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Testis-Specific Isoform of Na+-K+ ATPase and Regulation of Bull Fertility. Int J Mol Sci 2022; 23:ijms23147936. [PMID: 35887284 PMCID: PMC9317330 DOI: 10.3390/ijms23147936] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 12/10/2022] Open
Abstract
An advanced understanding of sperm function is relevant for evidence-based male fertility prediction and addressing male infertility. A standard breeding soundness evaluation (BSE) merely identifies gross abnormalities in bulls, whereas selection based on single nucleotide polymorphisms and genomic estimated breeding values overlooks sub-microscopic differences in sperm. Molecular tools are important for validating genomic selection and advancing knowledge on the regulation of male fertility at an interdisciplinary level. Therefore, research in this field is now focused on developing a combination of in vitro sperm function tests and identifying biomarkers such as sperm proteins with critical roles in fertility. The Na+-K+ ATPase is a ubiquitous transmembrane protein and its α4 isoform (ATP1A4) is exclusively expressed in germ cells and sperm. Furthermore, ATP1A4 is essential for male fertility, as it interacts with signaling molecules in both raft and non-raft fractions of the sperm plasma membrane to regulate capacitation-associated signaling, hyperactivation, sperm-oocyte interactions, and activation. Interestingly, ATP1A4 activity and expression increase during capacitation, challenging the widely accepted dogma of sperm translational quiescence. This review discusses the literature on the role of ATP1A4 during capacitation and fertilization events and its prospective use in improving male fertility prediction.
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Interaction of ouabain and progesterone on induction of bull sperm capacitation. Theriogenology 2019; 126:191-198. [DOI: 10.1016/j.theriogenology.2018.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 11/06/2018] [Accepted: 12/01/2018] [Indexed: 01/16/2023]
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Lisanova OV, Shchelkunova TA, Morozov IA, Rubtsov PM, Levina IS, Kulikova LE, Smirnov AN. Approaches to the design of selective ligands for membrane progesterone receptor alpha. BIOCHEMISTRY (MOSCOW) 2013; 78:236-43. [DOI: 10.1134/s0006297913030048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Morrill GA, Kostellow AB, Moore RD, Gupta RK. Plasma membrane events associated with the meiotic divisions in the amphibian oocyte: insights into the evolution of insulin transduction systems and cell signaling. BMC DEVELOPMENTAL BIOLOGY 2013; 13:3. [PMID: 23343451 PMCID: PMC3577484 DOI: 10.1186/1471-213x-13-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 12/22/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND Insulin and its plasma membrane receptor constitute an ancient response system critical to cell growth and differentiation. Studies using intact Rana pipiens oocytes have shown that insulin can act at receptors on the oocyte surface to initiate resumption of the first meiotic division. We have reexamined the insulin-induced cascade of electrical and ion transport-related plasma membrane events using both oocytes and intact plasma membranes in order to characterize the insulin receptor-steroid response system associated with the meiotic divisions. RESULTS [(125)I]Insulin binding (K(d) = 54 ± 6 nM) at the oocyte plasma membrane activates membrane serine protease(s), followed by the loss of low affinity ouabain binding sites, with a concomitant 3-4 fold increase in high affinity ouabain binding sites. The changes in protease activity and ouabain binding are associated with increased Na(+)/Ca2(+) exchange, increased endocytosis, decreased Na(+) conductance resulting in membrane hyperpolarization, increased 2-deoxy-D-glucose uptake and a sustained elevation of intracellular pH (pHi). Hyperpolarization is largely due to Na(+)-channel inactivation and is the main driving force for glucose uptake by the oocyte via Na(+)/glucose cotransport. The Na(+) sym- and antiporter systems are driven by the Na(+) free energy gradient generated by Na(+)/K(+)-ATPase. Shifts in α and/or β Na(+)-pump subunits to caveolar (lipid raft) membrane regions may activate Na/K-ATPase and contribute to the Na(+) free energy gradient and the increase in both Na(+)/glucose co-transport and pHi. CONCLUSIONS Under physiological conditions, resumption of meiosis results from the concerted action of insulin and progesterone at the cell membrane. Insulin inactivates Na(+) channels and mobilizes fully functional Na(+)-pumps, generating a Na(+) free energy gradient which serves as the energy source for several membrane anti- and symporter systems.
