Search Results

You are looking at 1 - 9 of 9 items for

  • Author: K. Ando x
  • Refine by access: All content x
Clear All Modify Search
Y. Takei
Search for other papers by Y. Takei in
Google Scholar
PubMed
Close
,
K. Ando
Search for other papers by K. Ando in
Google Scholar
PubMed
Close
, and
M. Kawakami
Search for other papers by M. Kawakami in
Google Scholar
PubMed
Close

ABSTRACT

A highly specific and sensitive radioimmunoassay has been developed for the measurement of eel atrial natriuretic peptide (ANP). The antiserum, raised against eel ANP-(1–27) did not cross-react with two other eel natriuretic peptides, i.e. eel ventricular natriuretic peptide and C-type natriuretic peptide (CNP), or with any mammalian ANPs, CNPs or brain natriuretic peptides so far identified. The minimal detectable amount was 0·39 fmol (0·90 pg)/tube with more than 99% confidence. Because of its high sensitivity, the radioimmunoassay makes it possible to measure eel ANP directly with only a few microlitres of plasma without extraction.

Using the radioimmunoassay we found high levels of ANP in the atrium (11 ± 2 pmol/mg wet tissue, n = 8), and much lower levels in the ventricle (56 ±8 fmol/mg, n=8) and the brain (22±1 fmol/mg, n = 8) of eels. Eel plasma contained a large amount of ANP (247 ± 66 fmol/ml, n= 8) compared with the levels reported in mammals, although atrial levels are similar between eels and mammals.

Gel-permeation chromography revealed that a major form of ANP stored in the eel atrium, ventricle and brain has a molecular mass of approximately 14 kDa but low molecular forms of about 3 kDa are predominant in eel plasma. A detailed analysis with reverse-phase high-performance liquid chromatography showed that a major molecular form circulating in eel plasma is ANP-(1–27). ANP-(1–27) was also detected in small amounts in the eel atrium, ventricle and brain.

Journal of Endocrinology (1992) 135, 325–331

Restricted access
F. Marumo
Search for other papers by F. Marumo in
Google Scholar
PubMed
Close
,
T. Masuda
Search for other papers by T. Masuda in
Google Scholar
PubMed
Close
,
Y. Masaki
Search for other papers by Y. Masaki in
Google Scholar
PubMed
Close
, and
K. Ando
Search for other papers by K. Ando in
Google Scholar
PubMed
Close

ABSTRACT

The presence of atrial natriuretic peptide (ANP) in canine cerebrospinal fluid (CSF) was clearly demonstrated and an attempt was made to determine its origin as either the brain or the atrium. The concentration of ANP in canine CSF was 0·78 ±0·37 pmol/l (n = 31) and showed no evident correlation with that in plasma (r =0·12). Physiological doses of human α-ANP (α-hANP) were continuously infused intravenously into nine dogs, and ANP concentrations in CSF and plasma were examined six to eight times within a 120-min period following this. The ANP level in CSF was not influenced by the systemic administration of α-hANP up to 180 min. Only one low molecular weight peak corresponding to α-hANP could be obtained from the CSF samples, while both low and high molecular weight peaks were observed for plasma ANP by gel permeation chromatography. In the atrial and hypothalamic tissue extracts the same kinds of peaks were also evident.

These results prove the presence of ANP in canine CSF and that it does not come from blood that has seeped across the blood–CSF barriers, but suggest that it may originate from the brain.

J. Endocr. (1988) 119, 127–131

Restricted access
Y Takei
Search for other papers by Y Takei in
Google Scholar
PubMed
Close
,
A Takahashi
Search for other papers by A Takahashi in
Google Scholar
PubMed
Close
,
T X Watanabe
Search for other papers by T X Watanabe in
Google Scholar
PubMed
Close
,
K Nakajima
Search for other papers by K Nakajima in
Google Scholar
PubMed
Close
, and
K Ando
Search for other papers by K Ando in
Google Scholar
PubMed
Close

Abstract

Ventricular natriuretic peptide (VNP) with 25 amino acid residues was isolated from the low molecular weight fraction of acid extracts of eel cardiac ventricles. No other short forms of VNP were recovered from the fraction. This peptide was named eel VNP(1–25) because it was a C-terminally truncated form of the previously isolated eel VNP(1–36) As observed before with eel VNP(1–36), eel VNP(1–25) had a much higher (146-fold) vasodepressor activity than human atrial natriuretic peptide (ANP) in eels, but was a third to a half as active in rats with respect to vasodepressor and natriuretic activities. Eel VNP(1–25) was generally less potent than eel VNP(1–36) for vasodepressor and natriuretic effects.

