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Biomedical subjects

Y Hashigami

Publications and source records attributed to Y Hashigami.

17 recordsLinked to original sources
PubMed1990

[Altered alpha atrial natriuretic peptide (ANP) concentrations in plasma, atria and hypothalamus in experimentally induced hyper- and hypothyroid rats].

In order to assess a possible involvement of thyroid hormone in atrial natriuretic peptide (ANP), experimentally induced hyper- and hypothyroid rats were employed, and the immunoreactive rat ANP (IR-ANP) concentrations in plasma, atria and brain regions including the hypothalamus were measured by a specific radioimmunoassay. Plasma IR-ANP concentration in hypothyroid rats was 14.5 +/- 2.9 (mean +/- SD) fmol/ml, significantly lower than that in control rats (p less than 0.05 vs control of 24.9 +/- 9.7 fmol/ml). Plasma IR-ANP concentration in hyperthyroid rats was 66.4 +/- 9.7 fmol/min, significantly higher than that in the controls (p less than 0.01). Atrial IR-ANP concentration in hyperthyroid rats was significantly lower than that in the controls (79.9 +/- 11.1 nmol/g vs 133.5 +/- 21.2 nmol/g (control), p less than 0.05), though no significant change was observed in atrial IR-ANP concentration in hypothyroid rats. While hypothalamic ANP concentration in hypothyroid rats was significantly lower than that in the controls (17.5 +/- 3.5 pmol/g vs 31.9 +/- 1.9 pmol/g (control), p less than 0.05), there was no significant change of that in the hyperthyroid rats. On reverse phase high performance liquid chromatography, the major peak in plasma and hypothalamus extract was thought to be identical to synthetic alpha-rat ANP (1-28). These results may suggest that in the hyperthyroid state an excessive amount of ANP is released from atria into the blood, and that in the central nervous system thyroid hormone involve ANP metabolism being different from the atrium.

Animals↗
PubMed1989

[Effects of neonatal administration of monosodium glutamate on four neuropeptide concentrations in the rat brain].

The present study was designed to measure concentrations of four neuropeptides in different brain regions in monosodium glutamate(MSG)-treated rats and to assess molecular forms of each peptide with gel and high performance liquid chromatography (HPLC). MSG(4mg/kg body weight) or 10% NaCl was injected subcutaneously on postnatal days 1, 3, 5, 7 and 9 to male littermates which were subsequently used on postnatal day 100. Rats were sacrificed by decapitation, and the brains were dissected into ten discrete regions. The brain extracts were subjected to measurement of four neuropeptides; somatostatin (SRIF), neuropeptide Y (NPY), atrial natriuretic polypeptide(ANP), and a novel pituitary polypeptide 7B2 by specific radioimmunoassays. Significant increase (p less than 0.01) in midbrain SRIF content was observed in MSG-treated rats, though there was no significant change in hypothalamic SRIF content. Significant reduction (p less than 0.05) in hypothalamic NPY content was also found in MSG-treated rats. Hypothalamic ANP content was similar in both MSG-treated and control rats. A significant increase of 7B2 content was found in substantia nigra/ventral tegmentum and hypothalamus (p less than 0.05 or p less than 0.01, respectively) in MSG-treated rats. These four immunoreactivities were further characterized by gel permeation or high pressure liquid chromatography (HPLC). Chromatographic analysis of SRIF immunoreactivity revealed that there were two distinctive peaks and smaller molecular weight component corresponding to SRIF. Fractionation of NPY or 7B2 immunoreactivity by gel permeation showed a single major peak which was identical to the synthetic NPY or 7B2 immunoreactivity from porcine pituitary extract. HPLC analysis for ANP immunoreactivity also showed that the major immunoreactive component corresponded to synthetic rat ANP. MSG treatment could not produce any major alterations in proportions of molecular forms studied. These results suggest that MSG treatment in neonates might produce the alterations in SRIF, NPY and 7B2 content in the discrete brain regions including the hypothalamus.

Animals↗
PubMed1989

Increased neuropeptide Y concentrations in cerebrospinal fluid from patients with aneurysmal subarachnoid hemorrhage.

