Patterns of adrenoceptor change during liver regeneration of the Wistar Kyoto rat: A binding study

Background. Adrenoceptors have been involved in the regulation of hepatocyt e proliferation after partial hepatectomy, as well as in primary culture. T his report characterizes alpha(1)- and beta-adrenoceptor change during the time-course of liver regeneration in adult Wister Kyoto rats. Methods. Saturation binding assays with [H-3]prazosin or [H-3]dihydroalpren olol (for alpha(1)- and beta-adrenoceptors, respectively) were done in live r plasma membranes from 6-month old rats subjected to 70% hepatectomy follo wed by hepatic regeneration. Results. [H-3]Prazosin and [H-3]dihydroalprenolol binding gave control B-ma x values of 101 +/- 10 and 12 +/- 1 fmol/mg protein and K-d of 0.50 +/- 0.1 0 and 4.1 +/- 0.4 nM for alpha(1)- and beta-adrenoceptors, respectively. al pha(1)-Adrenoceptor number and K-d increased at 24 and 48 h and returned to control values at 72 and 96 h after surgery, whereas P-adrenoceptors augme nted at 48 and 72 h, with a K-d, change at 24 and 48 h posthepatectomy. Conclusions. These results suggest that dual control of alpha(1)- and beta- adrenoceptor membrane expression could be involved in different steps durin g hepatocyte proliferation, and that Wistar Kyoto rats have a different adr enoceptor pattern expression from other rat strains. (C) 1999 IMSS, Publish ed by Elsevier Science Inc.