasm in mice with testicular feminization

Summary Testicular neoplasms occur spontaneously in androgen insensitive mice with testicular feminization (tfm/y); they are composed of Leydig cells, lipid-laden cells, fibroblastlike cells, and macrophages. The small Leydig cells in the periphery of the tumor are structurally similar to nontumorous tfm/y Leydig cells, whereas centrally located large Leydig cells contain numerous lipid droplets, mitochondria with tubular cristae, and abundant smooth endoplasmic reticulum. The lipid-laden cells exhibit a crescentic nucleus which is displaced toward the periphery of the cytoplasm by a large lipid vacuole. The fibroblastlike cells have a large amount of rough endoplasmic reticulum, lysosomes, free ribosomes, and lipid vacuoles. Macrophages are characterized by numerous layered and dense osmiophilic structures closely associated with crystalshaped bodies. An in vitro study shows that, in comparison with the normal testes, the tfm/y tumors produce significantly less testosterone but a larger quantity of androstenedione. Also, the tumors are capable of converting progesterone to estrone and estradiol-17. The plasma level of testosterone is significantly lower in tumor-bearing animals than in normal littermates, but slightly higher than in the nontumorous tfm/y animals. Since the abnormal steroid enzyme activity is found in both tumor-bearing and nontumorous tfm/y mice, the basic cause of aberrations in sex steroid production appears to be genetic rather than the direct result of alterations in their Leydig cells.     

Paracrine regulation of testicular function

Data from several experimental approaches have been reviewed and the findings clearly indicate the existence of multiple interactions between testicular cells and the potential role of these interactions in the paracrine control of testicular functions. Both testicular interstitial fluid and spent media from cultured Sertoli cells had an acute steroidogenic effect on Leydig cells, and this effect is not species specific. The secretion of this steroidogenic factor(s), which is probably a protein, is enhanced by previous FSH treatment of Sertoli cells. Coculture for 2-3 days of pig Leydig cells with homologous or heterologous Sertoli cells enhances Leydig cell specific functions (hCG receptor number and hCG responsiveness) and induces Leydig cell hypertrophy. A similar but less pronounced trophic effect is seen when Leydig cells are cultured with spent media from Sertoli cells cultured in the presence of FSH and high concentrations of insulin, but the spent media from Sertoli cells cultured in the absence of these two hormones inhibits Leydig cell specific functions. Somatomedin-C might play an important role in the positive trophic effect of Sertoli cells on Leydig cells, since this peptide is secreted by Sertoli cells and it has trophic effects on the specific function of Leydig cells. Moreover, Sertoli cells, probably through a diffusible factor and cell-to-cell contacts, control the multiplication, meiotic reduction and maturation of germ cells. In turn, the activity of Sertoli cells is modulated by the stage of neighbouring germ cells. Thus, if a normal Sertoli cell function (which depends not only on FSH but also on Leydig and myoid cell secretory products) is an absolute requirement for germ cell multiplication and maturation, these cells, in turn, cyclically regulate Sertoli cell function and through these cells the size and probably the function of Leydig cells.     

Rat testicular interstitial fluid contains mediators of vasopermeability

An intradermal injection of testicular interstitial fluid (IF) produced a marked increase in vasopermeability in a dose-dependent manner. Likewise bovine follicular fluid caused a smaller but significant response. The effect of IF was associated with accumulation of polymorphonuclear leucocytes (PMNs) inside the dermal venules and with their adherence to the venular endothelium. A minor but significant response was noticed after injecting anterior chamber fluid, but there was no response after an injection of amniotic fluid or serum intracutaneously. Destroying the Leydig cells with ethane dimethanesulphonate did not change the vasopermeability-increasing effect of IF, but after denaturation of IF proteins the effect was diminished by about 50%. Intravenous administration of hCG did not increase the ability of IF to cause the effect. These results suggest that rat testicular interstitial fluid contains mediators of vasopermeability, probably specific for the testis and also follicular fluid. The vasopermeability effect of IF does not seem to depend on the collecting time or on Leydig cells and is at least partly mediated by PMNs which are seen in the dermal venules shortly after an injection of IF.     

Testicular lipids in mice with testicular feminization

Morphological, histochemical and biochemical studies of the testis of mice with testicular feminization (tfm/y) reveal a large accumulation of lipids in Leydig cells and in Sertoli cells. In Leydig cells of tfm/y mice, lipid droplets do not exhibit the special relationship with smooth endoplasmic reticulum that exists in normal adult Leydig cells. Compared to the surgically-cryptorchid control, the tfm/y testis contains more lipid in Leydig cells but less in Sertoli cells. There are also quantitative differences in testicular lipids in tmf/y and normal testes but no significant differences were noted between tfm/y and surgically-cryptorchid testes. The testes of both the genetically defective and surgically-cryptochid animals contain increased amounts of total lipids and phospholipids, and of free and esterified cholesterols. Exogenous testosterone has no effect on lipids or other characteristics of these cells. The present results suggest that the increased lipids in tfm/y mice result from a genetic disorder that asserts itself (1) in Leydig cells where it is associated with, and is probably a result of, impaired lipid metabolism and steroidogenesis, and (2) in Sertoli cells where it is perhaps attributable to arrested spermatogenesis and impaired steroidogenesis.