文摘
The study was aimed to investigate the existence of at least two kinds of P2Y receptors linked to steroidogenesis in bovine adrenocortical fasciculata cells (BAFCs). Extracellular nucleotides facilitated steroidogenesis in BAFCs. The potency order was UTP > adenosine 5′-(γ-thio) triphosphate (ATPγS) > ATP > 2-methylthio ATP (2MeSATP) > adenosine 5′-(β-thio) diphosphate (ADPβS) > α,β-methylene ATP (α,β-me-ATP), β,γ-methylene ATP (β,γ -me-ATP). ATPγS (10–100 μM) remarkably stimulated both total inositol phosphates (IPs) production and cyclic AMP (cAMP) accumulation. Competitive displacement experiments by using [35S]ATPγS as a radioactive ligand in BAFCs showed that the potency under these unlabelled ligands was ATPγS > ATP > ADPβS > 2MeSATP > UTP > α,β-me-ATP, β,γ-me-ATP. These suggest that two different binding sites of [35S]ATPγS, namely P2Y receptors, exist in BAFCs, and that these receptors are linked to steroidogenesis via distinct second messenger systems in the cells.