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J M Orth

Publications and source records attributed to J M Orth.

30 records · Page 2Linked to original sources
PubMed1986

FSH-induced Sertoli cell proliferation in the developing rat is modified by beta-endorphin produced in the testis.

To probe the possible role of endogenous opiates in Sertoli cell proliferation during testicular development, the effect of interfering with beta-endorphin action either in vivo or in vitro was determined. The percent of Sertoli cells dividing was measured with quantitative autoradiography in [methyl 3H]-thymidine-exposed fetal testes maintained in organ culture with or without FSH, in the presence or absence of the opiate blocker naloxone. After 1 or 2 days in culture, naloxone enhanced the rise in Sertoli cell proliferation seen with FSH alone, while 2 days of incubation with naloxone alone markedly raised the percent of Sertoli cells dividing above that in untreated cultures. Moreover, when endorphin antiserum was injected directly into testes of pups and Sertoli cell proliferation in vivo measured 8 or 19 h later, there was a dramatic increase in the percent of Sertoli nuclei labeled by [methyl 3H]-thymidine compared to controls. These findings suggest that beta-endorphin produced within the testis is a paracrine modifier of the proliferative response of Sertoli cells to FSH. This implies that communication occurs between Leydig and Sertoli cells during development via endogenous testicular opiates.

Animals↗
PubMed1985

Gonadal dysfunction in the spontaneously diabetic BB rat: alterations of testes morphology, serum testosterone and LH.

Serum testosterone, luteinizing hormone (LH), testicular histology and ultrastructure were examined in 91 spontaneously diabetic BB, semi-starved, and control Wistar rats. Between 80-120 days of age serum testosterone was decreased (1.67 +/- .25 vs. 2.95 +/- .48 ng/ml; P less than .05) in the BB rats compared to controls but not different from semi-starved rats. LH values were similar in control and BB rats (49.4 +/- 10.9 vs. 46.8 +/- 6.2 ng/ml). Abnormal lipid droplets were noted within Leydig cells at this period. From 121-150 days of age serum testosterone was lower in BB (1.38 +/- .23 vs. 3.42 +/- .45 vs. 2.94 +/- .81 ng/ml; P less than .05) than controls or semi-starved rats. Serum LH was not significantly higher in controls than in BB rats (63.2 +/- 7.4 vs. 36.6 +/- 12 ng/ml; P = NS). Between 151-200 days of age, there was further lipid accumulation in Leydig cells in the BB rat and occasional epithelial disorganization. After 200 days, serum testosterone decreased (P less than .05) to similar levels in both control and BB rats (1.42 +/- .87 vs. 1.22 +/- .25; P = NS) and was similar in BB rats after 250 days (1.02 +/- .2 ng/ml). After 250 days of age Leydig cell morphology appeared relatively normal but marked alterations were apparent in Sertoli cells, germ cells and morphology of the tubule wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1984

Hemicastration causes and testosterone prevents enhanced uptake of [3H] thymidine by Sertoli cells in testes of immature rats.

Rat pups were hemicastrated and uptake of [3H] thymidine by Sertoli cells in the remaining testis was compared to that in testes of sham-operated pups at intervals of from 8 h to 21 days after surgery. Labeled thymidine was administered subcutaneously 2 h before sacrifice. Testes were processed for light microscope autoradiography and the percent of Sertoli cell nuclei that had incorporated [3H] thymidine was determined by scoring nuclei in tissue sections as labeled or unlabeled. The percentage of cells labeled was increased in hemicastrates over intact controls by 8 h after surgery and testicular hypertrophy became apparent in hemicastrates by the following day. Labeling of Sertoli cells in hemicastrates remained elevated for 4 days and then returned to normal. When plasma levels of gonadotropins were measured in both groups 4 days after surgery, follicle-stimulating hormone (FSH) was found to be more than twice normal in hemicastrates while luteinizing hormone (LH) was unchanged. The effect of testosterone on the response of Sertoli cells to hemicastration was also examined. In hemicastrates, 2 days of androgen therapy depressed, and an additional 2 days abolished, the proliferative response of the Sertoli cells. Our findings suggest that increased proliferation of Sertoli cells within the remaining testis is involved in the enlargement of the testis that follows hemicastration. They also imply that prevention of compensatory hypertrophy by testosterone involves interference with this response of Sertoli cells in some way. Finally, our data implicate FSH in control of Sertoli cell proliferation in vivo in immature rats.

