scholarly journals Elevated Steroidogenesis, Defective Reproductive Organs, and Infertility in Transgenic Male Mice Overexpressing Human Chorionic Gonadotropin

Endocrinology ◽  
2003 ◽  
Vol 144 (11) ◽  
pp. 4980-4990 ◽  
Author(s):  
Susana B. Rulli ◽  
Petteri Ahtiainen ◽  
Sari Mäkelä ◽  
Jorma Toppari ◽  
Matti Poutanen ◽  
...  
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Fusion Gene ◽  
Direct Action ◽  
Fold Increase ◽  
Reproductive Organs ◽  
Seminiferous Tubules ◽  
Male Mice ◽  
Α Subunit

Abstract We previously developed a transgenic (TG) mouse model that overexpresses the human chorionic gonadotropin (hCG) β-subunit under the universal human ubiquitin C promoter, displaying in males a modest 3-fold increase in circulating levels of LH/hCG bioactivity. The males were fertile and presented with a mild reproductive phenotype. To achieve higher levels of hCG, a double TG model was generated by cross-breeding the hCGβ-expressing mice with another TG line harboring a ubiquitin C/common α-subunit fusion gene. The double-TG mice expressed excessive levels of dimeric hCG, with 2000-fold elevated circulating LH/hCG bioactivity. These male mice were infertile, primarily due to inability to copulate, and they showed enhanced testicular androgen production despite clear down-regulation of LH/hCG receptors. Their intratesticular inhibin B was unaltered, but serum FSH was markedly reduced. Apparently the chronic hCG hyperstimulation led to focal Leydig cell proliferation/hypertrophy at 6 months of age, but failed to promote testicular tumors. Even though full spermatogenesis occurred in most of the seminiferous tubules, progressive tubule degeneration was apparent as the males grew older. The prostate and seminal vesicles were enlarged by distension of glandular lumina. Functional urethral obstruction was indicated by distension and sperm accumulation in distal vas deferens as well as by dilated urinary bladder and enlarged kidneys. The abnormal function of accessory sex glands and/or lower urinary tract as a consequence of the disturbed sex hormone balance or direct action of hCG may be the main cause of infertility in this model. The present study provides in vivo evidence that exposure of male mice to chronically elevated levels of hCG severely affects their urogenital tract function at multiple sites and causes infertility, but, unlike in LH/hCG overexpressing female mice, it is not tumorigenic.

scholarly journals Biological Properties of a Novel Follicle-Stimulating Hormone/Human Chorionic Gonadotropin Chimeric Gonadotropin

Endocrinology ◽  
2006 ◽  
Vol 147 (9) ◽  
pp. 4205-4212 ◽  
Author(s):  
Louise M. Garone ◽  
Elena Ammannati ◽  
Theresa S. Brush ◽  
David J. Fischer ◽  
Enrico Gillio Tos ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Biological Properties ◽  
Glycoprotein Hormone ◽  
Α Subunit ◽  
Recombinant Human Fsh

A chimeric recombinant human gonadotropin, termed C3, demonstrates both follitropic and lutropic bioactivities. The α-subunit construct for C3 is comprised of the recombinant wild-type human glycoprotein hormone α-subunit. The β-subunit DNA construct for C3 encodes residues 1–145 from human chorionic gonadotropin (hCG)-β with the exceptions that FSHβ amino acid 88 (D) is substituted for hCGβ amino acid 94 (R) and FSHβ amino acids 95–108 (TVRGLGPSYCSFGE) are substituted for hCGβ amino acids 101–114 (GGPKDHPLTCDDPR). C3 is a potent FSH and LH agonist able to bind and to signal through FSH and LH receptors in vitro. In in vivo bioassays optimized to quantify each type of activity, C3 was found to have lutropin and follitropin potencies at levels similar to those of recombinant human LH and recombinant human FSH, respectively. In immature rats, C3 was sufficient to support the maturation of normal ovarian follicles. Moreover, a significant portion of follicles matured by C3 ruptured in response to an ovulatory hCG stimulus and gave rise to morphologically normal oocytes. Furthermore, a low dose of C3 promoted weight gain in the rodent uterus, suggesting it also supported preparation for implantation without histological evidence of excessive luteinization of the ovary. In summary, the biological properties of C3 indicate that its chimeric nature has resulted in a fully functional, dual-acting human gonadotropin.

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.

scholarly journals Solution structure of the α-subunit of human chorionic gonadotropin

1999 ◽  
Vol 260 (2) ◽  
pp. 490-498 ◽  
Author(s):  
Paul J. A. Erbel ◽  
Yasmin Karimi-Nejad ◽  
Tonny De Beer ◽  
Rolf Boelens ◽  
Johannis P. Kamerling ◽  
...  
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Solution Structure ◽  
Α Subunit

scholarly journals Overexpression of the Matrix Metalloproteinase Matrilysin Results in Premature Mammary Gland Differentiation and Male Infertility

1998 ◽  
Vol 9 (2) ◽  
pp. 421-435 ◽  
Author(s):  
Laura A. Rudolph-Owen ◽  
Paul Cannon ◽  
Lynn M. Matrisian
Keyword(s):  
Matrix Metalloproteinase ◽  
Transgenic Animals ◽  
Reproductive Organs ◽  
Mammary Development ◽  
Seminiferous Tubules ◽  
Interstitial Tissue ◽  
Wild Type ◽  
The Matrix

To examine the role of matrilysin (MAT), an epithelial cell-specific matrix metalloproteinase, in the normal development and function of reproductive tissues, we generated transgenic animals that overexpress MAT in several reproductive organs. Three distinct forms of human MAT (wild-type, active, and inactive) were placed under the control of the murine mammary tumor virus promoter/enhancer. Although wild-type, active, and inactive forms of the human MAT protein could be produced in an in vitro culture system, mutations of the MAT cDNA significantly decreased the efficiency with which the MAT protein was produced in vivo. Therefore, animals carrying the wild-type MAT transgene that expressed high levels of human MAT in vivo were further examined. Mammary glands from female transgenic animals were morphologically normal throughout mammary development, but displayed an increased ability to produce β-casein protein in virgin animals. In addition, beginning at approximately 8 mo of age, the testes of male transgenic animals became disorganized with apparent disintegration of interstitial tissue that normally surrounds the seminiferous tubules. The disruption of testis morphology was concurrent with the onset of infertility. These results suggest that overexpression of the matrix-degrading enzyme MAT alters the integrity of the extracellular matrix and thereby induces cellular differentiation and cellular destruction in a tissue-specific manner.

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