title: Prolactin (PRL) induction of cyclooxygenase 2 (COX2) expression and prostaglandin (PG) production in hamster Leydig cells.
abstract: Serum prolactin (PRL) variations play a crucial role in the photoperiodic-induced testicular regression-recrudescence transition in hamsters. We have previously shown that cyclooxygenase 2 (COX2), a key enzyme in the biosynthesis of prostaglandins (PGs), is expressed mostly in Leydig cells of reproductively active hamsters with considerable circulating and pituitary levels of PRL. In this study, we describe a stimulatory effect of PRL on COX2/PGs in hamster Leydig cells, which is mediated by IL-1β and prevented by P38-MAPK and JAK2 inhibitors. Furthermore, by preparative isoelectric focusing (IEF), we isolated PRL charge analogues from pituitaries of active [isoelectric points (pI): 5.16, 4.61, and 4.34] and regressed (pI: 5.44) hamsters. More acidic PRL charge analogues strongly induced COX2 expression, while less acidic ones had no effect. Our studies suggest that PRL induces COX2/PGs in hamster Leydig cells through IL-1β and activation of P38-MAPK and JAK2. PRL microheterogeneity detected in active/inactive hamsters may be responsible for the photoperiodic variations of COX2 expression in Leydig cells.
authors.affiliation: Laboratorio de Esteroides, Instituto de Biología y Medicina Experimental, CONICET, Vuelta de Obligado 2490 (1428), Ciudad de Buenos Aires, Argentina.
authors.forename: María Eugenia
authors.initials: ME
authors.lastname: Matzkin
authors.forename: Verónica
authors.initials: V
authors.lastname: Ambao
authors.forename: Mónica Herminia
authors.initials: MH
authors.lastname: Carino
authors.forename: Soledad Paola
authors.initials: SP
authors.lastname: Rossi
authors.forename: Lorena
authors.initials: L
authors.lastname: González
authors.forename: Daniel
authors.initials: D
authors.lastname: Turyn
authors.forename: Stella
authors.initials: S
authors.lastname: Campo
authors.forename: Ricardo Saúl
authors.initials: RS
authors.lastname: Calandra
authors.forename: Mónica Beatriz
authors.initials: MB
authors.lastname: Frungieri
mesh_terms: D000818:Animals; D006224:Cricetinae; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D053583:Interleukin-1beta / Q000378:metabolism; D053614:Janus Kinase 2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D007985:Leydig Cells / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D008297:Male; D010766:Phosphorylation; D017440:Photoperiod; D010902:Pituitary Gland / Q000378:metabolism; D011388:Prolactin / Q000494:pharmacology / Q000502:physiology*; D011453:Prostaglandins / Q000096:biosynthesis*; D020033:Protein Isoforms / Q000378:metabolism; D018123:Receptors, Interleukin / Q000378:metabolism; D011981:Receptors, Prolactin / Q000378:metabolism; D013737:Testis / Q000166:cytology / Q000502:physiology; D013739:Testosterone / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D053583:Interleukin-1beta; D011453:Prostaglandins; D020033:Protein Isoforms; D018123:Receptors, Interleukin; D011981:Receptors, Prolactin; D013739:Testosterone; D011388:Prolactin; D051546:Cyclooxygenase 2; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2; D048051:p38 Mitogen-Activated Protein Kinases