PARENT SESSION
Epididymis and Sperm Maturation

EPIDIDYMAL PHENOTYPE IN LH RECEPTOR KNOCKOUT ANIMALS AND THE EFFECT OF TESTOSTERONE REPLACEMENT THERAPY.

Lei, Zhenmin¹, Mishra, Suresh¹, Zou, Wei¹, Xu, Bingrui¹, Foltz, Mark¹, Rao, Ch.¹, ¹

ABSTRACT- Human, rhesus monkey and rat epididymides contain LH receptors, which were thought to mediate the sperm maturation promoting actions of LH. We used LH receptor knockout animals in the present study to advance our current understanding of the importance of epididymal LH signaling. Null mice were infertile with dramatically reduced serum testosterone levels, intraabdominal testes with a marked reduction of their weight and an arrested spermatogenesis, micropenis and rudimentary secondary accessory sex organs including epididymides (null = 1.7 ± 1.0 mg; wild-type = 194 ± 63 mg). Quantitative morphometric analysis revealed a dramatic decrease in luminal diameter of the proximal and distal caput and cauda epididymides and the absence of clear and halo cells in the epithelial lining. The height of principal epithelial cells also showed a dramatic decrease with less than 10% containing stereocilia, a dramatic decrease in cilia length, change from basal to central location of nuclei in epithelial cells, and weaker periodic acid-Schiff reaction positive substance. Semi-quantitative RT-PCR revealed that while androgen receptor mRNA levels were unaffected, estrogen receptor (ER) mRNA levels increased, ER mRNA levels decreased. Western blot and immunocytochemistry analyses showed that 67 kDa ER and 60 kDa ER, which were primarily present in epithelial and stromal cells, were increased by about 100% and decreased by 50%, respectively. To test whether these epididymal changes were due to decreased testosterone levels, we placed null animals on 42-day testosterone replacement therapy. The therapy did not restore fertility, even though it partially improved spermatogenesis, reversed ER and ER changes, and stimulated epididymal growth to a size comparable to that in wild-type siblings. However, the luminal diameter of proximal and distal caput and cauda epididymides, height of principal epithelial cells in proximal caput epididymides, the number of ciliated epithelial cells and cilia length did not completely recover. These data suggest that although testosterone is important, alone it may not be sufficient, and quite possibly, LH signaling could also be required for complete recovery of epididymal morphology and function.

KEY WORDS: epididymides, LH receptor knockout, estrogen receptors, androgen receptors