Presence of growth hormone receptors in carp liver and intestine.

Membranes were prepared from tissues of the carp Ctenopharynogodon idellus including liver, kidney, intestine, adipose tissue, ovary, gill, heart, muscle and spleen. The carp liver and intestine membranes bound 125I-labeled bovine growth hormone and the binding could be displaced by cold bovine growth hormone. No changes in the ability to bind 125I-labeled bovine growth hormone occurred after treatment of the carp liver membrane with DNase, RNase, alpha-amylase and beta-glucosidase, suggesting that neither nucleic acids nor carbohydrates played an important part in the hepatic binding of growth hormone. Treatment of carp liver membranes with either chymotrypsin or trypsin produced a decrease in the growth hormone binding activity, indicating that the growth hormone receptor on carp liver membrane is a protein. Treatment of carp liver membranes with p-chloromercuribenzoate brought about a reduction in 125I-bGH binding. The inhibition could be reversed by dithioerythritol, suggesting the involvement of essential sulfhydryl group in bGH binding.