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Biomedical subjects

F Dray

Publications and source records attributed to F Dray.

At least 73 records · Page 4Linked to original sources
PubMed1983

High, vasopressin-reversible, immunoreactive somatostatin in specific hypothalamic nuclei of rats with diabetes insipidus (Brattleboro rats).

Somatostatin content was studied in brain nuclei and pituitary lobes of homozygous Brattleboro rats lacking vasopressin (DI rats) with and without vasopressin replacement, and their corresponding controls, heterozygous Brattleboro (HZ) rats and Long-Evans (LE) rats. High, vasopressin-reversible, somatostatin levels occurred in DI rats. The changes in somatostatin were localized to the nucleus periventricularis and to brain areas receiving somatostatin projections from this nucleus, including the eminentia mediana. In contrast, vasopressin administration failed to alter somatostatin levels in HZ rats. In brain areas not belonging to the somatostatin periventricular system, the peptide concentration in DI rats was not higher than that of LE controls. High somatostatin levels were present in the intermediate lobe of the pituitary gland. Somatostatin was higher in DI and HZ rats when compared to LE rats. In the posterior pituitary lobe, HZ rats had higher, and DI rats lower, somatostatin than control LE rats. These results suggest that rat brain and pituitary vasopressin and somatostatin systems are interrelated.

Animals↗
PubMed1983

Familial and constitutional bleeding disorder due to platelet cyclo-oxygenase deficiency.

Three family members from two successive generations had a bleeding tendency. Their template bleeding time was prolonged and platelet aggregation induced by ADP and adrenaline showed no second wave; collagen at low to moderate concentrations failed to aggregate and release ATP, whereas higher amounts aggregated and released. Aggregation and release due to thrombin, ristocetin, and synthetic epoxy derivatives (U 44069 and U 46619) were normal. Arachidonate (AA) was inactive, and was not converted either in thromboxane (TX) A2 activity evaluated on the rabbit aorta strip, nor in TXB2 evaluated by radioimmunoassay and by radiochromatography. The parallel impairment of TXB2 and PGE2 formation by the patient's platelets are compatible with a platelet cyclo-oxygenase deficiency. This study suggests that transmission is autosomal dominant, and confirms that cyclo-oxygenase is not needed for aggregation and ATP release by high amounts of collagen.

Adolescent↗
PubMed1983

Effect of catecholestrogens on prostaglandin release by rat pituitaries superfused in vitro.

We studied the action of catecholestrogens on prostaglandin and LH release by female rat pituitaries superfused in vitro. Their actions were compared to those of estradiol (E2) at the same concentration (10(-6) M). By comparison with E2 the action of 2-OHE2 was only the same on total PGE2 release. 4-OHE2-17 beta stimulated LH like E2 but the values for PGD2 and PGE2 were about 20-30% lower. However, the release of 6-keto-PGF1 alpha was about 35% higher. 4-OHE2-17 alpha had no comparable action on PG release but stimulated a significant LH release. There was no action on TxB2 in any case.

Animals↗
PubMed1983

Localization of substance P- and enkephalin-like immunoreactivity in relation to catecholamine-containing cell bodies in the cat dorsolateral pontine tegmentum: an immunofluorescence study.

The distribution of tyrosine hydroxylase-, substance P- and enkephalin-immunoreactive neurons in the cat dorsolateral pons was studied using the indirect immunofluorescence method of Coons. To allow for the visualization of substance P- and enkephalin-immunoreactive cell bodies, colchicine was injected either in the ventricular space or in the cerebral tissue. The distribution of the tyrosine hydroxylase-immunoreactive cell bodies corresponded with the well-known distribution of catecholamine cells in this area of the brain. The observation of adjacent sections treated separately with tyrosine hydroxylase- and enkephalin-antiserum revealed that most catecholaminergic cells contain enkephalin-immunoreactivity. In addition to this catecholamine-enkephalin cell population, a moderate number of substance P-immunoreactive cell bodies was found in dorsolateral pons. The peribrachial nuclei were found to be densely supplied with substance P- and enkephalin-immunoreactive fibers, whereas the medial subdivisions, which contain the majority of the catecholamine cells in the dorsolateral pons, display a moderate number of immunoreactive fibers. These results are suggestive of interactions between peptide-containing and catecholaminergic neurons and also between-peptide-containing and non-catecholamine-containing neurons in the cat dorsolateral pons.

