Related Experiment Video
Updated: Jul 12, 2026
05:49
Robust Generation of Hepatocyte-like Cells from Human Embryonic Stem Cell Populations
Published on: October 26, 2011
Age-related changes in the hepatic endoplasmic reticulum: a quantitative analysis
Science (New York, N.Y.)
|September 2, 1977
Summary
The surface area of hepatic endoplasmic reticulum in rats significantly increases until 20 months of age, then declines by 30 months. These age-related changes are primarily due to the smooth endoplasmic reticulum.
Area of Science:
- Hepatology
- Cell Biology
- Aging Research
Background:
- The hepatic endoplasmic reticulum plays a crucial role in cellular metabolism and detoxification.
- Understanding age-related changes in cellular organelles is vital for comprehending liver function decline.
- Previous studies have not fully elucidated the specific age-dependent alterations in hepatic endoplasmic reticulum morphology.
Purpose of the Study:
- To investigate the age-related changes in the surface area of the hepatic endoplasmic reticulum in Fischer 344 rats.
- To determine whether changes in the endoplasmic reticulum are specific to its smooth or rough forms.
- To assess the impact of aging on the Golgi membranes in rat hepatocytes.
Main Methods:
- Morphometric analysis was employed to quantify the surface area of cellular organelles.
- Fischer 344 rats of varying ages (1, 20, and 30 months) were utilized for the study.
- Specific measurements focused on the hepatic endoplasmic reticulum (smooth and rough) and Golgi membranes.
Main Results:
- A twofold increase in the surface area of the hepatic endoplasmic reticulum was observed between 1 and 20 months of age.
- A significant decrease in hepatic endoplasmic reticulum surface area occurred between 20 and 30 months of age.
- No significant age-related changes were found in the surface area of the rough endoplasmic reticulum or Golgi membranes.
Conclusions:
- The smooth endoplasmic reticulum undergoes significant age-dependent surface area modifications in rat hepatocytes.
- Aging leads to a biphasic change in smooth endoplasmic reticulum surface area, with an initial increase followed by a decrease.
- These findings highlight the dynamic nature of the smooth endoplasmic reticulum in response to aging and suggest its potential role in age-related hepatic dysfunction.
Related Concept Videos
01:39Endoplasmic Reticulum
Endoplasmic ReticulumThe endoplasmic reticulum (ER) is an extensive network of membranous sacs and tubules in eukaryotic cells, continuous with the outer membrane of the nucleus. This structural continuity integrates nuclear and cytoplasmic processes and facilitates efficient intracellular transport. This allows mRNA to move directly from the nucleus to ribosomes for efficient protein synthesis. As a result, the ER serves as a central site for the synthesis, processing, and distribution of...
01:43The Endoplasmic Reticulum
The endoplasmic reticulum or ER makes up for more than half of the membranes in a cell and accounts for 10% of total cell volume. It is also the primary protein and lipid synthesis factory for most cell organelles, such as the Golgi apparatus, lysosomes, secretory vesicles, and the plasma membrane. Despite being the most extensive and functionally complex subcellular organelle, ER was the last to be discovered. After years of deliberation, Keith Porter and George Palade in the year 1954,...
01:21Smooth Endoplasmic Reticulum
Smooth endoplasmic reticulum or smooth ER is a sub-organelle with specialized functions in animal cells and plant cells. It is often associated with the tubule morphology of the endoplasmic reticulum.
The ER provides optimal conditions for synthesizing steroid hormones and lipids, such as phospholipids and triglycerides. Traditionally, lipid metabolism was considered to be a smooth ER function. However, there is no direct evidence to prove that rough ER is completely excluded from lipid...
The ER provides optimal conditions for synthesizing steroid hormones and lipids, such as phospholipids and triglycerides. Traditionally, lipid metabolism was considered to be a smooth ER function. However, there is no direct evidence to prove that rough ER is completely excluded from lipid...
01:32Export of Misfolded Proteins out of the ER
After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
01:26Effect of Hepatic Disease on Pharmacokinetics: Drug Dosing and Hepatic Blood Flow
Chronic liver disease significantly impacts drug metabolism due to alterations in hepatic blood flow and enzyme accessibility. This disruption affects the body's pharmacokinetics—the movement and processing of drugs within the system. Key enzymes crucial for metabolizing medications become less accessible, changing how drugs are processed and utilized. Furthermore, liver disease influences the synthesis of plasma proteins, such as albumin and globulins, which play critical roles in drug binding...
01:22Effect of Hepatic Disease on Pharmacokinetics: Pathophysiologic Assessment and Liver Function Test
In clinical practice, the direct measurement of hepatic blood flow to evaluate liver function presents significant challenges due to the intricate and specialized nature of the necessary techniques. Consequently, healthcare professionals often rely on empirical estimates derived from thorough patient examinations and liver function tests to gauge liver health. Among the tools at their disposal, the Child–Pugh and MELD scoring systems stand out for their ability to categorize and assess the...