We investigated the possible relation between neuropeptides and cerebral vasoconstriction in samples of ventricular or cisternal cerebrospinal fluid from 14 patients with subarachnoid hemorrhage. Neuropeptide Y, calcitonin gene-related peptide, atrial natriuretic peptide, and pituitary polypeptide 7B2 were present in the cerebrospinal fluid of these patients. Concentrations of calcitonin gene-related peptide and 7B2 were not significantly different from those in control subjects, but that of atrial natriuretic peptide was significantly lower. Although the mean concentration of neuropeptide Y was not significantly higher than control, consecutive determinations showed an increase 6-11 days after the onset of subarachnoid hemorrhage. An initially high 7B2 concentration decreased gradually, although half the patients showed a second increase greater than 10 days after the onset. Considering the well-recognized vasoconstrictive effect of neuropeptide Y, it is possible that this increase in its concentration in the cerebrospinal fluid plays a role in the pathogenesis of the cerebral vasospasm that is often seen after subarachnoid hemorrhage.

Aged↗
PubMed1989

Immunoreactive 7B2 concentrations in rats with various endocrine conditions.

Changes in 7B2 immunoreactivity in the pituitary as well as in the other brain regions and gut after various endocrine situations were investigated. Gonadectomy and neonatal monosodium glutamate (MSG) treatment resulted in an appreciable increase in the pituitary 7B2 concentration, though 7B2 content in the MSG treated pituitary was not significantly different when calculation was performed on a per pituitary gland basis. The 7B2 concentration in the cerebellum, midbrain and cortex in thyroxine treated rats showed a significant increase, which might indicate possible thyroid hormone involvement in 7B2 metabolism in the brain. The pituitary 7B2 concentration during the estrous cycle did not change significantly. These results suggest that pituitary 7B2 may correlate to the pituitary gonadotropins and that brain 7B2 content may be modulated by thyroid hormones.

Adrenalectomy↗
PubMed1989

Pituitary protein 7B2-like immunoreactivity in cerebrospinal fluid: comparison with other neuropeptides.

A pituitary protein, designated 7B2, was demonstrated to be present in the cerebrospinal fluid (CSF) obtained from control subjects and patients with various cerebrovascular accidents (CVAs). Although there was not any significant difference in mean immunoreactive 7B2 concentrations among various CVA groups, the CSF immunoreactive 7B2 levels in control subjects were 10 to 100 times higher than those in control plasma samples. Immunoreactive calcitonin gene-related peptide (CGRP) and immunoreactive atrial natriuretic peptide (ANP) levels in the CSF were comparable to those in corresponding normal plasma samples. The CSF ANP concentrations in patients with cerebral bleeding and subarachnoid hemorrhage were significantly lower than those in control subjects. Gel chromatography or high-performance liquid chromatography indicated that the main immunoreactivities of 7B2, CGRP, and ANP coeluted with corresponding standard material. The high CSF concentrations of immunoreactive 7B2 observed might indicate a functional role of 7B2 in the central nervous system.

Adult↗
PubMed1988

Plasma and urine concentrations of atrial natriuretic peptide in patients with diabetes mellitus.

To examine whether plasma and urine concentrations of human atrial natriuretic peptide (hANP) are altered in patients with diabetes mellitus (DM), plasma and urine hANP concentrations were evaluated in 86 patients with diabetes mellitus using an extraction procedure. The mean recovery rate of extraction was 71.8 +/- 0.6% (mean +/- SEM). The major immunoreactive component of hANP in extracted plasma and urine appeared to be identical to synthetic alpha hANP as judged by reverse-phase high-performance liquid chromatography (HPLC). The patients were divided into three groups according to their renal complications. The patients in group 1 had no apparent abnormality in serum creatinine, serum or urine beta 2-microglobulin (beta 2-MG), or urine N-acetyl-beta-D-glucosaminidase (NAG); those in group 2 showed either beta 2-MG or NAG abnormality but no creatinine abnormality. The patients in group 3 were though to have an established diabetic nephropathy and showed a serum creatinine increase. Plasma ANP concentrations in groups 1, 2, and 3 were 10.7 +/- 2.1, 19.9 +/- 5.6, and 39.2 +/- 9.9 fmol/ml, respectively. These values in groups 2 and 3 were significantly higher than the control values (p less than 0.05 or p less than 0.01 versus 6.2 +/- 0.7 fmol/ml). Urine ANP concentrations in group 1 were also within normal range, though those in groups 2 and 3 markedly increased in comparison with normal values.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Pituitary, hypothalamic and pancreatic 7B2 concentrations in rats with streptozotocin-induced diabetes and spontaneously diabetic mice.

