Synthesis of taurocholate by rat fetal liver in organ culture: effects of cortisol in vitro.

1979 ◽  
Vol 237 (2) ◽  
pp. E177 ◽  
Author(s):  
T O Graham ◽  
D H Van Thiel ◽  
J M Little ◽  
R Lester

Taurocholate production by fetal hepatic organ cultures was measured by radioimmunoassay. Taurocholate production was maximal on day 1 of in vitro incubation, but was demonstrable in organ cultures maintained for periods up to 15 days. Explants obtained from fetuses of 18 gestational days of age produced only 82 pmol taurocholate per milligram dry weight of tissue during the first 24 h of incubation. Explants obtained from fetuses 21 gestational days of age produced 1,043 pmol taurocholate per milligram dry weight. The presence of cortisol (2.0 X 10(-6) M) in the incubation medium increased synthesis of taurocholate by rat fetal liver in which total taurocholate rose 50-fold above control after 120 h of incubation. In increasing concentrations from 2.0 X 10(-9) M to 2.0 X 10(-7) M, cortisol produced an incremental rise in taurocholate. However, additional increases in cortisol dose failed to provide further stimulation, and taurocholate production was inhibited by cortisol concentrations of 2.0 X 10(-5) M. The results provide further validation for the technique of fetal hepatic organ culture. They demonstrate that taurocholate synthesis is increasing rapidly during the final stages of gestation and show that cortisol augments taurocholate synthesis in a dose-response pattern.

Development ◽  
1962 ◽  
Vol 10 (4) ◽  
pp. 465-470
Author(s):  
Charles L. Foote ◽  
Florence M. Foote

Earlier reports (Foote & Foote, 1958a, b, 1959) describe growth and maintenance in vitro of larval organs, particularly gonads, of Rana catesbeiana and Xenopus laevis. Immature germ cells of both testes and ovaries are well maintained in vitro, especially if the culture medium is supplemented with watersoluble sex-hormonal substances, although germ cells in process of maturation become necrotic. Recently some urogenital organs from the salamander, Pleurodeles waltlii, have been grown in vitro. Tissues and organs from this amphibian might prove to be more suitable for tissue and organ culture investigations than those of Anurans. Animals at three different ages were used in this study: recently hatched larvae, metamorphosing animals, and adults. To determine whether sex differentiation would occur in vitro, trunk portions of young larvae of Pleurodeles waltlii of developmental stages 37–38 (Gallien & Durocher, 1957) were placed in organ cultures.


1992 ◽  
Vol 263 (3) ◽  
pp. R619-R623
Author(s):  
I. Vatnick ◽  
A. W. Bell

Ontogeny of fetal hepatic and placental growth and in vitro oxygen consumption (VO2) was investigated in fetal lambs at 75, 100, and 136 days postconception. Fetal hepatic relative weight and placental absolute and relative weights declined during this period. Oxygen consumption per gram dry weight of fetal liver and maternal placenta declined between mid and late gestation while fetal placental VO2 was unchanged. Estimated VO2 of the whole placenta did not change while the estimated total hepatic VO2 increased more than threefold between 75 and 136 days. Total hepatic VO2 was highly correlated with total placental VO2 at 136 days (r = 0.84). The results suggest that the placenta reaches its maximum growth and metabolic capacity before 100 days and possibly at or before midgestation. Changes in hepatic weight-specific total VO2, in addition to the declining relative size of the fetal liver, must contribute to the progressive decline in metabolic rate of the whole fetus during the second half of pregnancy. Correlations between placental and fetal liver weights and metabolic rates suggest the possibility of placental regulation of fetal hepatic growth and metabolism.


Blood ◽  
1978 ◽  
Vol 52 (3) ◽  
pp. 560-568 ◽  
Author(s):  
G de Klerk ◽  
C Kruiswijk ◽  
AA Hart ◽  
R Goudsmit

Abstract Investigations on the mouse fetal liver cell bioassay for erythropoietin (ESF) have revealed that iron present in test sera significantly dilutes the radiolabel (59Fe) and thus decreases 59Fe incorporation into heme. A method of correction for the influence of iron on the dose-response relationship of human sera is presented. Application of this method made it possible to assay human sera up to culture concentrations of 150 microliter/ml. It was shown that a corrected serum dose-response curve showed parallelism to the curve of an ESF standard preparation. This suggests similarity of the active principles and allows valid estimation of a potency ratio.


1976 ◽  
Vol 231 (4) ◽  
pp. 1124-1128 ◽  
Author(s):  
RC deBelle ◽  
NR Blacklow ◽  
M Baylan ◽  
JM Little ◽  
R Lester

