Compartmentalization of human growth hormone by cultured human lymphocytes

Ronald (Ron) Rosenfeld, R. L. Hintz

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Initial reports of the interaction between human GH (hGH) and IM-9 cells described rapid and reversible binding to membrane receptors. In this study we present further investigations of hGH binding to IM-9 cells and suggest that this interaction does not demonstrate equilibrium kinetics but, rather, involves compartmentalization of both hormone and receptor. Incubation of IM-9 cells with [125I]hGH failed to demonstrate steady state binding. After 8 h at 30 C, specific binding was 100% greater than at 90 min (P125I]hGH, the total percentage of [125I]hGH which was both specifically bound and nondissociable increased as a function of the duration of association. Similarly, after 30 min of incubation, trypsinization of the cells failed to dissociate 50% of bound hormone, with a time-dependent increase in the trypsin-resistant fraction. Incubation of IM-9 cells with [125I]hGH and 10-4 M cycloheximide failed to alter the nondissociability of bound hGH, suggesting that new protein synthesis is not required for compartmentalization. When cells incubated with [125I]hGH for 2-6 h were solubilized in 1 M acetic acid and chromatographed over Sephadex G-75, over 70% of the cell-bound radioactivity eluted in the region of intact hGH. The data presented support the concept that membrane-bound hGH does not remain in equilibrium with the extracellular environment but is rapidly compartmentalized in a manner causing the hormone to become relatively inaccessible to dissociating agents. In view of these findings, the concept of hormone-receptor binding as a totally reversible association between ligand and membrane receptor sites, requires reevaluation.

Original languageEnglish (US)
Pages (from-to)368-375
Number of pages8
JournalJournal of Clinical Endocrinology and Metabolism
Volume51
Issue number2
StatePublished - 1980
Externally publishedYes

Fingerprint

Lymphocytes
Human Growth Hormone
Hormones
Membranes
Association reactions
Radioactivity
Cycloheximide
Acetic Acid
Trypsin
Ligands
Kinetics
Proteins
Cell Communication

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology, Diabetes and Metabolism

Cite this

Compartmentalization of human growth hormone by cultured human lymphocytes. / Rosenfeld, Ronald (Ron); Hintz, R. L.

In: Journal of Clinical Endocrinology and Metabolism, Vol. 51, No. 2, 1980, p. 368-375.

Research output: Contribution to journalArticle

Rosenfeld, Ronald (Ron) ; Hintz, R. L. / Compartmentalization of human growth hormone by cultured human lymphocytes. In: Journal of Clinical Endocrinology and Metabolism. 1980 ; Vol. 51, No. 2. pp. 368-375.
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