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Biomedical subjects

I Oshima

Publications and source records attributed to I Oshima.

At least 73 records · Page 4Linked to original sources
PubMed1983

[Hypothalamic-pituitary-ovarian function in puerperal women].

Hypothalamic-pituitary-ovarian function in women during the first month postpartum has been studied. The plasma LH-RH level in puerperal women was very low on days 5 and 10 postpartum and thereafter increased, but was still significantly lower on day 30 postpartum than that in eumenorrheic women on day 8 or 9 of the normal cycle. Serum FSH reached a very low level on days 5 and 11 postpartum, then gradually increased to a slightly higher level on day 30 postpartum than that in eumenorrheic women. The serum estradiol level fell immediately after delivery and remained low until day 30 postpartum. No response of serum FSH or LH to LH-RH was found on day 11 postpartum. However, daily injections of LH-RH from days 5 through 10 postpartum caused an increased secretion in FSH on day 11 postpartum, both basally and in response to LH-RH. On day 20 postpartum, serum FSH responded excessively to LH-RH in all women, but the response in serum LH was restored in a half of them. The mean basal level of serum FSH was significantly higher in cases demonstrating the response in serum FSH and LH than that in cases demonstrating the response in only serum FSH. Serum FSH and LH showed excess and normal responses respectively to LH-RH on day 30 postpartum. It is concluded that hypothalamic secretion of LH-RH decreases during the first month postpartum, especially for the first 10 days, and the low basal level of serum FSH and unresponsiveness of the pituitary to LH-RH observed in the early puerperium may result from hypothalamic hypofunction.

Adult↗
PubMed1981

Distribution volume, metabolic clearance and plasma half disappearance time of exogenous luteinizing hormone releasing hormone in normal women and women with obesity and anorexia nervosa.

Synthetic LRH was infused into normal women and women with obesity and anorexia nervosa to determine the distribution volume (DV), metabolic clearance rate (MCR) and half disappearance time (t 1/2) of plasma LRH. In normal women, the DV of LRH ws 12.1 +/- 0.9 (mean +/- SE) 1, the MCR was 1478.9 +/- 39.8 ml/min (28.5 +/- 1.2 ml/min/kg body weight) and the initial t 1/2 was 5.6 +/- 0.4 min. In obese patients the DV (20.6 +/- 1.5 l) was significantly higher than that in normal subjects (P < 0.005), but the MCR and t 1/2 were not significantly different from those in normal subjects. In patients with anorexia nervosa the DV and MCR were 6.5 +/- 1.1 l and 621.8 +/- 110.5 ml/min (17.9 +/- 2.4 ml/min/kg body weight), respectively, which were both significantly lower than those in normal subjects (P < 0.02), while the t 1/2 (7.3 +/- 0.1 min) was longer than in normal subjects (P < 0.02). These data suggest that 1) the abnormal responses of some hormones to provocation tests observed in obese patients and patients with anorexia nervosa should be evaluated in consideration of changes in the DV and metabolic clearance of hormones in these conditions, and 2) in patients with anorexia nervosa changes in MCR and t 1/2 may reflect low metabolism of LRH.

Adult↗
PubMed1980

Regulation of motilin secretion in the postprandial state in man.

The effect of various nutrients and hormones on motilin release was examined in normal volunteers and postvagotomy patients to investigate the mechanism of motilin secretion in the postprandial state. The ingestion of a mixed meal, protein and fat elevated the plasma motilin level, but the oral glucose load and arginine infusion lowered it. Although gastrin infusion showed no effect on the plasma motilin concentration, the infusion of insulin or glucagon inhibited motilin release in vivo. The patients, who underwent a selective or truncal vagotomy, also revealed a rise in plasma motilin after meal ingestion, suggesting that motilin could be released even in the absence of gastric acid and vagal stimulus. The perifusion experiments demonstrated that motilin release from human duodenal mucosa into the perfusate was stimulated markedly by low pH and 15 mM taurocholate, but not affected by the perifusion of 20 mM glucose, 20 mM arginine, 100 mU/l insulin or 30 nM glucagon. These results indicate that the motilin release induced by meal ingestion depend upon the balance of food components and that in normal subjects duodenal acidification, bile acid and unknown factors contained in the mixed meal may participate at least in part in postprandial motilin release. The inhibitory effect of glucose on motilin release may be attributable to a certain mediator mechanism which remains to be studied.

Adult↗
PubMed1979

[Endocrine function before and after treatment in patients with anorexia nervosa (author's transl)].

