Spermatogenesis-preventing substance in Japanese eel

Development ◽  
2002 ◽  
Vol 129 (11) ◽  
pp. 2689-2697 ◽  
Author(s):  
Takeshi Miura ◽  
Chiemi Miura ◽  
Yasuko Konda ◽  
Kohei Yamauchi
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Culture System ◽  
Sequence Similarity ◽  
Expression System ◽  
Japanese Eel ◽  
Homology Search ◽  
Amino Acid Sequence Similarity ◽  
Spermatogonial Proliferation

Under fresh-water cultivation conditions, spermatogenesis in the Japanese eel is arrested at an immature stage before initiation of spermatogonial proliferation. A single injection of human chorionic gonadotropin can, however, induce complete spermatogenesis, which suggests that spermatogenesis-preventing substances may be present in eel testis. To determine whether such substances exist, we have applied a subtractive hybridisation method to identify genes whose expression is suppressed after human chorionic gonadotropin treatment in vivo. We found one previously unidentified cDNA clone that was downregulated by human chorionic gonadotropin, and named it ‘eel spermatogenesis related substances 21’ (eSRS21). A homology search showed that eSRS21 shares amino acid sequence similarity with mammalian and chicken Müllerian-inhibiting substance. eSRS21 was expressed in Sertoli cells of immature testes, but disappeared after human chorionic gonadotropin injection. Expression of eSRS21 mRNA was also suppressed in vitro by 11-ketotestosterone, a spermatogenesis-inducing steroid in eel. To examine the function of eSRS21 in spermatogenesis, recombinant eSRS21 produced by a CHO cell expression system was added to a testicular organ culture system. Spermtogonial proliferation induced by 11-ketotestosterone in vitro was suppressed by recombinant eSRS21. Furthermore, addition of a specific anti-eSRS21 antibody induced spermatogonial proliferation in a germ cell/somatic cell co-culture system. We conclude that eSRS21 prevents the initiation of spermatogenesis and, therefore, suppression of eSRS21 expression is necessary to initiate spermatogenesis. In other words, eSRS21 is a spermatogenesis-preventing substance.

scholarly journals Hyperexpression of biologically active human chorionic gonadotropin using the methylotropic yeast, Pichia pastoris

1999 ◽  
Vol 22 (3) ◽  
pp. 273-283 ◽  
Author(s):  
C Sen Gupta ◽  
RR Dighe
Keyword(s):  
Pichia Pastoris ◽  
Structure Function ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Recombinant Expression ◽  
Expression System ◽  
Biologically Active ◽  
Maximal Response ◽  
Glycoprotein Hormone

Human chorionic gonadotropin (hCG), a heterodimeric glycoprotein hormone, is composed of an alpha subunit noncovalently associated with the hormone-specific beta subunit. The objective of the present study was recombinant expression of properly folded, biologically active hCG and its subunits using an expression system that could be used for structure-function studies while providing adequate quantities of the hormone for immunocontraceptive studies. We report here expression of biologically active hCG and its subunits using a yeast expression system, Pichia pastoris. The recombinant hCGalpha and hCGbeta subunits were secreted into the medium and the levels of expression achieved at shake culture level were 24 and 2.7-3 mg/l secretory medium respectively. Co-expression of both subunits in the same cell resulted in secretion of heterodimeric hCG into the medium. The pichia-expressed hCG was immunologically similar to the native hormone, capable of binding to the LH receptors and stimulating a biological response in vitro. Surprisingly, the maximal response obtained was twice that obtained with the native hCG. The level of expression of hCG achieved was 12-16 mg/l secretory medium and is expected to increase several-fold in a fermentor. Thus the Pichia expression system is capable of hyperexpressing properly folded, biologically active hCG and is suitable for structure-function studies of the hormone.

