Gonadotropin secretion during aging in women: Review article

Rossmanith, Winfried G.

doi:10.1016/0531-5565(94)00030-7

Cited by 24 publications

(13 citation statements)

References 24 publications

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“…40,41 The persistent estrus syndrome induced by orthotopic ovarian transplantation after ovariectomy or X-ray irradiation was characterized by similar changes in ovarian steroidogenesis and masculinization in female rats. 26,30 We failed to find any references to the effect of the LL regimen on hematopoietic tissue and lung tumor development. There is evidence of the oncostatic effect of melatonin on mammary tumor growth in vitro and in vivo experiments.…”

Section: Discussionmentioning

confidence: 89%

Effect of exposure to light‐at‐night on life span and spontaneous carcinogenesis in female CBA mice

Anisimov

Baturin

Popovich

et al. 2004

Intl Journal of Cancer

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The effect of constant illumination on the development of spontaneous tumors in female CBA mice was investigated. Fifty female CBA mice starting from the age of 2 months were kept under standard light/dark regimen (12 hr light: 12hr dark; LD) and 50 CBA mice of similar age were kept under constant illumination (24 hr a day, 2,500 Lux, LL). Exposure to the LL regimen decreased food consumption but did not influence body weight, significantly accelerated age-related disturbances in estrous function, and was followed by a significant increase in spontaneous tumor incidence in female CBA mice. Tumor incidence as well as the number of total or malignant tumors was significantly increased in the LL group compared to the LD group (p < 0.001). The incidence of lung adenocarcinomas, leukemias and hepatocarcinomas was 7/50; 6/50 and 4/50 in the LL group and 1/50; 0/50 and 0/50 in the LD group. Mice from the LL groups had shorter life spans then those from the LD group. The data demonstrate, for the first time, that exposure to constant illumination was followed by increases in the incidence of spontaneous lung carcinoma, leukemias and hepatocarcinoma in female CBA mice. Alternation of the day and night circadian cycle is an important regulator of a wide variety of physiological rhythms in organisms. Light exposure at night has been found to be related to a number of serious behavioral and health problems including cancer. In rodents, light-at-night leads to disruption of the ovulatory cycle followed by hyperplastic processes and tumor development in mammary gland, ovaries and uteri. 1,2 A tumor-promoting effect of exposure to the LL regimen was shown on chemical carcinogenesis in the mammary gland of rats. [3][4][5][6] Prolonged light exposure suppresses the night peak of melatonin, the 'hormone of the night.' 7,8 Melatonin is the principal hormone of the pineal gland, the small neuroendocrine gland connected with the brain that mediates information on light from the retina to the organism. 7,8 A significant increase in the risk of breast and colorectal cancers was shown in women who frequently did not sleep during the period of the night, about 1:30 a.m., when melatonin levels are typically the highest. 9 -12 The 'Melatonin hypothesis' suggests reduced pineal melatonin production might increase human breast cancer risk because lower melatonin output would lead to an increase in female sex hormones and stimulate proliferation of breast tissue. 13 Data on the enhancing effect of constant illuminations on spontaneous endometrial carcinogenesis in BDII/Han rats 14 agree with this suggestion. There are data on the promoting effect of the LL regimen on hepatocarcinogenesis induced by N-nitrosodimethylamine (DENA) in rats 15 and on the development of neurogenic and kidney tumors in progeny of rats exposed to N-nitrosomethylurea in utero. 16 We report, for the first time, that exposure to constant illumination increased the incidence of spontaneous lung carcinoma, leukemias and hepatocarcinoma in female CBA mice. MATERIAL AND ME...

