Growth hormone binding and stimulation of amino acid uptake in epithelial cells of rat ventral prostate.
The binding of [125I]-human growth hormone (hGH) was studied in epithelial cells isolated from rat ventral prostate. Binding and degradation were dependent on time and temperature. The effect of a lysosomotropic agent suggested internalization and lysosomal degradation of the hormone. Dissociation and stoichiometric studies indicated the existence of a single class of GH receptors with a Kd of 0.7 nM and a binding capacity of 46 fmol hGH bound mg-1 cell protein. The receptor appeared to possess a somatotrophic nature since lactogenic hormones such as human placental lactogen and rat prolactin exhibited a very low degree of competition (whereas a variety of unrelated hormones and neuropeptides showed no effect). GH-stimulated leucine uptake by the cells in a time- and dose-dependent manner, half maximal effect being observed at 0.32 nM GH thus suggesting a direct relationship with the binding step.
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D004848:Epithelium / Q000378:metabolism; D013006:Growth Hormone / Q000378:metabolism* / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008247:Lysosomes / Q000378:metabolism; D008297:Male; D011467:Prostate / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011986:Receptors, Somatotropin / Q000378:metabolism
D000596:Amino Acids; D011986:Receptors, Somatotropin; D013006:Growth Hormone