Expression and regulation of prolactin-like protein messenger RNA in undifferentiated chicken granulosa cells.
Prolactin-like protein (PRL-L; LOC417800) is a homolog of PRL in non-mammalian vertebrates and can act as a functional ligand of PRL receptor (PRLR). Despite its widespread expression in extrapituitary tissues, mechanisms of regulation of PRL-L in the chicken ovary remain unknown. In this study, we first examined PRL-L expression in chicken ovarian developing follicles. PRL-L transcript levels were highest (P<0.05) in follicular walls of <2mm follicles and progressively declined during follicle maturation. Undifferentiated granulosa cells of 6-8mm follicles had higher (P<0.05) PRL-L mRNA levels than differentiated granulosa cells of F3, F2 or F1 follicles. In cultured undifferentiated granulosa cells, levels of PRL-L transcript were increased (P<0.05) by follicle stimulating hormone (FSH) treatment while were not altered by the addition of luteinizing hormone (LH). In addition, 10ng/ml non-glycosylated (NG-) and 1ng/ml glycosylated (G-) PRL increased (P<0.05) but at higher levels (100 or 1000ng/ml) both showed no effects on PRL-L expression. Furthermore, 100ng/ml NG-PRL enhanced (P<0.05) FSH-induced PRL-L expression, whereas the effects of G-PRL were not significant. These results suggest that PRL-L mRNA is differentially expressed in the follicular hierarchy and its high abundance in undifferentiated granulosa cells is under the regulation of FSH or PRL variants independently or in combination. Moreover, in undifferentiated granulosa cells we also provide evidence for a positive role for PKA, PKC and PI3K signaling while a negative role for ERK2 in mediating FSH stimulation of PRL-L transcription.
Department of Animal Science, McGill University, Macdonald Campus, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada.
Shenqiang
S
Hu
Department of Animal Science, McGill University, Macdonald Campus, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada.
Raj
R
Duggavathi
Department of Animal Science, McGill University, Macdonald Campus, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada. Electronic address: david.zadworny@mcgill.ca.
David
D
Zadworny
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002645:Chickens / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006031:Glycosylation / Q000187:drug effects; D006062:Gonadotropins / Q000494:pharmacology; D006107:Granulosa Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011388:Prolactin / Q000235:genetics* / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
D017868:Cyclic AMP-Dependent Protein Kinases; D005640:Follicle Stimulating Hormone; D006062:Gonadotropins; D019869:Phosphatidylinositol 3-Kinases; D011388:Prolactin; D011493:Protein Kinase C; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger; D058570:TOR Serine-Threonine Kinases
Chicken; Follicle development; Granulosa cells; Ovary; Prolactin-like protein; Signaling pathway