Growth-related variation of alpha 2-adrenergic receptivity in the HT 29 adenocarcinoma cell-line from human colon.
The human colon adenocarcinoma cell-line HT 29 has been shown to possess functional alpha 2-adrenergic receptors. Here, [3H] clonidine was used as radioligand to study the evolution of alpha 2-adrenergic receptivity during the time course of HT 29 cell culture. Scatchard analysis of the saturation curves indicates that the number of [3H]clonidine binding sites increases throughout the 17 day culture period. The maximal number of alpha 2-adrenoceptors is found during the stationary phase of growth, when cell density is high and mitotic rate low. Moreover, the use of adrenaline and clonidine as alpha 2-adrenergic agonists reveals a relationship between the number of receptors and the intensity of the biological effect associated with their stimulation (inhibition of the VIP-induced cyclic AMP accumulation).
Paris
H
H
Bouscarel
B
B
Cortinovis
C
C
Murat
J C
JC
D000230:Adenocarcinoma / Q000032:analysis*; D002460:Cell Line; D002462:Cell Membrane / Q000032:analysis; D003000:Clonidine / Q000378:metabolism; D003110:Colonic Neoplasms / Q000032:analysis*; D000242:Cyclic AMP / Q000378:metabolism; D006801:Humans; D011942:Receptors, Adrenergic, alpha / Q000032:analysis*; D014316:Tritium; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D011942:Receptors, Adrenergic, alpha; D014316:Tritium; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D003000:Clonidine