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1.
F Croze P Gysen A Demoulin P Franchimont 《Comptes rendus des séances de la Société de biologie et de ses filiales》1980,174(2):205-210
Three preparations of inhibin extracted from ram rete testis fluid (RTF) and from human seminal plasma (HSP) reduce tritiated thymidine incorporation into testicular desoxyribonucleic acids (DNA) in vitro. Effect of low molecular inhibin from RTF is dose-dependent. Castrated ram serum does not modify testicular DNA synthesis in vitro. Besides their suppressive action on follicle stimulating hormone (FSH) secretion in vivo and in vitro, these inhibin preparation display a direct inhibiting effect on testicular DNA synthesis and, thus, on mitotic activity. Identity between inhibin and testicular chalones are discussed. 相似文献
2.
Inhibin (follicle stimulating hormone suppressing factor) isolated from ovine testes has been characterized for its biological activity using a variety of tests. The bioassay used — inhibition of the human chorionic gonadotropin induced increment in the mouse uterine weight-demonstrates that there is a significant increment in specific activity (approx. 300-fold) with the progress of purification. Eventhough the final product has not been obtained in a homogenous state it has been possible to show that(a) [125I]-labelled inhibin is preferentially taken up and retained by the pituitary, pretreatment of rats with testosterone facilitating this uptake;(b) it is able to suppress specifically the levels of follicle stimulating hormone in castrated as well as immature intact rats and (c) treatment of immature male rats with inhibin preparation for ten days results in impairment of testicular function as judged by3H-thymidine incorporation into testicular DNA and testicular hyaluronidase activity. 相似文献
3.
J. P. G. Williams 《Cell proliferation》1970,3(2):155-159
Vinblastine inhibits the synthesis of DNA in mouse fetuses in utero, the incorporation of tritiated thymidine into the gut of the parent is, however, not altered. This selective effect, although found with other spindle inhibitors, is not due to the mitotic arresting property of the drug. 相似文献
4.
W C Claycomb 《The Journal of biological chemistry》1976,251(19):6082-6089
A single injection of either isoproternol or N6, O2'-dibutyryl adenosine 3':5'-monophosphate (dibutyryl cyclic AMP) results in an inhibition in the rate of [3H]thymidine incorporation into DNA of differentiating cardiac muscle of the neonatal rat. This inhibition is not due to substantially altered cellular uptake or catabolism of [3H]thymidine. Inhibition of [3H]thymidine incorporation by isoproterenol or dibutyryl cyclic AMP is potentiated by theophylline. Maximal inhibition (95%) is observed 24 h after administration of isoproterenol, and the rate of incorporation returns to a value 80% of control by 72 h. Norepinephrine also inhibits [3H]thymidine incorporation whereas cyclic GMP, N2, 02-Dibutyryl guanosine 3':5'-monophosphate (dibutyryl cyclic GMP), and phenylephrine have little effect. Equilibrium sedimentation analysis of cardiac muscle DNA in neutral and alkaline cesium chloride gradients using bromodeoxyuridine as a density label indicate that isoproterenol and dibutyryl cyclic AMP inhibit [3H]thymidine incorporation into DNA that is replicating semiconservatively. Administration of isoproterenol or dibutyryl cyclic AMP to neonatal rats inhibits by approximately 60% the incorporation of [3H]thymidine into DNA of tissue slices of cardiac muscle prepared 16 h later. [3H]Thymidine incorporation into DNA of tissue slices is into chains that were growing in vivo. This incorporation is linear for at least 4 h of incubation and is inhibited by isoproterenol and dibutyryl cyclic AMP. Inhibition is not due to altered cellular uptake of [3H]thymidine nor is it due to a cytotoxic action. Several other compounds which elevate intracellular levels of cyclic AMP (epinephrine, norepinephrine, glucagon, and prostaglandin E1) also inhibit [3H]thymidine incorporation into DNA or cardiac muscle tissue slices. Cyclic GMP, dibutyryl cyclic GMP, sodium butyrate, and phenylephrine have little effect. Isoproterenol administered together with theophylline to neonatal rats signficantly stimulates the in corporation of [3H]phenylalanine into total cardiac muscle protein and into myosin. This enhanced incorporation may be due in part to an increase in the cellular uptake of [3H]phenylalanine. DNA synthesis decreases progressively in differentiating cardiac muscle of the rat during postnatal development and essentially ceases by the middle of the third week (Claycomb, W. C. (1975) J. Biol. Chem. 250, 3229-3235). In reviewing the literature it was found that this decline in synthetic activity correlates temporally with a progressive increase in tissue concentrations of norepinephrine and cyclic AMP and with the anatomical and physiological development of the adrenergic nerves in this tissue. Because of these facts and data presented in this report it is proposed that cell proliferation and cell differentiation in cardiac muscle may be controlled by adrenergic innervation with norepinephrine and cyclic AMP serving as chemical mediators. 相似文献
5.
