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R Mornex

Publications and source records attributed to R Mornex.

At least 127 records · Page 7Linked to original sources
PubMed1977

Thyroxine secretion by isolated hog thyroid cells: a cyclic AMP independent pathway.

The release of 131I-labeled thyroxine (T4) from isolated hog thyroid cells was increased 1.5--2-fold by thyrotropin (TSH). Dibutyryl cyclic AMP failed to reproduce this TSH action. In this in vitro system another cell activity, T4 synthesis, was stimulated in an essentially identical fashion by TSH and dibutyryl cyclic AMP (time course of action, dose-response relationship). 3-Isobutyl-1-methylxanthine (IBMX), 0.5 mM, did not alter the basal [131I]T4 release whereas it enhanced the [131I]T4 synthesis. TSH, 60 MU/ml, increased the intracellular cyclic AMP concentration 3-4-fold. Chlorpromazine (5 X 10(-4)M) abolished the TSH stimulation of cyclic AMP accumulation but did not alter the TSH-induced increase in [131I]T4 secretion. It is concluded that the TSH action on [131I]T4 secretion by isolated thyroid cells is not mediated by the adenylate cyclase-cylic AMP system.

Animals↗
PubMed1977

Perchlorate ion enhances mouse thyroid responsiveness to thyrotropin, human chorionic gonadotropin and long acting thyroid stimulator.

Perchlorate treatment of mice increased by 1.5-2-fold the thyroid secretory response to TSH, hCG and LATS, in the McKenzie bioassay. Perchlorate alone did not increase basal plasma radioactivity. Perchlorate augmentation of the secretory response index was roughly proportional to the level of stimulation; it was similar for all three stimulators despite their different time courses of action which were unaltered by perchlorate; it was the same whether perchlorate administration preceded, coincided with or shortly followed injection of the stimulator, a finding in keeping with the slow clearance of this ion. The perchlorate effect was dose-related, although within a narrow range (6.25-12.5 microng/mouse). Near-maximal per chlorate effect was obtained with a dose (12.5 microng) which, when tested in different experimental conditions (MMI-blocked thyroid), discharged 80% of intrathyroidal radioiodide. Perchlorate exerted its augmenting effect by enhancing thyroid secretion: it increased plasma radioiodothyronines and radioiodide concentrations without decreaseing the blood disappearance rates of iodide and iodothyronines. The potentiating effect of perchlorate probably takes place at a step prior to cyclic AMP action since it did not affect dbcAMP-stimulated secretion. The perchlorate effect may be indirect, through mobilization of minute amounts of intrathyroidal iodide.

Animals↗
PubMed1976

Leydig-cell agenesis: a cause of male pseudohermaphroditism.

We studied a 35-year-old patient with female external genitalia, primary amenorrhea and XY karytotype. Plasma testosterone was 10 ng per deciliter, which did not change after administration of human chorionic gonadotropin, increased to 22 ng per deciliter after ACTH, and decreased to 0.9 ng per deciliter after dexamethasone. Plasma delta 4-androstenedione, dehydroepiandrosterone and 17-hydroxyprogesterone were in the normal range. Plasma luteinizing hormone was high, but follicle-stimulating hormone normal (7.5 mlU per milliliter). There were two testes with epididymis and vas deferens, but no Mullerian structures. Microscopical examination showed hyalinization of tubules, which were lined by normal Sertoli cells and occasional immature germ cells. No Leydig cells were seen. After castration follicle-stimulating hormone increased to 43 mlU per milliliter. We conclude that this case of male pseudohermaphroditism was probably due to a Leydig-cell agenesis, that the epididymis and vas deferens can be developed in such a condition and the follicle-stimulating hormone secretion is regulated, at least in part, by a non-androgen substance secreted by Sertoli cells.

Adrenal Glands↗
PubMed1976

[Low thyrotrope hormone: a new entity].

The combination of the TRH stimulation of TSH release with the plasma iodide (PII) increase test, which gives a physiological measure of TSH basal activity, allows characterization of a syndrome we have called a low pituitary TSH reserve. These patients were euthyroid, had a normal PII increase test but a mild or no response to TRH. It was chiefly found in acromegaly and diabetes mellitus, after prolonged high levels of thyroid hormones or hypophysectomy. It appears to be a transient state between normal and abnormal thyrotropin function. So the absence of TSH increase after TRH injection can be of diagnostic value only when other tests of thyrotropin function are performed.

Acromegaly↗
PubMed1976

Evidence for a secretion of thyroxine by isolated hog thyroid cells.

