Binding of beta-adrenergic receptors in human skin.
Radioligand-binding experiments were performed with crude membrane homogenates (CMH) from human skin in order to investigate the epidermal beta-adrenergic receptor (beta AR) density. CMH were prepared from leftovers of split-thickness skin grafts by sequential homogenization and centrifugation procedures to yield essentially epidermal fragments. Saturation experiments with the non-selective beta-adrenoceptor antagonist (-)-[125I]-iodocyanopindolol (ICYP) as radioligand showed saturable specific binding isotherms. Scatchard transformation of the data demonstrated high-affinity binding of ICYP to a single class of beta AR (Bmax = 80 +/- 10 fmol/mg protein; KD = 8 pM +/- 0.9; n = 8). beta AR antagonists displaced ICYP in a monophasic displacement pattern. The IC50 values were (nmol/1) propranolol (non-selective) 24.8; ICI 118,551 (beta 2 selective) 14.7; CGP-12177 (non-selective) 28.9; bisoprolol (beta 1 selective) 1500; CGP-20712A (beta 1 selective) 8990. beta AR agonists displaced ICYP with a potency ranking isoprenaline greater than adrenaline greater than noradrenaline. We conclude that epidermal crude membrane homogenates prepared from human split-thickness skin contain a high population of beta 2-adrenergic receptors. These receptors may be studied to further investigate the nature of human epidermal beta-adrenergic mechanisms.
Steinkraus
V
V
Department of Dermatology, University of Hamburg, Germany.
Steinfath
M
M
Körner
C
C
Mensing
H
H
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D015603:Keratinocytes / Q000648:ultrastructure; D008297:Male; D008566:Membranes / Q000648:ultrastructure; D008854:Microscopy, Electron; D008875:Middle Aged; D011485:Protein Binding; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D012867:Skin / Q000648:ultrastructure*
D011943:Receptors, Adrenergic, beta