Alterations in gene expression and steroidogenesis in the testes of transient cerebral ischemia in male rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Serum testosterone levels have been found lower in acute ischemic stroke male patients. However, the exact mechanism remains unclear. In the present study, we measured serum testosterone levels, steroidogenesis- related genes and Leydig cells number in experimental transient cerebral ischemia male rats to elucidate the mechanism.</p><p><b>METHODS</b>The middle cerebral arteries of adult male Sprague-Dawley rats were sutured for 120 minutes and then sacrificed after 24 hours. Blood was collected for measurement of serum testosterone, follicular stimulating hormone and estradiol levels, and testes were collected for measurement of steroidogenesis-related gene mRNA levels and number of Leydig cells.</p><p><b>RESULTS</b>Serum testosterone levels in rats after cerebral ischemia were significantly lower (0.53 ± 0.16) ng/ml, n = 7, mean ± SE) compared with control ((2.33 ± 0.60) ng/ml, n = 7), while serum estradiol and follicular stimulating hormone levels did not change. The mRNA levels for luteinizing hormone receptor (Lhcgr), scavenger receptor class B member 1 (Scarb1), steroidogenic acute regulatory protein (StAR), cholesterol side chain cleavage enzyme (Cyp11a1), 3β-hydroxysteroid dehydrogenase 1 (HSD3β1), 17α-hydroxylase/20-lyase (Cyp17a1) and membrane receptor c-kit (kit) were significantly downregulated by cerebral ischemia, while luteinizing hormone, Kit ligand (KitL), 17β-hydrosteroid dehydrogenase 3 (HSD17β3) and 5α-reductase (Srd5a1) were not affected. We also observed that, relative to control, the Leydig cell number did not change.</p><p><b>CONCLUSIONS</b>These results indicate that transient cerebral ischemia in the brain results in lower expression levels of steroidogenesis-related genes and thus lower serum testosterone level. Transient cerebral ischemia did not lower the number of Leydig cells.</p>

Ionic mechanism underlying chance of L-type Ca~(2+) current in isolated rat ventricular myocytes induced by hypercholesterolemia / 中国药理学通报

Aim To investigate the effect of hypercholesterolemia on L-type Ca2+(ICa-L) current and intracellular calcium concentration ([Ca2+]i) in single ventricular myocytes of hypercholesterolemic rats.Methods 12 male wistar rats were randomly divided into two dietary groups:a group fed a normal diet(n=6)and a group fed high-cholesterol diet(n=6) for 4 weeks,respectively. The level of serum lipid was examined.Zymolytic method was used to isolate single ventricular myocytes from hypercholesterolemic and normal rats,which were loaded with Ca2+-sensitive fluorescent indicator Fluo-3/AM.[Ca2+]i represented by fluorescent intensity(FI)was measured by laser scanning confocal microscope.Whole cell patch clamp technique was used to record ICa-L.Results There was no significant influence exhibited on TG level.However, the serum total cholesterol(TC)level of hypercholesterolemic rats was much higher than that of model control group; at the test potential of 0 mV, ICa-L decreased from(-8.56?1.29)pA/pF(Control)to(-5.24?0.90) pA/pF(HC)(n=6 in each group,P