Isolated thyroid cells prepared from hog thyroid glands by tryptic dispersion were incubated with 131I- for 1--6 h. Free [131I]thyroxine was identified in the incubation medium by three chromatographic methods. Neither [131I]iodotyrosines nor [131I]triiodothyronine were detected. The [131I]thyroxine released in the medium by 100 mul of cells (packed cell volume) after a 6-h incubation period amounted to 1.16% (S.E. = +/- 0.39) of the total radioactivity. The medium [131I]thyroxine represented 15--25% of the total [131I]thyroxine synthesized during the 6 h of incubation. Thyrotropin, 1--60 munits/ml, increased the medium [131I]thyroxine content 2-4 fold. Dibutyryl cyclic AMP mimicked the effect of thyrotropin. The amount of medium [131]thyroxine was strictly related to the amount of incubated cells but was independent of the volume of the incubation medium. When prelabeled cells were incubated in the presence of methimazole the increase in medium [131I]thyroxine was quantitatively related to a decrease in the intracellular [131I]thyroxine. Addition of dinitrotyrosine, an inhibitor of the deiodinase activity, induced the release of iodotyrosines in the incubation medium. That the incubation supernatant of isolated thyroid cells did contain free thyroxine but not iodotyrosines suggests that the normal mechanisms of proteolysis of thyroglobulin and deiodination of iodotyrosines inside the cells are preserved. From these data, it was concluded that the thyroxine release by isolated cells represents a real secretion.

Animals↗
PubMed1976

[Mental anorexia: gonadotrophic response to clomifene citrate. Sixteen cases].

Sixteen patients with anorexia nervosa and secondary amenorrhoea received clomiphene citrate, eight before any other treatment (200 mg of clomiphene citrate per day for four days) and eight others after partial or total correction of weight loss (50 mg of clomiphene citrate per day for five days). Menstruation occurred in four patients of the second group. An elevation of plasma LH was demonstrated in 4 cases in the first group and 7 of the second group. Variation in FSH was not always parallel with LH. The authors discuss the physiopathological mechanism of gonadotrophic insufficiency in anorexia nervosa and define the role of clomiphene citrate in the treatment of this disorder.

Adolescent↗
PubMed1976

[Neuroaminergic control of anterior pituitary secretions (author's transl)].

The demonstration and identification of monoamines and of aminergic tracts in the central nervous system has permitted a study of their role in the control of the liberation of hypothalamic releasing hormones. Knowledge of the role of these hypothalamic neurohormones in the release of pituitary hormones is at present under study. The role of monoamines in the control of pituitary hormone functions depends narrowly on pharmacological methods intervening either in the synthesis of neuroamines or in their action on a specific receptor. The authors consider successively the implication of monoamines in the control of liberation of ACTH, GH, TSH, prolactin and gonadotropic hormones. The role of aminergic mechanisms in the physiology of pituitary releasing hormones forms an integral part of homeostasis. Knowledge of these mechanisms leads to a clinical study of their role in disorders of hypothalamo-pituitary function.

Acromegaly↗
PubMed1976

Thyrotropin deficiency after polonged high levels of plasma thyroid hormones.

In order to elucidate the mechanism of the Farquharson phenomenon, we studied the thyrotropin function in three groups of patients who had had high plasma levels of thyroid hormones for prolonged period of time : 3 patients (group A) had taken thyroid hormones for several years. One month after discontinuation of the treatment two of them were hypothyroid; in both of them plasma TSH did not increase after injection of TRH. Spontaneous recovery occured in those two patients respectively five and nineteen months after the end of the drug administration. One year after having stopped the treatment the third patient was apparently euthyroid; however, she was proved to have a complete TSH deficiency. Group B consisted of 27 patients who were studied after surgical ablation of toxic adenoma. Four of them were hypothyroid one to four months after surgery and had no response to TRH. Fifteen out of the 23 remaining patients were euthyroid but had such a lack of response to TRH from 5 days to one year after surgery. Group C consisted of forty three patients treated for Graves' disease and who had been euthyroid for at least one year following the treatment. Seven of them exhibited no or a subnormal response to TRH. Finally, thirteen patients (from groups A, B and C) who did not respond to TRH were given 10 mg TRH orally twice a day for two weeks. A normalization of the TRH test was then demonstrated in three patients and a partial recovery in three others. Thus, there is a frequent thyrotropin deficiency after prolonged high levels of plasma thyroid hormones which can disappear spontaneously or after chronic TRH administration.

Administration, Oral↗
PubMed1975

Ophthalmic Graves' disease.

Ophthalmic Graves' disease is a peculiar clinical condition, characterized by ocular symptoms, without thyrotoxicosis. A survey of 22 observed cases is discussed. This condition is 25 times less frequent than classical Graves' disease. The eye symptoms include upper lid retraction, exophthalmos, and severe ophthalmopathy. Unilateral symptoms are frequent (16 out of 22). A negative T3 suppression test was found in half of the patients. LATS was detectable in 3 out of 17 of the cases. The stimulation of TSH secretion by TRH was normal in 3 out of 6 of the cases. When the tests were combined and repeated, a positive response was found in 8 out of 9 of the exophthalmic patients, and in 3 out of 9 of the patients with lid retraction. Appreciation of the course of the disease necessitates a prolonged follow-up; transformation into classical thyrotoxicosis have been observed. Our clinical studies bring into focus the relationship of ocular symptoms with Graves' disease and Hashimoto's disease.

Adult↗
PubMed1974

[Pherormones].

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Aggression↗