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J C Hutson

Publications and source records attributed to J C Hutson.

At least 37 records · Page 2Linked to original sources
PubMed1989

Follicle-stimulating hormone-induced lactate secretion by cultured Sertoli cells does not require extracellular calcium.

Sertoli cells of the testis secrete lactate in response to follicle-stimulating hormone (FSH). It is thought that the developing germ cells use lactate as an energy substrate preferentially over glucose. However, the biochemical mechanism(s) involved in the regulation of lactate secretion in response to FSH are unknown. The purpose of this study was to determine if extracellular calcium was important for the actions of FSH during this response. It was found that the FSH-induced increase in lactate production by Sertoli cells was not dependent upon the presence of extracellular calcium. However, A23187 (a calcium ionophore) stimulated lactate secretion in the presence of extracellular calcium. When FSH and A23187 were tested together at maximal concentrations, more lactate was secreted than when either FSH or A23187 was tested alone. Neither verapamil, nifedipine nor diltiazem (calcium channel "blockers") were able to inhibit the ability of FSH to increase lactate secretion. These results indicate that FSH-induced secretion of lactate by cultured Sertoli cells is not dependent upon extracellular calcium.

Animals↗
PubMed1988

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.

Animals↗
PubMed1987

Peritubular cells influence Sertoli cells at the level of translation.

Conditioned medium from cultured peritubular cells (PTCM) was capable of increasing the incorporation of amino acids into acid-precipitable material in cultured Sertoli cells, while the incorporation of uridine into acid-precipitable material was unaffected. PTCM did not influence intracellular cAMP accumulation in a manner similar to follicle-stimulating hormone (FSH). PTCM was able to stimulate androgen-binding protein (ABP) secretion by Sertoli cells even in the presence of a maximal dose of FSH. PTCM increased the rate at which peptides are elongated 5-fold over control medium or medium from control fibroblasts. These studies indicate that peritubular cells influence Sertoli cells through different mechanisms than FSH and exert their influence, at least in part, at the level of translation by increasing the rate of peptide elongation.

Androgen-Binding Protein↗
PubMed1985

Biochemical consequences of follicle-stimulating hormone binding to testicular macrophages in culture.

The present studies demonstrate that testicular macrophages respond to follicle-stimulating hormone (FSH) by: 1) stimulating the rate of incorporation of amino acids into secreted proteins; 2) increasing the rate of incorporation of uridine into RNA; and 3) enhancing the accumulation of intracellular cyclic adenosine monophosphate (cAMP; which was potentiated by the addition of 1 mM 3-isobutyl-1-methylxanthine; MIX). In addition, dibutyryl cAMP (dbcAMP) enhanced the incorporation of amino acids into secreted proteins; however, this cAMP analog had no effect on the incorporation of uridine into RNA. Finally, it was demonstrated that testicular macrophages possess specific receptors with a high affinity for FSH.

Amino Acids↗
PubMed1985

In vivo effects of follicle-stimulating hormone on testicular macrophages.

The effect of an intraperitoneal injection of various hormones on the incorporation of amino acids and uridine into acid-precipitable material by subsequently isolated testicular macrophages was investigated. It was found that treatment with follicle-stimulating hormone (FSH), but not luteinizing hormone (LH) or insulin, significantly increased incorporation of amino acids into secreted (but not cellular) protein and uridine incorporation into cellular RNA in a dose-dependent manner. Maximal responsiveness was observed at a dose of 50 micrograms of the hormone. These studies demonstrate that FSH has an action on testicular macrophages in vivo.

Amino Acids↗
PubMed1985

Effects of testicular macrophage-conditioned medium on Leydig cells in culture.

