Immunohistochemical localization of chorionic gonadotrophin on baboon placenta, dispersed trophoblast cells and those derived from blastocysts grown in vitro

Bambra, Charanjit S.; Tarara, Ross P.

doi:10.1530/jrf.0.0880009

Cited by 7 publications

(5 citation statements)

References 18 publications

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“…CG was used at a concentration of 10 nM (bioactivity ϭ 1.8 IU/ ml; NIH/NHPP) in all experiments. This concentration approximates the measurable levels of CG in the baboon blastocyst culture medium [21].…”

Section: Preparation Of Cellssupporting

confidence: 64%

Signal Transduction Pathways Activated by Chorionic Gonadotropin in the Primate Endometrial Epithelial Cells1

Srisuparp¹,

Straková²,

Brudney³

et al. 2003

Biology of Reproduction

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Successful implantation requires synergism between the developing embryo and the receptive endometrium. In the baboon, infusion of chorionic gonadotropin (CG) modulates both morphology and physiology of the epithelial and stromal cells of the receptive endometrium. This study explored the signal transduction pathways activated by CG in endometrial epithelial cells from baboon (BE) and human (HES). Incubations of BE and HES cells with CG did not significantly alter adenylyl cyclase activity or increase intracellular cAMP when compared with Chinese hamster ovarian cells stably transfected with the full-length human CG/luteinizing hormone (LH) receptor (CHO-LH cells). However, in BE and HES cells, CG induced the phosphorylation of several proteins, among them, extracellular signal-regulated protein kinases 1 and 2 (ERK 1/2). Phosphorylation of ERK 1/2 in uterine epithelial cells was protein kinase A (PKA) independent. This novel signaling pathway is functional because, in response to CG stimulation, prostaglandin E(2) (PGE(2)) was released into the media and increased significantly 2 h following CG stimulation. CG-stimulated PGE(2) synthesis in epithelial cells was inhibited by a specific mitogen-activated protein kinase (MEK 1/2) inhibitor, PD 98059. In conclusion, immediate signal transduction pathways induced by CG in endometrial epithelial cells are cAMP independent and stimulate phosphorylation of ERK 1/2 via a MEK 1/2 pathway, leading to an increase in PGE(2) release as the possible result of cyclooxygenase-2 activation.

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Section: Preparation Of Cellssupporting

confidence: 64%

Signal Transduction Pathways Activated by Chorionic Gonadotropin in the Primate Endometrial Epithelial Cells1

Srisuparp¹,

Straková²,

Brudney³

et al. 2003

Biology of Reproduction

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“…Since cell respiration yields CO 2 , we assumed that the glucose-mediated rise in sperm beat frequency cannot only be explained by the production of ATP but also by the generation of HCO 3 −. Downstream pathways of HCO 3 − include direct activation of the sperm-specific soluble adenylyl cylase (sAC) [12], [13], elevation of the intracellular cAMP content and protein phosphorylation of several target proteins by protein kinase A (PKA) [14], [15]. We therefore investigated the glucose-mediated acceleration of flagellar beat during inhibition of CAs by EZA and AZA, sAC by KH7 and 2'OH-E and PKA by H89.…”

Section: Discussionmentioning

confidence: 99%

“…Whereas the ATP generated during glycolysis helps sperm to maintain the resting beat stable, HCO 3 − is the only substance known so far in sperm to speed up their flagellar beat [10], [11], enabling them to travel along the uterus to reach the egg in the ampulla. Once inside the sperm cell, HCO 3 − directly activates the sperm-specific adenylyl cyclase (sAC) [12], [13] which, in turn, raises the intracellular level of cAMP, thereby stimulating protein kinase A (PKA) [14], [15], [16] and initiating the acceleration of beat frequency. Besides the above mentioned glycolytic enzymes the fibrous sheath is also a scaffold for A-kinase anchor protein 3 (AKAP3), A-kinase anchor protein 4 (AKAP4) and testis-specific A-kinase anchor protein 80 (TAKAP-80) (Fig.…”