Animals↗
PubMed1984

The role of follicle-stimulating hormone in controlling Sertoli cell proliferation in testes of fetal rats.

Proliferation of Sertoli cells in the rat testis occurs only during the perinatal period and is maximal during fetal life. This interval is thus of critical importance in establishing the complement of Sertoli cells that populates the adult testis. FSH has been implicated in this process, but direct evidence in support of its involvement is lacking. In the present study, we have used in vivo and in vitro approaches to determine whether FSH produced by the fetal pituitary has a role in regulating Sertoli cell division in the fetal testis of the rat. On day 18 of gestation, just before the onset of maximal Sertoli cell proliferation, fetuses were either decapitated in utero or given antiserum to FSH. Light microscope autoradiography was then used to compare uptake of [3H]thymidine by Sertoli cell nuclei in testes from decapitated or antiserum-treated fetuses to that in corresponding controls on the following day. Both treatments produced dramatic and equal reductions in the percentages of Sertoli cells preparing to divide on day 19, suggesting that FSH from the fetal pituitary stimulates Sertoli cell proliferation in fetal testes. The effect of FSH or (Bu)2cAMP on Sertoli cell proliferation was also studied in vitro by placing testes from intact or decapitated fetuses into organ culture, with or without exogenous hormone or cyclic nucleotide. In all cases, [3H]thymidine was present for the final 4 h of culture. When testes were placed into medium containing isotope immediately after their removal from the fetus, the difference in labeling between testes from intact and decapitated fetuses was similar to that measured in vivo. After testes from decapitated fetuses were cultured for 8 h with or without FSH or (Bu)2cAMP, labeling of Sertoli cells in the treated group increased markedly over that in untreated cultures. After 28 h of exposure to FSH or (Bu)2cAMP, labeling in testes from decapitated fetuses remained significantly higher than that in corresponding untreated controls. In contrast, when testes from intact rats were cultured for 8 h in the presence of either cAMP or FSH, (Bu)2cAMP, but not FSH, brought about an increase in the percentage of Sertoli cells labeled compared to the control value. However, after exposing these testes to either FSH or (Bu)2cAMP for 28 h, the percentage of Sertoli cells labeled was greatly enhanced. Taken together, the data obtained from these experiments identify FSH as a major factor in controlling expansion of the Sertoli cell population during fetal development of the rat.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

Gonadal dysfunction in the spontaneously diabetic BB rat.

Diabetes which occurs spontaneously in the BB Wistar rat is associated with reduced fertility, predominantly in breeding males. In the first month of diabetes, there is a significant (p less than 0.05) reduction in serum testosterone associated with a transient decrease of serum LH and the accumulation of lipid in Leydig cells. Between one and three months of diabetes, there is an increase in both serum testosterone and LH and a further deposition of lipid droplets in Leydig cells. From three to six months of diabetes, there is a reduction of serum testosterone similar to age-matched controls, but high serum LH levels persist. Similar levels of LH and testosterone are noted after six months of diabetes, and all BB rats show marked changes in seminiferous tubules. These morphological changes in tubules consist of increased tubular wall thickness, severe germ-cell depletion, and Sertoli-cell vacuolization. Similar morphological changes of testes associated with generalized atrophy are noted in all control rats after 16 months of age. Decreased fertility in the BB rat appears to be associated with a primary disorder of Leydig cells, which precedes changes in seminiferous tubules consistent with accelerated aging. Preliminary data in impotent diabetic men suggest that the BB rat may be a valuable model for investigating human diabetic impotence and infertility.

Age Factors↗
PubMed1983

Environmental stress alters the developmental pattern of delta 5-3 beta-hydroxysteroid dehydrogenase activity in Leydig cells of fetal rats: a quantitative cytochemical study.

Quantitative cytochemistry was used to determine the effect of subjecting pregnant rats to environmental stress on the activity of delta 5-3 beta hydroxysteroid dehydrogenase (3 beta-HSD) in Leydig cells of their fetuses. Enzyme activity was measured by microspectrophotometry in individual Leydig cells in cryostat sections of fetal testes on Days 16-21 postconception. Fetuses of stressed mothers lacked the peak of enzyme activity on Days 18 and 19 of gestation that is characteristic of Leydig cells of normal fetuses at this time. In addition, both before and after these 2 days, 3 beta-HSD activity in Leydig cells of stressed fetuses was significantly higher than normal. The altered developmental pattern of 3 beta-HSD activity in the stressed fetuses largely corresponds to the changes in plasma testosterone found previously in male fetuses of mothers exposed to the same regimen of stress. Thus, in the fetal Leydig cell, the activity of 3 beta-HSD, a key steroidogenic enzyme, can be modified by environmental stress, and provides an index of steroidogenic activity of the fetal testes and of the titers of circulating testosterone.