A new technique has been developed in which mammalian fetal liver can be maintained in organ culture for prolonged periods with intact structure and function. Near-term rat fetal liver explants were incubated in vitro for periods of up to 3 wk with preservation of normal cellular morphology and intercellular (organ) relationships. [14C]cholate was incorporated into tissue and medium conjugates at a constant rate during 21 days in vitro. During a 24-h incubation with radioactively labeled cholic acid, bile acid conjugates accumulated in tissues to a maximum value by 6 h and maintained this value through 24 h. During the same 24-h incubation with [14C]cholate, conjugates were secreted into the medium at a constant rate. Addition of 8 X 10(-4) M taurine to the medium during a 4-day incubation produced a threefold enhancement in the rate of conjugate formation in tissues and medium. Enhanced conjugation in the presence of additional taurine was due almost entirely to increased taurocholate formation and no significant difference was observed in the amount of glycocholate formed. Exposure of explants to 3.6 X 10(-4) M cycloheximide for prolonged periods resulted in inhibition of conjugate formation, but when this concentration of cycloheximide was maintained for only 24 h a significantly (P less than 0.001) increased rate of conjugate formation was observed. The results indicate that metabolic processes in the organ-culture system are in a state of dynamic equilibrium and that morphologic integrity and specific hepatocytic function are maintained after 21 days in vitro. Preferential taurocholate formation was demonstrated in rat fetal liver, and the data suggest that glycine and taurine interact with separate enzymatic systems in bile acid conjugation. The possible mechanisms that mediate the effect of cycloheximide are discussed.


2000 ◽  
Vol 78 (11) ◽  
pp. 897-903 ◽  
Author(s):  
François Guerrero ◽  
Mickael Theron ◽  
Philippe Sebert

We examined in vitro vascular reactivity of eels previously acclimatized to 10.1 MPa hydrostatic pressure (HP) for 21 days. The isometric tension developed by ventral aortic rings was measured at atmospheric pressure. Dose-response curves for either acetylcholine (ACh) or noradrenaline (NA), as well as contractions evoked by 80 mM K+, were compared with time-matched experiments conducted on rings obtained from control eels. Results showed that neither the optimal tension nor the maximal force of the K+-evoked contraction were significantly modified, suggesting that acclimatization to high HP did not change the vascular smooth muscle contractile machinery. The dose-response curve to ACh was not significantly changed. Conversely, although NA always relaxed aortic rings, the response of acclimatized eels was significantly reduced over the entire range of the agonist concentration tested (10-8 to 10-3 M), except for the lowest one (10-9 M). The maximal amplitude of the NA-induced relaxation was significantly reduced in aortic rings from acclimatized eels as compared with non-acclimatized samples (339.3 ± 86.5 vs. 744.3 ± 72.1 mg·mg-1 dry weight, P < 0.005). Our results suggest that acclimatization to high HP could selectively alter the control of vascular tone by catecholamines.Key words: fish, high pressure, vascular smooth muscle, adrenoceptors, cholinergic receptors.


2005 ◽  
Vol 123-124 ◽  
pp. 155-172 ◽  
Author(s):  
F.L. Mould ◽  
R. Morgan ◽  
K.E. Kliem ◽  
E. Krystallidou

Blood ◽  
1975 ◽  
Vol 46 (1) ◽  
pp. 85-90 ◽  
Author(s):  
JR Zucali ◽  
V Stevens ◽  
EA Mirand

Abstract Mouse fetal liver tissue has been cultured and shown to produce and release into the culture medium an erythropoietically active substance for up to 30 days of culture. Since this substance can be completely neutralized by an antiserum to erythropoietin and shows a dose-- response relationship in the plethoric mouse assay, it is suggested that the culture medium contains erythropoietin, a hormone important in the regulation of erythropoiesis. Using this procedure, we have obtained the equivalent of about 20.7 unites of erythropoietin from five T-flasks (75 sq cm) over the 30-day culture period.


1977 ◽  
Vol 233 (6) ◽  
pp. E457 ◽  
Author(s):  
G E Shambaugh ◽  
R A Koehler ◽  
N Freinkel

The effects of fasting on the oxidative disposition of selective fuels in tissues of the rat conceptus were examined on day 20 of gestation. Placentas and portions of fetal liver and brain from fed and 48-h fasted mothers were incubated in vitro with artificial mixtures containing glucose, lactate, and beta-hydroxybutyrate in concentrations simulating those that obtain in fed or 48-h fasted animals in vivo. Oxidative contributions from individual components were evaluated by separate incubations in which only one of the three fuels was 14C-labeled. As judged by the evolution of 14CO2, rates of oxidation of individual fuels by tissues of the conceptus appeared to be conditioned by ambient fuel concentrations rather than the dietary status of the mother. Additional studies indicated that evolution of 14CO2 from glucose or lactate may be depressed directly by adding beta-hydroxybutyrate to the incubation medium. This substitutive property of beta-hydroxybutyrate may "spare" glucose and lactate within the placenta for transfer to the fetus and preserve glucose and lactate availability for biosynthetic rather than oxidative disposition within the fetus.


Blood ◽  
1975 ◽  
Vol 46 (1) ◽  
pp. 85-90
Author(s):  
JR Zucali ◽  
V Stevens ◽  
EA Mirand

Mouse fetal liver tissue has been cultured and shown to produce and release into the culture medium an erythropoietically active substance for up to 30 days of culture. Since this substance can be completely neutralized by an antiserum to erythropoietin and shows a dose-- response relationship in the plethoric mouse assay, it is suggested that the culture medium contains erythropoietin, a hormone important in the regulation of erythropoiesis. Using this procedure, we have obtained the equivalent of about 20.7 unites of erythropoietin from five T-flasks (75 sq cm) over the 30-day culture period.


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