ISSN:1663-2818    

DOI:10.1159/000182747

出版商:S. Karger AG    

年代:1993

数据来源: Karger

ISSN:1663-2818    

DOI:10.1159/000182748

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

The aging process is controlled by dual mechanisms. One is the mechanism which programs ultimate cell death and therefore determines the life-span at birth. The other is the mechanism which causes aging stochastically by damaging certain substances with time in life. Now, these mechanisms have been investigated on genetical bases. Whatever the mechanisms involved in aging, increasing evidence suggests the important roles of oxygen free radicals in the process of aging.

ISSN:1663-2818    

DOI:10.1159/000182749

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Morphological changes which take place in ovarian arteries at different ages in human and monkey, were investigated by light microscopy, transmission electron microscopy and scanning electron microscopy. The ovarian arteries in both species were characterized by a spiral configuration throughout their course. The hilar and medullar arteries were especially convoluted. In the pubertal monkey, the hilar and medullary arteries exhibited some intimal thickenings in which smooth muscle cells of a synthetic phenotype were longitudinally arranged. These arteries in adult monkeys had considerable intimal thickening. In a 30-year-old woman, arteries with intimal thickenings were detected in the hilus and medulla. Around 40 years of age, the intima of the arteries were considerably thickened with a diameter usually equal to half of the wall. In women after menopause, the tunica intima of these arteries was approximately two-thirds or more of the total artery wall thickness. Spiral arteries of the ovary were also thickened with advancing age.

ISSN:1663-2818    

DOI:10.1159/000182750

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

The functions of human ovary change dynamically around the menopausal period. A decrease of the number of primordial follicles and an increase of fibrous tissues are observed histologically in the aged ovary. As endocrinological aspects at menopause, the synthesis and secretion of ovarian steroid hormones such as estrogens and progesterone decrease, followed with the resultant increases of pituitary gonadotropins. However, the mechanism of menopause and ovarian aging is not well understood. Thus, to study the regulatory mechanism of ovarian dysfunction by aging, we analyzed the accumulation of mitochondrial DNA (mtDNA) mutation in the human ovary in women of various ages. The amplification of a 5.5-kb region in mtDNA with polymerase chain reaction revealed a 0.5-kb band in ovarian samples obtained from menopausal and postmenopausal women, which means that the 5.0-kb deletion of mtDNA in ovarian tissue starts at the menopausal period. The close relationship between the occurrence of ovarian mtDNA deletion and the menstrual irregularity was also observed. These observations suggest that the accumulation of the deleted mtDNA may be a regulating factor of dysfunction of the ovary by aging.

ISSN:1663-2818    

DOI:10.1159/000182752

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

The present study was undertaken to clarify the physiological role of the free radical-scavenger system in the control of estrogen production in the human ovary with age. Both superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the homogenate of the ovary significantly decreased from the premenopausal period to the menopausal period. The lipid peroxide content, however, showed a small and gradual decrease from the premenopausal to the postmenopausal period. In the premenopausal women, aromatase (Ar) activity in the microsomal fraction of the ovary showed a sharp decline and a significant negative correlation with age. Significant positive correlations were found between SOD and Ar activity, and between GSH-Px and Ar activity. Treatments of homogenate of the ovary with 10, 50 and 100 µM of H2O2 resulted in a decrease in Ar activity in a dose-dependent manner. Moreover, treatment with 10 and 50 µM of H2O2 produced a more significant decrease in the Ar activity in the premenopausal women than that in the postmenopausal women. Treatments with 0.01, 0.1, 1.0 and 10.0U of GSH-Px before administration of 50 µM of H2O2, on the other hand, induced a recovery of the Ar activity in a dose-dependent manner. The present study showed the inhibitory effect of peroxide on Ar activity, which was attenuated by GSH-Px. These results seem to suggest that these age-related, relatively free radical predominant environments in the human ovary may have an important role in the decrease of estrogen production through the effects on the Ar activi

ISSN:1663-2818    

DOI:10.1159/000182753

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

The relation between the alignment of chromosomes in the aged oocyte and its capacities of fertilization and development of oocytes was examined. More embryos in the condition of insemination at 12 and 16 h after human chorionic gonadotropin (hCG) however grew into two and more cell stages than those in the insemination of 20, 24 and 28 h. Some embryos in the group of insemination at 12, 16 and 20 h after hCG injection had grown into the blastocyst stage. The embryos inseminated 24 h after hCG and later had shown no further development. Twelve hours after hCG injection, 67% of oocytes have chromosomes on a straight line (A), and 29% have chromosomes scattered in one group (B). Three percent of oocytes have them separated toward both spindle ends (C) and 2% of oocytes have no chromosomes (D). At 16 h after hCG, the alignments of chromosomes are almost the same as that of 12 h after hCG injection. At 20 h after hCG, the most common alignment of chromosomes was scattered in a small group. The alignment of chromosomes of most oocytes was splitting at 24 and 28 h after hCG injection. Thus the oocytes with the chromosome alignment of A or B can be fertilized and developed into the blastocyst stage. The alignment of A and B lasts only about 8 h after ovulation, and the time was extremly restricted for oocytes to develop normally.

ISSN:1663-2818    

DOI:10.1159/000182754

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

A decline in fertility, defined as the number of implantation sites, was observed in mice as they aged; the decline started at 30 weeks of age and reached a nadir by 60 weeks when no implantation was detected. Epidermal growth factor (EGF) levels in the submandibular gland and plasma increased as the female mice aged, and sialoadenectomy (surgical removal of the submandibular glands) attenuated the rise in the plasma EGF level without affecting the overall health or survival of the animals. Uterine weight at 10-20 weeks of age was about 70 mg, and it significantly increased with age. This weight has increased more than 2-fold by 60 weeks. These changes closely followed the increase in the concentrations of EGF in the submandibular gland and the plasma. After sialoadenectomy, uterine weight decreased immediately and remained at about 50-60 mg throughout the experimental period. Interestingly, sialoadenectomized mice became pregnant at an older age than the controls. These findings suggest that elevated levels of EGF may have a physiological role in fertility decline in aging mice perhaps via uterine hypertrophy.

ISSN:1663-2818    

DOI:10.1159/000182755

出版商:S. Karger AG    

年代:1993

数据来源: Karger

ISSN:1663-2818    

DOI:10.1159/000182756

出版商:S. Karger AG    

年代:1993

数据来源: Karger

ISSN:1663-2818    

DOI:10.1159/000182751

出版商:S. Karger AG    

年代:1993

数据来源: Karger