A specific radioimmunoassay (RIA) has been developed for the measurement of eel VNP. The antiserum, raised against eel VNP(1–36), was highly specific and did not exhibit significant cross-reactivity with eel ANP and C-type natriuretic peptide, even though their amino acid sequences have more than 60% homology with that of eel VNP. The sensitivity of assay was 0·5 fmol/tube for eel VNP(1–36) with more than 99% confidence. Such high sensitivity permitted direct assaying of VNP with only a few microlitres of plasma.

In fresh water eels, the concentration of VNP in the cardiac ventricle was higher than those in the atrium or brain and that of ANP in the ventricle. Thus, VNP seems to be a ventricular hormone. Although ANP is a major circulating hormone in mammals, the plasma concentration of VNP was threefold higher than that of ANP. The RIA coupled with gel-permeation chromatography revealed that a 14 kDa form, probably proVNP, and smaller forms (3–6 kDa) circulate in eel plasma. Reversephase high performance liquid chromatography identified both VNP(1–36) and VNP(1–25) in eel plasma; VNP(1–36) appeared to be a major form.

Journal of Endocrinology (1994) 141, 81–89

Restricted access
M. Shichiri
Search for other papers by M. Shichiri in
Google Scholar
PubMed
Close
,
N. Miyasaka
Search for other papers by N. Miyasaka in
Google Scholar
PubMed
Close
,
Y. Hirata
Search for other papers by Y. Hirata in
Google Scholar
PubMed
Close
,
K. Ando
Search for other papers by K. Ando in
Google Scholar
PubMed
Close
, and
F. Marumo
Search for other papers by F. Marumo in
Google Scholar
PubMed
Close

ABSTRACT

To elucidate the circulating forms of human atrial natriuretic peptide (hANP) in collagen disease, we analysed plasma samples obtained from 21 patients with systemic lupus erythematosus, rheumatoid arthritis or progressive systemic sclerosis with no clinical evidence of cardiac involvement. The findings were compared with those obtained from 21 healthy control subjects. Plasma hANP-like immunoreactivity was normal in all but three of the controls and in two patients with the nephrotic syndrome due to lupus nephritis. Reverse-phase high-performance liquid chromatography, gel permeation chromatography and subsequent radioimmunoassay for hANP revealed that the circulating hANP consisted of α-hANP, β-hANP and γ-hANP in the patients with collagen disease whereas α-hANP predominated in the control group. β-hANP appeared in 18 of the 21 patients but was not observed in the controls. These data suggest that β-hANP circulates in the plasma of patients with collagen disease even when no myocardial involvement is apparent and that the appearance of β-hANP is not always associated with an increase in total plasma hANP-like immunoreactivity. Thus the appearance of β-hANP in plasma is not a phenomenon specific to congestive heart failure.

Journal of Endocrinology (1991) 130, 159–161

Restricted access
F. Marumo
Search for other papers by F. Marumo in
Google Scholar
PubMed
Close
,
O. Matsubara
Search for other papers by O. Matsubara in
Google Scholar
PubMed
Close
,
Y. Masaki
Search for other papers by Y. Masaki in
Google Scholar
PubMed
Close
,
K. Togashi
Search for other papers by K. Togashi in
Google Scholar
PubMed
Close
,
K. Ando
Search for other papers by K. Ando in
Google Scholar
PubMed
Close
, and
N. Hasegawa
Search for other papers by N. Hasegawa in
Google Scholar
PubMed
Close

ABSTRACT

Brain natriuretic peptide (BNP) is a novel peptide that has actions similar to atrial natriuretic peptide (ANP). The present study investigated BNP localization in the heart, ANP and BNP contents in several organs, and ANP and BNP clearance through these organs. In the morphological study, it was shown that porcine BNP-like immunoreactivity was mainly distributed in the granules of the atrium. The content of porcine BNP-like immunoreactivity in the atrium was extremely high, about 100-fold greater than in the ventricle. From the determination of porcine BNP and ANP contents of such organs as the heart, kidney and liver and also plasma, it was shown that porcine BNP concentration was approximately one order of magnitude lower than that of ANP, and clearance rates of ANP and porcine BNP from these organs were similar and not significantly different between the organs. These results suggest that the modes of secretion and degradation of porcine BNP are not the same as those of ANP.