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Affiliation(s)
- Gene A Morrill
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Adele B Kostellow
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Richard D Moore
- The Biophysics Laboratory, State University of New York, Plattsburgh, NY, 12901, USA
| | - Raj K Gupta
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Morrill GA, Kostellow AB, Askari A. Caveolin-Na/K-ATPase interactions: role of transmembrane topology in non-genomic steroid signal transduction. Steroids 2012; 77:1160-8. [PMID: 22579740 DOI: 10.1016/j.steroids.2012.04.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 04/04/2012] [Accepted: 04/10/2012] [Indexed: 12/14/2022]
Abstract
Progesterone and its polar metabolite(s) trigger the meiotic divisions in the amphibian oocyte through a non-genomic signaling system at the plasma membrane. Published site-directed mutagenesis studies of ouabain binding and progesterone-ouabain competition studies indicate that progesterone binds to a 23 amino acid extracellular loop of the plasma membrane α-subunit of Na/K-ATPase. Integral membrane proteins such as caveolins are reported to form Na/K-ATPase-peptide complexes essential for signal transduction. We have characterized the progesterone-induced Na/K-ATPase-caveolin (CAV-1)-steroid 5α-reductase interactions initiating the meiotic divisions. Peptide sequence analysis algorithms indicate that CAV-1 contains two plasma membrane spanning helices, separated by as few as 1-2 amino acid residues at the cell surface. The CAV-1 scaffolding domain, reported to interact with CAV-1 binding (CB) motifs in signaling proteins, overlaps transmembrane (TM) helix 1. The α-subunit of Na/K-ATPase (10 TM helices) contains double CB motifs within TM-1 and TM-10. Steroid 5α-reductase (6 TM helices), an initial step in polar steroid formation, contains CB motifs overlapping TM-1 and TM-6. Computer analysis predicts that interaction between antipathic strands may bring CB motifs and scaffolding domains into close proximity, initiating allostearic changes. Progesterone binding to the α-subunit may thus facilitate CB motif:CAV-1 interaction, which in turn induces helix-helix interaction and generates both a signaling cascade and formation of polar steroids.
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Affiliation(s)
- Gene A Morrill
- Department of Physiology & Biophysics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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Mohanty BK, Gupta BL. A marked animal-vegetal polarity in the localization of Na(+),K(+) -ATPase activity and its down-regulation following progesterone-induced maturation. Mol Reprod Dev 2011; 79:138-60. [PMID: 22213374 DOI: 10.1002/mrd.22012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 11/22/2011] [Indexed: 01/01/2023]
Abstract
The stage-VI Xenopus oocyte has a very distinct animal-vegetal polarity with structural and functional asymmetry. In this study, we show the expression and distribution pattern of Na(+),K(+) -ATPase in stage-VI oocytes, and its changes following progesterone-induced maturation. Using enzyme-specific electron microscopy phosphatase histochemistry, [(3) H]-ouabain autoradiography, and immunofluorescence cytochemistry at light microscopic level, we find that Na(+),K(+) -ATPase activity is mainly confined to the animal hemisphere. Electron microscopy histochemical results also suggest that polarized distribution of Na(+),K(+) -ATPase activity persists following progesterone-induced maturation, and it becomes gradually more polarized towards the animal pole. The time course following progesterone-induced maturation suggests that there is an initial up-regulation and then gradual down-regulation of Na(+),K(+) -ATPase activity leading to germinal vesicle breakdown (GVBD). By GVBD, the Na(+),K(+) -ATPase activity is completely down-regulated due to endocytotic removal of pump molecules from the plasma membrane into the sub-cortical region of the oocyte. This study provides the first direct evidence for a marked asymmetric localization of Na(+),K(+) -ATPase activity in any vertebrate oocyte. Here, we propose that such asymmetry in Na(+),K(+) -ATPase activity in stage-VI oocytes, and their down-regulation following progesterone-induced maturation, is likely to have a role in the active state of the germinal vesicle in stage-VI oocytes and chromosomal condensation after GVBD.
