Search PubMed⌕ Search

Biomedical subjects

H Kawabe

Publications and source records attributed to H Kawabe.

At least 91 records · Page 5Linked to original sources
PubMed1983

Effect of metoclopramide on the secretion of aldosterone and other adrenocortical steroids.

The aim of this study was to determine the effect of metoclopramide, a dopamine antagonist, on the secretion of aldosterone and other adrenocortical steroids in normal subjects. An i.v. bolus injection of 10 mg of metoclopramide significantly increased the plasma PRL, plasma aldosterone and 18-hydroxycorticosterone, but the plasma renin activity, plasma deoxycorticosterone, corticosterone and cortisol remained unchanged. The changes in plasma aldosterone induced by metoclopramide were significantly correlated with the basal levels of plasma aldosterone and renin activity. These results suggest that the response of plasma aldosterone to metoclopramide in normal subjects is influenced by the basal activity of renin-angiotensin-aldosterone system and the late step of aldosterone synthesis is stimulated by metoclopramide.

18-Hydroxycorticosterone↗
PubMed1983

Mechanism of the central effects of dopamine and metoclopramide on aldosterone regulation in the rat.

To investigate the mechanism of the central action of dopamine and its antagonist, metoclopramide, on the regulation of aldosterone, studies were performed in 54 conscious rats with and without bilateral nephrectomy. In normal and sham-operated rats, intracerebroventricular injection of dopamine resulted in a significant suppression of plasma renin activity and plasma aldosterone at 30 min, and intracerebroventricular injection of metoclopramide resulted in a significant elevation of plasma renin activity and plasma aldosterone at 30 min without altering the plasma corticosterone and potassium levels. In bilaterally nephrectomized rats, the plasma renin activity was significantly reduced and it did not respond to dopamine or metoclopramide. In these rats, intracerebroventricular injection of metoclopramide exerted no effect on the plasma aldosterone, but intracerebroventricular injection of dopamine increased the plasma aldosterone slightly. However, this increase was not statistically significant. These findings suggest that the dopaminergic system in the brain is involved in the regulation of aldosterone secretion, mainly with changes in the peripheral renin-angiotensin axis in rats.

Adrenocorticotropic Hormone↗
PubMed1983

In vivo and in vitro effects of metoclopramide on aldosterone secretion in rats.

This study was designed to investigate the effects of metoclopramide, a dopamine antagonist, on in vivo and in vitro aldosterone production in the rat. In addition, we examined the effect of various levels of sodium intake on the response of plasma aldosterone to metoclopramide. Metoclopramide (2-50 mg/kg) was given by ip injection to conscious rats. Metoclopramide induced a dose-related increase in plasma aldosterone, whereas it only increased plasma renin activity at high doses (20 and 50 mg/kg). The response of plasma aldosterone to 10 mg/kg of metoclopramide in the low-sodium group was greater than that in the high-sodium group. Metoclopramide had no effect on aldosterone production in isolated zona glomerulosa cells in vitro.

Adrenal Glands↗
PubMed1983

Effect of the intracerebroventricular injection of dopamine on blood pressure in the spontaneously hypertensive rat.

To examine the role of the central dopaminergic system in blood pressure regulation, dopamine was injected into the cerebral lateral ventricles of conscious, unrestrained spontaneously hypertensive rats (SHR), deoxycorticosterone (DOC)-salt hypertensive rats and Wistar-Kyoto normotensive rats (WKY). Intracerebroventricular (i.c.v.) injection of dopamine produced a significant dose-dependent decrease in blood pressure in the SHR as well as in the WKY and DOC-salt hypertensive rats. However, the SHR were significantly more sensitive than were the other 2 groups of rats. In the SHR, this central depressor effect of dopamine was significantly attenuated by pretreatment with i.c.v. metoclopramide, but not by phentolamine, suggesting that central dopamine receptors rather than alpha-adrenoceptors are involved in the mediation of the actions of dopamine in the brain. These results suggest that the central dopaminergic system plays a more important role in the regulation of blood pressure in the SHR than in the WKY and DOC-salt hypertensive rats.

Animals↗
PubMed1983

Prolactin, renin and catecholamines in essential hypertension.

In 40 male patients with essential hypertension less than the age of 36 years, the plasma prolactin (PRL), plasma renin activity (PRA) and plasma catecholamines (noradrenaline (NA) and adrenaline (A)) were determined simultaneously. Those levels were significantly increased compared to the levels in 14 age-matched healthy male control subjects. Furthermore, there were significant correlations between the PRL and plasma NA or PRA (p less than 0.05 in each case), and between the PRA and plasma NA (p less than 0.05). However, no significant relationships were observed between systolic or diastolic blood pressure and PRL, plasma NA or PRA. These findings indicate that the central dopaminergic activity is reduced in a number of young adults with essential hypertension, and that in the patients with the reduced central dopaminergic activity, the peripheral sympathetic activity is stimulated and PRA is also increased probably due to the increased peripheral sympathetic activity, and the possibility exists that such changes are related to the development of hypertension.

