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L Loriaux

Publications and source records attributed to L Loriaux.

11 recordsLinked to original sources
PubMed1990

The hypothalamic-pituitary-adrenal axis in infantile malnutrition.

We studied the circadian rhythm and the response of the hypothalamic-pituitary-adrenal (HPA) axis to ovine corticotrophin releasing hormone (oCRH) stimulation and dexamethasone suppression in 32 children with grade II-III marasmus. Children were studied prior to and after nutritional rehabilitation. Mean baseline plasma cortisol concentrations were elevated at admission and decreased significantly after nutritional rehabilitation. Mean +/- SEM plasma cortisol response to oCRH increased from a basal of 480 +/- 41 to a peak of 582 +/- 58 nmol/l at the time of admission, and from a basal of 234 +/- 27 to a peak of 532 +/- 41 nmol/l after caloric rehabilitation. Dexamethasone suppression in the malnourished group was associated with a decrease in the mean +/- SEM basal plasma cortisol concentration from 397 +/- 44 to 171 +/- 44 nmol/l. After caloric rehabilitation, basal cortisol levels decreased from 259 +/- 27 to 22 +/- 5 nmol/l following dexamethasone. Our results support the concept that malnutrition is associated with decreased responsiveness to oCRH and incomplete dexamethasone suppression, and that these abnormalities are restored after nutritional rehabilitation.

Child, Preschool↗
PubMed1985

Impaired adrenal reserve in the Watanabe Heritable Hyperlipidemic rabbit: implications for LDL-receptor function in steroidogenesis.

The cholesterol required for steroidogenesis may be provided by the novo biosynthesis or through the delivery of cholesterol by the circulating lipoproteins. By studying adrenocortical function, structure and biosynthetic capacity in an animal model devoid of the classical, high-affinity low density lipoprotein (LDL) receptor pathway, the respective roles of de novo cholesterolgenesis and lipoprotein cholesterol delivery were investigated. The Watanabe Heritable Hyperlipemic (WHHL) rabbit lacks the LDL-receptor pathway. The activity of the rate-limiting enzyme in cholesterolgenesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase was 4- to 15-fold greater than normal in the WHHL adrenal gland. The basal corticosterone concentrations were normal in the WHHL rabbit; however, the corticosterone concentration increased by less than 50% of normal after an intravenous ACTH injection. Electron-microscopic evaluation of adrenocortical cells from the WHHL rabbits disclosed significantly increased mitochondrial surface area and diminished amounts of cytosolic lipid and lysosomal area. These data indicate that the mammalian adrenal gland utilizes endogenously synthesized cholesterol as well as cholesterol delivered through the LDL-receptor pathway. Moreover, in the absence of the LDL-receptor pathway, endogenously produced cholesterol is sufficient for normal basal glucocorticoid function.

Adrenal Glands↗
PubMed1985

Active clearance of corticotropin-releasing factor from the cerebrospinal fluid.

Intracerebroventricular injection of corticotropin-releasing factor (CRF) in animals activates behavioral, motor, metabolic and sympathetic responses similar to those seen with stress. To explore the pharmacokinetics of this peptide in the primate ventricular CSF, we determined the clearance of ovine 125I-CRF from the CSF and compared it to that of 111In-DTPA, a substance cleared by bulk flow. 125I-CRF was cleared from the ventricular fluid sixfold more rapidly than bulk flow. This suggests that the CSF may be a pathway for physiological distribution of this releasing factor to active sites within the central nervous system, and that a mechanism exists for active removal of CRF from the ventricular CSF.

Animals↗
PubMed1984

Corticotropin releasing factor administered into the ventricular CSF stimulates the pituitary-adrenal axis.

Ovine corticotropin releasing factor (CRF) given intracerebroventricularly to rhesus monkeys at doses of 0.1-1 microgram/kg activates the pituitary-adrenal axis. The increases of plasma cortisol concentrations after intraventricular injection of CRF were similar to those observed after intravenous administration of this releasing factor and occurred without elevation of plasma concentrations of CRF, measured by radioimmunoassay. Thus, the cerebrospinal fluid (CSF) can serve as a conduit for delivery of CRF to the pituitary gland.

Animals↗
PubMed1983

EEG and evoked potentials in precocious puberty.

We recorded brain stem auditory evoked potentials, pattern reversal visual evoked potentials and electroencephalograms in 19 children, 2-8 years old. Sixteen had precocious puberty and three had precocious adrenarche. Two of the children with precocious puberty had hypothalamic hamartomas, one had an optic glioma, and one had a history of hydrocephalus. The EEG was abnormal in 7 patients: three had diffuse slowing, and four showed possible paroxysmal features. BAEPs and VEPs were normal in all patients. This study showed no abnormalities in two conduction pathways of the central nervous system and no evidence of a deleterious effect of hormonal aberrations in patients with precocious puberty. Abnormal EEG in these patients is more likely to reflect occult diencephalic disease than widespread neurophysiological dysfunction.

Brain Diseases↗
PubMed1977

Adrenomyeloneuropathy: a probable variant of adrenoleukodystrophy. I. Clinical and endocrinologic aspects.

We have studied four unrelated males with a heritable disorder that we term adrenomyeloneuropathy; limited clinical information is available on a fifth case. All had adrenal insufficiency beginning in childhood and developed progressive spastic paraparesis in the third decade. Hypogonadism of variable severity was present in all four cases appropriately examined. Neurologic features included peripheral neuropathy, impotence, and sphincter disturbances. Late manifestations were cerebellar dysfunction in one case and dementia and hemiparesis in another. A family history of adrenal disease or spastic paraparesis was present in two cases and absent in one; in the other two, no family history was available. Although males are predominantly affected, the mode of inheritance is uncertain. Adrenomyeloneuropathy probably represents a clinically and genetically distinct variant of childhood adrenoleukodystrophy.

Addison Disease↗
PubMed1972

Estrone sulfate: production rate and metabolism in man.

Since estrone sulfate (E(1)S) is present at high concentration in plasma, we have examined the parameters of the plasma estrone, estradiol, E(1)S system. The metabolic clearance rate of E(1)S was 157 liter/day (range 70-292) in men and women. Estimated plasma production rates of E(1)S were (mugrams per day): men, 77; women, early follicular phase, 95; women, early luteal phase, 182. The conversion of plasma estrone and estradiol to E(1)S was measured and from these data and the metabolic clearance rates of the estrogens, the transfer factors were rho(E) (1) (E) (1) (S) = 0.54 and rho(E) (2) (E) (1) (S) = 0.65. Using average production rates, all plasma E(1)S could be shown to be derived from plasma estrone and estradiol. The conversion of plasma E(1)S to plasma estrone and estradiol was studied. The calculated transfer factors were: rho(E) (1) (SE) (1) = 0.21, rho(E) (1) (SE) (2) = 0.014. Essentially, similar data were obtained when E(1)S was given by mouth to two subjects. WE CONCLUDE: (a) E(1)S is a major circulating plasma estrogen and has a long plasma half-life; (b) the large contributions of estrone and estradiol to plasma E(1)S are more than sufficient to account for all the circulating plasma E(1)S.

Adolescent↗