Masateru Nishiki

Serum antibodies to human pituitary membrane antigens in patients with autoimmune lymphocytic hypophysitis and infundibuloneurohypophysitis

Serum antipituitary antibodies were investigated by the immunoblotting method using human anterior pituitary membrane preparation as the antigen.

Pituitary adenylate cyclase activating polypeptide (PACAP) stimulates growth hormone release from GH3 cells through type II PACAP receptor

Effect of pituitary adenylate cyclase activating polypeptide (PACAP) on growth hormone (GH) release from GH3 cells was studied in a dynamic superfusion system. PACAP-38 and PACAP-27 stimulated GH release from superfused GH3 cells. The stimulatory effect of PACAP-38 was comparable to those of vasoactive intestinal polypeptide (VIP) and PACAP-27 at a concentration of 1 nM, but the duration of action was more prolonged in PACAP-38 than in the other two peptides. PACAP(6-38), a selective antagonist of PACAP, as well as a VIP antagonist blunted the GH release induced by PACAP-38 and VIP. An antagonist of GH-releasing factor (GRF) at a concentration of 1 microM, however, did not affect the GH release induced by PACAP-38. These findings suggest that PACAP and VIP stimulate GH release from GH3 cells through type II PACAP receptor but not through the GRF receptors.

Possible involvement of vasoactive intestinal polypeptide in the central stimulating action of pituitary adenylate cyclase-activating polypeptide on prolactin secretion in the rat

Effect of pituitary adenylate cyclase-activating polypeptide (PACAP) on prolactin (PRL) secretion was studied in Wistar strain male rats in vivo. Intravenous injection of PACAP-38 and PACAP-27 resulted in a dose-related increase in plasma PRL levels both in conscious rats and in urethane-anesthetized rats. In anesthetized animals, i.c.v. injection of PACAP-38 and PACAP-27 also elicited a dose-related increase in plasma PRL. The PRL secretion induced by i.c.v. injection of PACAP-38 was attenuated by pretreatment with rabbit antiserum to vasoactive intestinal polypeptide (VIP). These findings suggest that PACAPs stimulate PRL secretion in the rat by acting not only directly on the pituitary but also indirectly through the central nervous system, at least partly, via hypothalamic VIP.

MPO-ANCA-positive IgA nephropathy successfully treated with tonsillectomy

A 20-year-old Japanese woman was admitted to a hospital because of gross hematuria. She was diagnosed with IgA nephropathy with a poor prognosis, based on the formation of many crescents in the glomerulus and monocyte infiltration in the interstitium in a renal biopsy specimen in February 2003. Myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA) was not identified at that time. After treatment with high-dose steroid pulse therapy and heparin/warfarin, her urinary protein improved, to 0.5 g/day. However, 1 year after the steroid pulse therapy, urinary protein was increased to 1.2 g/day, associated with repeated episodes of tonsillitis. A second renal biopsy was performed, and showed an improving tendency, compared to the findings of the previous one, although some crescent formation and adhesions of Bowmans capsule remained. Interestingly, MPO-ANCA was positive in the serological examination done at this time. One month and a half after the second renal biopsy, she had a tonsillectomy, followed by a regimen of 5 mg oral prednisolone daily, in order to prevent the progression of IgA nephropathy. After the tonsillectomy, her urinary protein level was markedly improved, at 0.14 g/day. Her creatinine clearance was ameliorated, at 102 ml/min, and in addition, MPO-ANCA had disappeared. This case suggests that an inflammation such as tonsillitis may be associated not only with the activity of IgA nephropathy but also with the production of MPO-ANCA.

Effects of rat galanin and galanin message associated peptide (GMAP) on rat growth hormone secretion and stimulating effect of γ-aminobutyric acid on galanin release from rat hypothalamus

Immunoreactive galanin and galanin message associated peptide (GMAP) were detectable in rat hypothalamus in the concentration of 563 +/- 23 and 14.3 +/- 3.1 fmol/hypothalamus, respectively. gamma-Aminobutyric acid (GABA) elicited a dose-related increase in galanin release from rat hypothalamic fragments, which was inhibited by picrotoxin, a GABA antagonist. Growth hormone (GH) secretion from rat anterior pituitary cells were stimulated by rat galanin, but not by GMAP. These findings suggest that hypothalamic galanin, but not GMAP, may play roles in GH secretion induced by GABAergic mechanisms in the rat.

Expression of hypothalamic corticotropin-releasing hormone-like immunoreactivity in isolated ACTH deficiency: A report of an autopsied case

A 77-yr-old man died of metastising adenocarcinoma of the lung. He had been treated with hydrocortisone for isolated ACTH deficiency for 9 yr. At autopsy, the pituitary and the adrenal glands were atrophic. Lymphocyte infiltration was not observed in the pituitary, the adrenal and the thyroid glands. Immunohistochemistry revealed selective loss of ACTH-like immunoreactivity in the pituitary gland whereas CRH-immunoreactive cells were found in the paraventricular nucleus of the hypothalamus. This is the first report demonstrating immunohistochemical examinations of the pituitary and the hypothalamus in isolated ACTH deficiency.