Distribution of PYY receptors in human fat cells: an antilipolytic system alongside the alpha 2-adrenergic system.
The antilipolytic effect of peptide YY (PYY) and neuropeptide Y has recently been shown in human adipocytes. PYY receptors were investigated in three human adipose deposits. A greater number of 125I-labeled PYY binding sites was found in femoral adipocyte membranes (maximal binding = 40 +/- 4 fmol/mg protein; dissociation constant = 0.3 +/- 0.1 nM) when compared with mammary and pericolonic adipose tissue. PYY receptors, like alpha 2-adrenergic sites, were largely expressed in femoral fat cells. Such a distribution was not specific either to inhibitory or to stimulating adenylyl cyclase systems since adenosine A1 and beta-adrenergic receptors were more numerous in pericolonic adipocytes. On isolated adipocytes, PYY (10(-7) M) inhibited lipolysis by 58 +/- 2% in femoral and 14 +/- 4% in pericolonic fat cells; epinephrine had the following similar response: 62 +/- 5 and 26 +/- 8%, respectively. A close relationship between the number of alpha 2-sites and PYY sites and the antilipolytic effects initiated by PYY and an alpha 2-agonist was observed. No significant differences were noted in the amount of Gi proteins in femoral and pericolonic adipocyte membranes.
Institut National de la Santé et de la Recherche Médicale, Unité 317, Institut Louis Bugnard, Université Paul Sabatier, Toulouse, France.
I
I
Castan
P
P
Valet
D
D
Larrouy
T
T
Voisin
A
A
Remaury
D
D
Daviaud
M
M
Laburthe
M
M
Lafontan
D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003106:Colon; D005269:Femur; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D008066:Lipolysis; D011869:Radioligand Assay; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000378:metabolism; D011964:Receptors, Gastrointestinal Hormone; D014018:Tissue Distribution
D011942:Receptors, Adrenergic, alpha; D011956:Receptors, Cell Surface; D011964:Receptors, Gastrointestinal Hormone; C082172:peptide YY receptor; D019204:GTP-Binding Proteins