J P Soulillou J Lucas C Fontenaille 《Comptes rendus des séances de la Société de biologie et de ses filiales》1975,169(1):42-47
DNA synthesis by the kidneys was studied in young rats by incorporation of tritiated thymidine. Peak of DNA synthesis was observed as soon as 24 hr after uninephrectomy. No significative difference was observed between control rats and those receiving various doses of serum obtained from uninephrectomized or sham operated rats. Serum of uninephrectomized rats did not increase DNA synthesis in kidney slices in vitro. 相似文献
6.
Changes in the rate of testicular DNA synthesis in the rat were studied at various times after single doses of 12 cancer chemotherapeutic agents. The animals were given intravenous injections of [14C]thymidine and [3H]thymidine 24 and 3 h, resp., before they were killed. By combining measurements of the free serum radioactivity and the testicular incorporation of the differentially labelled precursor, different response patterns were obtained for agents with different modes of action. The DNA-damaging agents cyclophosphamide, chlorambucil, thio-TEPA, busulphan, CCNU and procarbacine, after some delay, caused a decrease of testicular thymidine incorporation and a corresponding increase of free serum radioactivity. The non-DNA-damaging agents 5-fluorouracil, methotrexate, hydroxyurea and cytosine arabinoside had a rapid effect on testicular thymidine incorporation and produced diverse response patterns different from that of the DNA-damaging agents. Actinomycin D and also vinblastine caused changes in testicular thymidine incorporation and showed response patterns different from those of the other agents. These results show that simple measurements of testicular DNA synthesis may provide useful information for the evaluation of genotoxic effects of chemical compounds and may help one to distinguish between DNA-damaging agents and metabolic inhibitors of DNA synthesis. 相似文献
7.
J. Martinez M. Riera † J. Lalucat † J. Vives-Rego ‡ 《Letters in applied microbiology》1989,8(4):135-138
The incorporation of tritiated ([3 H]-) thymidine into DNA by axenic laboratory cultures of a common marine blue-green algae and two marine eukaryotic algae was measured. Tritiated thymidine was incorporated into the cold TCA fraction of the cyanobacterium and eukaryote algae. However, only in the culture of cyanobacterium was the thymidine consistently incorporated into DNA. Considering the usual algal densities in natural habitats, thymidine concentrations and incubation times, our data do not preclude the use of thymidine incorporation in bacterial production studies in marine environments. 相似文献
8.
The effects of somatostatin on the spontaneous and TSH--stimulated incorporation of tritiated thymidine into the rat thyroid lobes incubated in vitro were investigated. The rate of 3H-thymidine incorporation was used as an index of thyroid follicular cells (TFC) proliferation. It was shown that: 1) somatostatin, at a concentration of 10(-7)M, decreased 3H-thymidine incorporation into DNA of TFC, 2) the highest somatostatin concentration, as tested in this study (10(-6)M), produced a similar decreasing effect; the decrease, in this case, did not attain significance vs. controls, 3) somatostatin, when employed together with TSH, suppressed the stimulatory effect of the latter hormone on 3H-thymidine incorporation into DNA of thyroid lobes. 相似文献
9.
A Lupulescu 《Prostaglandins》1975,10(4):573-579
The effect of exogenous prostaglandins E1, E2 and F2alpha (PGE1, PGE2 and PGF2alpha) on 3H-leucine, 3H-uridine, 3H-thymidine and 3H-proline incorporation in experimental cutaneous wounds has been studied in rats. Prostaglandins E1 and E2 markedly stimulate the incorporation of these tritiated precursors, into protein, RNA, DNA and collagen synthesis, whereas F2 inhibits it. All tested prostaglandins exhibit their maximum effect within the first hours following administration. Most active is PGE1. These observations indicate that application of prostaglandins significantly stimulate incorporation with protein, RNA, DNA and collagen synthesis in the skin of wounded rats and thus, may play a role in epidermal cell growth and division as well as in scar-forming tissue. 相似文献
10.