3-Hydroxysteroid Dehydrogenases↗
PubMed1982

Proliferation of Sertoli cells in fetal and postnatal rats: a quantitative autoradiographic study.

Proliferation of Sertoli cells during fetal and postnatal development of the rat was examined and quantified with light microscope autoradiography. Fetuses in utero were injected subcutaneously with 3H-thymidine. The percentages of Sertoli nuclei that had incorporated label were determined in autoradiographs from fetuses aged 16 through 21 days of gestation. To compare the degree of Sertoli cell proliferation during fetal development with that occurring after birth, pups were also studied at intervals between the day of birth and 3 weeks of age. For each fetus or pup, at least 500 Sertoli cell nuclei in each of three sections were scored as labeled or unlabeled. These data were subjected to analysis of variance and the Newman-Keuls test. The percentage of Sertoli cells incorporating 3H-thymidine increased progressively from day 16 of gestation onward, to a maximum of 26.8% on day 20, two days before birth. Thereafter, this percentage dropped steadily until, in pups 21 days after birth, no labeled Sertoli cells were detected. These findings highlight the fetal period as the time of greatest expansion of the Sertoli cell population and indicate that, at birth, proliferation of these cells is already on the decline.

Animals↗
PubMed1979

Ultrastructural changes in Leydig cells of streptozotocin-induced diabetic rats.

Hyperglycemia (experimental diabetes) was induced in adult male rats by destruction of the pancreatic beta cells with a single intravenous injection of streptozotocin (STZ). Testes from diabetic, from insulin-treated diabetic, and from sham-injected normal rats were fxed by vascular perfusion. The fine structure of Leydig cells was examined at two, three, and four weeks after the STZ injection in the untreated diabetic animals, and at four weeks in the controls and insulin-treated diabetic rats. A number of morphological changes was observed in Leydig cells of untreated diabetic animals. Most obvious of these was an accumulation of lipid droplets, not normally present in Leydig cells in adults of this species. Smooth endoplasmic reticulum (SER) was markedly reduced in Leydig cells of the hyperglycemic rats. Several types of intracellular bodies were seen exclusively in Leydig cells of the untreated diabetic animals. Many resembled secondary lysosomes or dense bodies, while others appeared to be autophagic vacuoles. In addition, a small, granule-containing lamellar structure was seen either within a typical dense body or free in the cytoplasm. Myelin-like structures were commonly observed within the cytoplasm of the Leydig cell or within mitochondria. The appearance of the mitochondria in diabetic rats was otherwise normal. The extracellular spaces surrounding Leydig cells from untreated hyperglycemic rats also contained large accumulations of myelin-like material. These structural changes appear to be direct consequences of the diabetic state of the animals, since the ultrastructure of insulin-treated diabetic rats did not differ from that of the controls. These findings may reflect an alteration or breakdown of Leydig cell components normally involved in the synthesis of androgen, and correlate with previous reports of lowered circulating levels of testosterone in diabetic rats.

Animals↗
PubMedDate not supplied

NCAM mediates adhesion between gonocytes and Sertoli cells in cocultures from testes of neonatal rats.

During neonatal development of the rat testis, gonocytes resume mitosis and display renewed motility to migrate toward the basal lamina, two events that occur in vitro when these cells are cocultured with Sertoli cells. However, although substantial evidence suggests that development of gonocytes depends on Sertoli cells, little is known of how these cell types interact beyond our previous observations that they communicate via gap junctions and adhere avidly to each other. In the present study, we utilized several approaches to examine the mechanism by which gonocytes adhere to Sertoli cells in vitro. First, we characterized this attachment in general by (1) determining its susceptibility to brief trypsinization in decreasing concentrations of Ca2+, (2) assessing the ability of gonocytes to adhere to Sertoli cells at reduced temperature, and (3) examining the effect of phospholipase C treatment on the number of gonocytes attached to a Sertoli cell monolayer. Because the findings suggested that a non-cadherin mechanism is involved, we used immunofluorescence to identify the presence of neural cell adhesion molecule (NCAM) at virtually all gonocyte-Sertoli cell (and Sertoli cell-Sertoli cell) boundaries and found that incubation of cocultures in the continuous presence of NCAM antibodies caused release of essentially all gonocytes (but not Sertoli cells) from the monolayer. We also found, in (3) above, that gonocyte-Sertoli cell adhesion was very susceptible to phospholipase C in cocultures isolated from newborns and maintained in vitro for 2 hours or 1 day but not in cultures maintained for 3 days. Moreover, cells isolated from pups 5 days old were as resistant to enzyme treatment at 2 hours postplating as were cultures from newborns after 3 days in vitro. Thus, the way in which gonocytes adhere to Sertoli cells appears to change during the immediate postnatal period, as reflected by the observed change in phopholipase sensitivity, perhaps indicating production of a phospholipase C-resistant NCAM isoform by several days after birth. These data constitute new information on the way in which postnatal gonocytes adhere to Sertoli cells and provide a basis for future work in our ongoing exploration of germ cell development in the neonatal rat testis.