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Morrill GA, Dowd TL, Kostellow AB, Gupta RK. Progesterone-induced changes in the phosphoryl potential during the meiotic divisions in amphibian oocytes: role of Na/K-ATPase. BMC DEVELOPMENTAL BIOLOGY 2011; 11:67. [PMID: 22054214 PMCID: PMC3248852 DOI: 10.1186/1471-213x-11-67] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 11/06/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND Progesterone triggers resumption of the first meiotic division in the Rana pipiens oocyte by binding to the N-terminal external loop of the catalytic subunit of Na/K-ATPase, releasing a cascade of lipid second messengers. This is followed by internalization of specific membrane proteins, plasma membrane depolarization and nuclear membrane breakdown, culminating in arrest at second metaphase. RESULTS Progesterone initiates an increase in phosphoryl potential during the first meiotic division, resulting in the accumulation of high energy protein phosphate by second metaphase arrest. 31P-NMR, with saturation transfer, demonstrates that the phosphocreatine level rises ~2 fold and that the "pseudo" first order rate constant for the creatine kinase reaction falls to ~20% of the control by the onset of nuclear membrane breakdown. 32PO4 pulse-labeling reveals a net increase in phosphorylation of yolk protein phosvitin during this period. The increased yolk protein phosphorylation coincides with internalization of membrane Na/K-ATPase and membrane depolarizatio CONCLUSIONS These results indicate that progesterone binding to the catalytic subunit of the Na-pump diverts ATP from cation regulation at the plasma membrane to storage of high energy phosphate in yolk protein. Phosvitin serves as a major energy source during fertilization and early cleavage stages and is also a storage site for cations (e.g. Na+, K+, Ca2+, Fe2+/3+) essential for embryonic development.
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Affiliation(s)
- Gene A Morrill
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Terry L Dowd
- Department of Chemistry, Brooklyn College of the City University of New York Brooklyn, New York 11210, USA
| | - Adele B Kostellow
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Raj K Gupta
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Girard C, Eychenne B, Schweizer-Groyer G, Cadepond F. Mineralocorticoid and glucocorticoid receptors in sciatic nerve function and regeneration. J Steroid Biochem Mol Biol 2010; 122:149-58. [PMID: 20678573 DOI: 10.1016/j.jsbmb.2010.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 07/21/2010] [Accepted: 07/24/2010] [Indexed: 12/20/2022]
Abstract
The contribution of the two corticosteroid (mineralocorticoid and glucocorticoid) receptor (MR and GR) pathways to the function and regeneration of the sciatic nerve was investigated. We found that the corticosterone-inactivating enzyme 11β-hydroxysteroid dehydrogenase type 2 (HSD2) was up-regulated 7 days after lesion in freeze-injured nerve. The maintenance of a low intracellular level of corticosterone by HSD2 activity in the regenerating nerve is concordant with the improvement of nervous function in injured animals (as measured by walking ability) after treatment by the GR antagonist mifepristone and with the reduction in GR participation in accumulation of the mRNA for numerous endogenous genes (from the renin-angiotensin system and other classical mineralocorticoid-responsive genes), in the same animals. Furthermore, using the MR antagonist spironolactone, we demonstrated that MR plays an active role in the function of the intact sciatic nerve: MR is required for walking ability and participates in the control of the accumulation of the mRNA for several endogenous genes. However, after injury, changes in gene expression cannot be fully explained by changes in MR/GR activity, due to an HSD2 effect, and other signalling pathway(s) induced by the lesion likely combine with the effect of the corticosteroid receptors.