About twice as much tritiated thymidine ([3H]TdR) is taken up by cells at the bottom of the crypt of the small intestine as by the rapidly cycling mid-crypt cells. However, the uptake of tritiated deoxyuridine ([3H]UdR) is even throughout the crypt. Exogenous thymidine is incorporated about four times and eight times more efficiently than deoxyuridine by the cells in the mid-crypt and cells at the bottom of the crypt, respectively. However all S phase cells in the crypt appear to be capable of using either precursors, i.e. either the de novo or salvage pathway. Since methotrexate (1 or 5 mg/kg) inhibits (at 5 mg/kg completely) the uptake of [3H]UdR, but has no effect on [3H]TdR uptake, the de novo and salvage pathways appear to be independent. Within the precision of the methods used in the experiments the 3 hr inhibition of the de novo pathway of deoxythymidylic acid (dTMP) synthesis by methotrexate does not produce any increase in utilization of the salvage pathway measured by incorporation of [3H]TdR into DNA. The increased efficiency of thymidine utilization by crypt base cells is not attributable to differences in accessibility of thymidine; differences in the rate of DNA synthesis or the size of the nuclei. It appears that crypt base cells (which include the putative stem cells) are efficient scavengers of [3H]TdR, and this might be related to the level of thymidine kinase activity within the cells, and/or to changes in the availability of endogenous thymidine (break-down products) which compete with exogenous [3H]TdR.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
11.
Abstract. About twice as much tritiated thymidine ([3 H]TdR) is taken up by cells at the bottom of the crypt of the small intestine as by the rapidly cycling mid-crypt cells. However, the uptake of tritiated deoxyuridine ([3 H]UdR) is even throughout the crypt.
Exogenous thymidine is incorporated about four times and eight times more efficiently than deoxyuridine by the cells in the mid-crypt and cells at the bottom of the crypt, respectively. However all S phase cells in the crypt appear to be capable of using either precursors, i.e. either the de novo or salvage pathway.
Since methotrexate (1 or 5 mg/kg) inhibits (at 5 mg/kg completely) the uptake of [3 H]UdR, but has no effect on [3 H]TdR uptake, the de novo and salvage pathways appear to be independent. Within the precision of the methods used in the experiments the 3 hr inhibition of the de novo pathway of deoxythymidylic acid (dTMP) synthesis by methotrexate does not produce any increase in utilization of the salvage pathway measured by incorporation of [3 H]TdR into DNA. the increased efficiency of thymidine utilization by crypt base cells is not attributable to (i) differences in accessibility of thymidine; (ii) differences in the rate of DNA synthesis or (iii) the size of the nuclei. 相似文献
Exogenous thymidine is incorporated about four times and eight times more efficiently than deoxyuridine by the cells in the mid-crypt and cells at the bottom of the crypt, respectively. However all S phase cells in the crypt appear to be capable of using either precursors, i.e. either the de novo or salvage pathway.
Since methotrexate (1 or 5 mg/kg) inhibits (at 5 mg/kg completely) the uptake of [
12.
Katsuyoshi Takatsuki Kenji Fujiwara Shigeki Hayashi Yasuhiko Ota Masao Torii Shunji Mishiro Itsuro Ogata Akira Sakuma Hiroshi Oka Toshitsugu Oda 《Life sciences》1981,29(25):2609-2615
The effect of insulin and/or glucagon on the cumulative incorporation of tritiated thymidine was studied using normal rats with post-hepatectomized regenerating livers. Although the cumulative incorporation value was low at 20 hr and increased thereafter, a significant difference was not found between control and treated rats up to 60 hr after the operation. However, when rats were distributed according to the time the incorporation reached a maximum, there was a significant difference in the distributions between control rats and rats treated with combined insulin and glucagon (P=0.0303); more rats showed maximum incorporation at earlier times after treatment. These results suggest that a combination of the two hormones accelerates DNA synthesis in post-hepatectomized regenerating liver of normal rats. 相似文献
13.
