TY - JOUR
T1 - Photoperiodic variation of Leydig cell numbers in the testis of the golden hamster
T2 - A possible mechanism for their renewal during recrudescence
AU - Hardy, Matthew P.
AU - Mendis‐Handagama, S. M.L.C.
AU - Zirkin, Barry R.
AU - Ewing, Larry L.
PY - 1987/11
Y1 - 1987/11
N2 - Golden hamster testes regress after short day exposure. The present study asks: 1) are Leydig cell numbers depleted during short days, and 2) if so, how are they replenished during recrudescence. Control hamsters were shown 14 h of light and 10 h of dark (LD 14:10) for 10 weeks (n = 12). Testicular regression was induced by LD 6:18 for 10 weeks (n = 4), and recrudescence by switching regressed hamsters to LD 14:10 for 3 and 5 weeks (n = 8 for each group). All hamsters were injected with [3H]thymidine [3 μCi/gm body wt., intraperitoneally (i.p.)] 1 h or 2 weeks before sacrifice. Leydig cell number per testis was determined by stereological analysis of sections of perfusion‐fixed testes, and labeling indices were determined by autoradiography. Leydig cell numbers were reduced significantly from 18.2 × 106 in control to 9.0 × 106 in regressed testes (p < 0.05); then increased to 14.0 × 106 and 17.9 × 106 in 3‐ and 5‐week recrudesced hamsters. The labeling index was nondetectable (n.d.) for regressed hamsters. In control and recrudescing hamsters the labeling index was measured at two times (t1 = 1 h vs. t2 = 2 weeks post‐injection): in controls, t1 = 0.22 ± 0.15% (mean ± SEM) vs. t2 = 0.28 ± 0.22%; in 1 week recrudesced, n.d. vs. 1.92 ± 0.77% (p < 0.05); at 3 wk, n.d. vs. 4.58 ± 1.74% (p < 0.05); at 5 weeks, 1.92 ± 0.61% vs. 2.25 ± 0.59%. These results are indicative of the existence of interstitial precursor cells that divide, then differentiate, and thus replenish the Leydig cell population during testicular recrudescence.
AB - Golden hamster testes regress after short day exposure. The present study asks: 1) are Leydig cell numbers depleted during short days, and 2) if so, how are they replenished during recrudescence. Control hamsters were shown 14 h of light and 10 h of dark (LD 14:10) for 10 weeks (n = 12). Testicular regression was induced by LD 6:18 for 10 weeks (n = 4), and recrudescence by switching regressed hamsters to LD 14:10 for 3 and 5 weeks (n = 8 for each group). All hamsters were injected with [3H]thymidine [3 μCi/gm body wt., intraperitoneally (i.p.)] 1 h or 2 weeks before sacrifice. Leydig cell number per testis was determined by stereological analysis of sections of perfusion‐fixed testes, and labeling indices were determined by autoradiography. Leydig cell numbers were reduced significantly from 18.2 × 106 in control to 9.0 × 106 in regressed testes (p < 0.05); then increased to 14.0 × 106 and 17.9 × 106 in 3‐ and 5‐week recrudesced hamsters. The labeling index was nondetectable (n.d.) for regressed hamsters. In control and recrudescing hamsters the labeling index was measured at two times (t1 = 1 h vs. t2 = 2 weeks post‐injection): in controls, t1 = 0.22 ± 0.15% (mean ± SEM) vs. t2 = 0.28 ± 0.22%; in 1 week recrudesced, n.d. vs. 1.92 ± 0.77% (p < 0.05); at 3 wk, n.d. vs. 4.58 ± 1.74% (p < 0.05); at 5 weeks, 1.92 ± 0.61% vs. 2.25 ± 0.59%. These results are indicative of the existence of interstitial precursor cells that divide, then differentiate, and thus replenish the Leydig cell population during testicular recrudescence.
UR - http://www.scopus.com/inward/record.url?scp=0023446077&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0023446077&partnerID=8YFLogxK
U2 - 10.1002/jez.1402440211
DO - 10.1002/jez.1402440211
M3 - Article
C2 - 3430123
AN - SCOPUS:0023446077
SN - 0022-104X
VL - 244
SP - 269
EP - 276
JO - Journal of Experimental Zoology
JF - Journal of Experimental Zoology
IS - 2
ER -