Adult↗
PubMed1983

Effects of contact lens wear on mitosis of corneal epithelium and lactate content in aqueous humor of rabbit.

Various types of contact lenses, i.e., poly-methyl-methacrylate hard lenses, poly-2-hydroxyethyl-methacrylate soft lenses and two kinds of gas-permeable hard lenses with different permeabilities to oxygen, were placed on one eye of the albino rabbit for varying lengths of time. Using the fellow eye as the control, studies were carried out of the effects of the lens wear on the mitosis in the corneal epithelium and the lactate concentration in the aqueous humor. The contact lens wear suppressed the mitosis and increased the concentration of aqueous lactate, the degree of changes being greater as the permeability of the lens to oxygen decreased and the period of wear became longer.

Animals↗
PubMed1982

Spectroscopic studies on bleomycin-iron complexes with carbon monoxide, nitric oxide, isocyanide, azide, and cyanide and comparison with iron-porphyrin complexes.

The bleomycin-iron complexes with CO, NO, C2H5NC, OH-, N-3, CN-, and CH3NH2 were characterized by electronic, ESR, 1H-NMR, and Mössbauer spectroscopies and the findings were compared with the corresponding hemoprotein complexes. The 1H-NMR and Mössbauer features for the CO and C2H5NC adducts of the bleomycin-Fe(II) complex are consistent with an S = 0 ferrous assignment. The OH-, CH3NH2, and N-3 adducts of the bleomycin-Fe(III) complex show the ESR, 1H-NMR, and Mössbauer spectra typical of a low-spin Fe(III). The unique Mössbauer parameters of the bleomycin-Fe(II)-NO complex demonstrate mixing between the NO pi- and the Fe 3d-orbitals. The magnitude of the proton chemical shifts over +/- 50 ppm indicates a high-spin ferric type for the bleomycin-Fe(III)-CN complex. The Mössbauer parameters (delta EQ = 0.89 and delta = 0.48 mm/s) of the CN- adduct differ substantially from those of typical low-spin hemoprotein-cyanide complexes. Except for the CN- adduct, the Mössbauer and crystal field parameters of these bleomycin-iron complexes are similar to those of the corresponding hemoprotein complexes.

Azides↗
PubMed1982

Mechanism of pressor effects of intraventricular injection of angiotensin II in the rat: role of vasopressin and renal nerves.

1. The role of the kidney and vasopressin in the increase of blood pressure obtained when angiotensin II is injected intraventricularly into rats has been investigated. 2. Intraventricular injection of angiotensin II led to a significant increase in blood pressure in the control and all sham-operated rats compared with that in unilaterally nephrectomized, one-kidney denervated rats and bilaterally nephrectomized rats. The degree of increase in blood pressure in unilaterally nephrectomized, one-kidney denervated rats was equal to that in bilaterally nephrectomized rats. 3. The increase in blood pressure in the bilaterally nephrectomized rats lasted significantly longer than that in the control and unilaterally nephrectomized, one-kidney denervated rats. 4. In the bilaterally nephrectomized rats plasma vasopressin was still higher 30 min after the intraventricular injection of angiotensin II than that of the control and unilaterally nephrectomized, one-kidney denervated rats. 5. These results suggest that the rise in blood pressure observed after intraventricular injection of angiotensin II is due partly to stimulation of the renal sympathetic nervous system and partly to increase in plasma vasopressin concentration.

Angiotensin II↗
PubMed1981

Purification, enzymatic properties, and active site environment of a novel manganese(III)-containing acid phosphatase.

A new manganese-containing acid phosphatase has been isolated and crystallized from sweet potato tubers. The pure enzyme contains one atom of manganese per Mr = 110,000 polypeptide and shows phosphatase activity toward various phosphate substrates. The pH optimum of the enzyme was 5.8 and the enzyme activity was inhibited by Cu2+, Zn2+, Hg2+, AsO43-, and MoO42-. This stable metalloenzyme is red-violet in color with an intense absorption band at 515 nm (epsilon - 2460). Our electronic, circular dichroism, and electron spin resonance findings strongly indicate that the Mn-valence state of the native enzyme is trivalent. When the Mn-enzyme is excited by the 5145 A line of Ar+ laser, prominent Raman lines at 1230, 1298, 1508, and 1620 cm-1 were detected. This Raman spectrum can probably be interpreted in terms of internal vibration of a coordinated tyrosine phenolate anion. The tryptophan-modified enzyme showed a positive Raman band at 370 cm-1, which is preferentially assigned to a Mn(III)-S streching mode. The modification of the Mn-enzyme by N-bromosuccinimide led to a large decrease in the fluorescence intensity of 335 nm which was dominated by its tryptophan residues within a considerable hydrophobic environment. The acid phosphatase activity was significantly decreased by the tryptophan modification. With respect to the active site donor sets, the Mn(III)-containing acid phosphatase is distinctly different from the Zn(II)-containing alkaline phosphatase. Of interest is also the appreciable similarity of some enzymatic and spectroscopic properties between the present enzyme and uteroferrin.

Acid Phosphatase↗