The pituitary protein, 7B2 has been demonstrated in the pancreas and is known to be present in very high concentrations in pancreatic endocrine tumors. To investigate whether any changes in 7B2 concentrations might be present in the pancreases affected by different types of diabetes and whether the diabetic state itself might affect pituitary and hypothalamic 7B2 concentrations, streptozotocin (STZ)-treated rats and mice with natural-onset diabetes (obese hyperglycemic, or ob/ob, mice and non-obese diabetic, or NOD, mice) were employed. A significant reduction in pancreatic 7B2 concentrations was found in STZ-treated rats. The pancreatic 7B2 concentration was significantly high in ob/ob mice (p less than 0.05, versus the concentration in their lean littermates, and the decrease observed in older NOD mice, appeared to parallel their insulin reserve. Pituitary and hypothalamic 7B2 concentrations were similar in STZ-treated and control rats. A reduction in pituitary and hypothalamic 7B2 concentrations was observed in older NOD mice (both p less than 0.01 versus respective values in younger mice). In ob/ob mice, a significant reduction was also found in hypothalamic 7B2 concentration (p less than 0.01 versus that in control mice). Gel permeation chromatography showed that 7B2 immunoreactivity comprised two molecular components, and the relative proportion in the pancreas differed from that in other tissues. In the pancreas, a smaller molecular component was predominant (elution coefficient, 0.62).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Changes in the plasma and urine alpha human atrial natriuretic peptide (alpha hANP) concentration in patients with thyroid disorders.

In order to assess the possible involvement of thyroid hormone in alpha human atrial natriuretic peptide (alpha hANP), we investigated the plasma and urine ANP concentration in patients with primary hyperthyroidism and hypothyroidism. Plasma and urine were extracted through Sep-Pak C18 cartridges and the urine ANP concentration was corrected by urine creatinine (cre. mg/dl) and expressed as fmol/mg.cre.. The plasma ANP concentration in patients with untreated hyperthyroidism (32.3 +/- 7.0 fmol/ml; n = 22) was higher than in normal subjects (p less than 0.01 vs control; 6.2 +/- 0.7 fmol/ml). After restoration to euthyroidism, the plasma ANP concentration (patients with treated hyperthyroidism) fell to normal (8.9 +/- 1.9 fmol/ml). The plasma ANP concentration in patients with untreated hypothyroidism (14.1 +/- 3.0 fmol/ml; n = 7) was higher than normal, but in two of them there was mild renal dysfunction and an incomplete right blundle branch block in the electrocardiogram. It was possible that these factors contributed to the observed increase in plasma ANP. However, a significant positive correlation was found between plasma ANP and free thyroxine (n = 40, r = 0.449; p less than 0.01) and free triiodothyronine (n = 40, r = 0.546; p less than 0.01). The urine ANP concentration in patients with untreated hyperthyroidism was markedly higher than in normal subjects (p less than 0.01), but in untreated hypothyroidism not significantly different from normal.

Adolescent↗
PubMed1988

Circulating concentrations of immunoreactive peptide 7B2 in certain pathophysiological conditions, and response to oral glucose load.

A peptide, 7B2, originally isolated from pituitary, is present in endocrine tumors, with high concentrations in pancreatic islet tumors. Plasma from most of these patients showed very high immunoreactivity to 7B2 (IR-7B2). To assess whether or not there is any alteration in circulating 7B2 concentrations due to age, sex, etc., we measured concentrations in plasma in 96 fasting healthy subjects, ages three months to 91 years; in patients with various other conditions, including pregnancy; and in cord blood. The response of circulating IR-7B2 to oral glucose was also evaluated. We found particularly high IR-7B2 concentrations in cord blood. Postnatally the concentrations were lower and decreased gradually with age to values for adults [15.6 (SE 2.9) pmol/L], increasing again significantly (P less than 0.01) in persons older than 70 years [37.1 (SE 32) pmol/L]. There was no significant sex-related difference in values for plasma. For the pathological conditions studied, we observed significantly supranormal values in patients with chronic renal failure [175.1 (SE 35.9) pmol/L]. Some of the pregnant patients in their third trimester also showed high values. A small but significant increase in plasma IR-7B2 was observed after a glucose load, both in control subjects and diabetics. Perhaps the kidney plays a major role in 7B2 degradation.

Adolescent↗
PubMed1985

Specific epidermal growth factor receptors on porcine and human thyroid membranes.

Specific, high affinity, saturable receptors for epidermal growth factor (EGF) have been demonstrated both on porcine and on human thyroid membranes. The binding affinities of porcine (Ka 3.0 X 10(-9) M) and human thyroid EGF receptors (Ka 1.75 X 10(-9) M) are very similar. TSH does not inhibit the binding of 125I-EGF to either membrane. These results suggest the possibility that EGF may be involved in the regulation of human as well as porcine thyroid follicular cell growth and function.