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Affiliation(s)
- Christelle Girard
- Unité Mixte de Recherche 788, Inserm and Université Paris-Sud 11, 94276 Le Kremlin-Bicêtre, France
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Morrill GA, Kostellow AB, Askari A. Progesterone modulation of transmembrane helix-helix interactions between the alpha-subunit of Na/K-ATPase and phospholipid N-methyltransferase in the oocyte plasma membrane. BMC STRUCTURAL BIOLOGY 2010; 10:12. [PMID: 20500835 PMCID: PMC2887865 DOI: 10.1186/1472-6807-10-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 05/25/2010] [Indexed: 11/10/2022]
Abstract
BACKGROUND Progesterone binding to the surface of the amphibian oocyte initiates the meiotic divisions. Our previous studies with Rana pipiens oocytes indicate that progesterone binds to a plasma membrane site within the external loop between the M1 and M2 helices of the alpha-subunit of Na/K-ATPase, triggering a cascade of lipid second messengers and the release of the block at meiotic prophase. We have characterized this site, using a low affinity ouabain binding isoform of the alpha1-subunit. RESULTS Preparations of isolated plasma membranes from Rana oocytes demonstrate that physiological levels of progesterone (or the non-metabolizable progestin R5020) successively activate phosphatidylethanolamine-N-methyltransferase (PE-NMT) and sphingomyelin synthase within seconds. Inhibition of PE-NMT blocks the progesterone induction of meiosis in intact oocytes, whereas its initial product, phosphatidylmonomethylethanolamine (PME), can itself initiate meiosis in the presence of the inhibitor. Published X-ray crystallographic data on Na/K-ATPase, computer-generated 3D projections, heptad repeat analysis and hydrophobic cluster analysis of the transmembrane helices predict that hydrophobic residues L, V, V, I, F and Y of helix M2 of the alpha1-subunit interact with F, L, G, L, L and F, respectively, of helix M3 of PE-NMT. CONCLUSION We propose that progesterone binding to the first external loop of the alpha1-subunit facilitates specific helix-helix interactions between integral membrane proteins to up-regulate PE-NMT, and, that successive interactions between two or more integral plasma membrane proteins induce the signaling cascades which result in completion of the meiotic divisions.
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Affiliation(s)
- Gene A Morrill
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461 USA
| | - Adele B Kostellow
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461 USA
| | - Amir Askari
- Department of Physiology, Pharmacology, Metabolism and Cardiovascular Sciences, College of Medicine, The University of Toledo, Toledo, OH 43614 USA
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Tramoni M, Gilleron J, Tahiri K, Carette D, Corvol MT, Segretain D, Pointis G, Savouret JF. Contraceptive steroids from pharmaceutical waste perturbate junctional communication in Sertoli cells. Biochimie 2009; 91:1366-75. [DOI: 10.1016/j.biochi.2009.09.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 09/16/2009] [Indexed: 11/16/2022]
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Kostellow AB, Morrill GA. Progesterone and subsequent polar metabolites are essential for completion of the first meiotic division in amphibian oocytes. Mol Cell Endocrinol 2008; 291:50-6. [PMID: 18599190 DOI: 10.1016/j.mce.2008.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 04/20/2008] [Accepted: 05/21/2008] [Indexed: 11/28/2022]
Abstract
We find that completion of the first meiotic division in Rana pipiens oocytes requires the sequential action of at least two steroids: progesterone and one or more subsequent polar metabolites of progesterone. Progesterone binding in vitro to oocyte surface receptors increases during the first 4-5h of exposure, followed by internalization of plasma membrane together with membrane-bound progesterone over the next hour. The internalized progesterone is metabolized to highly polar polyhydroxylated steroid(s) prior to nuclear membrane disappearance at 8-9h. Polar steroids alone cannot induce meiosis, but do so in oocytes pretreated with progesterone for 1h. Similarly, the non-metabolizable progestin R5020 cannot induce meiosis but does if oocytes are subsequently exposed to polar steroids. An inhibitor of steroid alpha-reductase (4-MA) prevents both progesterone metabolism and progesterone-induced meiosis. However, meiosis does occur if 4-MA is followed by a polar steroid. Thus, progesterone binding at the oocyte surface initiates a process which requires polar progesterone metabolites for completion of the first meiotic division.
