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Naoki Hattori, Akira Shimatsu, Chutaro Yamanaka, Toru Momoi and Hiroo Imura

Abstract. Nocturnal urinary growth hormone levels in children with short and normal stature were measured by a sensitive enzyme immunoassay. Urinary GH excretion during sleep correlated positively with peak plasma GH values during pharmacological (r = 0.74, P < 0.001) and sleep (r = 0.85, P < 0.001) tests. The amounts of urinary GH excretion during sleep differed significantly from each other in the following groups: complete GH deficiency (mean ± sem: 0.1 ± 0.1 ng/m2 of body surface area; range: < 0.1–0.4), partial GH deficiency (1.6 ± 0.3 ng/m2; 0.2–3.1), and short stature without GH deficiency (3.7 ± 0.6 ng/m2; 0.7–11.5). No significant difference was found between short stature without GH deficiency and normal stature (5.0 ± 0.5 ng/m2; 2.1 – 10.5). Measurement of nocturnal urinary GH excretion is a simple method for screening of GH excretion and may be helpful in the differentiation of the various etiologies of short stature in children.

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Kiyoshi Kikuchi, Masayuki Kaji, Toru Momoi, Haruki Mikawa, Yosuke Shigematsu and Masakatsu Sudo

Abstract. To elucidate the mechanism of hypogonadotropic hypogonadism in a patient with X-linked congenital adrenal hypoplasia, we studied the effects on serum LH and FSH of repeated iv administration of GnRH (400 μg, over 2 h, once a day, for 14 consecutive days), pulsatile sc administration of GnRH (5 μg every 90 min during days 1 ~ 56, 10 μg every 90 min during days 57 ~ 91) and an iv bolus injection of 10 mg of naloxone. The repeated administration of GnRH restored the hyporesponsiveness of serum FSH and increased serum testosterone level from < 1.0 to 1.7 nmol/l, but the impaired LH response to the standard GnRH test was not improved. The pulsatile administration of GnRH for 91 consecutive days did not induce a clinical or a biochemical change of puberty. Serum testosterone remained undetectable < 1.0 nmol/l, the hyporesponsiveness of serum LH was not improved, but basal FSH level was significantly increased and the impaired FSH response to the standard GnRH test was slightly improved. Naloxone had no effect on serum LH or FSH before or during the pulsatile administration. We conclude that hypogonadotropic hypogonadism in our patient is due to the pituitary dysfunction and that the endogenous opioid peptides may not play a role in the mechanism of inhibited gonadotropin secretions.

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Chutaro Yamanaka, Toru Momoi, Ichiro Fujisawa, Kiyoshi Kikuchi, Masayuki Kaji, Tohru Yorifuji, Hiroshi Sasaki, Masakatsu Sudo, Junji Konishi and Haruki Mikawa

Abstract.

We studied the neurohypophyseal function of 20 patients with complete GH deficiency owing to pituitary stalk transection by means of the water deprivation and the hypertonic saline infusion test. In TI-weighted magnetic resonance images, high-signal intensity of the posterior lobe of the hypophysis was missing in all the patients. An ectopic posterior lobe was observed at the proximal stump of the transected stalk in 17 patients, whereas the 3 patients without ectopic posterior lobe had overt diabetes insipidus or intractable nocturnal enuresis. After water deprivation, 3 patients with large ectopic posterior lobes (length along the pituitary stalk axis exceeding 5 mm) showed urinary osmolality and plasma AVP levels as high as those of 13 patients with partial GH deficiency in whom magnetic resonance images revealed no abnormalities. On the other hand, 14 patients with small ectopic posterior lobes (length less than 5 mm) showed significantly lower urinary osmolality and plasma AVP levels than the patients with large ectopic posterior lobes (p<0.01 and p<0.01, respectively) and the patients with partial GH deficiency (p<0.01 and p<0.01, respectively). Urinary osmolality in the patients with small ectopic posterior lobes, however, was higher than that in 3 patients without ectopic posterior lobes (p<0.01). During the hypertonic saline infusion test, peak plasma AVP levels in the patients with small ectopic posterior lobes were significantly lower than those in the patients with partial GH deficiency (p<0.01). These findings suggest that the remaining neurohypophyseal function in patients with transected pituitary stalk correlates with the size of the ectopic posterior lobe, and that partial diabetes insipidus may be the diagnosis in some of the patients with small ectopic posterior lobes.