ラット性機能に及ぼす環境物質の影響

ニコチン, カフェイン, アルコール, コカコ-ラについて

抄録

Environmental substances, such as nicotine, cotinine (a metabolite of nicotine), alcohol, caffeine etc., have some favorable or unfavorable effects on physical health. In this study, the effects of these environmental substances on the genital organs of the female rats were morphologically and endocrinologically investigated.
Fifty four mature female Wistar rats, with regular estrus cycles, were divided into the 9 groups. That is, a control group (C), a nicotine 1μg group (N1), a nicotine 10/./g group (N10), a nicotine 20, μg group (N20), a cotinine 10μg group (Co), a caffeine 1mg group (Ca), a saline solution group (S), a Coca-Cola free drinking group (Coke), and an alcohol 1ml group (AL). These chemicals were administered daily in 0.1ml of saline solution intraabdominally, though 1ml of alcohol was orally given daily and Coca-Cola was ingested ad libitum.
These substances were administered for 20-24 weeks. And estradiol (E₂) and prolactin (PRL) concentration in the blood sera were estimated by radioimmunoassay on the first day of estrus after 2 weeks of drug administration, and the day after 20-24 weeks of drug administration.
Endometrium, subsequently obtained from each rat, was fixed, post-fixed, dehydrated, embedded and observed by electron microscopes (H-500 and H-600). The sexual cycles were initially irregular and finally entered constant estrus. (This phenomenon was fastest observed in the N10 group.)
There was no significant differences in PRL levels between the experimental groups and the control group.
E₂ concentrations, however, increased in the nicotine groups after 2-4 weeks, and then tended to decrease after 24 weeks. Ultrastructural observation after 2 weeks revealed that the endometrium retained active secretory features. After 20-24 weeks, however, the endometrium became atrophic. The endometrium in the other experimental groups did not become atrophic.
The effects of nicotine on the anterior pituitary hormone were also examinied.
Twenty mature female rats with regular estrus cycles were divided into 4 groups according to the substance administered a control group (C), a nicotine 10μg group (N'10), a nicotine 100μg group (N'100), a nicotine 1000μg group (N'1000). Nicotine at the 3 different concentrations, was administered intraabdominally at 13 : 30 on proestrus day. The blood sera were examined at 14 : 00, 17 : 00, and 20 : 00 to estimate follicle stimulating hormone (FSH) and luteinizing hormone (LH) concentration by RIA. FSH levels did not vary significantly LH levels increased significantly in the 10μg nicotine group at 17 : 00 (p< 0.05), but decreased in the 100μg and 1000μg nicotine groups at 17 : 00 (p <0.01). Nicotine stimulated the function of the ovary and the uterus, when it was administered for short periods. When it was administered for long periods, however, it caused low sexual function. These facts were corroborated by the evidence of diminished estradiol levels and the atrophic condition of the ovaries and the endometrium. Caffeine and Coca-Cola had little influence on sexual function, if they were consumed in limited amounts during daily use.Alcohol had some influence, acting on the reproductive organs to prolong the estrus cycle, and to atrophy the endometrium. [Adv Obster Gynecol 47(2) : 300-315, 1995 (H7.3)]