Kobayashi, Tsuneo, Takayuki Matsumoto, Kazuyuki Ooishi, and Katsuo Kamata. Differential expression of ␣2D-adrenoceptor and eNOS in aortas from early and later stages of diabetes in Goto-Kakizaki rats. Am J Physiol Heart Circ Physiol 287: H135-H143, 2004; 10.1152/ajpheart.01074.2003.-The aim of the present study was to compare vascular dysfunction between the early (12 wk old) and later (36 wk old) stages of spontaneous diabetes in GotoKakizaki (GK) rats. We also evaluated the aortic expression of the ␣2D-adrenoceptor and endothelial nitric oxide synthase (eNOS). Vascular reactivity was assessed in thoracic aortas from age-matched control rats and 12-and 36-wk GK rats. Using RT-PCR and immunoblots, we also examined the changes in expression of the ␣2D-adrenoceptor and eNOS. In aortas from GK rats (vs. those from age-matched control rats): 1) the relaxation response to ACh was enhanced at 12 wk but decreased at 36 wk; 2) the relaxation response to sodium nitroprusside was decreased at both 12 and 36 wk, 3) norepinephrine (NE)-induced contractility was decreased at 12 wk but not at 36 wk, 4) the expressions of ␣1B-and ␣1D-adrenoceptors were unaffected, whereas those of ␣2D-adrenoceptor and eNOS mRNAs were increased at both 12 and 36 wk; and 5) NE-and ACh-stimulated NOx (nitrite and nitrate) levels were increased at 12 wk, although at 36 wk ACh-stimulated NOx was lower, whereas NE-stimulated NOx showed no change. These results clearly demonstrate that enhanced ACh-induced relaxation and impaired NE-induced contraction, due to NO overproduction via eNOS and increased ␣2D-adrenoceptor expression, occur in early-stage GK rats and that the impaired AChinduced relaxation in later-stage GK rats is due to reductions in both NO production and NO responsiveness (but not in eNOS expression).Type 2 diabetes; ␣2D-adrenoceptor; endothelium; nitric oxide synthase; relaxation DIABETES MELLITUS is an important risk factor for the development of atherosclerosis. Numerous epidemiological studies have indicated that the insulin resistance and hyperinsulinemia associated with Type 2 diabetes make important contributions to the development of hypertension and atherosclerotic lesions. Although an accumulating body of evidence indicates that endothelium-dependent relaxation is weaker both in a Type 1 diabetic model, namely, streptozotocin (STZ)-induced diabetic rats (11, 26, 32, 39 -41), and in Type 2 diabetic rats (28, 44, 50, 51), we (29) and others (6, 42) have noted an augmented or unaltered endothelium-dependent relaxation at an early stage in STZ-induced diabetes. In fact, there is clinical and experimental evidence of augmented blood flow at early stages of diabetes (9, 24). In the Type 1 model STZ-induced diabetic rat, Pieper (42) showed that there is an early (for 1 day) increase in endothelium-dependent relaxation, followed by a reversion phase (for 1-2 wk), in which relaxation is normal, and then a final phase (for 8 wk) of impaired relaxation. In a Type 2 model, the obese Zucker rat, the aorta has been reported to exhibit eith...

The objective of this study was to evaluate the superovulatory response to a single SC administration of pFSH (Antrin R-10) dissolved in saline in Japanese Black cattle. Forty Japanese Black cows were divided into 5 groups. All cows received a progesterone releasing intravaginal device (PRID) at a random stage of the oestrous cycle except the day of oestrus (Day 0). Superovulatory treatments were initiated on Day 4 with single SC administration of 20 AU pFSH dissolved in 10 mL of saline (Group A) or 50 mL of saline (Group B), or 30 AU pFSH dissolved in 10 mL of saline (Group C) or 50 mL of saline (Group D). Conventional superovulatory treatment (Group E) was also initiated on Day 4 with 20 AU pFSH in decreasing doses in IM administration twice a day for 3 days (5/5, 3/3, and 2/2 in the am/pm). Each administration was carried out in the neck region. For oestrus induction, all animals were treated with prostaglandin F2α (750 μg of cloprostenol) on Day 4, and then the PRID was removed on Day 6 in the morning. The GnRH (10 μg of buserelin) was administrated at 31 h after PRID removal to induce ovulations. The cows were artificially inseminated at 24 h after GnRH treatment, and embryos were recovered 7 days after the insemination. Blood samples were collected at 0, 2, 4, 6, 8, 10, 24, 31, 48, 55, 72, and 79 h after the first pFSH administration, and serum pFSH concentration was measured using time-resolved fluorescence immunoassay. Percentage data were arcsine transformed before analysis, and one-way ANOVA was used for statistical analysis (P < 0.05). There were no significant (P > 0.05) differences among groups in the number of corpus luteum, total number of ova/embryos, number of transferable embryos, and percentage of transferable embryos. The concentrations of pFSH in serum increased in all groups 2 h after each administration and reached a peak at 8 h in Groups A and C, at 10 h in Groups B, D, and E, and then in all groups it decreased gradually. The concentrations of pFSH in serum decreased to the base level (the level at 0 h) in Group A at 55 h and in Group C at 72 h after the first pFSH administration. At 79 h, serum pFSH was still detected in Groups B, D, and E. These results suggest that the single SC administration of 20 AU pFSH that is the same dose as the conventional treatment is able to induce a superovulatory response comparable to that of conventional treatment in Japanese Black cattle. Table 1.Superovulatory responses (mean ± SE) in different treatment groups