Biomedical subjects
Publications and source records attributed to J J Legros.
During immersion in sitting position to the neck of 9 normal adult males, no change has been observed in the concentration of circulating ADH (1.91 +/- 0.58 versus 2.08 +/- 0.76 pg.ml-1) after 45 minutes. In the same period, diuresis is significantly increased (1.26 +/- 0.14 versus 3.9 +/- 1.19 ml.min-1).
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More than two thirds of the patients suffering from "psychogenic" erective sexual impotency display a paradoxical LH response to the injection of 200 micrograms of TRH. As it is known that similar responses exist in patients with gonadotropic cell adenomas, we undertook a tomographic examination of the sella turcica in 8 such patients. In none of the patients did the results favour the existence of a microadenoma. Though the hypothesis of an infra-radiological microadenoma cannot be excluded, it is highly plausible that the origin of the paradoxical response observed is a functional impairment of the hypothalamo-hypophyso-gonadal regulation.
This study indicates that total immunoreactive circulating neurophysins (IRN) increased in male rats submitted to acute restraint stress. Total immunoreactive serum corticosterone levels also were elevated, confirming the stressful character of the restraint situation. It is speculatively suggested that IRN elevations due to stress are the reflection of a corticotropin releasing factor (CRF)-IRN product.
Neurophysin II (hNpII) but not hNpI serum levels were higher than normal (greater than 2.85 ng/ml) in 9 of 20 patients admitted to the metabolic ward for alcohol withdrawal therapy; a normalization was observed within the first week of alcohol withdrawal. The higher levels of hNpII were felt to reflect alcohol impregnation for the following reasons: 1) on admission, levels of most of the alcoholism blood markers were higher in the group of patients with high hNpII levels than in the group with normal hNpII levels; 2) hNpII levels were correlated with most of the alcoholism blood markers, mainly gamma-glutamyl transpeptidase (r = 0.63, P less than 0.001) in the 20 patients of the study; 3) patients with high hNpII levels admitted to greater alcohol and less anxiolytic drug intake immediately before admission. The physiopathological meaning and hypothetical psychological consequence of this hNpII increase remain to be defined.
Oxytocin and bovine neurophysin I (bNpI) were estimated by radioimmunoassay in jugular vein plasma which was collected continuously from 18 bulls. No release of peptides was observed during successive matings with a cow in oestrus or during successive mountings on a cow with ejaculations into an artificial vagina. Stimulation with an electro-ejaculator or, to a smaller extent, massage of the seminal vesicles and ampullae per rectum caused an increase of oxytocin accompanied by a release of bNpI. It is speculated that the release of these peptides is due to stimulation of afferent pelvic nerves in the rectal wall. Basal molar ratios of bNpI/oxytocin in the plasma were highly variable, often showing a large excess of either bNpI or oxytocin. After the onset of peptide release induced by stimulation, molar ratios approached 1:1. This might indicate that hormone release is by exocytosis. Basal bNpI does not provide a good reflection of the oxytocin level.
In the present study, we have tested the cortical arousal (Flicker's Test) and mnesic function (Buschke Test) before and after a short-term Lysine-Vasopressin (LVP) treatment in normal senescent male (Age: 64,3 +/- 3,4). We have not been able to evidence any objective nor subjective improvement in the LVP versus placebo treated group. We do not know the origins of the discrepancies between the different clinical studies published so far concerning the influence of exogenous vasopressin on memory in man.
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The hormonal responses to breast-feeding were studied during the first 3 post-partum weeks in ten women smoking more than fifteen cigarettes/day and in a control group. Basal PRL levels were significantly lower in smokers compared with non-smokers, but suckling induced acute increments in serum PRL and oxytocin-linked neurophysin, which were not influenced by smoking. The lactational pattern was normal, but smokers weaned their babies significantly earlier compared with non-smokers. Heavy cigarette smoking women have lower basal PRL levels and this may shorten the period of lactation.
