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Biomedical subjects

R Kakihana

Publications and source records attributed to R Kakihana.

At least 19 recordsLinked to original sources
PubMed1980

Endocrine effects of meternal alcoholization: plasma and brain testosterone, dihydrotestosterone, estradiol, and corticosterone.

Maternal ethanol consumption was associated with reduced levels of dihydrotestosterone in the brains of 1--2-day-old male rats when compared to those of sex-matched pups obtained from dames that were fed sucrose. In contrast, brain levels of corticosterone were increased significantly in the pups of ethanol-fed animals when compared to those from sucrose-fed controls. Brain and plasma estradiol did not differ between groups. These results suggest that maternal ethanol consumption may influence the central nervous system and plasma levels of certain steroidal hormones in the offspring.

Alcoholism↗
PubMed1980

Brain corticosterone in lactating rats: possible relation to the attenuation of the pituitary-adrenocortical response to stress.

In an attempt to elucidate the mechanism of suppression of the plasma corticosterone stress response in the lactating female rats, nonstress levels of corticosterone in plasma and hypothalamus, cerebral cortex, hippocampus and pituitaries were determined in the lactating and nonlactating Sprague-Dawley rats at 1600-1700 hr by the protein binding assay. The brain corticosterone levels were significantly higher (64-92%) in the lactating than in nonlactating rats, while the plasma corticosterone levels were identical. We conclude that the suppression of the stress response in the lactating female rats is directly or indirectly related to the high basal levels of corticosterone in the brain, which result from a chronic hyperactivation of the endocrine axis.

Animals↗
PubMed1978

The fluorometric assay of rat plasma corticosterone: evaluation of nonspecific fluorescence.

An analysis of 168 plasma samples from intact rats, one to 35 days of age, was performed using both brief and specific fluorometric procedures. The amount of fluorescence produced by the brief procedure which could be attributed to corticosterone ranged from a maximum of 72% to a minimum of 16% of the total fluorescence value. Corticosterone represented 50% or more of the brief assay value in only five out of 18 groups of animals assayed. Following statistical analysis of the nonspecific fluorescence, a significant variation was found due to the age of the animal. A highly significant increase in nonspecific fluorescence was found in 21-day old animals following histamine injection. It was concluded that the brief fluorometric assays for corticosterone were of little value if specificity was desired.

Aging↗
PubMed1978

Regional uptake of endogenous corticosterone by rat brain following stress.

The stress-induced changes in the corticosteroid levels in four brain regions were studied in female Sprague-Dawley rats using the fluorometric assay following column chromatographic separation. Fifteen min after novelty stress, the corticosteroid levels increased 1.5-, 1.5- and 1.7-fold in hippocampus, hypothalamus and cerebral cortex, respectively, compared to 6-fold increase in plasma (60 mug/d1). In the second study in which the animals were sacrificed 60 min after ethanol stress (I.P. injection of 2 g/kg in 20% solution with physiological saline), there were 2.5-, 3.5- and 4.7-fold increases in hypothalamus, hippocampus and cerebral cortex, respectively, compared to 4-fold increase in plasma (77 mug/d1). There were marked increases of corticosterone in the pituitaries after stress. The results confirm the differential regional distribution of corticosteroid in the brain and the stress-induced corticosteroid elevations. These results support the idea that the brain levels of corticosteroid are determined by the existing plasma levels and by the duration of the hormone elevation. The possible significance of the brain levels of corticosterone is discussed.

Animals↗
PubMed1977

Circadian rhythms of ethanol consumption by mice: a simple computer analysis for chronopharmacology.

On the assumption that a sinusoidal curve adequately described the circadian rhythm of food or fluid consumption by mice, the whole daily pattern can be derived from a few observations. Examples are presented to show that the assumption is valid. This simple curve-fitting by computer is also applicable to analysis of blood levels of drugs administered in the food or drinking fluid. The method should be useful for estimating the magnitude of daily fluctuations in pharmacological variables, including drug intake rates and circulating drug levels.

Alcohol Drinking↗
PubMed1976

Circadian rhythm of corticosterone in mice: the effect of chronic consumption of alcohol.

The effect of chronic consumption of alcohol on the circadian variations of the plasma corticosterone investigated in DBA/2J male mice. After 15 weeks of alcohol consumption (3.8%w/v for the first week and 7.5% for subsequent weeks) the alcohol groups exhibited a flattened circadian corticosterone curve, the level being intermediate between the peak and trough values of the water control groups. The diurnal patterns of food and liquid consumption were still present at the 10th week of alcohol treatment in the alcohol groups, although the absolute amount of food and liquid consumed at each of the 6-h intervals was somewhat different between the alcohol and water groups. The blood alcohol showed a peak at early morning with the mean of 100 mg/100 ml, but the levels of alcohol during the remaining periods were remarkably stable, the means ranging from 30 to 46 mg/100 ml. Chronic consumption of alcohol, even relatively low concentrations, appears to affect the neural sites in the CNS controlling the circadian rhythm of ACTH release.

Alcoholism↗
PubMed1976

Circadian rhythm of corticosterone levels in rat brain.

In the present study the circadian changes which occur in the levels of corticosterone in the brain and plasma in Sprague-Dawley rats are reported. The levels of corticosterone in the brain were found to have a daily trough and crest with timing similar to that observed for the plasma steroid. In addition, the effect of histamine stress on the corticosterone content of the particulate and the soluble fractions at the trough and crest was examined. The levels of both brain fractions were significantly higher 20 min after histamine injection. The time of day at which the stress was applied was not a significant factor in the magnitude of the stress response.

Animals↗
PubMed1975

Alcohol withdrawal convulsions in genetically different populations of mice.

Individual Swiss-Webster mice differed in the intensity of their withdrawal reactions after a standard regimen of alcohol administration, and offspring resembled their parents in this respect. Inbred strains of mice also differed in the severity of their alcohol withdrawal reactions. C57BL mice showed almost no convulsions on handling. These results indicate that a genetic factor participates in determining the severity of alcohol withdrawal seizures in mice. The sensitivity to excitant actions of reserpine paralleled the sensitivity to alcohol withdrawal reactions in three strains of mice but not among individual mice of a genetically heterogeneous stock. The strain correlation between these traits was therefore fortuitous and does not demonstrate a common biochemical lesion in alcohol-withdrawn and reserpine-treated mice.

Alcoholism↗