Signaling by extracellular nucleotides in anterior pituitary cells.
Pituitary cells secrete ATP, which acts as an autocrine and/or paracrine extracellular messenger on two families of purinergic receptors: G-protein-coupled P2Y receptors (P2YRs) and ion-conducting P2X receptors (P2XRs). Lactotrophs and GH(3)-immortalized cells express the P2Y(2)R subtype. Several P2XR subtypes are expressed in pituitary cells. Gonadotrophs and somatotrophs express P2X(2a)R and P2X(2b)R, which occur as heteromeric channels. Lactotrophs and GH(3) cells express one or more ion-conducting subtypes from among P2X(3)R, P2X(4)R and P2X(7)R in homomeric form. Thyrotrophs and corticotrophs also express P2XRs, but their identification requires further study. Pituitary cells express purinergic P1 receptors, which are activated by adenosine. The A(1)R subtype of these receptors is expressed in melanotrophs and GH(3) cells. In this review, we briefly discuss the expression and coupling of A(1)R and P2Y(2)R, and focus on the expression and Ca(2+) signaling of P2XRs.
Stojilkovic
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SS
Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, 20892-4510, Bethesda MD, USA. stankos@helix.nih.gov
Koshimizu
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T
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D019898:Autocrine Communication; D020013:Calcium Signaling; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D019899:Paracrine Communication; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018047:Receptors, Purinergic P1 / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D018047:Receptors, Purinergic P1; D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D020962:Heterotrimeric GTP-Binding Proteins