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Affiliation(s)
- Adele B Kostellow
- Department of Physiology & Biophysics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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Morrill GA, Kostellow AB, Askari A. Progesterone binding to the alpha1-subunit of the Na/K-ATPase on the cell surface: insights from computational modeling. Steroids 2008; 73:27-40. [PMID: 17936318 PMCID: PMC2275170 DOI: 10.1016/j.steroids.2007.08.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 08/22/2007] [Accepted: 08/23/2007] [Indexed: 11/26/2022]
Abstract
Progesterone triggers the resumption of meiosis in the amphibian oocyte through a signaling system at the plasma membrane. Analysis of [(3)H]ouabain and [(3)H]progesterone binding to the plasma membrane of the Rana pipiens oocyte indicates that progesterone competes with ouabain for a low affinity ouabain binding site on a 112kDa alpha1-subunit of the membrane Na/K-ATPase. Published amino acid sequences from both low and high affinity ouabain binding alpha1-subunits are compared, together with published site-directed mutagenesis studies of ouabain binding. We propose that the progesterone binding site is located in the external loop (23 amino acids) between the M1-M2 transmembrane helices. Analysis of loop topology and the countercurrent hydrophobicity/polarity gradients within the M1-M2 loop further suggest that the polar beta and hydrophobic alpha surfaces of the planar progesterone molecule interact with opposite sides of the amino acid loop. The 19-angular methyl group of progesterone is essential for activity; it could bind to the C-terminal region of the M1-M2 loop. Maximum biological activity requires formation of hydrogen-bond networks between the 3-keto group of progesterone and Arg(118), Asp(129) and possibly Glu(122-124) in the C-terminal region of the loop. The 20-keto group hydrogen may in turn hydrogen bond to Cys(111) near the M1 helix. Peptide flexibility undergoes a maximal transition near the midway point in the M1-M2 loop, suggesting that folding occurs within the loop, which further stabilizes progesterone binding.
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Affiliation(s)
- Gene A Morrill
- Department of Physiology & Biophysics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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Chien EJ, Liao CF, Chang CP, Pu HF, Lu LM, Shie MC, Hsieh DJY, Hsu MT. The non-genomic effects on Na+/H+-exchange 1 by progesterone and 20α-hydroxyprogesterone in human T cells. J Cell Physiol 2007; 211:544-50. [PMID: 17323380 DOI: 10.1002/jcp.20962] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Progesterone is an endogenous immunomodulator and can suppress T-cell activation during pregnancy. We have previously shown that the non-genomic effects of progesterone, especially acidification, are exerted via plasma membrane sites and suppress cellular genomic responses to mitogens. This study aimed to show that acidification is due to a non-genomic inhibition of Na(+)/H(+)-exchange 1 (NHE1) by progesterone and correlate this with immunosuppressive phytohemagglutinin (PHA)-induced T-cell proliferation. The presence of amiloride-sensitive NHE 1 was identified in T cells. The activity of NHE1 was inhibited by progesterone but not by 20alpha-hydroxyprogesterone (20alpha-OHP). Furthermore, 20alpha-OHP was able to compete with progesterone and release the inhibitory effect on the NHE1. The inhibition of NHE1 activity by progesterone-BSA demonstrated non-genomic action via plasma membrane sites. Finally, co-stimulation with PHA and progesterone or amiloride, (5-(N, N-dimethyl)-amiloride, DMA), inhibited PHA-induced T-cell proliferation, but this inhibition did not occur with 20alpha-OHP and PHA co-stimulation. However, when DMA was applied 72 h after PHA stimulation, it was able to suppress PHA-induced T-cell proliferation. This is the first study to show that progesterone causes a rapid non-genomic inhibition of plasma membrane NHE1 activity in T cells within minutes which is released by 20alpha-OHP. The inhibition of NHE1 leads to immunosuppressive T-cell proliferation and suggests that progesterone might exert a major rapid non-genomic suppressive effect on NHE1 activity at the maternal-fetal interface in vivo and that 20alpha-OHP may possibly be able to quickly release the suppression when T cells circulated away from the interface.