Animals↗
PubMed1983

Presence of somatostatin, enkephalins, and substance P-like peptides in cultured neurons from embryonic chick cerebral hemispheres.

The presence of peptides in pure cultures of neurons from 8-day-old chick embryo cerebral hemispheres has been investigated by means of specific radioimmunoassays and chromatographic purification. Somatostatin, Met-enkephalin, Leu-enkephalin, and substance P immunoreactive substances have been detected in 8-day-old cultures grown in serum-free culture medium. The peptides were present in the cellular extracts, as well as in the culture medium extracts. beta-Endorphin, thyroliberin, luteinizing hormone-releasing hormone, and ACTH could not be detected. The largest amount was accounted by somatostatin (48 +/- 2 ng/mg protein). Some 60% of the somatostatin-immunoreactive material was found in the culture medium. Met-enkephalin, Leu-enkephalin, and substance P were present at lower concentrations: 1.61 +/- 0.27, 0.24 +/- 0.02, and 0.14 +/- 0.005 ng/mg protein, respectively. The identities of somatostatin- and enkephalin-immunoreactive materials were confirmed by high pressure liquid chromatography. The findings suggest that cultured neurons that express dopaminergic and GABAergic properties contain peptides similar, if not identical, to somatostatin, Met-enkephalin, Leu-enkephalin, and substance P.

Animals↗
PubMed1983

Selective decrease in immunoreactive somatostatin in rat intermediate pituitary lobe after stalk section.

Immunoreactive somatostatin is present in the intermediate pituitary lobe of the rat and, to a lesser extent, in the posterior lobe. Section of the pituitary stalk results in a marked (80%) decrease in somatostatin in the intermediate pituitary lobe, but no change in the peptide levels in the posterior lobe. These results indicate that a substantial part of intermediate lobe somatostatin is located in nerve fibers originated in the brain.

Animals↗
PubMed1983

Vitamin E prolongs survival and function of porcine Leydig cells in culture.

Vitamin E (alpha-tocopherol) is known to be required for testicular function but its action on specific testicular cells has not yet been studied. The present study used porcine Leydig cell cultures, in a hormone-supplemented medium, to study the effect of vitamin E (vit E) on Leydig cells. It was seen that the addition of vit E to the medium led to an increase in cell survival, lengthening the life span of the cultures from 3-4 days to more than a week. The Leydig cells maintained their LH/hCG receptors and responsiveness throughout this period as evidenced by an increase in testosterone (T) and prostaglandin secretion. The hCG stimulated T levels were synergistically increased in the presence of vitamin E, while basal levels of T secretion were not changed. Other secretory products of Leydig cells are prostaglandins E2 and F2 alpha. It was found that the addition of vit E inhibited both the basal prostaglandin levels and the stimulated levels by 90%. Maximal effects on all of these parameters were seen at 10 ng/ml vit E. It is obvious that vit E plays a critical role in maintaining porcine Leydig cells in primary cultures beyond the first 3 days. This vitamin seems to be involved both in steroidogenesis and in prostaglandin production in the Leydig cells. The exact mechanism of the action of vit E these two biosynthetic pathways remains to be determined.

Animals↗
PubMed1983

In-vitro prostanoid production by the rat vas deferens.

Prostaglandins (PGs), E-2, F-2 alpha, 6-keto-F-1 alpha and thromboxane B-2 (TXB-2), produced in vitro by the vas deferens of rats at different stages of sexual maturation (10, 35 and 100 days of age), were estimated by radioimmunoassay. Reversed-phase high-performance liquid chromatography was used to evaluate the RIA and to give a more complete profile, after incubation of the vas deferens with [14C]arachidonic acid. The amount of PGE-2 released into the medium after incubation at 37 degrees C for 5 min increased with age, and was the predominant prostanoid in the adult vas deferens. In prepubertal organs, 6-keto-PGF-1 alpha predominated. TXB-2 was always a minor product. The addition of exogenous arachidonic acid (10 micrograms/ml/20 mg tissue), provoked a higher production of the four compounds. PGE-2 and PGF-2 alpha levels were reduced after castration or hypophysectomy and were re-instated after treatment with testosterone propionate. PGE-2 was much more sensitive to hormonal deprivation than PGF-2 alpha. The production of 6-keto-PGF-1 alpha was not significantly affected by the above treatments.

