Age-Related Changes in Prolactin Cell Percentage and Serum Prolactin Levels in Intact and Neonatall·y Gonadectomized Male and Female Rats

1982 ◽  
Vol 113 (3) ◽  
pp. 211-217 ◽  
Author(s):  
Sumio Takahashi ◽  
Seiichiro Kawashima
Keyword(s):  
Female Rats ◽  
Serum Prolactin ◽  
Male And Female ◽  
Prolactin Cell ◽  
Cell Percentage ◽  
Male And Female Rats ◽  
Age Related ◽  
Age Related Changes

CIRCADIAN FLUCTUATIONS OF SERUM HORMONE LEVELS IN PREPUBERTAL MALE AND FEMALE RATS

1976 ◽  
Vol 83 (2) ◽  
pp. 269-279 ◽  
Author(s):  
K. D. Döhler ◽  
W. Wuttke
Keyword(s):  
Age Groups ◽  
Serum Testosterone ◽  
Female Rats ◽  
Serum Prolactin ◽  
Male And Female ◽  
Hormone Levels ◽  
Male And Female Rats ◽  
Serum Lh ◽  
Serum Hormone ◽  
Old Females

ABSTRACT Diurnal variations in serum hormone levels during 2 different stages of prepubertal development were investigated in male and female rats. Groups of 13 to 18 and 25 to 30 day old male and female rats were decapitated at 4-hour by intervals during a period of 24 h. Their blood was collected and hormones were measured by radio-immunoassay. FSH levels were constantly high in 13 to 18, but low in 25 to 30 day old females. FSH was low in younger males, and significantly higher but without diurnal fluctuations in the older males. Serum LH was low in approximately 40% of the 13 to 18 day old females, while 40% had moderately high levels, and the remaining females extremely high levels of the hormone. Most of the extremely high LH peaks were found at 15.00 h and some at 03.00 h. Older females and males of both age groups had constantly low serum LH levels. Serum oestradiol was high in males and females during days 13 to 18, but it was lower in the 25 to 30 day old animals. In the young females prolactin was slightly elevated between 15.00 h and 19.00 h, while in the males the serum prolactin fluctuations were not significant. Serum testosterone was low in females at all times. The 13 to 18 day old males had higher testosterone levels than the 25 to 30 day old males. Both groups showed slight, but insignificant fluctuations in serum testosterone. These results confirm result published previously and furthermore they demonstrate the existence of circasemedian or circadian rhythms for both the gonadotrophins and gonadal steroids. These results, also suggest that the maturation of the positive feedback action of oestradiol on gonadotrophin release in female rats occurs between day 10 and 20.

scholarly journals Differential Effects of Extended Exercise and Memantine Treatment on Adult Neurogenesis in Male and Female Rats

2018 ◽  
Author(s):  
Shaina P Cahill ◽  
John Darby Cole ◽  
Ru Qi Yu ◽  
Jack Clemans-Gibbon ◽  
Jason S Snyder
Keyword(s):  
Nmda Receptor ◽  
Cell Density ◽  
Adult Neurogenesis ◽  
Environmental Enrichment ◽  
Antidepressant Drugs ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Age Related ◽  
Males And Females

ABSTRACTThe creation of new neurons in adulthood has potential for treating a number of disorders that are characterized by neurodegeneration or impaired plasticity. Animal models of reduced neurogenesis, and studies of the volume and structural integrity of the hippocampus in humans, suggest a possible therapeutic role for adult neurogenesis in age-related cognitive decline, depression, and schizophrenia. Research over the past 20 years has identified a number of approaches for enhancing adult neurogenesis, such as exercise, NMDA receptor antagonists, antidepressant drugs and environmental enrichment. However, despite the chronic nature of many disorders that impact the human hippocampus, most animal studies have only examined the efficacy of neurogenic treatments over relatively short timescales (∼1 month or less). Additionally, investigations into the regulation of neurogenesis typically include only 1 sex, even though many disorders that affect the hippocampus differentially impact males and females. Here, we therefore tested whether two known pro-neurogenic treatments, running and the NMDA receptor antagonist, memantine, could lead to long-term increases in neurogenesis in male and female rats. We found that continuous access to a running wheel (cRUN) initially increased neurogenesis in both sexes, but effects were minimal after 1 month (both sexes) and completely absent after 5 months (males). Similarly, a single injection of memantine (sMEM) only transiently increased adult neurogenesis in both males and females. To determine whether extended increases in neurogenesis were possible with 2 months of RUN and MEM treatments, we subjected rats to interval running (iRUN), weekly memantine injections (mMEM), or combined treatments (iRUN-mMEM, mMEM-iRUN). We found that 2 months of iRUN increased DCX+ cell density in females but iRUN-mMEM treatment increased DCX+ cell density in males. However, analyses with thymidine analogs revealed that neurogenesis was minimally increased during the initial phases of the 2 month treatments. Collectively, our findings identify sex differences in the efficacy of neurogenic manipulations, which may be relevant for designing plasticity-promoting treatments that target the hippocampus.

scholarly journals Age-related Individual Behavioural Characteristics of Adult Wistar Rats

2021 ◽  
Author(s):  
Sergey Sudakov ◽  
Elena Alekseeva ◽  
Galina Nazarova ◽  
Valentina Bashkatova
Keyword(s):  
Motor Activity ◽  
Wistar Rats ◽  
Individual Characteristics ◽  
Female Rats ◽  
Related Individual ◽  
Male And Female Rats ◽  
Age Related ◽  
Behavioural Characteristics ◽  
Plus Maze ◽  
Age Related Changes

The aim of this work was to study age-related changes in the behaviour of adult Wistar rats using the open field (OF) and elevated plus maze (EPM) tests. Behavioural changes related to motor activity and anxiety were of particular interest. Results showed that as male and female rats progressed from 2 to 5 months of age there was a decrease in the level of motor and exploratory activities, and an increase in the level of anxiety. Age-related changes were dependent upon initial individual characteristics of behaviour. For example, animals that demonstrated high motor activity at 2 months become significantly less active by 5 months, and animals that showed a low level of anxiety at 2 months become more anxious by 5 months. Low-activity and high-anxiety rats did not show any significant age-related changes in OF and EPM tests from 2 to 5 months of age, except for a decrease in the number of rearings in EPM. Significant individual differences in the behaviour of rats in OF and EPM tests observed at 2 months were not apparent by 5 months.

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