The aim of this study was to determine the relationship between the coat color appearance of Korean brindle cattle and the changes of relevant hormone levels that may affect the hair pigmentation during different stages of growth and maturation. In mature cattle, levels of both ACTH and DHEA in Korean brindle cattle with brown color were significantly higher than those with black color (p<0.05). Levels of α-MSH in Korean brindle cattle with whole brindle (≧50%) color were significantly higher than those with brown color (p<0.05). In calves of Korean brindle cattle at 2 to 6 months, the concentration of estradiol was significantly higher in calves with whole brindle color than those with part brindle color (p<0.05), when the coat color was confirmed. After 6 month of coat color confirmation, levels of testosterone and ACTH increased in calves with part brindle color and were significantly higher than those with whole brindle color (p<0.05). In calves of Korean brindle cattle at 1 or 2 months, there were no significant differences in hormone levels of estradiol, ACTH, DHEA and α-MSH between the calves with brindle color and brown color, except estradiol before brindle color appearance. Changes of relevant hormone levels at different stage of growth and maturation may affect the pigmentation of coat during the development of cattle. In addition to the current study correlating the different coat colors with relevant hormone levels, investigation of the coat color associated genes expressed in Korean brindle cattle may further clarify the mechanisms of coat color changes during their development.

본 연구결과 조농비가 다른 사료를 각각 급여한 젖소에 서 임신초기의 유방 크기는 HF군이 LF군 보다 2.4배 가량 유의하게 컸으나, 임신중기와 착유기 동안에는 두 군 간에 차이가 없었다. Estradiol의 혈중농도는 두 군 모두 사춘기 부터 서서히 증가하여 임신기간 동안 사춘기의 2~3.5배가 량이 되었으며, 두 군간 유의한 차이는 나타나지 않았다. 착유기 전 기간에 걸쳐서도 estradiol의 농도는 두 군간 차 이가 없었다. Progesterone의 혈중 농도는 사춘기부터 증가 하기 시작하여 임신중기까지 두 군 모두 비슷한 농도로 유지되었으며, 시험 전 기간에 걸쳐 두 군간 유의한 차이는 없었다. 산유량 4% FCM은 두 군 모두 분만 후 증가하다 LF군은 분만 100일, HF군은 150일을 기점으로 감소하였다. 그러나, 분만 후 50일까지를 제외하고 그 후 전 기간에 걸 쳐 양질 조사료 함량이 높은 사료를 급여한 HF군의 젖소 에서 산유량이 유의하게 높았으며, 분만 250일 까지도 높 은 산유량을 유지하였다. 우유 내 체세포 수는 분만초기를 제외하고 착유기 전 기간 동안 HF군에서 유의하게 감소하 였다. 유지율은 분만 후 비유 초기에 LF군에서 다소 높게 나타났으나, 그 이후부터는 두 군간 차이가 없었으며, 그 밖에 우유 내 단백율, 고형율, MUN 모두 두 군간 차이는 관찰되지 않았다. 산유량과 체세포 수 및 유지율을 기초로 계산한 유대에 있어 HF군이 LF군에 비하여 최고 141.5% 증대되었다. 본 연구결과로부터 젖소의 양질 조사료의 함 량을 적당 수준으로 증가시킴으로써 유방의 크기나 관련 호르몬의 변화 없이 우유의 생산량을 증대시키고 우유의 질을 높일 수 있을 것으로 평가되었다.

The present study investigated the hypothesis that a extremely low frequency magnetic field (ELF-MF) partially suppresses the synthesis of human growth hormone (HGH) in a group of 28 primary schoolchildren living nearby and 60 primary schoolchildren aged 12 years living far away from overhead transmission power lines from December 2003 to April 2004 in Seoul, Korea. The mean personal exposure levels of the primary schoolchildren living nearby overhead transmission power line were 0.37 μT, whereas the levels for the primary schoolchildren living away from overhead transmission power line was 0.05 μT. From simple analyses, the mean growth hormone levels in the primary schoolchildren living nearby were lower than away from overhead transmission power line, and statistically significant differences in the levels of the growth hormone (p = 0.0316), whereas not statistically significant differences in the levels of the growth hormone related to the distance from residence to power line less and more than 100 m by cut-off point (p = 0.4017). In conclusion, these results may indicate that urinary levels of nocturnal growth hormone are altered in primary schoolchildren exposed to extremely low frequency magnetic field at overhead transmission power line.

This study was conducted to investigate the effect of unilateral ovariectomy on the embryo survival and changes of plasma progesterone and estradiol concentration. Mature Angora rabbits were divided into 2 groups (Superovulation and unilateral ovariectomy after superovulation). Unilateral ovariectomied rabilts were subdivided into two groups according to the time of ovariectomy (24 hours and 96 hours after mating). The results obtained were summarized as follows; 1. After unilateral ovariectomy, survival rate and collecting rate of embryos recovered from contralateral and ipsilateral oviduct and uterus were not different, and were lower than intact rabbits. 2. Plasma progesterone concentration at 93, 99, 102 and 114 hours after HCG injection in superovulated rabbits were 12.9 0.5, 34.8 5.1, 12.2 2.7 and 43.4 5.8ng/ml, respectively. Mean progesterone concentrations were significantly higher at 99 and 114 hours than at 93 and 102 hours (p <0.05). But plasma estradiol concentration was not different. 3. Plasma progesterone concentration in unilateral ovariectomized rabbits was somewhat decreased after unilateral ovariectomy. Plasma estradiol concentration was not different.

한국 남성의 연령 증가에 따른 혈중 luteinizing hormone(LH), testosterone(T), 그리고 타액 T 수준 변화를 조사하였다. 혈중LH 수준은 40대까지 유의한 변화를 보이지 않았으나(20s, ; 30s, ; and 40s, ), 50대 이상에서 유의하게 증가하였다(50s, and 60s, ). 또한, 혈중 T 수준도 40대까지는 변화하지 않았으나(20s, , 30s, , 40s, ng/mL), 50대 이후 유의하게 감소하였다(