M. Moorghen P. Ince Karen J. Finney A. J. Watson A. L. Harris 《In vitro cellular & developmental biology. Animal》1991,27(11):873-877
Summary The in-vitro effects of hydroxyurea 5-FU and 5-FUdR have been extensively studied in experimental systems employing cell-line
techniques. In this study we investigated the effects of these drugs on the levels of incorporation of labeled nucleosides
into DNA in explants of intact rat colonic mucosa maintained in organ culture. The effects of the nucleoside transport inhibitors
nitrobenzylthioinosine (NBMPR) and dipyridamole—which are modulators of antimetabolite cytotoxicity—on the incorporation of
tritiated thymidine [(3H]TdR) into DNA were also studied. The incorporation of tritiated TdR into DNA was reduced by hydroxyurea but was not altered
by either 5-FU or 5-FUdR. The levels of tritiated deoxyuridine were reduced by 5-FU and 5-FUdR in separate experiments; this
is in keeping with thymidylate synthase inhibition. NBMPR and dipyridamole also reduced 3H-TdR incorporation into DNA. These
results can be explained in terms of the known mechanisms of action of these drugs. This experimental model is therefore useful
in assessing the effects of antimetabolites and nucleoside transport inhibitors in intact colonic mucosa. 相似文献
14.
de Jong KP Brinker M van Veen M Daemen T Scherphof GL Slooff MJ 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1999,21(6):498-504
OBJECTIVE: To monitor liver regeneration following partial hepatectomy, liver cell proliferation can be measured by assaying in vivo [3H]thymidine incorporation into liver cell DNA. We hypothesized that [3H]thymidine incorporation into whole liver tissue parallels [3H]thymidine incorporation into liver cell DNA, both in high proliferating and low proliferating liver. STUDY DESIGN: Liver cell proliferation in rats after partial hepatectomy or a sham operation was studied by measuring incorporation of [3H]thymidine into various fractions of liver tissue on days 1, 2, 3, 4 and 10 after surgery. RESULTS: [3H]thymidine incorporation into whole liver tissue and in the protein fraction correlated well with DNA-specific [3H]thymidine incorporation into regenerating (r > .80, P < .0001) and nonregenerating liver (r > .69, P < .005). [3H]thymidine incorporation into DNA was < 5% of the total amount of administered [3H]thymidine in both sham-operated and hepatectomized rats. Significant differences in [3H]thymidine incorporation into partially hepatectomized livers as compared to sham-operated rat livers were found on days 1 and 2 (whole liver tissue and protein fraction) or day 1 (DNA) after surgery. CONCLUSION: [3H]thymidine incorporation into whole liver tissue is a simple technique that can be used for the study of liver cell proliferation after partial hepatectomy in rats. 相似文献
15.
Validity of the tritiated thymidine method for estimating bacterial growth rates: measurement of isotope dilution during DNA synthesis. 总被引:23,自引:21,他引:2
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The rate of tritiated thymidine incorporation into DNA was used to estimate bacterial growth rates in aquatic environments. To be accurate, the calculation of growth rates has to include a factor for the dilution of isotope before incorporation. The validity of an isotope dilution analysis to determine this factor was verified in experiments reported here with cultures of a marine bacterium growing in a chemostat. Growth rates calculated from data on chemostat dilution rates and cell density agreed well with rates calculated by tritiated thymidine incorporation into DNA and isotope dilution analysis. With sufficiently high concentrations of exogenous thymidine, de novo synthesis of deoxythymidine monophosphate was inhibited, thereby preventing the endogenous dilution of isotope. The thymidine technique was also shown to be useful for measuring growth rates of mixed suspensions of bacteria growing anaerobically. Thymidine was incorporated into the DNA of a range of marine pseudomonads that were investigated. Three species did not take up thymidine. The common marine cyanobacterium Synechococcus species did not incorporate thymidine into DNA. 相似文献
16.
Summary [3H] thymidine incorporation into DNA of the parotid (PA) gland of adult and 20-day-old rats and into DNA of the pancreas (PANC) of 20-day-old rats was increased markedly following a 2-day regimen of isoproterenol (ISO) administration. However, when the submandibular-sublingual (SM-SL) glands had been removed just prior to initiation of the ISO injections, the [3H] thymidine incorporation into PA and PANC was inhibited, and cpm/mg protein of these organs was even lower than that of organs of untreated rats with SM-SL glands present. Removal of the PA glands just prior to initiation of the ISO regimen had no effect on the ISO-induced [3H] thymidine incorporation into DNA of PANC but partially inhibited that of the submandibular (SM) gland. It is suggested that the inhibitory effects on DNA and RNA synthesis that follow removal of SM-SL glands are attributable to the growth factors (epidermal growth factor and nerve growth factor) found in the rat SM gland. These factors appear to regulate normal DNA synthetic activity of exocrine glands as well as
1-adrenoceptor mediated DNA synthesis. Cellular hypertrophy induced by the ISO was less markedly affected by absence of the SM glands, but a partial inhibition of [3H] uridine incorporation into RNA of PA of adult rats also occurred when SM-SL glands were removed prior to initiation of the ISO-regimen. 相似文献
17.
