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Postnatal development and sublobular distribution of cytochrome P-450 in rat liver: a microphotometric study
J Watanabe1, Y Asaka, S Kanamura
1Department of Anatomy, Kansai Medical University, Osaka, Japan.
Insights
Cytochrome P-450 (P-450) expression significantly increases in rat hepatocytes during the perinatal period. Postnatal development reveals distinct P-450 distribution patterns between periportal and perivenular cells.
Area of Science:
- Hepatology
- Developmental Biology
- Biochemistry
Background:
- Cytochrome P-450 (P-450) enzymes are crucial for xenobiotic metabolism and endogenous compound synthesis.
- Understanding P-450 expression during development is vital for assessing drug efficacy and toxicity.
- Hepatocyte heterogeneity in P-450 content is known in adult animals but poorly characterized during development.
Purpose of the Study:
- To investigate the developmental expression patterns of P-450 in rat hepatocytes.
- To analyze P-450 content differences between periportal and perivenular hepatocytes during peri- and postnatal growth.
- To identify key developmental stages influencing P-450 distribution.
Main Methods:
- Microphotometry was used to quantify P-450 content.
- Measurements were taken in periportal and perivenular hepatocytes of male rats.
- Analysis covered the period from gestation day 19 to postnatal day 45.
Main Results:
- A marked increase in P-450 content occurred in both hepatocyte zones from gestation day 19 to postnatal day 5.
- From 5 to 45 days of age, periportal P-450 content showed a slight increase, while perivenular P-450 content increased progressively.
- Distinct P-450 distribution heterogeneity between periportal and perivenular hepatocytes emerged after 7 days of age, reaching adult levels by 45 days.
Conclusions:
- The perinatal period is characterized by a significant surge in hepatic P-450 expression.
- Sublobular P-450 heterogeneity develops postnatally, becoming apparent before weaning.
- Differential P-450 expression in periportal and perivenular hepatocytes continues to evolve after weaning.
Abstract:
To study the process of expression of cytochrome P-450 (P-450) in hepatocytes during development, we measured microphotometrically the P-450 content in periportal and perivenular hepatocytes of male rats during peri- and postnatal growth. From Day 19 of gestation to Day 5 after birth, P-450 content in both periportal and perivenular hepatocytes increased markedly (periportal 1046%; perivenular 819%). The content in periportal hepatocytes remained unchanged from 5 to 20 days of age, and increased slightly (24%) from 20 to 45 days of age. However, the content in perivenular hepatocytes increased progressively (105%) between 5 and 45 days of age. The difference in P-450 content became apparent between periportal and perivenular hepatocytes after 7 days of age. The content in periportal or perivenular hepatocytes reached the adult level at 45 days of age. Therefore, the perinatal period is the time at which a marked increase in P-450 occurs in hepatocytes throughout the liver lobule. The subsequent period before weaning is the time at which the sublobular heterogeneous distribution of P-450 appears. The period after weaning is the time at which a slight increase in P-450 content in periportal hepatocytes and a marked increase in the enzyme in perivenular hepatocytes takes place.