Conditioned medium from cultures of testicular macrophages was capable of stimulating testosterone production in a dose-dependent manner when added to Leydig cells in vitro. Significant stimulation of testosterone production by Leydig cells was observed after 4 h of exposure to testicular macrophage-conditioned medium (TMCM) and thereafter increased progressively for up to 24 h. Treatment of Leydig cells with TMCM together with a maximal dose of LH resulted in greater production of testosterone by Leydig cells than with either agent when used separately. Conditioned medium from macrophages treated with FSH was twice as potent as TMCM from untreated cells. This dose of FSH had no direct effect on Leydig cells. Conditioned medium from cultures of peritoneal macrophages had less effect on testosterone production by Leydig cells than testicular macrophage-conditioned medium. It is proposed that secretory products from testicular macrophages play an important role in testicular function.

Animals↗
PubMed1984

Altered biochemical responses by rat Sertoli cells and peritubular cells cultured under simulated diabetic conditions.

The purpose of the present study was to determine whether the secretion of androgen-binding protein and lactate by 16-day-old rat Sertoli cells is altered when these cells are cultured in simulated diabetic conditions. Incorporation of 3H-uridine into RNA by peritubular cells cultured in simulated diabetic conditions was also studied. The cells were exposed to various concentrations of glucose, beta-hydroxybutyrate, sodium bicarbonate (to alter the pH of the medium), mannitol (to influence the osmolarity of the medium), or a combination of these compounds. All of the metabolic parameters when tested alone or in combination were capable of increasing lactate secretion by Sertoli cells above control values. Basal secretion of androgen-binding protein, however, was not influenced by an individual component or when all components were tested together. FSH-stimulated levels of androgen-binding protein secretion was depressed only when the Sertoli cells were exposed to all the components simultaneously. Incorporation of uridine by peritubular cells was decreased by exposing the cells to butyrate or mannitol, while no effect was observed with glucose treatment. These results indicate that Sertoli cell and peritubular cell function can be directly altered by several specific metabolic parameters associated with diabetes.

3-Hydroxybutyric Acid↗
PubMed1984

Altered responses to androgen in diabetic male rats.

In male rats, experimentally induced diabetes mellitus has been reported to be associated with reduced serum levels of gonadotropins and testosterone as well as decreased sex accessory organ weights. The purpose of the present study was to determine if the decreased accessory organ weights and gonadotropin levels observed in diabetic animals result from alterations in the ability of target tissues to respond to testosterone. Adult, male, Wistar rats were injected with streptozotocin (STZ) and either maintained as untreated diabetics or treated with daily injections of insulin. Semi-starved animals were included to control for any effects on the reproductive system due to body weight change alone. These three groups, plus intact controls, were maintained for 30 days with one-half of the animals from each group receiving silastic tubing implants of testosterone of various lengths. It was determined that, in uncontrolled diabetic and semi-starved animals, the serum levels of LH, FSH, and testosterone were decreased, as were the weights of seminal vesicles and ventral prostate glands. Insulin treatment restored LH, FSH, and testosterone levels to normal. Sex accessory glands exhibited slight, but significant, recovery in diabetic animals treated with insulin. Implants of testosterone that resulted in physiologic serum levels of testosterone were effective in depressing serum LH and FSH levels as well as in maintaining normal seminal vesicle and ventral prostate weights in control and semi-starved animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Testicular macrophages: isolation, characterization and hormonal responsiveness.