6-Ketoprostaglandin F1 alpha↗
PubMed1982

Evidence for the presence of enkephalin in catecholaminergic neurones of cat locus coeruleus.

The distribution of enkephalin (Enk) and tyrosine hydroxylase (TH) immunoreactivity in the cat locus coeruleus (LC) has been studied with indirect immunofluorescence technique. After intratissular injection of colchicine numerous enkephalin-containing cell bodies were seen throughout the rostrocaudal extent of the LC complex. Comparison of 8 micrometers-thick consecutive sections treated with antiserum to Enk of TH, a specific marker for catecholaminergic neurons, shows that most cells containing TH also present Enk immunoreactivity. This study provides the first evidence for the coexistence of enkephalin and catecholamine in CNS neurons.

Animals↗
PubMed1982

Specific binding of [3H]prostaglandin E2 to rat brain membranes and synaptosomes.

There is saturable, reversible and specific binding for [3H]prostaglandin E2 (PGE2) to rat brain membranes. This binding is of high affinity, selectively distributed with a maximum in the hypothalamus, the amygdala and the posterior pituitary, and is associated subcellularly with the synaptosomal fraction. This specific PGE2 binding has the characteristics expected for receptors, so opening new perspectives which might clarify the role of PGs in the brain.

Amygdala↗
PubMed1982

In vitro prostaglandin synthesis by various rat renal preparations.

Prostaglandin synthesis by eight different structures from the rat kidney (while cortex, cortical tubules, glomeruli, outer medulla, papilla, glomerular cultured epithelial and mesangial cells, cultured interstitial medullary cells) was measured in vitro after incubation with [14C] arachidonic acid using high-performance liquid chromatography followed by RIA with four specific anti-prostaglandin antibodies (prostaglandin E2, prostaglandin F2 alpha, 6 keto-prostaglandin F1 alpha, thromboxane B2). Prostaglandin production by the whole cortex and cortical tubules was very low. The order of abundance for isolated glomeruli was thromboxane B2 great than prostaglandin E2 greater than prostaglandin F2 alpha greater than 6 keto-prostaglandin F1 alpha. Mesangial cells synthesized prostaglandin E2 at a markedly high rate, in decreasing order: prostaglandin F2 alpha, thromboxane B2 and 6 keto-prostaglandin F1 alpha. The same order of abundance was observed for epithelial cells. The papilla synthesized essentially prostaglandin E2 and prostaglandin F2 alpha, whereas the main product for the outer medullar was 6 keto-prostaglandin F1 alpha. Cultured interstitial cells synthesized mainly prostaglandin E2 and to a lesser extent prostaglandin F2 alpha. Unidentified peaks eluting between 6 keto-prostaglandin F1 alpha and thromboxane B2 were also observed chiefly with glomeruli but they were absent with the medullary preparations. They disappeared after incubation with indomethacin or aspirin and represented for glomeruli the greatest percentage of conversion of [14C] arachidonic acid. These results show that the prostanoid profile varies markedly with the different regions and cells of the rat kidney.

Animals↗
PubMed1982

Biotin-responsive immunoregulatory dysfunction in multiple carboxylase deficiency.

The immunoregulatory system has recently been shown to require prostaglandins (PG) for its activation in man. We report here an impairment of immunoregulatory function, due to defective PGE monocytic production, in a 12-month-old boy with multiple carboxylase deficiency (MCD). The abnormal immune-response was corrected in vitro by adding PGE to the medium. Moreover, PGE deficiency and immunoregulatory dysfunction responded to biotin administration in vivo. It is suggested that the PGE deficiency in MCD could result from an impaired activity of a biotin enzyme, acetyl CoA carboxylase, since the product of this enzyme reaction, malonyl CoA, is required for prostaglandin synthesis.

Biotin↗