Effect of partial hepatectomy on the expression of seven rat sulphotransferase mRNAs

1. The effect of partial hepatectomy on the expression of sulphotransferase (SULT) mRNA was studied. SULTs fall into two distinct classes based on sub strate preference: phenol SULT1 family (SULT1A1, SULT1B1, SULT1C1 and SULT1 E2) and hydroxysteroid SULT2 family (SULT20/21, SULT40/41 and SULT60). 2. Hepatic expression of SULT mRNA was analysed in the sham-hepatectomised rat (sham) and in the partially hepatectomised (PH) rat at various times af ter PH. Northern-blot analysis with [alpha-P-32]dATP-labelled oligonucleoti de probes specific for individual SULT mRNAs was used to monitor hepatic SU LT mRNA expression. In general, SULT mRNAs underwent a decrease in expressi on after PH and the magnitude of decrease was dependent on the SULT isoform . 3. The decrease in SULT mRNA expression was resolved and even induced (SULT 40/41 in the female rat) by 10-30 days after PH. Of the phenol SULT isoform s, both SULT1C1 and SULT1E2 mRNAs were significantly decreased by 18-24 h a fter PH in the male rat. The other phenol SULTs (SULT1A1 and SULT1B1) tende d to decrease in the male rat after PH, but the decreases were not statisti cally significant. Expression of SULT20/21 mRNA was decreased in the female rat (80 % at 24 h) and fully recovered by 10 days. SULT40/41 mRNA tended t o decrease after PH; however, the decrease was not statistically significan t. SULT 60 mRNA was decreased from 24 to 96 h after PH. 4. Thus, during the period of rapid liver growth that occurs after partial hepatectomy, SULT mRNA expression is decreased. The phenomenon of decreased SULT mRNA expression is similar to other states of rapid liver growth (e.g . cancer tissue and young animals) in which expression of SULT enzymes is c haracteristically low.