[Hypercorticism. Physiopathology, clinical and biological diagnosis].
Explore the source record for details and available documents.
Adrenocortical Hyperfunction↗
Biomedical subjects
B Conte-Devolx
Publications and source records attributed to B Conte-Devolx.
Phaeochromocytoma in multiple endocrine neoplasia type 2 A: survey of 100 cases.
OBJECTIVE: We report clinical, biochemical, morphological and histological data of phaeochromocytoma in 40 French families and in apparently sporadic cases of multiple endocrine neoplasia (MEN) type 2 A (medullary thyroid carcinoma, phaeochromocytoma, with or without hyperparathyroidism). DESIGN: This retrospective study was obtained from cases registered by the 'Groupe d'Etudes des Tumeurs à Calcitonine' from 1968 to 1990. We analysed the cases having sufficiently precise data on phaeochromocytoma with Pigas Software. PATIENTS: Characteristics of phaeochromocytoma in 100 patients with MEN 2 A were reviewed. Phaeochromocytoma was bilateral in 51%. The disease was inherited in 94 patients from 40 families (40 probands, 54 relatives), and was apparently sporadic in six. RESULTS: In this series, diagnostic circumstances were highly suggestive of phaeochromocytoma in 39.8% of the cases, whereas in 43.2%, diagnosis was made through systematic investigations of patients, either before (27.3%) or after (13.6%) thyroidectomy, or after discovery of hyperparathyroidism (2.3%). Fifteen per cent of patients were detected by family screening. Sudden death occurred in 8.9%, malignant phaeochromocytoma in 3%, and ectopic tissue in 4% of the cases. Urinary metanephrines appeared to be the most sensitive screening test. The extent of clinical symptoms was not associated with a particular hormonal pattern. Bilateral adrenalectomy was performed in 60% (in one step in 50%, in two steps in 10%). In these patients, bilateral histological lesions were observed in 92.5%. Simultaneous diagnosis for adrenal and thyroid disease was made in 73.4%, but phaeochromocytoma may be diagnosed before (9.6%) or after (17%) medullary thyroid carcinoma, with an interval greater than 2 years in 25 cases. CONCLUSION: Owing to variable clinical symptoms of phaeochromocytoma in these 100 cases of MEN 2 A, systemic biological adrenal assay is required. The search for phaeochromocytoma in medullary thyroid carcinoma (and vice versa) has to be systematically performed, even in apparently sporadic cases. Screening for phaeochromocytoma must be repeated for years, owing to the frequency of bilateral adrenal disease.
Adrenal Gland Neoplasms↗
Neostigmine stimulates growth hormone-releasing hormone release into hypophysial portal blood of conscious sheep.
GH secretion is stimulated by the administration of cholinesterase inhibitors (such as pyridostigmine and neostigmine) in several species, including man. On the basis of indirect experiments, it has been postulated that this action is mediated by a decrease in hypothalamic somatostatin release. We have investigated the effect of neostigmine in sheep, since it is possible to collect hypophysial portal blood for GH-releasing hormone (GHRH) and somatostatin determination in this species under a conscious unstressed state. First, after i.v. injection of neostigmine (1 mg), a significant increase in plasma GH levels and an unequivocal potentiation of the GH response to GHRH were observed. Then, we observed that i.v. injection of neostigmine (1 mg) induced an immediate, short-lasting (30 min), and marked increase in GHRH (126.1 +/- 17 vs. 14.5 +/- 2.1 pg/ml; P < 0.01) levels in hypophysial portal blood of rams chronically implanted with perihypophysial cannulae. No change in somatostatin secretion was recorded during the same period. These data suggest that the stimulating effect of cholinergic drugs on GH secretion is mediated by stimulation of GHRH release. A direct effect of neostigmine at the level of pituitary gland is possible and may explain the potentiation of GHRH-induced GH release.
Animals↗
[Stress. Neuroendocrine aspects].
All kind of stress produce an endocrine response. These hormonal responses can serve as stress indicators. The main peripheral endocrine responses to stress are the activation of adrenal corticoids, the stimulation of Growth Hormone (GH) and prolactin secretion, and the inhibition of insulin and gonadal secretion. Except for the inhibition of insulin release, all these hormonal variations depend on the adenohypophysis activity: stimulation of Adrenocorticotrophin hormone (ACTH), GH and prolactin, and inhibition of gonadotrophins (LH-FSH) secretions. Several lines of evidence demonstrate that specific hypothalamic Neuro-hormones stimulate or inhibit the hypophysial activity in response to stress. However, due to methodological difficulties, only measurements of peripheral hormones can be used as stress indicators.
