• Korean Journal of Veterinary Research
• /
• v.34 no.4
• /
• pp.735-744
• /
• 1994

Catheters were placed into the external jugular veins of immature female rats. On the following day (day 28 of age), the animals were injected subcutaneously with pregnant mare serm gonadotropin(PMSG): 4IU(control) or 20IU(superovulation). Each animal was sequentially bled at Ohr and 12hr and subsequently at 6hr intervals until sacrifice at 72hr after PMSG. The superovulatory dose of PMSG significantly(P<0.05) increased the ovulatory response by 4.0 fold above controls. On the other hand, superovulated oocytes displayed considerably different stages of meiotic maturation: prophase I (14.7%), anaphase I (36.2%), telophase I (10.3%), metaphase I/II (32.4%), while in control rats a majority of the oocytes examined(94.0%) consistently showed a metaphase II configuration. Serum luteinizing hormone(LH) levels were determined by RIA. Both groups exhibited a similar time relationship with two distinct peaks: an initial slight rise at 0-18hr and a second sharp rise at 54-60hr. However, there was a marked change in the magnitude of LH levels between the two groups. In superovulated animals, prior to the second peak, overall LH levels were significantly(P<0.001) higher than controls. In contrast, at the peak occurring at 60hr, LH concentrations were significantly(P<0.001) reduced by 54% below that of control. Additionally, a maximum increase of mean ${\Delta}LH$ between two peaks was much less in superovulated as compared to control rats. The initial prolonged elevation of serum LH before 54hr in superovulated rats was found to result from actual cross-reaction of the injected PMSG with LH antibody in the assay, while a precipitous second elevation between 54hr and 60hr resulted primarily from an endogenous LH surge. This study clearly defines time-course features of serum LH in PMSG-treated rats. The overall results indicate that, following superovulatory treatment with PMSG, the increased ovulatory response is primarily associated with PMSG-derived intrinsic gonadotropin, and that the recovery of immature or asynchronously mature oocytes at ovulation may reult from the circulatory alteration of LH activity characterized by an initial prolonged elevation of serum LH and its subsequent attenuation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.14 no.4
• /
• pp.375-380
• /
• 1985

This experiment was undertaken to investigate and compare the effect of salt on the lipid composition in serm and liver of rats. The average body weight gains and food efficiency ratio were not affected by supplementation with salt in diet. Total cholesterol and free cholesterol levels in serum of all experimental diet group were slightly increased by supplementation with salt, while triglyceride levels were significantly increased. HDL-cholesterol levels of all salt supplementation groups were slightly lower than that of the control group, while LDL, VLDL-cholesterol levels of these groups were higher than that of the control group. The ratio of LDL, VLDL-cholesterol to HDL-cholesterol; so called, atheorgenic index, in serum of salt diet groups was slightly higher than that of the control groups. The ratio of LDL, VLDL-lipoprotein to HDL-lipoprotein in salt diet group were significantly higher than that of the control group. The weight of the liver was not affected by diet, but total cholesterol and triglyceride levels of the liver in salt diet groups were higher than that of the control group.