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Updated: Aug 10, 2026

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Phosphopeptide Analysis of Rodent Epididymal Spermatozoa
Published on: December 30, 2014
High-affinity binding of T3 to epididymis nuclei
A G Del Rio1, A M Blanco, O Pignataro
1Department of Clinical Biochemistry, University of Buenos Aires, Argentina.
Archives of Andrology
|June 23, 2000
Summary
Thyroid hormones directly impact epididymis function. Researchers found specific triiodothyronine (T3) receptors in epididymal cell nuclei, confirming direct thyroid hormone effects on sperm maturation.
Area of Science:
- Reproductive Endocrinology
- Cell Biology
- Endocrinology
Background:
- Thyroid hormones are crucial for male reproductive health, influencing sperm parameters and epididymal morphology.
- Previous studies indicated hypothyroidism impairs epididymal function, but direct hormonal action on the epididymis remained unconfirmed.
Purpose of the Study:
- To investigate the presence of specific high-affinity binding sites for triiodothyronine (T3) in epididymal cell nuclei.
- To determine if thyroid hormones exert direct effects on the epididymis.
Main Methods:
- Isolated epididymal nuclei from prepuberal male Wistar rats.
- Incubated nuclei with varying concentrations of radio-labeled T3 (125I-T3).
- Analyzed binding data using Scatchard analysis to determine receptor characteristics.
Main Results:
- Identified a single class of high-affinity T3 binding sites within epididymal nuclei.
- Quantified the association constant (Ka) and maximal binding capacity, indicating specific receptor binding.
- Observed a Ka of 3.06 x 10^9 M⁻¹ and a maximal binding capacity of 0.11 pmol T3/μg DNA.
Conclusions:
- Epididymal cell nuclei possess specific receptors for thyroid hormone T3.
- This finding provides direct evidence that thyroid hormones act directly on the epididymis to regulate its function.
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