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Oxytocin has been suggested to have behavioral effects opposite to those of vasopressin, and exogenous vasopressin is known to induce ACTH release in man. Thus, we tested the influence of exogenous oxytocin on blood levels of ACTH and cortisol during insulin-induced hypoglycemia and after vasopressin injection. Our results demonstrate an inhibitory effect of exogenous oxytocin on ACTH release and support the hypothesis of a reciprocal, balanced modulation of behavioral and neuroendocrine function by the two closely related neurohormones, vasopressin and oxytocin.
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Eight patients with severe craniocerebral trauma were studied prospectively to assess the effects of the injury on sodium and water balance. Hyponatremic hypo-osmolar states occurred in 5 of the 8 patients. The cause was an inappropriate secretion of antidiuretic hormone (I.S.A.D.H.). We found an early I.S.A.D.H. (appearing within 2-3 days post trauma) whose presence was related to the craniocerebral injury (2 cases). We also found a late I.S.A.D.H. which may represent a response to positive-pressure ventilation, semi-recumbent position and centrally acting drugs. This tardive I.S.A.D.H. appeared 9-10 days after admission (3 cases). Radioimmunoassay for circulating and ventricular C.S.F. neurophysins shows an early and transitory increase of hNpI (the carrier of A.D.H.). hNpI was detectable during the hyponatremic hypo-osmolar states, thus demonstrating an inappropriate secretion of A.D.H.
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The excretion of immunoreactive vasopressin (AVP) and neurophysins was determined in 24 h urine samples from 62 normal healthy children of various ages. Five groups of children were selected: group I (n = 7, aged 2 to 3 years), group II (n = 13, aged 3 to 5 years), group III (n = 16, aged 5 to 7 years), group IV (n = 16, aged 7 to 9 years), group V (n = 10, aged 9 to 11 years). The method used for urine AVP determination consisted of an extraction using a procedure slightly modified from that of Miller and Moses [14], coupled to a radioimmunoassay. The following urinary AVP excretions were obtained: group I mean: 70.8 ng/m2/24 h range: 51-150 ng, group II mean: 54.1 ng/m2/24 h range: 17-113.6 ng, group III mean: 55.2 ng/m2/24 h range: 18-106 ng, group IV mean: 39.9 ng/m2/24 h range: 11.7-77.9 ng, group V mean: 39.4 ng/m2/24 h range: 25.8-64 ng. The excretion of AVP was significantly correlated to the daily urinary osmolality (P less than 0.001) whether expressed in ng/24 h (r = 0.41) o rin ng/m2/24 h (r = 0.4.7). Neurophysins excretion ranging between 7 and 1,278 ng/24H is too variable to allow interpretation.
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In 13 patients suffering from renal dysfunction and treated by chronic haemodialysis, the mnemic functions appeared within the limits of normality and there was no positive correlation between blood levels of neurophysines and free cortisol. On the other hand, a negative correlation was found between levels of neurophysine I and items 3 and 5 of the memory test PRM. This negative result indicates that in haemodialyzed patients a discrepancy may exist between blood levels of neurophysines and vasopressin release, or that there is no direct relationship between plasma and CSF concentrations of such hormones.
The influence of a i.v. injection of 2 I.U. of synthetic oxytocin (Oxy, Syntocinon) on plasma cortisol has been tested in 6 normal volunteers (age 22 to 33) and compared to a similar saline injection in a blind, cross-over design. Before injection basal cortisol is similar in Oxy (12.1 +/- 2.3 micrograms/100 ml M +/- Se) and saline (11.7 +/- 3.5) groups; in the Oxy group a significant (2 p less than 0.01) decrease of cortisol was noticed from the 45th min until the end of the test (120 min): the last mean level being 5.2 +/- 0.9 in the Oxy group compared to 12.9 +/- 1.8 in the saline group (2 p less than 0.005). Although the mechanism of action of Oxy on cortisol plasma levels remains to be investigated our results are in agreement with a proper action of Oxy and vasopressin at the level of the corticotroph cells or with a proper action of Oxy or of one of its metabolite (Pro-Leu-Gly-NH2 for example) on proopiomelanocorticotropic function.