Macrophages were isolated from rat testes with trypsin treatment and established in culture using a differential attachment technique. The cells were maintained in culture in Medium 199 at 32 degrees C. The cells were then characterized for their ability to express traditional immunological function as well as to secrete lactate under the regulation of various hormones. The results indicate that viable cultures of macrophages were obtained since: 1) the cells stained intensely for nonspecific esterase, 2) they possessed Fc receptors on their cytoplasmic membranes, 3) they were capable of phagocytosing 3H-labeled E. coli and carbon particles, and 4) they were highly resistant to the effects of trypsin to induce detachment from the culture substrate. These cultures were not contaminated with Leydig cells or Sertoli cells since they were negative for 3 beta-hydroxysteroid dehydrogenase and did not secrete androgen-binding protein (ABP). Most importantly, these cells were capable of responding to follicle-stimulating hormone (FSH) in a dose-dependent manner by increasing the secretion of lactate. Maximal stimulation was observed with 1 microgram FSH/ml which resulted in a 2.5-fold increase over control values. Dibutyryl cyclic AMP (dbcAMP) also caused a dose-related increase in lactate production by these cells. Luteinizing hormone (LH), insulin, testosterone or 17 beta-estradiol had no similar effect on lactate production by these cells. Peritoneal macrophages were not responsive to FSH or dbcAMP. These studies demonstrate that a highly enriched population of testicular macrophages can be maintained in culture and express several immunological characteristics traditionally ascribed to macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Sertoli cell function in diabetic, insulin-treated diabetic, and semi-starved rats.

It is well documented that long-term diabetes mellitus results in numerous deleterious consequences. However, considerable controversy exists concerning male reproductive function in diabetes. The purpose of this investigation was to study several endocrine parameters in diabetic male rats with emphasis on Sertoli cell function. Male Wistar rats were injected with streptozotocin and then either left untreated for 30 days or injected with insulin so as to prevent spillover of glucose into the urine. These two groups were compared with control animals that had only been injected with the vehicle for streptozotocin. Semi-starved control animals were included to determine if any of the potential endocrine alterations were related to body weight changes which occur in streptozotocin-injected rats. It was found that FSH, LH, PRL, and GH serum levels were reduced in diabetic animals. Only FSH was restored to normal by insulin injections. The testis, seminal vesicle, and epididymis weights were all reduced in diabetic animals. Insulin injections raised all organ weights; however, only testis weights were fully restored. Levels of epididymal ABP activity were found to be higher in diabetic animals when expressed per mg protein. Similar patterns of organ weight loss and hormonal alterations were observed in semi-starved rats. However, epididymal levels of ABP activity were unaffected by the semi-starved condition. While weight loss should be taken into consideration when interpreting cause and effect relationships in streptozotocin-treated animals, epididymal ABP levels appear to be well correlated with the altered metabolic state characteristic of diabetes.

Androgen-Binding Protein↗
PubMed1981

Peritubular cell influence on the efficiency of androgen-binding protein secretion by Sertoli cells in culture.

The efficiency of androgen-binding protein (ABP) secretion into the medium of cultured Sertoli cells was increased by the addition of peritubular cells into the culture system. There was a positive correlation between the number of peritubular cells added to the cultures and the amount of ABP secreted. These responses were observed in cultures treated with highly purified FSH or in untreated cultures. Medium that had been exposed to peritubular cells before exposure to Sertoli cells did not mimic the effect observed when peritubular cells were added directly to Sertoli cells. The efficiency of ABP secretion by Sertoli cells was not a function of plating density, since the amount of ABP per mg cellular protein did not vary significantly among cultures of Sertoli cells which contained a wide variation in the numbers of cells present. These results suggest that peritubular cells play a role in regulating ABP secretion and thus support the hypothesis that cell to cell communication exists between these two cell types of the seminiferous tubule.

Androgen-Binding Protein↗
PubMed1980

Effects of serum components on the morphology of Sertoli cells in culture.

