Nitric oxide synthase activity and progesterone release by isolated corpora lutea of rabbits in the early and mid-luteal phases of pseudopregnancy are modulated differently by prostaglandin E-2 and prostaglandin F-2alpha via adenylate cyclase and phospholipase C

By examining in vitro the effects of prostaglandin E-2 (PGE-2) and prostaglandin F-2alpha (PGF-2alpha) induced in the corpora lutea (CL) of pseudopregnant rabbits, we have demonstrated that these prostaglandins modulate luteal nitric oxide synthase (NOS) activity and progesterone production differently, depending on the age of the CL. On CL obtained on day 4 of pseudopregnancy (day-4), PGE-2 was found to depress NOS total activity to 13% of control and to significantly increase basal progesterone secretion by 61%, while PGF-2alpha had no effect. On day-9 CL, PGE-2 was ineffective, but PGF-2alpha caused a 2.5-fold increase of NOS activity and a marked decrease in progesterone production. Using specific inhibitors, we found that the regulatory actions of PGE-2 in vitro are mediated via the adenyl cyclase/protein kinase A (PKA) second messenger system, while the PGF-2alpha-induced luteolytic effects on day-9 CL depend upon activation of the phospholipase C/protein kinase C (PKC) system. The different responsiveness of day-4 and day-9 CL to PGE-2 and PGF-2alpha could depend on receptor availability for these two prostaglandins, even if other cellular mechanisms cannot be excluded. The present study supports a functional role for NOS in regulating the steroidogenic capacity of rabbit CL, and reveals a novel interaction between a stimulatory G-protein-coupled receptor and PKC/PKA-mediated signal transduction modulating NOS activity.

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Prostaglandin receptors and role of G protein-activated pathways on corpora lutea of pseudopregnant rabbit in vitro

Journal of Endocrinology ◽

10.1677/joe.0.1680141 ◽

2001 ◽

Vol 168 (1) ◽

pp. 141-151 ◽

Cited By ~ 31

Author(s):

C Boiti ◽

D Zampini ◽

M Zerani ◽

G Guelfi ◽

A Gobbetti

Keyword(s):

Protein Kinase ◽

G Protein ◽

Corpora Lutea ◽

Progesterone Production ◽

Kinase C ◽

Ligand Interactions ◽

Pka Pathway ◽

Oxide Synthase

Studies were conducted to characterize receptors for prostaglandin (PG) F(2alpha) (PGF(2alpha)) and PGE(2), and the signalling pathways regulating total nitric oxide synthase activity and progesterone production in rabbit corpora lutea (CL) of different luteal stages. CL were obtained at days 4, 9 and 13 of pseudopregnancy and cultured in vitro for 2 h with PGF(2alpha) or PGE(2) and with activators and inhibitors of G protein (Gp), phospholipase C (PLC), protein kinase C (PKC), adenylate cyclase (AC) and protein kinase A (PKA). High affinity PGF(2alpha) receptor (K(d)=1.9+/-0.6 nM mean+/-s.e.m. ) concentrations increased (P< or =0.01) four- to five-fold from early to mid- and late-luteal phases (50.6+/-8.5, 188.3+/-36.1 and 231.4+/-38.8 fmol/mg protein respectively). By contrast, PGE(2) receptor (K(d)=1.6+/-0.5 nM) concentrations decreased (P< or =0.01) from day 4 to day 9 and 13 (27.5+/-7.7, 12.4+/-2.4 and 16.5+/-3.0 fmol/mg protein respectively). The Gp-dependent AC/PKA pathway was triggered only on day 4 CL, mimicking the PGE(2) treatment and increasing progesterone production. In both day 9 and day 13 CL, the Gp-activated PLC/PKC pathway evoked a luteolytic effect similar to that induced by PGF(2alpha). The time-dependent selective resistance to PGF(2alpha) and PGE(2) by rabbit CL is mediated by factors other than a lack of luteal receptor-ligand interactions.

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Regulation of nitric oxide synthase isoforms and role of nitric oxide during prostaglandin F2alpha-induced luteolysis in rabbits

Reproduction ◽

10.1530/rep.0.1250807 ◽

2003 ◽

pp. 807-816 ◽

Cited By ~ 23

Author(s):

C Boiti ◽

G Guelfi ◽

D Zampini ◽

G Brecchia ◽

A Gobbetti ◽

...

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Time Course ◽

Plasma Concentrations ◽

Physiological Role ◽

Total Activity ◽

Corpora Lutea ◽

Prostaglandin F ◽

Oxide Synthase

Total activity of nitric oxide synthase (NOS) and the gene expression of both endothelial NOS (eNOS) and inducible NOS (iNOS) isoforms in corpora lutea of pseudopregnant rabbits were examined during prostaglandin F(2alpha) (PGF(2alpha))-induced luteolysis. Corpora lutea were collected at 0, 6, 12, 24 and 48 h after an injection of PGF(2alpha) at day 9 of pseudopregnancy. At 12 h after PGF(2alpha) administration, luteal mRNA encoding eNOS decreased (P0.05) by 40% and remained low throughout the subsequent 36 h, whereas eNOS protein increased (P0.05) two- to threefold. By contrast, expression of mRNA encoding iNOS was poor and remained fairly constant, but transcription increased eightfold (P0.01) within 6 h after PGF(2alpha) treatment and then decreased to values similar to those of controls. Total NOS activity increased twofold (P0.01) at 6 h after treatment and remained high thereafter, whereas progesterone concentrations in explanted corpora lutea decreased (P0.01) from 302.4+/-42.3 pg x mg(-1) at day 9 to 58.6+/-8.3 at 48 h later, and peripheral plasma concentrations of progesterone declined too. Long-term administration of Nomega-nitro-L-arginine methyl ester (0.6 g l(-1) per os) from day 2 of pseudopregnancy onward partially blocked the luteolytic action of PGF(2alpha) administered at day 9 of pseudopregnancy. In nitric oxide (NO)-deficient rabbits, progesterone concentrations remained higher (P0.01) than in controls at 24-48 h after PGF(2alpha) administration (4.5 to 3.2 ng x ml(-1), respectively). These data are the first to characterize NOS activity. The time course of expression of eNOS and iNOS in rabbit corpora lutea during PGF(2alpha)-induced luteolysis gives additional support to a physiological role of NO in the regulation of regression of corpora lutea in rabbits.