Adrenocorticotropic Hormone↗
[Malignant endocrine tumor of the pancreas associated with high blood thyrocalcitonin levels].
A case of thyrocalcitonin-secreting endocrine tumour of the pancreas is reported. Endocrine pancreatic tumours are neoplasias evolving over a long period; most of them are multisecreting, usually with a predominant secretion responsible for clinical symptoms. In this particular case the retrospective diagnosis of a thyrocalcitonin-secreting tumour of the pancreas was made by immunocytochemical study of the pancreatectomy specimen. One year after pancreatectomy, the persistence of clinical signs and a plasma thyrocalcitonin level higher than 25,000 pg/ml led to the discovery of a liver metastasis. An immunocytochemical study of the segmental hepatectomy specimen showed a single population of thyrocalcitonin-secreting cells identical with those found in the pancreatic tumour. In this context, radioimmunological assays of peptides and immunocytochemistry seem to be the best diagnostic methods.
Aged↗
Age-related changes in cortico-releasing factor, somatostatin, neuropeptide Y, methionine enkephalin and beta-endorphin in specific rat brain areas.
We investigated the age-related changes in the tissular protein, cortico-releasing factor (CRF), somatostatin (SOM), neuropeptide Y(NPY), methionine enkephalin (M-ENK) and beta-endorphin (beta-END) levels in frontal cortex, hippocampus, striatum and hypothalamus of young (4-month-old), mature (18-month-old) and senescent (26-month-old) Wistar male rats, bred in a specific pathogen free environment. Between the age of 4 and 18 months, the tissular protein levels increased in all 4 structures studied. The CRF and SOM levels increased in the hippocampus, while the NPY levels decreased. During this time, the NPY content increased in the striatum, whereas the SOM and M-Enk striatal levels decreased. Concomitantly, the NPY and beta-End levels decreased in the hypothalamus. Interestingly, no significant variations were found to occur in the frontal cortex whatever the neuropeptide studied. Between the age of 18 and 26 months, no significant changes in the tissular protein levels were detected, except in the hippocampus. The changes in the neuropeptide concentrations observed during this period depended on the neuropeptide and the brain structure studied. The CRF and beta-End levels decreased in the frontal cortex and the hypothalamus, respectively. The NPY peptidergic systems seem to be preferentially affected by aging processes since 3 out of the 4 structures studied--the frontal cortex, the striatum and the hypothalamus--showed a decrease in their tissular NPY content. During the same period, none of the 5 neuropeptides studied were affected in the hippocampus.
Aging↗
Acute changes in growth hormone-releasing hormone secretion after injection of BIM 23014, a long acting somatostatin analog, in rams.
BIM 23014 is a somatostatin analog displaying an increased biological half life due to resistance to enzymatic degradation. This peptide inhibits GH release directly at the level of pituitary somatotrophs. In addition, an action of BIM 23014 at the level of the hypothalamus is possible since somatostatinergic fibers and receptors have been identified on GH-RH neurons. To evaluate the effect of BIM 23014 on GH-RH secretion, hypophysial portal blood (HPB) was continuously collected in conscious sheep. Twelve rams (40-45 kg, 9-month-old) with chronically implanted perihypophysial cannulae were i.v. injected with BIM 23014 (1 mg) or saline. HPB and jugular blood were collected for 3-5 hours before and after the injection for the determinations of GH-RH and GH concentrations respectively. The acute injection of BIM 23014 induced a rapid decrease of plasma GH within the first two hours. Simultaneously, GH-RH in HPB decreased significantly. After reaching a nadir, GH concentrations increased to values greater than baseline. A similar rebound in GH-RH levels in HPB was also observed. These data indicate that BIM 23014 acts at the level of GH-RH hypothalamic neurons, in addition to its well-know effect on the pituitary gland.
Animals↗
Effect of chronic active immunization anti-corticotropin-releasing factor on the pituitary-adrenal function in the sheep.