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Affiliation(s)
- Eileen Jea Chien
- Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.
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Abstract
This minireview summarizes the role that progesterone (P4) plays in regulating granulosa and luteal cell function. These actions include the stimulation of P4 synthesis and the inhibition of estrogen synthesis, mitosis, and apoptosis. P4 also plays a key role in the ovulatory process. Although P4's actions are well documented, the mechanism or mechanisms that mediate all of these actions have not been defined. In addition to P4-induced gene transcription that is mediated by the nuclear P4 receptors (PGR-A and PGR-B), three other receptor/signal transduction pathways could account for P4's intraovarian actions. These pathways could be mediated by 1) the PGR localizing at or near the plasma membrane and activating SRC family kinases, 2) a membrane progestin receptor that responds to P4 by lowering intracellular cAMP and increasing MAPK 3/1 activity, and 3) a membrane receptor complex composed of serpine 1 mRNA binding protein (also known as PAIRBP1 or RDA288) and progesterone receptor membrane component 1. Ligand activation of this complex likely leads to an increase in protein kinase G activity, the maintenance of low basal intracellular free calcium, and the inhibition of granulosa and luteal cell mitosis and apoptosis. Given the complexity of P4's actions within the ovary, it is likely that all of these receptor/signal transduction pathways influence some aspect of ovarian function with the specific P4 response dependent on 1) the expression pattern of these putative P4 receptors, 2) the P4 binding affinity of each receptor system, and 3) the amount of available P4.
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Affiliation(s)
- John J Peluso
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut 06030, USA.
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Morrill GA, Schatz F, Kostellow A, Bloch E. Gonadotropin stimulation of steroid synthesis and metabolism in the Rana pipiens ovarian follicle: sequential changes in endogenous steroids during ovulation, fertilization and cleavage stages. J Steroid Biochem Mol Biol 2006; 99:129-38. [PMID: 16678716 DOI: 10.1016/j.jsbmb.2006.01.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Accepted: 01/06/2006] [Indexed: 11/21/2022]
Abstract
Steroid synthesis and metabolism have been followed in Rana pipiens ovarian follicles, denuded oocytes and eggs during ovulation, fertilization and cleavage stages (blastula formation). Under physiological conditions, gonadotropin stimulation of the fully grown follicle leads to progesterone synthesis from [(3)H]acetate as well as formation of much smaller amounts of 17alpha-hydroxyprogesterone, androstenedione, pregnanedione and pregnanediol. Progesterone levels increase during completion of the first meiotic division, but by ovulation progesterone disappears from the egg. Plasma membrane-bound progesterone is taken up into the oocyte cortical granules and is largely metabolized to 5alpha-pregnane-3alphaol,20-one and 5beta-pregnane-3alpha,17alpha,20beta-triol coincident with internalization of 60% of the oocyte surface (and >90% of bound progesterone) by the end of the hormone-dependent period. The principal steroid in the ovulated egg is 5beta-pregnane-3alpha,17alpha,20beta-triol. There is a rapid efflux of 5beta-pregnane-3alpha,17alpha,20beta-triol into the medium immediately following fertilization and residual steroid levels remain low in the developing blastula. Dissociated blastulae cells prepared from stage 9 1/2 embryos concentrate both pregnenolone and progesterone from the medium with minimal metabolism. The results indicate that the ovarian follicle has the ability to synthesize and metabolize progesterone but that this ability disappears in the ovulated egg. The progesterone metabolites formed during meiosis are largely released at fertilization.
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Affiliation(s)
- Gene A Morrill
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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