Journal of Endocrinology (1992) 132, 101–106

Restricted access
N. Takemura
Search for other papers by N. Takemura in
Google Scholar
PubMed
Close
,
H. Koyama
Search for other papers by H. Koyama in
Google Scholar
PubMed
Close
,
T. Sako
Search for other papers by T. Sako in
Google Scholar
PubMed
Close
,
K. Ando
Search for other papers by K. Ando in
Google Scholar
PubMed
Close
,
S. Motoyoshi
Search for other papers by S. Motoyoshi in
Google Scholar
PubMed
Close
, and
F. Marumo
Search for other papers by F. Marumo in
Google Scholar
PubMed
Close

ABSTRACT

The present study describes the concentration and molecular form of atrial natriuretic peptide (ANP) in Holstein dairy cattle with mild (bacterial endocarditis; BEC) or severe (dilated cardiomyopathy; DCM) heart failure. Significant increases in plasma concentration of ANP were observed in cattle with DCM (73·3 ± 16·02 pmol/l, n=4, P<0·01) and BEC (20·6± 3·45 pmol/l, n=7, P<0·05), when compared with those in control cattle (14·5± 1·84 pmol/l, n= 12). The concentration of ANP in cattle with DCM was significantly (P<0·01) higher compared with that in cattle with BEC. Plasma concentration of ANP correlated significantly with right atrial pressure (r =0·95, P<0·01) and left ventricular end-diastolic pressure (r= 0·84, P<0·01). Gel-permeation chromatography of ANP in plasma and the right atrium from control and cattle with BEC revealed a single peak corresponding to the elution position of authentic human ANP(99–126) in plasma, and two peaks corresponding to those of authentic human ANP(99–126) and pro-ANP in the atrial extract. In cattle with DCM, however, peaks corresponding to the elution positions of authentic human β-ANP and/or pro-ANP were detected in addition to the peak corresponding to ANP(99–126). The content of ANP in the right atrium of cattle with DCM was significantly (P<0·05) increased compared with that in control cattle and those with BEC. The present study therefore suggests that the synthesis and secretion of ANP might be stimulated by atrial distention induced by increased atrial pressure. This suggestion is supported by the fact that the middle molecular weight form of ANP, possibly corresponding to human β-ANP, was detected in both the plasma and atria of the cattle with severe heart failure.

Journal of Endocrinology (1990) 124, 463–467

Restricted access
T Agustsson
Search for other papers by T Agustsson in
Google Scholar
PubMed
Close
,
K Sundell
Search for other papers by K Sundell in
Google Scholar
PubMed
Close
,
T Sakamoto
Search for other papers by T Sakamoto in
Google Scholar
PubMed
Close
,
V Johansson
Search for other papers by V Johansson in
Google Scholar
PubMed
Close
,
M Ando
Search for other papers by M Ando in
Google Scholar
PubMed
Close
, and
B Th Bjornsson
Search for other papers by B Th Bjornsson in
Google Scholar
PubMed
Close

A number of studies on the Atlantic salmon (Salmo salar), have reported changes in plasma GH during parr-smolt transformation, but there is a lack of information about the endocrinology of the GH system during this process. In order to elucidate the mechanisms underlying these changes in plasma GH levels during the parr-smolt transformation of Atlantic salmon, GH mRNA expression in the pituitary was studied together with total pituitary GH content, in vitro GH secretion rate and plasma GH and IGF-I levels. Atlantic salmon were kept in outside tanks, under natural condition from early February until late June. Approximately three times a month fish were killed and pituitaries and blood were sampled for investigation. Further, pituitaries were moved to the laboratory for in vitro GH secretion studies. The results show that the GH system is first activated by an increase in GH secretion rate, which leads to an increase in plasma GH levels and causes a drop in the total GH content of the pituitary. This drop in pituitary GH content is later reversed by an increased GH synthesis seen as an increase in GH mRNA expression. Maximal activation of the GH system is seen to occur in early May, when plasma IGF-I levels reach highest levels, after which a certain deactivation of the GH system takes place. The data show that plasma levels of GH are to a large extent regulated by the secretion rate from the pituitary, although changes in the GH clearance rate are also likely to take place and influence the plasma GH levels. The study further underlines the significant role that the GH-IGF-I axis plays in the parr-smolt transformation of the Atlantic salmon.

Free access
S Ando
Search for other papers by S Ando in
Google Scholar
PubMed
Close
,
H Nakamura
Search for other papers by H Nakamura in
Google Scholar
PubMed
Close
,
S Sasaki
Search for other papers by S Sasaki in
Google Scholar
PubMed
Close
,
K Nishiyama
Search for other papers by K Nishiyama in
Google Scholar
PubMed
Close
,
A Kitahara
Search for other papers by A Kitahara in
Google Scholar
PubMed
Close
,
S Nagasawa
Search for other papers by S Nagasawa in
Google Scholar
PubMed
Close
,
T Mikami
Search for other papers by T Mikami in
Google Scholar
PubMed
Close
,
H Natsume
Search for other papers by H Natsume in
Google Scholar
PubMed
Close
,
R Genma
Search for other papers by R Genma in
Google Scholar
PubMed
Close
, and
T Yoshimi
Search for other papers by T Yoshimi in
Google Scholar
PubMed
Close

Abstract

Clinical resistance to thyroid hormone (RTH) has been classified into generalized resistance to thyroid hormone (GRTH) and pituitary resistance to thyroid hormone (PRTH) types. Since similar mutations have been identified in tri-iodothyronine (T3) receptor (TR) β gene in GRTH and PRTH, and since considerable overlap has been seen in the clinical manifestations in patients with GRTH and PRTH, two subtypes of RTH are now considered to be a continuous spectrum with the same genetic defect. A point mutation at amino acid Arg 338 to Trp (R338W) which we identified in a patient with PRTH is very interesting, since R338W has been found in several other patients with PRTH, raising the possibility that this mutation may tend to associate with a phenotype of PRTH.

