Action of Pregnancy and Various Progesterones on Hepatic Microsomal Activities

Feuer, G.

doi:10.3109/03602537909046437

Cited by 57 publications

(12 citation statements)

References 48 publications

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“…Parturition terminates exposure to maternal humoral substances (such as progesterone) which have been postulated to depress synthesis of microsomal enzymes in the foetal liver (Feuer 1979). This is consistent with the observation that particularly rapid development of metabolic pathways occurs during the first 24 h after birth.…”

Section: Elimination Processes and Therapy In Neonatal Foalssupporting

confidence: 83%

Antimicrobial selection and dosage in the treatment of equine bacterial infections

Baggot

Prescott

1987

Equine Veterinary Journal

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Summary The success of antimicrobial therapy depends on administration of an agent to which the pathogenic microorganisms are susceptible at the concentrations attained at the site of infection. The route of administration, size of the dose and dosing interval must be appropriate for the drug preparation selected. With penicillins in particular, dosage can be tailored to the severity of the infection and quantitative susceptibility of the microorganism. This approach cannot be applied to aminoglycosides because their relatively narrow margin of safety limits the amount which can be administered. In severe infections it is important quickly to establish effective antimicrobial concentrations, which means that the choice of drug must be based on experience in treating the particular type of infection (empiric selection) and its dosage be adequate to produce a high peak concentration in the plasma. In treating septicaemic conditions of neonatal foals the deficit in serum immunoglobulins should be corrected, and it is advisable to administer antimicrobial agents or combinations that produce a bactericidal effect at dosages modified for immature physiological processes.

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Section: Elimination Processes and Therapy In Neonatal Foalssupporting

confidence: 83%

Antimicrobial selection and dosage in the treatment of equine bacterial infections

Baggot

Prescott

1987

Equine Veterinary Journal

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“…The reduction of monooxygenase activities has been attributed to the pronounced hormonal changes that occur during pregnancy, in particular to the higher plasma levels of progesterone and its metabolites. Data showing that progesterone and its metabolites cause in vitro inhibition of P450-catalyzed reactions (17) apparently support this interpretation. Results from in vivo studies, however, do not seem to be consistent with this hypothesis.…”

Section: Rate Of O-dealkylationmentioning

confidence: 89%

Effects of pregnancy and protein-energy malnutrition on monooxygenase O-dealkylation activity in rat liver microsomes

Kuriyama

De-Oliveira

Fidalgo-Neto

et al. 2000

Braz J Med Biol Res

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Xenobiotic metabolism is influenced by a variety of physiological and environmental factors including pregnancy and nutritional status of the individual. Pregnancy has generally been reported to cause a depression of hepatic monooxygenase activities. Low-protein diets and protein-energy malnutrition have also been associated with a reduced activity of monooxygenases in nonpregnant animals. We investigated the combined effects of pregnancy and protein-energy malnutrition on liver monooxygenase O-dealkylation activity. On pregnancy day 0 rats were assigned at random to a group fed ad libitum (well-nourished, WN) or to a malnourished group (MN) which received half of the WN food intake (12 g/day). WN and MN rats were killed on days 0 (nonpregnant), 11 or 20 of pregnancy and ethoxy-(EROD), methoxy-(MROD) and penthoxy-(PROD) resorufin Odealkylation activities were measured in liver microsomes. Only minor changes in enzyme activities were observed on pregnancy day 11, but a clear-cut reduction of monooxygenase activities (pmol resorufin min -1 mg protein -1 ) was noted near term (day 0 vs 20, means ± SD, Student t-test, P<0.05) in WN (EROD: 78.9 ± 15.1 vs 54

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“…A reverse relationship has been obtained for N-desmethyldiazepam. Little is known about drug metabolism in pregnancy (18,19). Neale and Parlee .…”

Section: Discussionmentioning

confidence: 99%

Placental transfer and distribution of pinazepam and its metabolite N-desmethyldiazepam in the maternal and fetal rabbit: effect of the stage of gestation

Pacifici

Cuoci

Placidi

1989

Eur. J. Drug Metab. Pharmacokinet.

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The distribution of pinazepam and its metabolite N-desmethyldiazepam was studied in fetuses of New Zealand rabbits on the 20th and 27th day of pregnancy. The concentrations of both compounds were also measured in the maternal brain, liver and uterus. Pregnant rabbits were sacrificed at 0.5, 2, 4 and 12 h after intravenous administration of pinazepam (5 mg/kg). The concentrations of pinazepam and N-desmethyldiazepam in various biological specimens were measured by a specific gas-chromatographic procedure. Pinazepam and N-desmethyldiazepam rapidly crossed the placenta. In 20 day old fetuses, comparable concentrations of pinazepam were found in the liver, brain, heart, lungs and kidneys. In contrast, the liver of 27 day old fetuses accumulated pinazepam at concentrations higher than the other tissues. The hepatic extraction of pinazepam, already described in adult rabbits (1), develops prenatally. A preferential accumulation of pinazepam rather than N-desmethyldiazepam was also observed in the maternal uterus. In this tissue the concentrations of pinazepam were 5-10 times higher on the 27th rather than the 20th day of pregnancy. The stage of pregnancy influences the distribution pattern of pinazepam in rabbit fetuses and their mothers.

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Action of Pregnancy and Various Progesterones on Hepatic Microsomal Activities

Cited by 57 publications

References 48 publications

Antimicrobial selection and dosage in the treatment of equine bacterial infections

Antimicrobial selection and dosage in the treatment of equine bacterial infections

Effects of pregnancy and protein-energy malnutrition on monooxygenase O-dealkylation activity in rat liver microsomes

Placental transfer and distribution of pinazepam and its metabolite N-desmethyldiazepam in the maternal and fetal rabbit: effect of the stage of gestation

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