Animals↗
PubMed1984

[Thyroid functions in nonthyroidal illness: specific changes in serum levels of thyroid hormones related in illness and the correlation between thyrotropin and free thyroid hormones in patients with nonthyroidal illnesses].

In order to assess the thyroid function of patients with nonthyroidal illness, 292 patients with nonthyroidal illness were employed in the present study. These patients were then subdivided into 6 groups according to their original illness. The groups consisted of patients with malignant illnesses (19 males and 10 females; mean age of 59.7 yr.), with chronic hepatitis (14 males and 8 females; mean age of 55.2 yr.), with liver cirrhosis (5 males and 6 females, mean age of 60.4 yr.), with uremia who had been receiving constant hemodialysis 2 approximately 3 times per week (52 males and 38 females; mean age of 48.1 yr.), with diabetes mellitus (50 males and 43 females; mean age of 52.3 yr.) and with cerebrovascular accident (21 males and 26 females; mean age of 74.9 yr.). In addition, 34 healthy persons (15 males and 19 females; mean age of 41.6 yr.) were also employed as controls. Because the differences between mean ages in these groups were significant, the relationship between age and thyroid function was examined. Significant positive correlations between age and total thyroxine (TT4) (r = 0.19; p less than 0.01), and reverse triiodothyronine (rT3) (r = 0.175; p less than 0.01) were found. A negative correlation was also found between age and total triiodothyronine (TT3) (r = 0.231; p less than 0.01). The serum levels of rT3 were elevated in patients with neoplasma and liver cirrhosis but significantly low in patients with uremia. These characteristic findings were correlated with the severity of each original disease such as % motarity, serum levels of cholinesterase, blood urea nitrogens and the blood sugar control in the diabetics. In these circumstances, multiple correlation analyses were performed in order to assess whether there might exist a negative feedback mechanism between thyrotropin and FT4/FT3. The highest partial correlation coefficient was obtained between thyrotropin and FT4. It might, therefore, be concluded that in patients with a nonthyroidal illness, decreased levels of serum thyroid hormones indicate not only the severity of the illness but also the supposed presence of a hypothyroid state.

Adult↗
PubMed1984

Cardiac performance and coenzyme Q10 in thyroid disorders.

To investigate the relationship between serum levels of Coenzyme Q10 and cardiac performance in thyroid disorders, we studied the cardiac performance and assessed serum levels of thyroid hormones and Coenzyme Q10 in 20 patients with hyperthyroidism, 5 patients with hypothyroidism and 10 normal subjects. A significant inverse correlation between thyroid hormones and Coenzyme Q10 levels was found by performing partial correlation analysis. Because low serum levels of Coenzyme Q10 were found in thyrotoxic patients and congestive heart failure may occur as a result of severe hyperthyroidism, 120 mg of Coenzyme Q10 was administered daily for one week to 12 hyperthyroid patients and the change in cardiac performance was assessed. Further augmentation of cardiac performance was found in hyperthyroid hearts, which were already augmented, after the administration of Coenzyme Q10. It appears, therefore, that the Coenzyme Q10 dose actually has a therapeutic value for congestive heart failure induced by severe thyrotoxicosis.

Adolescent↗
PubMed1982

[Effects of gamma-oryzanol on the hypothalamo-pituitary axis in the rat].

The effects of gamma oryzanol (gamma-OZ), a ferulic acid of triterpene alcohol, on the synthesis and release of the growth hormone (GH) and prolactin (PRL) in vitro and turnover rates of hypothalamic catecholamines were investigated. A single subcutaneous injection of 20 mg/kg of gamma-OZ suppressed GH synthesis and PRL release 1 hour after the injection. gamma-OZ increased medial basal hypothalamic (MBH) dopamine (DA) content, and the DA content was decreased by a treatment of alpha-methyl-p-tyrosine (alpha MpT), a tyrosine hydroxylase inhibitor, indicating increased synthesis and release of DA in MBH by gamma-OZ. gamma-OZ did not alter norepinephrine (NE) content in MBH, while the NE content was significantly decreased, indicating unchanged synthesis and increased release of NE in MBH by gamma-OZ. These results may explain the previous data concerning the changes in serum levels of GH and PRL by gamma-OZ and also suggest that gamma-OZ can affect the synthesis and/or release of at least two hypothalamic neurotransmitters, DA and NE, resulting in the alterations of anterior pituitary hormone synthesis and/or release.

Animals↗