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Biomedical subjects

R Mornex

Publications and source records attributed to R Mornex.

At least 109 records · Page 6Linked to original sources
PubMed1979

Participation of serotonin in thyrotropin release. II. Evidence for the action of serotonin on the phasic release of thyrotropin.

During a 12-h light 12-h dark schedule (lights off at 1900 h), male Sprague-Dawley rats show a circadian rhythm of plasma TSH with a zenith near midday. The participation of serotonin (5HT) in the phasic release of TSH was studied using both pharmacological and surgical-stereotaxical approaches. Animals treated with parachlorophenylalanine methyl ester (pCPA), an inhibitor of 5HT synthesis (one or two injections of 250 mg/kg each) showed a reduction or a disappearance of the diurnal peak of TSH, respectively. Additional treatment by 5-hydroxytryptophan, a precursor of 5HT, completely, restored the diurnal TSH peak. Treatment with 5,6-dihydroxytryptamine creatine sulfate, a neurotoxin which selectively destroys 5HT terminals, also induced alterations of the diurnal peak of TSH. There were no major modifications observed in the low nocturnal levels of TSH in rats treated with pCPA, 5-hydroxytryptophan, or 5,6-dihydroxytryptamine. The major serotoninergic innervation of the hypothalamus originates from the raphe dorsalis or centralis; destruction of these two nuclei caused a quasiabolition of the diurnal TSH peak (only a low amplitude TSH circadian rhythm persisted). Hypothalamic 5HT content was measured in the majority of these experiments; the greatest depletions (near 90%) were observed after two injections of pCPA or in rats bearing raphe lesions. We conclude that the diurnal peak of TSH, observed during the physiological circadian rhythm, is serotoninergic dependent.

5,6-Dihydroxytryptamine↗
PubMed1979

[Pheochromocytoma].

Explore the source record for details and available documents.

Adrenal Gland Neoplasms↗
PubMed1979

[Malignant pheochromocytoma].

The reported incidence of malignant pheochromocytoma varies from series to series. In this series 4 cases (7.2 p. 100) were observed out of a total of 55. In two cases the tumour progressed rapidly but in the other two cases, metastases were detected 3 to 12 years after the apparent cure of a histologically benign pheochromocytoma. The urinary levels of catecholamines and their metabolites gave no indication of the underlying malignancy. The diagnosis was only made from the clinical and radiological detection of metastases (2 hepatic, 2 bone). There is no satisfactory treatment and various therapeutic methods have to be used in succession; surgery for a single metastasis, radiotherapy and antiadrenergic agents to combat clinical manifestations. The natural history of this tumour is relatively long.

Adrenal Gland Neoplasms↗
PubMed1979

[Place of sulpirid test in the diagnosis of pheochromocytoma (author's transl)].

42 patients suspected of pheochromocytoma underwent to sulpirid and glucagon tests. 6 patients had pheochromocytoma: 3 failed to respond to glucagon and 2 to sulpirid. The 36 other patients had no clinical or blood pressure changes after sulpirid injection. We did not know any complication in positive tests and any clinical unconfort in negative tests. These results confirm the interest of sulpirid test in pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1978

Participation of serotonin in thyrotropin release. I. Evidence for the action of serotonin on thyrotropin releasing hormone release.

Injection of serotonin (5-HT) into the third ventricle of the rat resulted in a rapid increase of serum TSH; a significant effect was observed 5 min after injection, whereas the maximal effect appeared 10 min after the injection of 1 microgram 5-HT. This stimulating effect of 5-HT was completely prevented by pretreatment with cyproheptadine, a blocker of 5-HT receptors, whereas fluphenazine, a dopamine receptor blocker, was unable to block it. Third venticle injection of 5-HT in rats bearing anterior hypothalamic lesions (which did not affect the suprachiasmatic nucleus or the medio-basal hypothalamus) also induced an increase of serum TSH similar to that observed in normal rats despite the fact that these animals show a lower basal TSH. In vitro, the addition of 5-HT to an incubation medium containing one hemi-anterior pituitary did not modify medium TSH, whereas 5-HT addition induced an increase of medium TSH in the system containing one hemi-anterior pituitary and two hypothalami. We conclude that 5-HT acts on TSH function probably through a stimulation of TRH release.

Animals↗
PubMed1978

Normal pregnancies after treatment of hyperprolactinemia with bromoergocryptine, despite suspected pituitary tumors.

Bromocryptine treatment was administered to 15 patients with amenorrhea and galactorrhea (AG) and to 1 patient with amenorrhea. All of them had increased plasma PRL levels. Of these 16 patients, 4 had a normal sella turcica (ST; group STO), 4 had a slight enlargement (group ST+), and 7 had a clear enlargement of ST (ST++) but no evidence of suprasellar extension. Ovulation was restored in 15 patients by bromocryptine treatment only. In one patient, ovulation resumed only after human pituitary gonadotropin treatment in combination with bromocryptine. There was no correlation between basal prolactinemia, PRL stimulability or suppressibility, the size of ST, or the efficiency of bromocryptine treatment. Every patient with normal LH response to either LRH or clomiphene or both resumed ovulation. Ovulation resumed in 3 patients among the 4 with abnormal LH response to either LRH or clomiphene or both. Among the 14 who desired pregnancy, 13 became pregnant. To date, 12 patients (ST++, 5; ST+, 3; STO, 4) have delivered normal babies. The courses of pregnancy were normal. During pregnancy, no change of ST was noted on lateral and frontal skull x-ray performed in every patient at trimonthly intervals. There was no change in the sellar index in 10 patients after pregnancy, as compared to the pretreatment status. In the presence of a pituitary adenoma or in patients with hyperprolactinemia and amenorrhea and galactorrhea, bromocryptine treatment may cure sterility without pituitary complication during pregnancy.

