title: Effects of second messengers on gap junctional intercellular communication of ovine luteal cells throughout the estrous cycle.
abstract: Corpora lutea (CL) from Days 5, 10, and 15 after superovulation were enzymatically dispersed, and a portion of the cells were elutriated to obtain fractions enriched with small or large luteal cells. Mixed, small, and large luteal cell fractions were incubated with no treatment or with agonists or antagonists of cAMP (dbcAMP or Rp-cAMPS), protein kinase C (PKC; TPA or H-7), or calcium (A23187, EGTA, or A23187 + EGTA). The rate of contact-dependent gap junctional intercellular communication (GJIC) was evaluated by laser cytometry. Media were collected for progesterone (P(4)) radioimmunoassay, and luteal cells cultured with no treatment were fixed for immunocytochemistry or frozen for Western blot analysis. Luteal cells from each stage of the estrous cycle exhibited GJIC. The dbcAMP increased (P < 0.05) GJIC for all cell types across the estrous cycle. The Rp-cAMPS decreased (P < 0.05) GJIC for small luteal cells on Day 5 and for all cell types on Days 10 and 15. The TPA inhibited (P < 0.01), but H-7 did not affect, GJIC for all cell types across the estrous cycle. The A23187 decreased (P < 0.05) GJIC for large luteal cells touching only small or only large luteal cells, whereas A23187 + EGTA decreased (P < 0.05) GJIC for all cell types across the estrous cycle. For the mixed and large luteal cell fractions, dbcAMP increased (P < 0.05), but TPA and A23187 + EGTA decreased (P < 0.05), P(4) secretion. The A23187 alone decreased (P < 0.05) P(4) secretion by large, but not by mixed, luteal cells. For all days and cell types, the rate of GJIC and P(4) secretion were correlated (r = 0.113-0.249; P < 0.01). Connexin 43 was detected in cultured luteal cells by immunofluorescence and Western immunoblotting. Thus, intracellular regulators like cAMP, PKC, or calcium appear to regulate GJIC, which probably is an important mechanism for coordinating function of the ovine CL.
authors.affiliation: Department of Animal and Range Sciences, North Dakota State University, Fargo, ND 58105, USA. anna_grazul-bilska@ndsu.nodak.edu
authors.forename: A T
authors.initials: AT
authors.lastname: Grazul-Bilska
authors.forename: L P
authors.initials: LP
authors.lastname: Reynolds
authors.forename: J J
authors.initials: JJ
authors.lastname: Bilski
authors.forename: D A
authors.initials: DA
authors.lastname: Redmer
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D003994:Bucladesine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D017077:Culture Media, Conditioned / Q000737:chemistry; D000242:Cyclic AMP / Q000819:agonists / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D030762:Estrous Cycle; D005260:Female; D005455:Fluorescent Antibody Technique; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology*; D007150:Immunohistochemistry; D007476:Ionophores / Q000494:pharmacology; D008184:Luteal Cells / Q000502:physiology / Q000648:ultrastructure*; D011374:Progesterone / Q000032:analysis / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D015290:Second Messenger Systems / Q000502:physiology*; D012756:Sheep / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
chemical_list: D002614:Chelating Agents; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D007476:Ionophores; D013873:Thionucleotides; C016957:adenosine-3',5'-cyclic phosphorothioate; D000001:Calcimycin; D011374:Progesterone; D004533:Egtazic Acid; D003994:Bucladesine; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000242:Cyclic AMP; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium