EFFECT OF COLCHICINE ON THE GOLGI-APPARATUS AND ON GERL OF RAT JEJUNAL ABSORPTIVE CELLS - ULTRASTRUCTURAL-LOCALIZATION OF THIAMINE PYROPHOSPHATASE AND ACID-PHOSPHATASE-ACTIVITY

Abstract

Ultrastructural localization of thiamine pyrophosphatase (TPP) and acid phosphatase (AcPase) activity was performed on jejunal absorptive cells of rats pretreated with the antimicrotubular agent colchicine and of control animals. Demonstration of TPP activity showed that most of the dislocated Golgi stacks after colchicine application lacked positively staining cisternae of the mature side. This cytochemical finding is in agreement with the morphologically demonstrable changes of the Golgi stacks resulting in a loss of polarity and evidences a colchicine-induced deficiency of the Golgi apparatus. The cytochemical localization of AcPase activity showed deposits of reaction product over lysosomes and GERL (Golgi-associated endoplasmic reticulum lysosome) and demonstrated a dislocation of GERL occurring concomitantly with the changes in the Golgi apparatus. The antimicrotubular effect of colchicine is well documented; thus the morphological and cytochemical changes of the Golgi apparatus and of GERL might be due to a disturbed microtubular function after application of this agent suggesting an influence of microtubules in the maintenance of the integrity of these organelles. This hypothesis includes the possibility of an involvement of microtubules in formation and differentiation of Golgi stacks and GERL as well as a kind of skeletal function being responsible for their characteristic structure and function.