INVESTIGADORES
SANCHEZ POZZI Enrique Juan
artículos
Título:
Induction of phase II biotransformation reactions in rat jejunum during lactation: possible involvement of prolactin
Autor/es:
LUQUITA, MARCELO G; CATANIA, VIVIANA A; ENRIQUE JUAN SANCHEZ POZZI; VORE, MARY; VEGGI, LUIS M; PELLEGRINO, JOSÉ M; MOTTINO, ALDO D
Revista:
BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 1999 vol. 1472 p. 82 - 92
ISSN:
0304-4165
Resumen:
The effect of lactation on UDP-glucuronosyltransferase (UGT) and
Glutathione S-transferase (GST) activities was studied in jejunum from
mother rats, 14 (LM14) and 21 (LM21) days after delivery. p-Nitrophenol
glucuronidation rate was increased in LM14 and LM21 rats while
conjugation of bilirubin and estrone was not affected and androsterone
glucuronidation was decreased. Additional studies, including Western
blotting and microsomal lipid analysis, revealed that the enhancement in
p-nitrophenol UGT activity is most likely associated with an inductive
process rather than with a modification in enzyme constraint. GST
activity towards 1-chloro-2,4-dinitrobenzene (CDNB) was also increased
in LM14 and LM21 while activity towards 1,2-dichloro-4-nitrobenzene
(DCNB) was not affected. Western blotting revealed a significant
increase in the cytosolic content of mu (rGSTM2) and pi (rGSTP1) class
subunits in LM14 and LM21 groups, while the alpha class subunit rGSTA2
remained unchanged. To evaluate the potential modulatory role of
prolactin on the same enzyme systems, ovariectomized rats were treated
with ovine prolactin (oPRL) at doses of 100, 200 and 300 microg/100 g
body wt. per day for 4 days. Hormone administration affected UGT
activities towards p-nitrophenol and androsterone and GST activity
towards CDNB in a way and magnitude consistent with those produced in
lactating rats, while conjugation of estrone, bilirubin and DCNB were
unchanged. Western blotting data were also consistent with those of
lactating rats. These results indicate that UGT and GST activities are
increased in rat jejunum during lactation, due to induction of some
specific isoforms, and that prolactin is the likely mediator of these
effects.