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Biomedical subjects

K Chikamori

Publications and source records attributed to K Chikamori.

At least 37 records · Page 2Linked to original sources
PubMed1985

In vivo and in vitro effects of angiotensin II on the release of beta-endorphin-like immunoreactivity.

The effect of angiotensin II (A II) on the release of beta-endorphin-like immunoreactivity (beta-END-LI) in rats was studied in vivo and in vitro. Intravenous injection of 1 microgram/100 g body weight of A II resulted in significant increase in the plasma beta-END-LI level after 10 and 20 min. Intraventricular injection of 1 ng/100 g body weight of A II also resulted in significant increase in the plasma beta-END-LI level after 10 min. A II at concentrations of 10(-12) M-10(-10) caused dose-dependent stimulation of beta-END-LI release from dispersed cells of rat anterior pituitary. On gel chromatography, the beta-END-LI released by incubation of the cells with 10(-10) M A II separated into two components which eluted in the same positions as human beta-lipotropin and human beta-endorphin, respectively. The ratio of beta-LPH to beta-END in these fractions was 5:1 on a molar basis. A II did not stimulate beta-END-LI release in Ca++-free-medium. [Sar1, Ala8]-A II at concentrations of 10(-9) M - 10(-7) M did not stimulate beta-END-LI release from the cells. Addition of [Sar1, Ala8]-A II to the incubation medium inhibited A II-induced beta-END-LI release from the cells. These results indicate that A II acts, at least in part, directly on anterior pituitary cells to stimulate beta-END-LI release and that calcium ion is involved in the mechanism of this effect.

Angiotensin II↗
PubMed1983

Alterations of gastrin secretion in obese rats with ventromedial hypothalamic lesions.

Basal plasma gastrin levels were significantly higher in obese rats induced by ventromedial hypothalamic lesions (VMH rats) than in sham-operated controls. Gastrin secretion in response to insulin hypoglycemia and a liquid diet load was higher in VMH rats than in controls. The antral gastrin concentration was also elevated in VMH rats. Pair-fed rats with VMH lesions showed increased gastrin secretion as did the non-pair-fed group. These results show that gastrointestinal hormone secretions as well as pancreatic endocrine function are abnormal in obese rats with VMH lesions. Increased gastrin secretion is probably induced by factors other then hyperphagia, such as disturbance of the autonomic nervous system due to the VMH lesions.

Animals↗
PubMed1981

Distribution volume, metabolic clearance and plasma half disappearance time of exogenous luteinizing hormone releasing hormone in normal women and women with obesity and anorexia nervosa.

Synthetic LRH was infused into normal women and women with obesity and anorexia nervosa to determine the distribution volume (DV), metabolic clearance rate (MCR) and half disappearance time (t 1/2) of plasma LRH. In normal women, the DV of LRH ws 12.1 +/- 0.9 (mean +/- SE) 1, the MCR was 1478.9 +/- 39.8 ml/min (28.5 +/- 1.2 ml/min/kg body weight) and the initial t 1/2 was 5.6 +/- 0.4 min. In obese patients the DV (20.6 +/- 1.5 l) was significantly higher than that in normal subjects (P < 0.005), but the MCR and t 1/2 were not significantly different from those in normal subjects. In patients with anorexia nervosa the DV and MCR were 6.5 +/- 1.1 l and 621.8 +/- 110.5 ml/min (17.9 +/- 2.4 ml/min/kg body weight), respectively, which were both significantly lower than those in normal subjects (P < 0.02), while the t 1/2 (7.3 +/- 0.1 min) was longer than in normal subjects (P < 0.02). These data suggest that 1) the abnormal responses of some hormones to provocation tests observed in obese patients and patients with anorexia nervosa should be evaluated in consideration of changes in the DV and metabolic clearance of hormones in these conditions, and 2) in patients with anorexia nervosa changes in MCR and t 1/2 may reflect low metabolism of LRH.

Adult↗
PubMed1980

[Studies on glucagon secretion in obese rats with hypothalamic lesions (author's transl)].

Glucagon secretion was studied in rats with electrolytic lesions of the bilateral ventromedial hypothalamic area (VMH-L) under various experimental conditions. The results obtained are as follows: 1. The basal plasma level of immunoreactive glucagon (IRG) was lowered in VMH-L rats 5 and 10 weeks after the operation. Plasma IRG levels after 24-hour starvation and during the arginine load were more significantly decreased in the VMH-L rats than in the control group. 2. The basal plasma level of immunoreactive insulin (IRI) showed significant positive correlations with body weight and Lee's index in these rats. The basal plasma level of IRG showed significant negative correlations with body weight, Lee's index and basal plasma IRI level. 3. In response to the arginine load, the plasma IRI level was significantly increased in VMH-L rats immediately after the operation, and the plasma IRG level was more significantly decreased in VMH-L rats 1 week after the operation than in the control group. 4. The response of plasma IRG to the arginine load was also lowered more in VMH-L rats than in rats pair-fed for 4 weeks after the operation. 5. 15 weeks after the operation, there was no significant difference in response of plasma IRI and IRG to the subcutaneous injection of epinephrine between VMH-L and control rats. These findings indicate that hypoglucagonemia in the VMH-L rats was induced by various factors, such as disorder of the autonomic nervous system, excessive insulin release, etc. The impairment of glucagon secretion may contribute to the development of obesity observed in rats with VMH-lesions.

Animals↗