Changes in serum isoamylase activities after fibergastroduodenoscopy and colonoscopy. Isoamylase after FGDS and FCS

The effects of endoscopic examination on the changes in serum amylase activity were investigated in hospitalized patients without salivary and pancreatic disorders. Sixty-nine patients were selected for the peroral fibergastroduodenal endoscopy and twenty-three patients for the peranal fibercolonoscopy. Blood samples were drawn before, immediately after, 4 hrs and 24 hrs after the termination of the examinations. The serum activities of the salivary type isoamylase increased in 7 out of 69 cases 4 hrs after the examination with the fibergastroduodenoscope, but none in all 23 cases after the examination with the fibercolonoscope. On the other hand, the serum activity of the pancreatic type isoamylase did not change following both examinations. A significant rise in serum cortisol levels was induced by both examinations. There were no correlations between the rise in salivary type isoamylase and that in serum cortisol levels. These results did not suggest that the increase of salivary type isoamylase was mediated by the hypophysio-adrenocortical axis. Other possible mechanisms were discussed.

Demonstration of immunoreactive somatostatin-like substance in villi and decidua in early pregnancy

With the use of the radioimmunoassay for growth hormone--releasing inhibiting factor (GIF), it was found that measurable amounts of GIF-like substance existed in the chorionic villi and decidua of pregnant women. The indirect immunofluorescent method revealed that the higher intensity of GIF-like immunofluorescence was presented in cytotrophoblasts rather than in syncytiotrophoblasts of the villi and in stromal cells of the decidua.

[Demonstration of immunoreactive GIF-like substance in villi and decidua by radioimmunoassay and immunofluorescence (author's transl)]

Since Arimura et al (1975) reported the radioimmunoassay for somatostatin (GIF), the concentration of GIF in various organ and brain regions were determined by radio-immunoassay. Dubois et al (1975) reported that immunohistochemically somatostatin was located in the discrete cells of the pancreas as well as the hypothalamus, and from this result, they presented the concept of local hormone instead of systemic hormone which was up to that time accepted in endocrinology. In this study, we developed the high specific anti-GIF serum using rabbits, and with the micro immunodiffusion method, we demonstrated that the precipitin band formed a circular fusion between the GIF and anti-GIF serum. This pattern of reaction was also seen in decidual immunodiffusion. In addition, we developed the radioimmunoassay for GIF using this anti-serum and measured immunoreactive GIF-like substances in villi and decidua of early pregnancy. The concentration of GIF-like substances with 2 N acetic acid extracted of villi and decidua were 0 to 30 pg/0.1 g dry weight. At the same time, we demonstrated the presence of GIF-like substance-containing cells in the villi and decidua by indirect immunofluorescent method. The intensity of immunofluorescence was in cytotrophoblast rather than syncytiotrophoblast, and decidual stromal cell also reacted to the immunofluorescence.

Effect of a bovine hypothalamic factor on the release and biosynthesis of growth hormone

Partial purification of growth hormone (GH)-releasing factor (GRF) by acid extraction followed by gel filtration on Sephadex G-25 has been attained from bovine hypothalami. When rat pituitaries were incubated in 2 ml Krebs Ringer-bicarbonate-glucose (KRBG) medium, a stimulatory effect of the GRF fraction on immunoreactive GH (IR-GH) release was observed, while that of the factor neither on GH synthesis nor release of the synthesized GH was demonstrated. Stimulation of the GH release was exerted maximally within 30 min of incubation. Cycloheximide and actinomycin D, at a concentration which inhibited protein and RNA synthesis to less than 5 and 20% of the control, respectively, were without effect on the stimulatory action of the factor on GH release. On the other hand, stimulation of GH synthesis was observed under incubation in 0.3 ml medium with the factor and enhancing effect of the factor on the IR-GH release was undetectable. These results suggest that stimulation of the release and synthesis of GH mediated by the hypothalamic GRF fraction is under influence of the pool size of incubation media.

Variety of GH and TSH responses to somatostatin in perfused rat pituitaries in vitro

One male rat pituitary placed in a chamber was perifused with cyclic somatostatin (GIF) for 30 min. Either 160 nM or 1.6 muM GIF caused a decrease in the release of GH. The release of TSH was also decreased by 160 nM GIF, and paradoxically increased by 1.6 muM GIF. Increasing the dose of GIF to 16 muM resulted in an abrupt rise in the release of both GH and TSH during the perfusion; then the level of GH decreased to the nadir level followed by an elevation above the base line, while that of TSH promptly fell back toward the base line. The release of PRL was not clearly affected by 16 muM GIF. [Tyr8]-GIF did not have such stimulatory activities. These results indicate that GIF not only inhibits the release of GH and TSH, but also stimulates that of GH and TSH in this system, depending on its dose.

