The trans Golgi face in rat small intestinal absorptive cells

Area of Science:

• Cell Biology
• Gastroenterology
• Histology

Background:

• Cell differentiation in the small intestine involves changes in the trans Golgi network.
• The structure termed GERL (Golgi associated endoplasmic reticulum lysosomes) has been debated as either part of the endoplasmic reticulum or Golgi apparatus.

Purpose of the Study:

• To investigate the cytochemical characteristics and cellular localization of GERL structures during small intestine cell differentiation.
• To clarify the identity of GERL as either Golgi-derived or endoplasmic reticulum-derived structures.

Main Methods:

• Cytochemical staining for thiamine pyrophosphatase, inosine diphosphatase, and acid phosphatase in small intestine crypt and villus cells.
• Ultrastructural analysis of Golgi apparatus and associated endoplasmic reticulum in differentiating enterocytes.

Main Results:

• Identical cisternae in both crypt and mature absorptive cells exhibited reactivity for thiamine pyrophosphatase, inosine diphosphatase, and acid phosphatase.
• Enzymatic patterns indicated that structures previously identified as GERL are consistent with Golgi cisternae, not endoplasmic reticulum.
• Endoplasmic reticulum adjacent to the Golgi in undifferentiated cells lacked acid phosphatase and showed no continuity with GERL.

Conclusions:

• GERL structures in the small intestine are best interpreted as specialized components of the Golgi apparatus, not the endoplasmic reticulum.
• Cell differentiation significantly impacts the organization and enzymatic profile of the trans Golgi face.
• The study refutes the role of GERL in lysosome production based on observed cytochemical and structural evidence.