Synthetic α-Subunit Peptides Stimulate Testosterone Productionin Vitroby Rat Leydig Cells*
- 1 May 1990
- journal article
- research article
- Published by The Endocrine Society in Endocrinology
- Vol. 126 (5) , 2555-2560
- https://doi.org/10.1210/endo-126-5-2555
Abstract
The glycoprotein hormones (LH, hCG, FSH, and TSH) have a common 92-amino acid .alpha.-subunit which is nonvalently linked to a hormone-specific .beta.-subunit. Synthetic peptides of the .alpha.-subunit have been shown to inhibit binding of [125I]iodo-hCG to rat ovarian membrane and [125]iodo-TSH to human thyroid membrane preparations. Synthetic overlapping peptides of the .alpha.-subunit of hCG were prepared by solid phase techniques and tested in a standard in vitro rat Leydig cell bioassay. Three regions in the .alpha.-subunit (.alpha.1-15, .alpha.30-45, and .alpha.71-85) were found to stimulate testosterone production. All three regions correlate with inhibition of hCG binding to ovarian receptors, but subtle differences exist between the binding sites and effector sites. These data indicate that the glycoprotein .alpha.-subunit has intrinsic bioactivity.Keywords
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