Section: Introductionmentioning

confidence: 99%

Glucose is a pH-Dependent Motor for Sperm Beat Frequency during Early Activation

2012

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To reach the egg in the ampulla, sperm have to travel along the female genital tract, thereby being dependent on external energy sources and substances to maintain and raise the flagellar beat. The vaginal fluid is rich in lactate, whereas in the uterine fluid glucose is the predominant substrate. This evokes changes in the lactate content of sperm as well as in the intracellular pH (pHi) since sperm possess lactate/proton co-transporters. It is well documented that glycolysis yields ATP and that HCO3− is a potent factor in the increase of beat frequency. We here show for the first time a pathway that connects both parts. We demonstrate a doubling of beat frequency in the mere presence of glucose. This effect can reversibly be blocked by 2-deoxy-D-glucose, dichloroacetate and aminooxyacetate, strongly suggesting that it requires both glycolysis and mitochondrial oxidation of glycolytic end products. We show that the glucose-mediated acceleration of flagellar beat and ATP production are hastened by a pHi ≥7.1, whereas a pHi ≤7.1 leaves both parameters unchanged. Since we observed a diminished rise in beat frequency in the presence of specific inhibitors against carbonic anhydrases, soluble adenylyl cyclase and protein kinase, we suggest that the glucose-mediated effect is linked to CO2 hydration and thus the production of HCO3− by intracellular CA isoforms. In summary, we propose that, in sperm, glycolysis is an additional pHi-dependent way to produce HCO3−, thus enhancing sperm beat frequency and contributing to fertility.

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“…The flow rate of the pump was 10 l͞h and the hourly infusate was 1.25 international units. The 24-h infusion of 30 international units is equivalent to the amount of CG secreted by dispersed baboon trophoblast cells cultured in vitro in a 24-h period (9). Endometrial tissue was harvested on day 10 PO for analysis.…”

Section: Methodsmentioning

confidence: 99%

Modulation of the baboon ( Papio anubis ) uterine endometrium by chorionic gonadotrophin during the period of uterine receptivity

Fazleabas

Donnelly

Srinivasan

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

156

181

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This study was undertaken to determine the modulation of uterine function by chorionic gonadotrophin (CG) in a nonhuman primate. Infusion of recombinant human CG (hCG) between days 6 and 10 post ovulation initiated the endoreplication of the uterine surface epithelium to form distinct epithelial plaques. These plaque cells stained intensely for cytokeratin and the proliferating cell nuclear antigen. The stromal fibroblasts below the epithelial plaques stained positively for ␣-smooth muscle actin (␣SMA). Expression of ␣SMA is associated with the initiation of decidualization in the baboon endometrium. Synthesis of the glandular secretory protein glycodelin, as assessed by Western blot analysis, was markedly up-regulated by hCG, and this increase was confirmed by immunocytochemistry, Northern blot analysis, and reverse transcriptase-PCR. To determine whether hCG directly modulated these uterine responses, we treated ovariectomized baboons sequentially with estradiol and progesterone to mimic the hormonal profile of the normal menstrual cycle. Infusion of hCG into the oviduct of steroidhormone-treated ovariectomized baboons induced the expression of ␣SMA in the stromal cells and glycodelin in the glandular epithelium. The epithelial plaque reaction, however, was not readily evident. These studies demonstrate a physiological effect of CG on the uterine endometrium in vivo and suggest that the primate blastocyst signal, like the blastocyst signals of other species, modulates the uterine environment prior to implantation.

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Immunohistochemical localization of chorionic gonadotrophin on baboon placenta, dispersed trophoblast cells and those derived from blastocysts grown in vitro

Cited by 7 publications

References 18 publications

Signal Transduction Pathways Activated by Chorionic Gonadotropin in the Primate Endometrial Epithelial Cells1

Signal Transduction Pathways Activated by Chorionic Gonadotropin in the Primate Endometrial Epithelial Cells1

Glucose is a pH-Dependent Motor for Sperm Beat Frequency during Early Activation

Modulation of the baboon ( Papio anubis ) uterine endometrium by chorionic gonadotrophin during the period of uterine receptivity

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