ACTH and cortisol diurnal variations and responses to two types of stress (insulin-induced hypoglycemia and isolation-restraint stress) or to an acute injection of lysine-vasopressin were studied in intact and anti-corticotropin-releasing factor (CRF) actively immunized rams. Immunization was obtained by the injection of synthetic ovine CRF coupled to BSA with carbodiimide. All animals developed antibodies anti-CRF and displayed an alteration of their general condition and a body weight reduction. The mean basal ACTH and cortisol secretion as well as the number and mean amplitude of diurnal pulses of these hormones was significantly reduced in the group of anti-CRF immunized rams. However, the reduction in all three parameters was much more pronounced for cortisol than for ACTH. No ACTH and cortisol response to insulin-induced hypoglycemia and isolation-restraint stress was observed. The stimulating action of lysine-vasopressin on ACTH release was significantly reduced as compared to controls. These results indicate that CRF is a major physiological component of the ovine hypothalamo-hypophysial-adrenal axis and participates in the events that regulate ACTH and cortisol diurnal variations and response to stress.
Adrenocorticotropic Hormone↗
Effect of chronic active immunization with antiarginine vasopressin on pituitary-adrenal function in sheep.
ACTH and cortisol diurnal variations and responses to two types of stress (insulin-induced hypoglycemia and isolation-restraint stress) and to an acute injection of CRF were determined in intact as well as in actively antiarginine vasopressin (AVP)-immunized rams. All immunized sheep developed antibodies to AVP, displayed diabetes insipidus, and looked healthy in spite of their lower gain weight. Basal secretion and diurnal variations of ACTH and cortisol were unaltered in the group of anti-AVP-immunized animals. In contrast, ACTH and cortisol responses to both types of stress and CRF injection were significantly reduced compared to those in controls. These results suggest that endogenous AVP plays a physiological role in the corticotropic response to stress. However, endogenous AVP does not appear to affect basal secretion and diurnal variations of ACTH and cortisol.
Adrenocorticotropic Hormone↗
Effects of metyrapone infusion on corticotropin-releasing factor and arginine vasopressin secretion into the hypophysial portal blood of conscious, unrestrained rams.
The effects of rapid changes of circulating cortisol levels on ACTH secretion and on corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) concentrations into hypophysial portal blood were studied in six adult rams. Pharmacological adrenalectomy was obtained by 3 h metyrapone infusion (100 mg.kg-1.h-1). Blockade of cortisol synthesis induced a tenfold increase of plasma ACTH levels accompanied by a moderate increase of CRF secretion (150% vs preinjection levels) and a large increment of AVP secretion (535% vs preinjection levels). ACTH levels remained high during the 3 h following the end of metyrapone infusion. During the same period, CRF secretion was still elevated (231% vs preinjection levels), while AVP secretion was further stimulated (2,151% vs preinjection levels). Subsequent hydrocortisone infusion (66 micrograms.kg-1.h-1) for 2 h induced a rapid decrease of both ACTH and AVP secretion, while CRF levels in hypophysial portal blood still remained elevated. These data suggest that changes in ACTH secretion induced by acute modifications of the negative glucocorticoid feedback are, in addition to the well documented direct effect of cortisol on the corticotropes, mainly mediated by variations of hypothalamic AVP secretion.
Animals↗
[Serum human growth hormone assay. Comparison of six assay kits].
Measurements of human growth hormone (hGH) plasma levels using mono or polyclonal antibodies based on kits are often highly variable depending upon the kit used. We compared six kits commercially available: one based on polyclonal antiserum, five based on monoclonal antisera. We measured 695 sera obtained in short stature children (GH deficiency or normal GH secretory) and adults (normal, hypopituitarism or acromegaly). Our results confirm the variability between the assays. The maximal variation was obtained with SBhGH kit which showed mean results 1.7 fold higher than those obtained with hGH Coatria. Using the OMS 80.205 standard with the six kits, we found a good correlation between the six kits indicating that the standard used in each case was not responsible for the observed variations. This suggest that the different antibodies used in these kits may recognize different isoforms of circulating hGH. In addition variations in reagents used in the different kits may also explain these discrepancies. The variations observed using these six commercially available kits may have important clinical repercussion and especially may impede the diagnosis in hGH deficiency in children.
Adolescent↗
Coxsackie thyroiditis.
Explore the source record for details and available documents.
Antibodies, Viral↗
[Bone density after iatrogenic subclinical long-term thyrotoxicosis. Measurement by dual photon absorptiometry].
Thyrotoxicosis may be held responsible for osteoporosis. The question is whether a very slight subclinical hyperthyroidism, as is desirable in the post-operative treatment of differentiated thyroid carcinoma, can in the long run be detrimental to bone tissue. In a series of 37 patients, aged 50.9 +/- 11.1 years, presenting with the features of subclinical hyperthyroidism of 8.0 +/- 4.8 years duration, the authors have been unable to find any change in paraclinical parameters of bone and calcium-phosphate metabolism. Thirty-six of these 37 patients showed no abnormal decrease of vertebral bone density measured by dual photon absorptiometry.