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Section: Discussionmentioning

confidence: 89%

Effect of exposure to light‐at‐night on life span and spontaneous carcinogenesis in female CBA mice

Anisimov

Baturin

Popovich

et al. 2004

Intl Journal of Cancer

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“…Some light may be shed on this issue by studies measuring serum gonadotropins or glycoprotein free a-subunit (FAS) in women as an index of GnRH release (Table 2). Although these studies differ in the age of experimental subjects, overall they show increases in gonadotropin concentrations from the pre-to the perimenopausal or early postmenopausal period (Rossmanith 1995, Gill et al 2002, but subsequent decreases in gonadotropin or FAS release from the early to the late postmenopausal period, including lower hormone concentrations and decreased pulse frequency (Ushiroyama et al 1999, Hall et al 2000. Thus, the chronologic age relative to reproductive failure is an important parameter in understanding species differences.…”

Section: In Vivo Studies In Primatesmentioning

confidence: 99%

“…Studies in women have measured serum gonadotropin (LH or FSH) or glycoprotein free a-subunit (FAS), the latter as a reflection of hypothalamic GnRH release (Gill et al 2002) to determine age-related changes. One study compared pulsatile gonadotropin release (frequency and amplitude) in postmenopausal women relative to premenopausal levels during the early follicular stage and showed that the postmenopausal women had increased pulse amplitude, but no change in pulse frequency, compared with the premenopausal cohort (Rossmanith 1995). However, because the premenopausal women were sampled during the early follicular stage, when pulsatile gonadotropin release is relatively low, it is difficult to generalize about increased gonadotropin release between pre-and postmenopausal women.…”

Section: Primatesmentioning

confidence: 99%

“…More insight is provided by studies comparing early and late postmenopausal women. The study by Rossmanith (1995) shows that, as aging progresses, gonadotropin levels decrease, as do gonadotropin pulse frequency and amplitude. Another group compared early postmenopausal women (45 -55 years) with late postmenopausal women (70 -80 years) and demonstrated significantly lower LH and FSH concentrations in older than younger postmenopausal women (Gill et al 2002).…”

Section: Primatesmentioning

confidence: 99%

“…It could be argued that because the perimenopause is characterized by decreased circulating estradiol concentrations relative to the premenopausal period (Gore et al 2004), the increased GnRH/gonadotropin secretion seen in monkeys (and possibly in early postmenopausal women) (Rossmanith 1995) is simply due to a diminution of estradiol negative feedback. However, this is probably not entirely the case, suggesting a hypothalamic and/or pituitary level of regulation.…”

Section: Primatesmentioning

confidence: 99%

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Neuroendocrine control of reproductive aging: roles of GnRH neurons

Yin

Gore²

2006

Reproduction

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The process of reproductive senescence in many female mammals, including humans, is characterized by a gradual transition from regular reproductive cycles to irregular cycles to eventual acyclicity, and ultimately a loss of fertility. In the present review, the role of the hypothalamic gonadotropin-releasing hormone (GnRH) neurons is considered in this context. GnRH neurons provide the primary driving force upon the other levels of the reproductive axis. With respect to aging, GnRH cells undergo changes in biosynthesis, processing and release of the GnRH decapeptide. GnRH neurons also exhibit morphologic and ultrastructural alterations that appear to underlie these biosynthetic properties. Thus, functional and morphologic changes in the GnRH neurosecretory system may play causal roles in the transition to acyclicity. In addition, GnRH neurons are regulated by numerous inputs from neurotransmitters, neuromodulators and glia. The relationship among GnRH cells and their inputs at the cell body (thereby affecting GnRH biosynthesis) and the neuroterminal (thereby affecting GnRH neurosecretion) is crucial to the function of the GnRH system, with age-related changes in these relationships contributing to the reproductive senescent process. Therefore, the aging hypothalamus is characterized by changes intrinsic to the GnRH cell, as well as its regulatory inputs, which summate to contribute to a loss of reproductive competence in aging females. Reproduction (2006) 131 403-414

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Endokrinologie der perimenopausalen Übergangsphase, der Postmenopause und des Seniums

Ortmann¹

Klinische Endokrinologie Für Frauenärzte

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Gonadotropin secretion during aging in women: Review article

Cited by 24 publications

References 24 publications

Effect of exposure to light‐at‐night on life span and spontaneous carcinogenesis in female CBA mice

Effect of exposure to light‐at‐night on life span and spontaneous carcinogenesis in female CBA mice

Neuroendocrine control of reproductive aging: roles of GnRH neurons

Endokrinologie der perimenopausalen Übergangsphase, der Postmenopause und des Seniums

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