S S Howards C J Flickinger D W Noller W B Panko 《Journal of reproduction and fertility》1979,55(2):401-405
The effects of vasectomy on testicular DNA production were studied in guinea-pigs at 2 weeks and 2 and 6 months after surgery. By 6 months, vasectomy had resulted in lower testicular weight and absolute DNA, RNA and protein contents, although RNA and DNA concentrations/protein were unchanged. Incorporation of thymidine into the testis had decreased by 2 weeks after vasectomy, and continued to do so unless the ductal system subsequently ruptured and formed a granuloma when thymidine incorporation returned to normal control levels. It is suggested that in the guinea=pig vasectomy alters spermatogenesis by reducing testicular DNA synthesis. 相似文献
18.
The incorporation of thymidine into DNA in the presence of hydroxyurea (HU) by guinea pig pancreatic slices following exposure to N-nitrosomethylurethane (NMUT) was used to follow DNA repair synthesis. HU was used to suppress normal replicative DNA synthesis. Slices from the duodenal segment of the pancreas were exposed for periods of 15 to 90 min to NMUT at concentrations of 2 to 20 mM, then incubated in tritiated thymidine ([H3]-TdR) free of carcinogen, and radioactivity in DNA was determined. NMUT induced a a dose- and time-dependent increase in HU-insensitive thymidine incorporation. This stimulated incorporation, which could be attributed to repair synthesis, occurred immediately following the treatment and was largely complete within 3 h. 相似文献
19.
Smooth muscle cells (SMC) from various arterial origins have been successfully maintained in culture. The present study evaluates the proliferative activity of aortic and mesenteric SMC in culture. Aortic and mesenteric SMC were obtained from male Wistar rats by explant and enzyme digestion techniques, respectively. Vascular SMC obtained by either method exhibited a characteristic hill-and-valley growth pattern in culture after confluence and were positively labelled with either anti-smooth muscle actin or myosin by an indirect immunofluorescent method. The rate of incorporation of thymidine into DNA and cell number counting were used as indices of proliferation in vitro. Vascular SMC from passages 4-33 were first synchronized with either Dullbecco's Modified Eagle's Medium (DME) or Ham's F-12 medium, supplemented with insulin-transferring-selenium (ITS), for 72 hours. SMC were then stimulated with 10% bovine serum for either 24 or 72 hours with the former processed for scintillation counting, the latter for cell number determination. The incorporation of tritiated thymidine into DNA following a 2 hour incubation was determined by scintillation counting after perchloric acid extraction. In terms of cell numbers, proliferative responses to bovine serum were determined by Coulter counting. Autoradiography was also carried out in some cultures to determine both thymidine and mitotic labelling indices. The rate of thymidine incorporation in aortic cells was 2-3 fold higher than in mesenteric cells. Aortic and mesenteric SMC lines exhibited similar cell cycle intervals in terms of total duration and individuals cycle parameters. However, the total thymidine index was higher in the aortic than mesenteric SMC.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
20.
G Rappay I S Komolov I Fazekas E Bácsy V V Abramova V P Fedotov 《Acta biologica Academiae Scientiarum Hungaricae》1980,31(1-3):249-255
Cell suspensions derived from adult rat anterior pituitary glands were cultured for up to eight days. Prolactin immunoreactivity and/or tritiated thymidine incorporation into DNA of cell nuclei were demonstrated in cells with and without thyroliberin (TRH) and somatostatin (SRIF) treatment. It has been established that (a) TRH, which is effective in releasing both thyrotropin and prolactin, may stimulate cell proliferation in other than its target cells; that (b) SRIF has no effect on lactotropic cell proliferation and augments thymidine incorporation into DNA of unidentified cells; that (c) immunoreactive lactotropic cells with tritium-labelled nuclei are present in each culture, independent of hypothalamic hormone treatments. 相似文献