In our previous study, we found that R338W had relatively less impaired transcriptional potency, weaker dominant negative activity on various T3 response elements and poor homodimer formation, as compared with another GRTH mutant. In this study, to investigate the functional properties of R338W further, especially in terms of the relation between transcriptional activity and dimer formations, we introduced the R338W mutation into the mutant receptors, K443E and F451X, constructing the double mutants, R338W/K443E and R338W/F451X. Both R338W/K443E and R338W/F451X showed negligible T3 binding and transcriptional activities. The dominant negative activities of K443E and F451X were, however, significantly weakened by introducing the R338W mutation. As a control, a double mutant G345R/K443E was constructed by introducing a point mutation, G345R, located in the same exon 9 as R338W, into the K443E mutant. Dominant negative activity did not differ between G345R/K443E and K443E. Homodimer formation was significantly reduced in the double mutants containing R338W, but not G345R.

In summary, introducing the R338W mutation, but not G345R, into the mutant TR significantly weakened the dominant negative activity, despite further impairment of the T3 binding and transcriptional activities.

Journal of Endocrinology (1996) 151, 293–300

Restricted access
Y Wang
Search for other papers by Y Wang in
Google Scholar
PubMed
Close
,
T Yano
Search for other papers by T Yano in
Google Scholar
PubMed
Close
,
A Kikuchi
Search for other papers by A Kikuchi in
Google Scholar
PubMed
Close
,
N Yano
Search for other papers by N Yano in
Google Scholar
PubMed
Close
,
H Matsumi
Search for other papers by H Matsumi in
Google Scholar
PubMed
Close
,
K Ando
Search for other papers by K Ando in
Google Scholar
PubMed
Close
,
Y Kasai
Search for other papers by Y Kasai in
Google Scholar
PubMed
Close
,
M Watanabe
Search for other papers by M Watanabe in
Google Scholar
PubMed
Close
,
R Okagaki
Search for other papers by R Okagaki in
Google Scholar
PubMed
Close
,
Y Osuga
Search for other papers by Y Osuga in
Google Scholar
PubMed
Close
, and
Y Taketani
Search for other papers by Y Taketani in
Google Scholar
PubMed
Close

The hypoestrogenic state induced by gonadotrophin-releasing hormone agonist (GnRHa) has been shown to be effective in the treatment of oestrogen-dependent disorders but to induce bone loss. Adding back low doses of oestrogen in GnRHa therapy has been proposed to prevent bone loss. The purpose of this study is to assess the efficacy of add-back therapy with different natural oestrogens such as oestrone (OE(1)), oestradiol (OE(2)) and oestriol (OE(3)). Three-month-old female rats (250 g) were subcutaneously administered microcapsules of leuprorelin acetate in doses of 1 mg/kg of body weight every 4 weeks. GnRHa therapy lasted 16 weeks, and pellets of OE(1), OE(2) or OE(3) (0.5 mg/pellet, 60 day release), as an add-back agent, were implanted at 8 weeks of treatment. At the end of treatment, GnRHa alone decreased bone mineral density of the femur and lumbar vertebrae, and increased serum levels of bone metabolic markers such as alkaline phosphatase and osteocalcin levels. As for cancellous bone histomorphometry, GnRHa decreased bone volume while it increased osteoid volume, osteoid surface, eroded surface, mineral apposition rate and bone formation rate. All the oestrogens tested prevented these changes caused by GnRHa therapy. GnRHa induced a significant increase in body weight and a marked reduction in uterine weight, which was not observed in OE(1) or OE(2) add-back group. Body weight and uterine weight of the OE(3) add-back group were the same as those of the GnRHa group. These findings indicate that GnRHa induces high turnover bone loss which can be prevented by concomitant administration of natural oestrogens such as OE(1), OE(2) and OE(3) to the same extent. In addition, OE(3) is unique in that it is much less effective than OE(1) and OE(2) in blocking body weight gain and in promoting growth of uterine tissues. Because of its tissue-selective actions, OE(3) could be considered as one of the most appropriate oestrogens used for GnRHa add-back therapy.

Free access