Studies of Sertoli cell structure, maturation, and function have been aided by the use of in vitro systems. Although numerous papers have appeared that utilize the Sertoli cell culture model, few papers have dealt with the characterization of these cells under various culture environments. Recently, it has been reported that the addition of serum to the culture medium prevents induction of long cytoplasmic appendages in cultured Sertoli cells that have been treated with FSH, TSH, or c-AMP. The purpose of this investigation was to determine which serum components, obtained by gel filtration, are capable of inhibiting the morphological response induced by FSH, TSH, or c-AMP. Sertoli cell-enriched cultures were prepared using collagenase and trypsin digestion, each followed by gravity sedimentation. Untreated cells grown on plastic or glass substrates assumed an epithelioid appearance after several days. Cells treated with FSH, TSH, or c-AMP formed long cytoplasmic appendages after 1-2 days. This response was prevented or reversed by the addition of fetal calf serum (10%), crystallized bovine serum albumin (0.25%-2%), or purified albumin obtained by gel filtration of whole serum (0.25%). It was also found that fractions that elute between the void volume and the initial albumin fractions (molecular weights of approximately 50,000 and greater) mimic the hormone-induced response after only 10-12 hours. The results of this investigation indicate that albumin is the primary serum component responsible for inhibiting morphological alterations induced by FSH, TSH, and c-AMP. Furthermore, it is apparent that the production of long filamentous cytoplasmic appendages in Sertoli cells can be induced by a wide variety of substances.

Animals↗
PubMed1980

Characteristics of mitochondria isolated by rate zonal centrifugation from normal liver and Novikoff hepatomas.

Mitochondria were isolated from whole homogenates of normal liver and Novikoff hepatomas using reorienting rate zonal centrifugation on sucrose gradients. The activities of several mitochondrial-specific enzymes and ultrastructure were compared in the two tissues. Our results indicate that cytochrome oxidase, lipoamide dehydrogenase, malate dehydrogenase, and succinate dehydrogenase activities are all higher in liver homogenates than in Novikoff hepatoma homogenates. Mitochondrial hexokinase, however, is much greater in the hepatoma than in liver. The activity of these enzymes in isolated mitochondria displayed a much different pattern. Both cytochrome oxidase and succinate dehydrogenase activities were higher in hepatoma mitochondria than in liver mitochondria. Lipoamide dehydrogenase and malate dehydrogenase, conversely, were higher in liver mitochondria. Hexokinase was found to be virtually absent in liver mitochondria but plentiful in hepatoma mitochondria. Ultrastructural studies have shown that the hepatoma mitochondria are much smaller in size, which results in a decreased rate of migration into the gradient. These studies have also shown that normal liver consists of predominantly "condensed" forms of mitochondria, whereas hepatoma contained a majority of "twisted" species. Experiments using 1% bovine serum albumin in the homogenization procedures and in the gradient have confirmed earlier observations that bovine serum albumin is essential for optimal isolation of neoplastic mitochondria.

Animals↗
PubMed1979

Considerations for establishing the validity of immunocytological studies.

Immunocytology has wide spread applications for localizing tissue antigens, as evidenced by the recent exploitation of this technique in biological studies. Documenting the immunological specificity of the staining reaction is one of the most important technical considerations in validating the accrued data in immunocytological studies. The purpose of this report is to discuss and emphasize the need for conducting physiological studies in addition to the traditional immunological method and specificity controls. The ability of antibodies to bind molecules other than those molecules used as the immunizing material is a well documented fact. Hypothetically, preabsorption of the primary antibody with its specific antigen, could reduce subsequent binding of this antibody to a cross reactive tissue antigen, thus providing false confirmation of staining validity. The results of our experience with a cross reacting system in addition to other previously reported examples are discussed.

Animals↗
PubMed1978

The effects of various hormones on the surface morphology of testicular cells in culture.

The purpose of this investigation was to study the effects of various hormones on the surface morphology of 20-day-old rat testicular cells in culture. Aggregates containing primarily Sertoli cells and germinal cells were obtained by enzymatic digestion. The surface morphology of the cells composing these aggregates was characterized under various culture conditions using light microscopy and scanning electron microscopy. The cytoplasmic processes of Sertoli cells became highly branched and filamentous after being cultured in the presence of rat, human or ovine FSH. Identical branching and filamentation was observed when Sertoli cells were cultured in rat TSH. Finally, numerous large blebs were observed on the surfaces of germinal cells cultured in the presence of insulin. These results suggest that the branching and filamentation of Sertoli cell cytoplasm observed after FSH stimulation are not specific for that hormone.

Animals↗