Human chorionic gonadotropin induces all stages of spermatogenesis in vitro in the male Japanese eel (Anguilla japonica)

1991 ◽  
Vol 146 (1) ◽  
pp. 258-262 ◽  
Author(s):  
Takeshi Miura ◽  
Kohei Yamauchi ◽  
Hiroya Takahashi ◽  
Yoshitaka Nagahama
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Anguilla Japonica ◽  
Japanese Eel

scholarly journals Priming with a gonadotropin-releasing hormone agonist before immature oocyte retrieval may improve maturity of oocytes and outcome in in vitro maturation (IVM) cycle: a case report

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
A. Smirnova ◽  
M. Anshina ◽  
E. Shalom Paz ◽  
A. Ellenbogen
Keyword(s):  
Fertility Preservation ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Oocyte Retrieval ◽  
Fertilization Rate ◽  
Gonadotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Nuclear Maturation ◽  
Gonadotropin Releasing Hormone Agonist

Abstract Background The concept of using a gonadotropin-releasing hormone agonist (GnRH-a) instead of human chorionic gonadotropin for triggering ovulation in patients treated with an antagonist protocol for in vitro fertilization (IVF) has become a routine clinical practice. It may promote oocyte nuclear maturation, resumption of meiosis and cumulus expansion. It seems that this attempt could be beneficial in an in vitro maturation (IVM) oocyte cycle performed for polycystic ovarian syndrome as well as for other indications such as urgent fertility preservation in patients with malignancies or unusual indications. Case presentation We present the case of a Caucasian patient who needed fertility preservation when routine natural IVF treatment did not yield oocyte retrieval, followed by three IVM cycles, priming ovulation with a GnRH-a. In total, 12 oocytes were obtained, all matured 4.5 hours after incubation in maturation media. The fertilization rate after intracytoplasmic sperm injection was 83%. Six good-quality embryos were vitrified. Conclusions It seems that triggering with a GnRH-a in selected cases may replace human chorionic gonadotropin in IVM of oocytes and could be highly beneficial in terms of obtaining high-grade embryos and possible pregnancy.

scholarly journals Translational Fusion of Two β-Subunits of Human Chorionic Gonadotropin Results in Production of a Novel Antagonist of the Hormone

Endocrinology ◽  
2007 ◽  
Vol 148 (8) ◽  
pp. 3977-3986 ◽  
Author(s):  
Satarupa Roy ◽  
Sunita Setlur ◽  
Rupali A. Gadkari ◽  
H. N. Krishnamurthy ◽  
Rajan R. Dighe
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Expression System ◽  
Biologically Active ◽  
Chain Molecule ◽  
Dependent Manner ◽  
Β Subunit ◽  
Single Chain ◽  
Α Subunit ◽  
Lh Receptor

The strategy of translationally fusing the α- and β-subunits of human chorionic gonadotropin (hCG) into a single-chain molecule has been used to produce novel analogs of hCG. Previously we reported expression of a biologically active single-chain analog hCGαβ expressed using Pichia expression system. Using the same expression system, another analog, in which the α-subunit was replaced with the second β-subunit, was expressed (hCGββ) and purified. hCGββ could bind to LH receptor with an affinity three times lower than that of hCG but failed to elicit any response. However, it could inhibit response to the hormone in vitro in a dose-dependent manner. Furthermore, it inhibited response to hCG in vivo indicating the antagonistic nature of the analog. However, it was unable to inhibit human FSH binding or response to human FSH, indicating the specificity of the effect. Characterization of hCGαβ and hCGββ using immunological tools showed alterations in the conformation of some of the epitopes, whereas others were unaltered. Unlike hCG, hCGββ interacts with two LH receptor molecules. These studies demonstrate that the presence of the second β-subunit in the single-chain molecule generated a structure that can be recognized by the receptor. However, due to the absence of α-subunit, the molecule is unable to elicit response. The strategy of fusing two β-subunits of glycoprotein hormones can be used to produce antagonists of these hormones.

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