Biological activities of tyrosine-containing somatostatin analogs on inhibition of secretion of thyrotropin and growth hormone

The following five tyrosine-containing analogs of somatostatin (GIF) were synthesized by the solid-phase method: Tyr-GIF: [Tyr6]-GIF; [Tyr7]-GIF; [Tyr8]-GIF; [Tyr11]-GIF. These analogs except [Tyr8]-GIF were demonstrated to possess almost the same potency to inhibit thyrotropin release stimulated by thyrotropin-releasing hormone as that of synthesized GIF in vivo. [Tyr8]-GIF had potencies less than 0.5% of GIF. They also had the activity to inhibit Nembutal-induced growth hormone rise. The structure-activity relationship and availability of these analogs for radioimmunoassay were discussed.

Extraction and partial purification of prolactin-release stimulating factor in bovine hypothalami

Partial purification of prolactin-release stimulating factor (PRF) was performed by Sephadex G-25 gel filtration of bovine hypothalamic extracts. PRF activity was evaluated on the basis of the measurement of immunoreactive prolactin released from the isolated rat hemipituitary in vitro. PRF activity was found in the fractions with Kav=0-0.49 and prolactin-release inhibiting activity was also detected in the fractions with Kav=0.69-0.89. The dose-response relationship was established between the partially purified PRF and its activity. The elution position of the partially purified PRF preceded that of TRH on Sephadex G-25. TRH at the dose of 100 nM stimulated the release of TSH in vitro, but not the release of prolactin. These results may indicate that there exists PRF with a relatively high molecular weight in the bovine hypothalamus.

Neonatal corticoid administration: effects upon adult pituitary growth hormone and hypothalamic growth hormone-releasing hormone activity

A single subcutaneous injection of 1 mg cortisone or cortisol acetate was given to rats during the first post-natal day. As others have reported, retardation of growth, detectable a week after birth, resulted. On reaching five to six weeks of age, treated rats had no detectable growth hormone (GH)-releasing activity in their hypothalami and little GH or thyrotrophin (TSH) activity in their pituitaries. These observations suggest that the growth retardation of rats treated neonatally with these steroids may be due, at least in part, to lack of pituitary GH resulting from impaired synthesis of GH-releasing hormone (GRH**) and also to lack of TSH.

Growth hormone-releasing activity in the hypothalami of kittens with lesions of the region of the paraventricular nuclei

An attempt was made to evaluate the growth hormone (GH)-releasing activity in extracts of the stalk-median eminence region (SME) from kittens with bilateral lesions of the paraventricular nuclei, which showed a marked growth retardation, and from sham-operated animals. SME extract from the sham-operated control kittens induced a significant decrease in pituitary GH content. However, SME extract from kittens with bilateral lesions in the region of the paraventricular nuclei failed to induce the depletion of pituitary GH content. The cerebral cortical extracts from both groups elicited no effect on pituitary GH. These results show that the hypothalamus of the lesioned kittens has no GH-releasing activity, i. e. GH-releasing factor (GRF) is lacking. This suggests that, in kittens, the area of the paraventricular nuclei plays an important role in the synthesis of GRF, so that destruction of this area causes growth impairment.

Mechanism of action of growth hormone in altering its own secretion rate: comparison with the action of dexamethasone

Administration of large doses of growth hormone (GH) (2 mg/100 g/day for 5 days) failed to modify growth hormone-releasing factor (GRF) activity in either 1) plasma and the hypothalamus of long-term hypophysectomized rats, 2) the hypothalamus of normal rats. An elevation of pituitary content of GH was observed in normal rats as a consequence of growth hormone treatment. In contrast to growth hormone, dexamethasone (50 μg/100 g/day for, 5 days) induced considerable decrease of GRF activity in both plasma and the hypothalamus of long-term hypophysectomized rats, as well as in the hypothalamus of normal rats.

No alteration of pituitary GH content was observed in normal rats as a consequence of chronic dexamethasone treatment. GH (1 mg/100 g) given 30 minutes before administration of a hypothalamic extract blocked the GH-depleting activity of the latter, while dexamethasone (50 μg/100 g) given one hour before apparently was ineffective.

It is suggested that growth hormone suppresses its own secretion rate acting directly on the pituitary gland, while the action of dexamethasone on GH secretion, takes place mainly at the level of the hypothalamus.