, 2006), the greater sensitivity of BN rats than of SHR or SD to induction of a spermatogonial block by radiation this website
cannot be attributed to higher levels of testosterone or FSH. To confirm that the action of testosterone and/or FSH was involved in the radiation-induced block of spermatogonial differentiation in these strains, we examined the effects of hormone suppression on spermatogenic recovery in BN and SHR rats at different times after 7.5?Gy (Fig.?7) and at 10?weeks after 5 and 10?Gy (data not shown). Hormone suppression decreased serum testosterone to below the limits of detection in both strains (Fig.?7A). IFT levels were reduced in BN rats to ~1?ng/mL and were reduced even more in SHR rats (Fig.?7B). However, these residual levels of intratesticular testosterone would not be expected to have Metformin
significant effects on spermatogenesis because the rats were also treated with flutamide. The suppressive treatment also markedly reduced serum FSH levels to about 1?ng/mL in all groups of rats (Fig.?7C) and reduced LH to undetectable levels (data not shown). Although hormonal suppression in control and treated rats markedly decreased testicular parenchymal weights to about 7% of control in both strains at the various dose and time points (Fig?8A,D), which was also evident by the decrease in tubule diameter (compare Fig.?9A and C), it induced differentiation in a high percentage of tubules in irradiated rats of both strains (Figs?8B and 9C). In BN rats, irradiation with 5?Gy and above almost completely eliminated the differentiating spermatogenic cells (TDI?<?2%); nevertheless, hormone suppression starting immediately after irradiation with 5?Gy restored the production of differentiated cells in 100% of tubules; however, with the low testosterone and FSH levels, <a href="http://www.selleckchem.com/products/AP24534.html
">Ponatinib in vitro differentiation could only proceed to the spermatocyte stage (Fig.?9D). There was incomplete recovery of spermatogonial differentiation at 10?weeks after 7.5?Gy, as only 88% of tubules showed differentiating cells, but recovery progressed with time so that by week 20 100% of tubules were differentiated (Fig.?8E). The higher dose of 10?Gy reduced the percentage of tubules showing differentiation at 10?weeks to 48%. In SHR rats, after the 7.5- and 10-Gy doses, which blocked all spontaneous recovery at 10?weeks after irradiation, hormonal suppression stimulated the production of differentiated cells in 100 and 90% of tubules respectively. Hormone suppression completely reversed the large increase in interstitial fluid accumulation observed in BN rats (Fig?8C,F). The modest increases in interstitial fluid observed in SHR rats after irradiation were also reversed by the hormone suppression. The human testis is characterized by high sensitivity to and delayed recovery of spermatogenesis after moderate doses of radiation.