Variations in binding of [3H]5-HT to cortical membranes during the female rat estrous cycle

The quantitative 2-[14C]deoxyglucose autoradiographic method was used to study the fluctuations of energy metabolism in discrete brain regions of female rats during the estrous cycle. A consistent though statistically nonsignificant cyclic variation in average glucose utilization of the brain as a whole was observed. Highest levels of glucose utilization occurred during proestrus and metestrus, whereas lower rates were found during estrus and diestrus. Statistically significant fluctuations were found specifically in the hypothalamus and in some limbic structures. Rates of glucose utilization in the female rat brain were compared with rates in normal male rats. Statistically significant differences between males and females at any stage of the estrous cycle were confined mainly to hypothalamic areas known to be involved in the control of sexual behavior. Glucose utilization in males and females was not significantly different in most other cerebral structures.

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Differential Expression of Secretogranin II and Chromogranin A Genes in the Female Rat Pituitary Through Sexual Maturation and Estrous Cycle

Endocrinology ◽

10.1210/endo-128-3-1374 ◽

1991 ◽

Vol 128 (3) ◽

pp. 1374-1380 ◽

Cited By ~ 17

Author(s):

Y. ANOUAR ◽

J. DUVAL

Keyword(s):

Differential Expression ◽

Estrous Cycle ◽

Sexual Maturation ◽

Chromogranin A ◽

Female Rat ◽

Secretogranin Ii ◽

Rat Pituitary

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Melatonin administration entrains female rat activity rhythms in constant darkness but not in constant light

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1988.255.2.r237 ◽

1988 ◽

Vol 255 (2) ◽

pp. R237-R242

Author(s):

E. M. Thomas ◽

S. M. Armstrong

Keyword(s):

Estrous Cycle ◽

Activity Rhythm ◽

Onset Time ◽

Circadian System ◽

Female Rats ◽

Male Rats ◽

Constant Darkness ◽

Female Rat ◽

Continuous Darkness ◽

Activity Rhythms

In female rats the luteinizing hormone (LH) is timed by the circadian system and is followed by a display of intense, estrogen-induced running behavior. This proestrous running on the night of ovulation can be used as a marker of the estrous cycle. Entrainment of the mammalian circadian system by exogenous melatonin (MT) has been demonstrated only in the activity rhythms of male rats. The present experiments were designed to study the effect of daily MT injections on activity rhythms and proestrous running of female rats in 1) continuous dim white light (LL) and 2) continuous darkness (DD). In LL, MT injections (50 micrograms/kg or 1 mg/kg) had no discernible effect on activity rhythms. In DD, four of the six MT-treated rats (100 micrograms/kg) entrained to the injection, and a fifth animal showed phase advances in its activity rhythm when onset of activity passed through injection time. The sixth animal was not injected with MT at activity onset time. None of the six control animals showed either effect. MT had no effect on the length of the estrous cycle. Thus MT injections can entrain circadian rhythms of activity and proestrous running in female rats in DD but not in LL.

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The influence of 17β-estradiol on annexin 1 expression in the anterior pituitary of the female rat and in a folliculo-stellate cell line

Journal of Endocrinology ◽

10.1677/joe-06-0132 ◽

2007 ◽

Vol 192 (2) ◽

pp. 429-442 ◽

Cited By ~ 9

Author(s):

Evelyn Davies ◽

Selma Omer ◽

John F Morris ◽

Helen C Christian

Keyword(s):

Cell Line ◽

Estrous Cycle ◽

Anterior Pituitary ◽

Stellate Cell ◽

Ovariectomized Rats ◽

Female Rat ◽

Annexin 1 ◽

17Β Estradiol ◽

Estrous Cycle Stage

Annexin 1 (ANXA1) is a Ca2+- and phospholipid-binding protein that plays an important role as a mediator of glucocorticoid action in the host-defence and neuroendocrine systems. Sex differences in hypothalamo–pituitary–adrenal (HPA) axis activity are well documented and a number of studies have demonstrated that gonadal steroids act as regulators of HPA activity. The aim of this study was to investigate the effect of ovariectomyand 17β-estradiol replacement, and estrous cycle stage, on anterior pituitary ANXA1 content. The amount of anterior pituitary ANXA1 determined by western blotting varied with estrous cycle stage with a peak at estrus declining to a trough at proestrus. Ovariectomy resulted in a significant (P<0.05) decrease in anterior pituitary ANXA1 content. Administration of 17β-estradiol (1 μg/100 g) significantly (P<0.01) increased anterior pituitary ANXA1 expression in the ovariectomized animals. In contrast, there was no change in pituitary ANXA1 content in response to 17β-estradiol in adrenalectomized and adrenalectomized/ovariectomized rats. Treatment of TtT/GF cells, a folliculo-stellate cell line, with 17β-estradiol (1.8–180 nM) increased ANXA1 mRNA expression and increased the amount of ANXA1 protein externalized in response to a dexamethasone stimulus. These results indicate that 17β-estradiol stimulates ANXA1 expression in the anterior pituitary and in vivo an adrenal factor contributes to the mechanism of action.

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Androgen- and Estrogen-Dependent Regulation of Insulin-Degrading Enzyme in Subcellular Fractions of Rat Prostate and Uterus

Experimental Biology and Medicine ◽

10.1177/153537020523000706 ◽

2005 ◽

Vol 230 (7) ◽

pp. 479-486 ◽

Cited By ~ 18

Author(s):

Daniel P. Udrisar ◽

Maria I. Wanderley ◽

Regina C. C. Porto ◽

Carla L. P. Cardoso ◽

Maria C. L. Barbosa ◽

...

Keyword(s):

Estrous Cycle ◽

Cytosolic Fraction ◽

Male Rat ◽

Insulin Degradation ◽

Nuclear Fraction ◽

Female Rat ◽

Insulin Degrading Enzyme ◽

Degrading Enzyme ◽

Uterine Growth ◽

Rat Prostate

Innumerous data support the fact that insulin-degrading enzyme (IDE) is the primary enzymatic mechanism for initiating and controlling cellular insulin degradation. Nevertheless, insulin degradation is unlikely to be the only cellular function of IDE, because it appears that some cellular effects of insulin are mediated by IDE as a regulatory protein. Insulin-degrading enzyme shows a significant correlation with various cellular functions, such as cellular growth and differentiation, and the expression of IDE is developmentally regulated. Besides insulin, other substrates are also degraded by IDE, including various growth-promoting peptides. It has also been shown that IDE enhances the binding of androgen to DNA in the nuclear compartment. It is also known that the androgen hormones have a stimulatory effect on prostate growth, and that estradiol stimulates uterine growth. To establish whether IDE is regulated by a cellular prostate/uterine growth stimulus, the present study assessed whether IDE was modified in quantity and activity during proliferative conditions (castration + testosterone in the male rat, or castration + estradiol or the proestrus phase of the estrous cycle in the female rat) and autolysis (castration or the metestrus phase of the estrous cycle) using cytosolic and nuclear fractions of rat prostate and cytosolic fractions of rat uterus. The activity and amount of IDE decreased in the cytosolic fraction with castration and during metestrus, and increased with testosterone or estradiol treatment and during proestrus. In the nuclear fraction, the quantity of the IDE followed the same pattern observed in the cytosolic fraction, although without degradative activity. The data presented here suggest that IDE may participate in prostatic and uterine growth and that the testosterone or estradiol and/or prostate and uterus insulin-like growth factors may be important factors for the expression and regulation of IDE in the prostate and uterus

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