In order to investigate changes in endocrine function, various tests were performed on eleven patients with anorexia nervosa. In two of them, endocrine function before and after treatment was also studied. The responses of plasma LH and FSH to LH-RH were decreased in the patients as were plasma LH-RH, and LH and FSH responses to the oral administration of clomiphene citrate. In more than half of the cases, plasma TSH showed a delayed response to TRH. The basal levels of plasma GH were elevated, and plasma GH responses to hypoglycemia or 1-arginine were lowered in half of the patients. Plasma GH showed a paradoxical rise after glucose load in three out of six cases. Plasma IRI responses to 1-arginine load were decreased in some cases, but plasma IRG responses to 1-arginine were rather excessive. Plasma IRI after glucose load showed low or delayed responses in most of the cases. After the body weight was increased to normal levels by the treatment, pituitary and pancreatic endocrine functions were normalized. These findings indicate that hypothalamic function is primarily impaired in this disease and causes nutritional disorder followed by the dysfunction of some endocrine organs. Such a possibility could be supported by the improvement of endocrine function after body weight has been recovered.

Adolescent↗
PubMed1979

Effect of transection on choline acetyltransferase, thyrotropin releasing hormone and substance P in the cat cervical cord.

The effects of a transection on the choline acetyltransferase activity, the thyrotropin releasing hormone and substance P contents in the cat cervical spinal cord have been investigated. Seven days after the hemitransection at the C1 level, the grey matter of the C6-7 levels of the spinal cord were dissected for the biochemical measurements. The choline acetyltransferase activity and the thyrotropin releasing hormone content remained unchanged in any regions in the grey matter following the high cervical transection. On the other hand, the substance P content was decreased by approx. 70% in the ventral horn. These results suggest that the fibers originating the supraspinal structures and terminating in the grey matter of the spinal cord, contain the substance P-releasing fibers, whereas there seems to be little cholinergic or thyrotropin releasing hormone-containing fibers.

Acetyltransferases↗
PubMed1979

Effect of pentobarbital and urethane on the release of hypothalamic somatostatin and pituitary growth hormone.

Hypothalamic somatostatin release was investigated in the rat to elucidate the mechanism of anesthetic action on growth hormone (GH) release from the pituitary. Intraperitoneal injection of sodium pentobarbital (5 mg/100 gm B.W.) significantly elevated serum GH levels and increased hypothalamic somatostatin concentration from basal values of 0.98 +/- 0.01 to 1.21 +/- 0.06 ng/mg wet wt. In contrast, urethane (150 mg/100 gm B.W., IP) administration lowered serum GH levels and hypothalamic somatostatin concentration (0.64 +/- 0.04 ng/mg wet wt.). However, the mean concentration of pancreatic somatostatin showed no change in either case. In rats receiving passive immunization with 0.5 ml rabbit antiserum to somatostatin (SRIF-AS), serum GH levels were significantly increased (67.5 +/- 12.3 ng/ml) and did not differ from those in the group treated with normal rabbit serum (NRS) plus pentobarbital (101.3 +/- 18.5 ng/ml). However, serum GH levels in rats injected with SRIF-AS plus pentobarbital were increased to higher values than in rats given SRIF-AS alone. When urethane was administered to rats after passive immunization with SRIF-AS, urethane-induced suppression of serum GH levels was markedly inhibited (5.5 +/- 2.0 vs. 33.5 +/- 7.5 ng/ml). These results suggest a possibility that the changes in serum GH levels observed with pentobarbital or urethane administration may be induced at least in one part by somatostatin released from the hypothalamus.

Animals↗
PubMed1978

Changes in hypothalamic LH-RH content and blood levels of LH-RH, gonadotropin and estradiol during the preovulatory stage of rat estrous cycle.

In order to investigate the sequence of events concerning gonadotropin surge, serum LH, FSH and estradiol concentrations were measured during the rat estrous cycle as well as hypothalamic and blood levels of LH-RH in the preovulatory stage. Normally cyclic female Wistar rats kept on 12 hr light (from 22.00 hr to 10.00 hr) and 12 hr dark were killed at different times of day during each stage of the cycle. The hypothalamus was quickly dissected out, divided into 3 portions (the anterior, middle and posterior) and extracted in 90% methanol. Blood LH-RH was extracted by affinity chromatography prior to radioimmunoassay. The content of LH-RH in the anterior and middle hypothalamus started to decrease between 1.00 hr-3.00 hr, reached its nadir at 6.00 hr on proestrus and recovered to its previous values on estrus. Almost simultaneously blood LH-RH concentration showed an increase of 18.3 pg/ml-8.8 pg/ml between 1.00 hr-3.00 hr, and then fell to less than 1.0 pg/ml at 6.00 hr. On the other hand, serum estradiol level began to elevate on diestrus II followed by its peak at 6.00 hr on proestrus, while the peaks of serum LH and FSH were observed at 8.00 hr and 10.00 hr, respectively. These studies indicate that the elevation of serum estradiol was followed by the release of LH-RH from the hypothalamus and the LH-RH may be responsible for the preovulatory discharge of gonadotropin.

Animals↗