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Biomedical subjects

T Ofuji

Publications and source records attributed to T Ofuji.

At least 73 records · Page 4Linked to original sources

Anaphylactic shock after synthetic adrenocorticotropin-(1-18) in a patient with isolated adrenocorticotropin and beta-lipotropin deficiency.

A 58-yr-old woman had frequent hypoglycemic attacks, undetectable levels of plasma cortisol, ACTH, and beta-lipotropin, and deficient responses of these hormones after insulin induced-hypoglycemia and metyrapone. Her GH responses to arginine infusion were normal as were her gonadotropin responses to LRH. Her TSH and PRL responses to TRH were abnormally high. Anaphylactic shock occurred after the injection of either synthetic ACTH-Z-(1-24) (Cortrosin-Z) or ACTH-(1-18) (Acthormone). She had received two prior injections of synthetic ACTH-Z-(1-24) 2 months earlier. Circulating anti-ACTH antibody was found in her plasma by radioimmunological methods, but this antibody did not prevent corticosterone production by ACTH in an in vitro ACTH bioassay system. The pathogenic significance of this antibody in the ACTH deficiency is doubtful, and the etiology of the isolated ACTH and beta-LPH deficiency is not clear.

Adrenocorticotropic Hormone↗

Changes in the molecular sieve of glomerular basement membrane in rats with aminonucleoside nephrosis.

Isolated and purified glomerular basement membranes (GBM) of normal and aminonucleoside (PAN) nephrosis rats were observed by electron microscopy after negative staining. Although GBM of normal rats appeared as a molecular sieve with uniform pores, GBM of nephrotic rats showed enlargement and elongation of the pores. For an average of fifty pores, the long dimension was 40.4+/-10.7 A and the short dimension 13.8+/-3.6 A in nephrosis whereas the long dimension was 12.3+/-2.5 A and the short dimension 8.4+/-1.0 A in normal rats. Changes in the pores in GBM were thought to result in increased permeability of serum protein and hence proteinuria.

Animals↗

[Factor(s) controlling the secretion of adrenocorticotropin (ACTH) in peripheral plasma (author's transl)].

The factor(s) controlling the secretion of ACTH in peripheral plasma are not well known. The effects of non-extracted and extracted plasma on ACTH secretion were investigated using rat anterior pituitary cell cultures. Medium ACTH was assayed by radioimmunoassay, and the corticotropin releasing activity (CRA) was expressed as ACTH released. One hundred ul of non-extracted plasma showed significant CRA, whereas greater volumes of plasma showed reduced activity. Non-extracted plasma (250 approximately 500 microliter) rather reduced the secretion of ACTH evoked by hypothalamic extract (HE). When plasma was extracted with 0.2 N-acetic acid-acetone and divided into an acid phase and an acetone-ether phase by adding ether, the CRA was recovered in the acid phase while no significant activity was observed in the acetone-ether phase. The acid phase extract of plasma showed a positive dose-response relationship between the amount of plasma extract (50 approximately 800 microliter plasma equivalent) and ACTH release in pituitary cell cultures. The organic phase of plasma extract inhibited HE-induced release of ACTH, and this ACTH-release inhibiting activity was presumed to be corticosterone. When the acid phase extract of 20 ml plasma was applied to a Sephadex G-25 (fine) and eluted with 0.2 N acetic acid, two peaks of CRA were observed. One eluted in the region of void volume and another eluted in the retarded region where no activity was found in chromatography of HE. HE increased both ACTH and cyclic AMP release, but the plasma extract reduced cyclic AMP release. These results suggest that plasma contains both CRA and ACTH release inhibiting activity which can be extracted separately, and that plasma CRA is different from the hypothalamic corticotropin releasing factor.

Adrenocorticotropic Hormone↗

ACTH release in pituitary cell cultures. Effect of neurogenic peptides and neurotransmitter substances on ACTH release induced by hypothalamic corticotropin releasing factor (CRF).

The effects of various neurogenic peptides and neurotransmitter substances on the release of ACTH induced by hypothalamic corticotropin releasing factor (HY-CRF) were investigated using monolayer cultured anterior pituitary cells. Test substances were given in combination with 0.05-0.1 hypothalamic extract (HE)/ml, because HE evoked a significant ACTH release and a linear dose response relationship was demonstrated sequentially between 0.0165 HE/ml and 0.5 HE/ml. Relative high doses of lysine-vasopressin showed a slight additive effect on the release of ACTH induced by 0.1 HE/ml. Leu-enkephalin, dopamine, prostaglandin E1 and E2 slightly reduced the release of ACTH induced by HY-CRF, but the inhibitory effect of these substances were not dose-related. Other tested substances including luteinizing hormone releasing hormone, thyrotropin releasing hormone, somatostatin, melanocyte stimulating hormone release inhibiting factor, beta-endorphin, neurotensin, substance P, vasoactive intestinal polypeptide, angiotensin II, norepinephrine, serotonin, acetylcholine, histamine and gamma-amino butyric acid showed neither agonistic nor antagonistic effect on the release of ACTH induced by HY-CRF. These results indicate that the release of ACTH is controlled specifically by HY-CRF and corticosterone, and modified slightly by some other substances such as vasopressin and prostaglandins, and that the effect of most other neurogenic peptides and neurotransmitter substances is negligible or non-physiological at the pituitary level.

Adrenocorticotropic Hormone↗