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Regulation of Sertoli-Germ Cell Adherens Junction Dynamics in the Testis Via the Nitric Oxide Synthase (NOS)/cGMP/Protein Kinase G (PRKG)/β-Catenin (CATNB) Signaling Pathway: An In Vitro and In Vivo Study1

Biology of Reproduction ◽

10.1095/biolreprod.105.040766 ◽

2005 ◽

Vol 73 (3) ◽

pp. 458-471 ◽

Cited By ~ 36

Author(s):

Nikki P.Y. Lee ◽

Dolores D. Mruk ◽

Ching-hang Wong ◽

C. Yan Cheng

Keyword(s):

Nitric Oxide ◽

Protein Kinase ◽

Nitric Oxide Synthase ◽

Germ Cell ◽

Signaling Pathway ◽

Adherens Junction ◽

Protein Kinase G ◽

Oxide Synthase

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Differential effects of protein kinase C on neuronal nitric oxide synthase activity in rat cerebellar slices and in vitro

Journal of Chemical Neuroanatomy ◽

10.1016/0891-0618(96)00138-x ◽

1996 ◽

Vol 10 (3-4) ◽

pp. 213-220 ◽

Cited By ~ 15

Author(s):

Daisuke Okada

Keyword(s):

Nitric Oxide ◽

Protein Kinase C ◽

Protein Kinase ◽

Nitric Oxide Synthase ◽

Neuronal Nitric Oxide Synthase ◽

Differential Effects ◽

Kinase C ◽

Oxide Synthase ◽

Nitric Oxide Synthase Activity

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Tetrahydrobiopterin-dependent stabilization of neuronal nitric oxide synthase dimer reduces susceptibility to phosphorylation by protein kinase C in vitro

FEBS Letters ◽

10.1016/s0014-5793(98)00993-4 ◽

1998 ◽

Vol 434 (3) ◽

pp. 261-264 ◽

Cited By ~ 14

Author(s):

Daisuke Okada

Keyword(s):

Nitric Oxide ◽

Protein Kinase C ◽

Protein Kinase ◽

Nitric Oxide Synthase ◽

Neuronal Nitric Oxide Synthase ◽

Kinase C ◽

Oxide Synthase

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Regulation of cyclooxygenase activity and progesterone production in the rat corpus luteum by inducible nitric oxide synthase

Reproduction ◽

10.1530/rep.0.1230663 ◽

2002 ◽

pp. 663-669 ◽

Cited By ~ 7

Author(s):

A Hurwitz ◽

Z Finci-Yeheskel ◽

A Milwidsky ◽

M Mayer

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Corpus Luteum ◽

Prostaglandin E ◽

No Production ◽

Luteal Cells ◽

Progesterone Production ◽

Nos Inhibitors ◽

Nos Inhibitor ◽

Oxide Synthase

This study explores interactions between the nitric oxide synthase (NOS) and the cyclooxygenase (COX) pathways in the regulation of progesterone production in early corpus luteum cells of rats. Nitric oxide (NO), prostaglandin E (PGE) and progesterone production was analysed in luteal cells of the rat corpus luteum exposed to inhibitors of non-specific NOS, inhibitors of inducible NOS (iNOS) and inhibitors of COX. Equine chorionic gonadotrophin (eCG)/hCG-primed rat corpus luteum cells produced NO, PGE and progesterone in a linear manner during 66 h of culture. Exposure of the cells to the non-specific NOS inhibitor, N(omega)-nitro-L-arginine (0.15 mmol l(-1)) for 48 h reduced NO, PGE and progesterone production to 21, 32 and 60% of that of the controls, respectively (P < 0.05 to P < 0.01). Another non-specific NOS inhibitor, N(omega)-methyl-L-arginine, produced similar inhibitions. Exposure of the cultured cells to S-ethylisothiourea (1 mmol l(-1)), a selective inhibitor of iNOS, suppressed the production of NO by 63%, PGE by 69% and progesterone by 48%. These findings indicate that production of PGE is regulated partly by iNOS, and that progesterone is probably regulated indirectly by the secondary changes in PGE. The addition of arachidonic acid to N(omega)-methyl-L-arginine-treated cells resulted in a significant increase in PGE and progesterone production (273 and 186%, respectively) without stimulating NO production. In contrast to the regulation exerted by the NO system on COX activity, the COX system does not modulate NO production in this model. This notion stems from the observation that the COX inhibitors acetylsalicylic acid (5 mmol l(-1)) and indomethacin (5 micromol l(-1)) suppressed PGE by 86 and 89%, respectively, and progesterone by 34 and 57%, respectively, but failed to inhibit NO production. The results from the present study indicate that iNOS-mediated NO production is involved in stimulating PGE synthesis in rat luteal cells, which may upregulate progesterone production.

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