Absorptiometry, Photon↗
Circulating blood glucose and hypothalamic-pituitary secretion.
Explore the source record for details and available documents.
Animals↗
Differences in the effects of acute and chronic administration of dexfenfluramine on cortisol and prolactin secretion.
Explore the source record for details and available documents.
Adrenocorticotropic Hormone↗
Insulin-induced hypoglycemia stimulates corticotropin-releasing factor and arginine vasopressin secretion into hypophysial portal blood of conscious, unrestrained rams.
Insulin-induced hypoglycemia (IIH) is a strong stimulator of pituitary ACTH secretion. The mechanisms by which IIH activates the corticotrophs are still controversial. Indeed, in rats the variations of corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) secretion in hypophysial portal blood (HPB) during IIH have been diversely appreciated. This may be due to the stressful conditions required for portal blood collection in rats. We studied the effects of IIH on the secretion of CRF and AVP in HPB and on the release of ACTH and cortisol in peripheral plasma in conscious, unrestrained, castrated rams. After the injection of a low (0.2 IU/kg) or high dose (2 IU/kg) of insulin, ACTH and cortisol levels in peripheral plasma increased in a dose-related manner. After injection of the low dose of insulin, CRF and AVP secretion in HPB were equally stimulated. After injection of the high dose of insulin, CRF secretion was further stimulated, while AVP release was dramatically increased. These results suggest that when the hypoglycemia is moderate, CRF is the main factor triggering ACTH release, and that the increased AVP secretion potentiates the stimulatory effect of CRF. When hypoglycemia is deeper, AVP secretion becomes predominant and may by itself stimulate ACTH release.
Adrenocorticotropic Hormone↗
Glucocorticoids regulate peptidyl-glycine alpha-amidating monooxygenase gene expression in the rat hypothalamic paraventricular nucleus.
Peptidyl-glycine alpha-amidating monooxygenase (PAM) is a posttranslational processing enzyme which catalyzes the formation of biologically active alpha-amidated peptides. The two major neuropeptides involved in the regulation of ACTH secretion [CRF and arginine vasopressin (AVP)], synthesized in the parvocellular part of the hypothalamic paraventricular nucleus (PVN), are amidated, and their synthesis and/or release is negatively regulated by glucocorticoids. In this study, using in situ hybridization, we have shown that PAM mRNA is abundantly expressed in the hypothalamic paraventricular and supraoptic nucleus. Surgical adrenalectomy (ADX) induced increases in PAM, CRF, and AVP mRNA in the parvocellular part of the PVN, while corticosterone treatment normalized these values. PAM and AVP gene expression were not changed in the magnocellular part of the PVN or in the supraoptic nucleus. These observations suggest that in addition to stimulation of CRF and AVP synthesis, ADX induces an increase in PAM synthesis in the PVN and, thus, support the hypothesis of increased secretion of both CRF and AVP after ADX.
Adrenalectomy↗
Corticotropin-releasing factor secretion increases in rat hypophysial portal blood during insulin-induced hypoglycemia.
To study the possible involvement of hypothalamic corticotropin-releasing factor (CRF) in the stimulation of adrenocorticotropic hormone (ACTH) release caused by insulin-induced hypoglycemia (IIH), we measured CRF secretion in hypophysial portal blood (HPB) in rats anesthetized with sodium thiopental after injection of insulin. Before treatment, systemic ACTH levels (952 +/- SE 143 pg/ml; n = 12) were well above normal values, probably reflecting the anesthetic and surgical stress consecutive to the preparation for portal blood collection. Insulin injection induced a significant increase of ACTH release within 15 min (1,588 +/- 168 vs. 741 +/- 144 pg/ml; n = 6, in vehicle-injected rats) which lasted for at least 1 h. CRF levels in HPB were 857 +/- SE 168 pg/ml (n = 13) during the first-hour pretreatment collection. Vehicle injection did not modify CRF secretion (759 +/- 142 pg/ml; n = 6). Insulin injection provoked a significant increase in CRF release (1,449 +/- 257 pg/ml; n = 7). These data suggest that an increased hypothalamic CRF secretion is responsible for the stimulation of pituitary ACTH release following IIH. The possible involvement of central neuromediators in the IIH-induced CRF production is discussed.
Adrenocorticotropic Hormone↗