Adult↗
PubMed1978

Approach to the mechanism of androgen overproduction in a case of Krukenbery tumor responsible for virilization during pregnancy.

Virilization may occur during pregnancy as the result of an ovarian Krukenberg tumor. mechanism of the androgen overproduction in this exceptional condition is still poorly understood. A new case is reported in which only in the postpartum clinical, endocrine, and endoscopic studies led to the diagnosis of an ovarian Krukenberg tumor secondary to a gastric carcinoma. In the mother, basal hormonal studies were done 1 and 4 weeks after delivery, then after gastric and ovarian surgery. Three months after delivery, ovarian steroid response to hCG (priming dose, 5000 IU; then 1500 IU every other day for 12 days) and a study of progesterone (P) metabolism at a steady state after a constant infusion of [3H]P and cold P (92 micrograms/min leads to blood production rate (BPR) of 152 mg/day designed to reproduce the BPR of P usually seen in pregnancy) were successively performed. Hormones were measured by specific RIAs after chromatographical purification. Basal hormonal levels were normal in the child. In the mother, on the 5th day postpartum, mean hormone levels (in nanograms per dl) were: testosterone (T), 4181; androstenedione (delta 4), 8876; 17 alpha-hydroxyprogesterone (17-OHP), 9746; P 1075; estrone (E1), 195; and estradiol (E2), 151. One month later, levels were normal for the follicular phase; T, 40; delta 4, 146; P, 52; E2, 9; and E2, 4.5. At both times, dehydroepiandrosterone was normal (703-750). Hormone levels increased progressively during hCG stimulation but their time course was different between hormones. At the end of the test, T. 144; delta 4, 746;' 17-OHP, 789; P, 723; E1, 37; and E2, 20. The MCR of P was decreased, 1450 liters/day (normal, 2020). Conversion ratios between products and precursor during constant infusion were normal. From these data, obtained in four different conditions (postpartum period, hCG stimulation, progesterone infusion, and after oophorectomy), the following can be concluded: adrenal production of dehydroepiandrosterone was normal; the ovarian overproduction of androgens likely resulted from the excessive reductive metabolism of both placental and ovarian P along the delta 4 steroid biosynthetic pathway by an hypertrophic stromal compartment; and HCG stimulation seems to be the necessary stimulus for this condition. The enhancement by T on its own peripheral production is also discussed.

Androgens↗
PubMed1978

[Study of the thyroid function by the I-M TRH test (2 mg) (author's transl)].

The responses of TSH, T3 and T4 to intramuscular administration of 2 mg of TRH were compared in the same subjects to those observed after intravenous injection of 200 microgram of TRH. In 12 normal subjects the TSH and T3 peaks were significantly higher after intramuscular injection. There was no difference in T4 levels. In 15 patients: 5 toxic adenomas after surgery and 10 Graves' disease after treatment the results were comparable for TSH and T3 by the two routes.

Adult↗
PubMed1977

[Do lithium salts have a place in the treatment of severe hyperthyroidism? (author's transl)].

In a patient with hyperthyroidism resulting in cachexia, severe cardiac complications and functional renal failure, and a second case of hyperthyroidism refractory to carbimazole as a result of iodine overload, the administration of 1 to 3 g of lithium gluconate every 1 to 3 days, in association with carbimazole, led to persistent clinical and biological improvement in 8 to 16 days. In the first case, the course was complicated by neurological intolerance (blood lithium 0.98 mEq/l) which responded to the temporary interruption of treatment and by a transient escape of thyroid function from the effects of lithium which disappeared after a slight adjustment in the dose. In the second case, the course under treatment was favourable from the outset. Thus in forms of hyperthyroidism in which usual forms of treatment are inadequate and where there is a risk of "acute crises", lithium may be valuable as adjuvant therapy. If the dose is regularly modified in order to obtain a daily blood lithium level of less than 0.60 mEq/l, and on condition of close clinical, electrocardiographic and ionic surveillance, cardiac and renal failure and neuropsychiatric disturbances do not prevent the use of lithium, which the authors feel to be of irreplaceable value.

Aged↗
PubMed1977

Comparison of adiphenine and TRH effects on TSH release by rat pituitary in vitro.

The mechanism of action of adiphenine on in vitro rat anterior pituitary TSH release was compared to that of the physiological stimulator TRH. The comparative study showed that adiphenine and TRH were able to increase TSH release in a dose-dependent manner, had similar time courses of action for equipotent stimulating concentrations and produced similar aspects of stimulated TSH cells. However, there were several differences between the effects of adiphenine and TRH. Adiphenine action was inhibited by 20 mM K+; was not calcium dependent; was inhibited by neither thyroid hormones nor somatostatin; was little affected by energy depression. It is concluded that adiphenine probably acts near the ultimate steps of the TSH release pathway and could be a useful pharmacological tool for studying the mechanism of TSH release.

Animals↗