ENHANCEMENT OF CYTOSOLIC AND MICROSOMAL GLUTATHIONE-S-TRANSFERASE ACTIVITIES IN LIVER AND SMALL-INTESTINE FROM FEMALE RATS DURING LACTATION

The influence of lactation on hepatic and intestinal glutathione S-tra nsferase activities in mother rats was studied. Cytosolic and microsom al activities were assessed 7, 14 and 21 days after delivery, using 1- chloro-2,4-dinitrobenzene as substrate. Cytosolic and microsomal activ ities from liver and small intestine determined 7 days post partum did not differ from those of virgin female rats. The hepatic cytosolic ac tivity was significantly increased with respect to that of virgin fema les 14 days after delivery and tended to revert to the control value o n day 21 of lactation, whereas the intestinal activity was increased o n day 14 and remained augmented even 21 days post partum. Although the respective microsomal activities showed percent increases higher than those of the cytosolic enzymes, they both exhibited a similar pattern of stimulation in response to lactation.