Animals↗
PubMedDate not supplied

Hst7: a male sterility mutation perturbing sperm motility, flagellar assembly, and mitochondrial sheath differentiation.

Hst7, a mouse hybrid sterility locus, has been mapped in close linkage to four other hybrid sterility loci, on proximal chromosome 17 within the t complex. When an allele (s) of Hst7 from the species Mus spretus is crossed into the Mus musculus domesticus (laboratory mouse) background, all male offspring are sterile. This occurs regardless of whether the Hst7 allele on the other chromosome 17 homolog is wild-type (+) or an allele (t) derived from the structurally variant homolog known as a t haplotype. Males of the Hst7 genotype s/+ produce sperm that, after release from the cauda epididymis, display moderate asthenospermia (straight line velocity = 49 +/- 4 microm/second, significantly lower than 102 +/- 7 microm/second for congenic wild-type controls) and normal morphology. However, males of the Hst7 genotype s/t produce sperm whose forward movement is below the detectable limit of the sperm motion analysis system. In addition, these sperm exhibit a variety of flagellar abnormalities, with about one third having normal heads attached to sacklike caudal regions. These sacks consist of membrane-delimited cytoplasm containing disorganized and/or misshapen axonemal elements. The remainder of the sperm from s/t mice have flagella with seemingly normal axonemes, although many exhibit enlarged areas of cytoplasm in their midpieces with extra layers of misaligned mitochondria. The s/t sperm mitochondria also display diffuse and vacuolated matrices reminiscent of meiotic germ cell and spermatid mitochondria. Observations of developing spermatids in the s/t testis reveal an unusual phenotype in which gaps of varying length occur in the mitochondrial wrapping of the midpiece. These data suggest that both the s and t alleles of Hst7 are defective alleles that contribute differentially to the severe asthenospermia phenotype and interact genetically to perturb flagellar development.

Alleles↗
PubMedDate not supplied

Expression of 140-kDa neural cell adhesion molecule in developing testes in vivo and in long-term Sertoli cell-gonocyte cocultures.

The basis for cell-cell adhesion in the seminiferous epithelium of the developing testis is doubtless critical in supporting events that are essential for the onset and maintenance of normal spermatogenesis. In this study, we applied immunoblotting and immunolocalization approaches for the following reasons: 1) to ask whether neural cell adhesion molecule (NCAM) underlies cell-cell interactions in vivo, as we previously showed for cells in vitro, 2) to characterize the isoform or isoforms of NCAM expressed during testicular development, and 3) to study NCAM expression in long-term Sertoli cell-gonocyte cocultures and to compare and contrast this pattern of expression with that in vivo. Our findings indicate that NCAM is found ubiquitously at cell-cell interfaces within the seminiferous cord from birth through day 10 and thereafter is restricted to interstitial cells. Moreover, only polysialic acid-negative 140-kDa NCAM is expressed in the testis or in coculture, an isoform whose properties are compatible with the concept of NCAM as both a direct modifier of cell function and an indirect influence on cell responses mediated by other external factors. In addition, we found that germ cells, potentially gonocytes or Type A spermatogonia, persist in long-term cocultures maintained for 15 days after isolation from 5-day-old rat pups and that NCAM continues to be expressed at high levels in these cultures. This observation is in marked contrast to our observation that NCAM gradually decreases and eventually disappears in vivo by postnatal day 15. Thus, our findings indicate that 140-kDa NCAM is prominent in neonatal testes but is down-regulated by as yet unidentified mechanisms thereafter. Our findings also indicate that down-regulation of NCAM fails to occur in hormone- and serum-free Sertoli cell-germ cell cocultures.

Animals↗