Elevated level of. beta. -adrenergic receptors in hepatocytes from regenerating rat liver

Journal Article · Wed Jan 01 00:00:00 EST 1986 · Exp. Cell Res.; (United States)

DOI:https://doi.org/10.1016/0014-4827(86)90537-9· OSTI ID:5783663

Sandnes, D; Sand, T E; Sager, G; Broenstad, G O; Refsnes, M R; Gladhaug, I P; Jacobsen, S; Christoffersen, T

Hepatocytes from regenerating rat liver show an enhanced epinephrine-sensitive adenylate cyclase activity and cAMP response, which may be involved in triggering of the cell proliferation. We have determined adrenergic receptors and adenylate cyclase activity in hepatocytes isolated at various time points after partial hepatectomy. The number of ..beta..-adrenergic receptors, measured by binding of (/sup 125/I)iodocyanopindolol ((/sup 125/I)CYP) to a particulate fraction prepared from isolated hepatocytes, increased rapidly after partial hepatectomy as compared with sham-operated or untreated controls. The maximal increase, which was observed at 48 h, was between 5- and 6-fold (from approx.1800 to approx.10,500 sites per cell). Thereafter, the number of ..beta..- adrenergic receptors decreased gradually. Competition experiments indicated ..beta../sub 2/-type receptors. Parallelism was found between the change in the number of ..beta../sub 2/-adrenergic receptors and the isoproterenol-responsive adenylate cyclase activity. The number of ..cap alpha../sub 1/-adrenergic receptors, determined by binding of (/sup 3/H)prazosin, was transiently lowered by about 35% at 18-24 h. with no significant change in K/sub d/. Although the results of this study do not exclude the possibility of post-receptor events, they suggest that the increased number of..beta../sub 2/-adrenergic receptors is a major factor responsible for the enhanced catecholamine-responsive adenylate cyclase activity in regenerating liver.

• Research Organization: Univ. of Oslo, Norway
• OSTI ID: 5783663
• Journal Information: Exp. Cell Res.; (United States), Vol. 165
• Country of Publication: United States
• Language: English

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