Circadian variations of DNA synthesis, mitotic activity, and cell size of hepatocyte population in young immature male mouse growing liver

Llanos, J. M. Echave; Aloisso, M. D.; M, Souto; Balduzzi, Romina; Surur, J. M.

doi:10.1007/bf02893540

Cited by 30 publications

(2 citation statements)

References 11 publications

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“…This is particularly true with respect to the times when the factors are injected and the controls are made, which must be related to the well-known circadian variations in growth variables (Echave Llanos 1967; Clausen and Elgjo 1984). These variables behave normally (Echave Llanos et al 1971;Surur et al 1985) only when partial hepatectomy is made at the optimal time in a circadian period (Souto and Echave Llanos 1985). The results obtained with normal plasma are a good example of this requirement.…”

Section: Discussionmentioning

confidence: 96%

Inhibiting effect of plasma from normal and tumour bearing mice on the mitotic rate of regenerating liver

Llanos

Moreno

Badrán

1986

Virchows Archiv B Cell Pathol

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Plasma from normal mice and from mice bearing the ES2 transplatable malignant tumour was injected intraperitoneally at a dose of 0.01 ml/g body weight in partially hepatectomized mice. Control animals were injected with a solution of sodium citrate in saline. The recipients were killed at the first (14:00 hours/48 h). These times are the time of day and the number of h after partial hepatectomy and second (14:00 hours/72 h) peak times after partial hepatectomy. The number of colchicine metaphases per 1000 nuclei was determined for hepatocytes and litoral cells. A different effect was obtained with plasma from tumour-bearing compared with normal mice. Plasma from both sources when injected 26 h after partial hepatectomy (16:00 hours/26 h) inhibited the mitotic activity of hepatocytes at the next peak of regenerative activity (14:00 hours/48 h). The plasma from tumour-bearing mice also inhibited the peak on the following day (14:00 hours/72 h), whereas plasma from normal mice had no inhibitory effect and, indeed, a compensatory wave was observed at this time. Furthermore, plasma from tumour-bearing mice also showed an inhibitory effect at the first peak (14:00hours/48 h) when injected at the time of partial hepatectomy (14:00 hours/00 h) or at 22 h before partial hepatectomy (16:00 hours/ -22 h) whereas the injection of plasma from normal mice at these times had no inhibitory effect. In the litoral cells the injection of plasma from tumour-bearing mice made 22 h before hepatectomy (16:00 hours/-22 h) led to a stimulation of mitotic activity which was controlled at 14:00 hours/48 h. Injection made at the time of partial hepatectomy (14:00 hours/00 h) caused inhibition at 14:00 hours/48 h and injection at 26 h after partial hepatectomy (16:00 hours/26 h) had no effect. The three injections of normal plasma did not modify the mitotic activity of litoral cells at either 14:00 hours/48 h or at 14" 00 hours/72 h.

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Section: Discussionmentioning

confidence: 96%

Inhibiting effect of plasma from normal and tumour bearing mice on the mitotic rate of regenerating liver

Llanos

Moreno

Badrán

1986

Virchows Archiv B Cell Pathol

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“…In previous papers we have analysed the physiological circadian rhythms of growth in the intact liver (Echave Llanos (1967b;Echave Llanos et al 1971 ;Surur et al 1984), and the circadian rhythm-related waves of proliferation in regenerating liver have been studied by Bade et al 1966. On the basis of this information, we determined the time of the day suitable for partial hepatectomy (Souto and Echave Llanos 1985), and the correct posthepatectomy time period for measuring the maximum inhibitory effect to tissue extracts (Echave Llanos 1967b). These are the times most suitable for partial hepatectomy, and when an injection of an extract produces maximum inhibition of the first post-hepatectomy regeneratory peak in the mitotic rate.…”

Section: Introductionmentioning

confidence: 99%

Inhibiting effect of a hepatoma extract on the mitotic rate of regenerating liver

Llanos

Badrán

Moreno

1986

Virchows Archiv B Cell Pathol

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Aqueous tumor extracts were prepared by the homogenization of a fast-growing, undifferentiated, transplantable malignant murine hepatoma in distilled water. After centrifugation, an aliquot of 0.01 ml of the supernatant g body weight was injected intraperitoneally into partially hepatectomized mice. Control animals were injected with saline. Groups of mice were killed at various times in relation to the hepatectomy. Four h before killing the animals were given Colcemid (1 ~tg/g body weight). The number of Colcemid-arrested mitoses in the hepatocytes and in the littoral cells, respectively, were counted in 140 microscopic fields. The extract significantly inhibited the mitotic rate in hepatocytes when the injection was given between 22 h before, and up to 26 h after hepatectomy. In the littoral cells, a slight initial stimulation was followed by a slight but significant inhibition which occurred when the injection was given at hepatectomy or until 18 h after hepatectomy. The effect was not modified by exposing the extracts to temperatures of 47 ~ C for 30 rain or 22 ~ C for 24 h, but 10 rain of boiling destroyed their inhibitory effect. Lyophilization and storing at -18~ for up to 4 weeks did not modify the effect. The mitosis-inhibiting effect was also measurable when the extract was injected subcutaneously. There was an almost linear dose-response curve. The results are discussed in relation to circadian rhythms, the pattern of liver cell proliferation after hepatectomy, and recent similar reports from the literature. The conclusion is drawn that extracts of a hepatoma contain one or more growth-inhibitory factors significantly active on regenerating liver cells, and less significantly on littoral cells.

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Circadian variation of epidermal growth factor receptor in mouse liver

Scheving

Tsai²,

Cornett

et al. 1989

Anat. Rec.

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The liver undergoes a biochemical and morphological circadian transformation. In this paper, we document circadian variation in the binding parameters of the hepatic epidermal growth factor receptor (EGFR). Liver membranes were prepared from ad libitum fed or fasted male CD2F1 mice killed at different circadian phases at 4 h intervals. Bmax (maximum binding) and Kd (dissociation constant) varied in a rhythmic fashion. The range of change for Bmax along the 24 h time scale was 423%. For Kd, it was 162%. Both peaked late in the dark span, and decreased late in the light span. Fasting and EGF treatment reduced Bmax and the amplitude of circadian variation.

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Circadian variations of DNA synthesis, mitotic activity, and cell size of hepatocyte population in young immature male mouse growing liver

Cited by 30 publications

References 11 publications

Inhibiting effect of plasma from normal and tumour bearing mice on the mitotic rate of regenerating liver

Inhibiting effect of plasma from normal and tumour bearing mice on the mitotic rate of regenerating liver

Inhibiting effect of a hepatoma extract on the mitotic rate of regenerating liver

Circadian variation of epidermal growth factor receptor in mouse liver

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