Inhibitory effect and mode of action of somatostatin on lipolysis in chicken adipocytes

The effect of somatostatin on lipolysis was investigated utilizing isolated chicken adipocytes. Somatostatin-14 and -28 inhibited basal lipolysis. This ability to suppress glycerol release (used as an index of lipolysis) was emphasized in presence of stimulated lipolysis. Concentration of 1 ng/ml somatostatin-14 (0.625 nM) and somatostatin-28 (0.312 nM) was found to inhibit completely the glycerol release induced by concentrations of glucagon up to 2 ng/ml (0.58 nM). The percentage of inhibition was dose-dependent. The antilipolytic effect of somatostatin-14 was also observed during ACTH and aminophylline-stimulated lipolysis. Among the mechanisms which could account for the inhibition, a possible competitive effect of somatostatin-14 with 125I-labelled glucagon binding to adipocyte membranes was excluded. The small inhibiting effect of somatostatin-14 on glycerol release prompted by dibutyryl cyclic AMP, together with the significant inhibiting effect on aminophylline-stimulated lipolysis argued for a reduction of cyclic AMP accumulation. The increase of cyclic AMP levels induced by glucagon was substantially reduced in presence of somatostatin-14. It was concluded that in chicken adipocytes somatostatin inhibited the rate of lipolysis and that reduction on cyclic AMP could be responsible, at least in part, for the antilipolytic effect.

Characterization of specific receptors for vasopressin in the pituitary gland

The present paper reports new findings concerning interaction of [3H]-Arginine-vasopressin with putative receptors in rat anterior pituitary gland. It shows the presence of a single type of receptor sites, with a limited binding capacity and a dissociation constant of nearly 1nM. The parent neurohormone oxytocin revealed weak affinity as compared with vasopressin [Ki = 100nM and Ki = 1nM, respectively]. None of the various peptides tested and, especially corticotropin-releasing factor CRF, competed for binding. Receptor characteristics appeared to be unaffected by lack of circulating vasopressin in Brattleboro rats presenting complete deficiency in synthesis of that peptide.

The autologous mixed lymphocyte reaction in patients with rheumatoid arthritis

In patients with rheumatoid arthritis (RA) a significantly decreased autologous mixed lymphocyte reaction (AMLR) was observed which varied widely and did not correlate with disease activity, clinical course or treatment schedules. When supernatants of AMLR cultures were tested for the presence of soluble factors no differences were found in regard to the suppression of allogeneic and mitogen induced lymphocyte proliferation. Furthermore both test groups failed to produce detectable amounts of interferon during the course of the AMLR, in contrast to the allogeneic situation were both RA patients and normal controls exhibited a similar interferon activity in the culture supernatants.

The binding of different lectins on peripheral blood mononuclear cells from patients with chronic inflammatory and malignant diseases

Peripheral blood mononuclear cells from patients with multiple myeloma, gastrointestinal tumors, and inflammatory bowel disease were analyzed for binding of various lectins. The results demonstrated that in most of the patients with multiple myeloma a significantly increased percentage of cells positive for Lotus tetragonolobus agglutinin (LTA), peanut agglutinin (PNA), soybean agglutinin (SBA), and wheat germ agglutinin (WGA), and a decreased number of Agaricus bisporus agglutinin (ABA) positive cells were present as compared to a normal control group. This could not be shown in malignant or inflammatory disorders of the gastrointestinal tract where only some patients exhibited an increased PNA and LTA binding, respectively. Patients with the systemic malignant disease differed from patients with solid localized tumors by a significantly altered number of ABA, LTA and SBA-positive peripheral blood mononuclear cells. Double fluorescence studies using monoclonal antibodies and lectins revealed that most of the cells expressing receptors for ABA had also receptors for OKT3, whereas most of the cells with receptors for LTA, PNA, SBA, and WGA were found to be positive for OKM.

Plasma levels of growth hormone, corticosterone and insulin, during induced hepatocyte synchronization in young rats

A wave of synchronous hepatocytes entering the cell cycle can be obtained in vivo after a subcutaneous injection (e.g. of casein) in rats at around Post-natal Day 10, when plasma growth hormone (GH) levels reach a low plateau (40 +/- 2 ng/ml) and liver cell proliferation rate is high. The present work reports the following changes in plasma hormone concentrations after synchronization of 20% of the hepatocyte population: (1) during the G1 phase (i.e. 6-12 hr after the mitogenic trigger), plasma GH concentration has dropped further (25 +/- 1.5 ng/ml). It was back to 90% of control levels during the S phase, mitosis and the following response including a transitory decrease in labelling index below control values. Injected together with the irritating mitotic trigger, a single dose of rat GH reduced the cell synchronization and post-synchronization effects by 50%. (2) Plasma corticosterone levels varied inversely to those of GH, increasing to twice the control values during G1 and were back to physiological levels when synchronized hepatocytes entered the S phase. (3) Variations in insulin levels were similar to that of corticosterone, with narrower ranges and reduced amplitudes. Our data suggest a possible correlation between the observed variations in plasma hormone levels and the induced synchronous hepatocyte response.

Ontogenetical variations of transcortin modulate glucocorticoid receptor function and corticotropic activity in the pituitary gland

This study was aimed at investigating the influence of tissue and plasma transcortin on pituitary glucocorticoid receptor function and corticotropic activity during development. "In vivo" nuclear uptake of (3H)corticosterone was found to be increased in pituitary glands from newborn rats which, unlike that of adults, lack transcortin-like material. Immature glands incubated "in vitro" likewise showed enhanced nuclear accumulation of tracer; the magnitude of uptake being inversely related to both tissue and plasma contents of transcortin. Competition studies indicate that pituitary transcortin modulates interaction of corticosterone with receptor binding sites and, hence, may interfere with steroid translocation to the nucleus. Moreover, we found that steroid-induced inhibition of ACTH release was highest in those pituitaries which were deficient in transcortin-like molecules. We conclude that the binder plays a modulating role in pituitary glucocorticoid receptor function.

The tissue architecture of synovial membranes in inflammatory and non-inflammatory joint diseases. I. The localization of the major synovial cell populations as detected by monoclonal reagents directed towards Ia and monocyte-macrophage antigens

Utilizing monoclonal reagents directed towards antigens of the monocyte-macrophage lineage and Ia antigens, the tissue architecture of synovial membranes obtained from patients with non-inflammatory joint diseases and patients with rheumatoid arthritis was studied. Emphasis was placed on the localization of the type I, type II and type III synoviocytes that previously had been defined by their cell surface phenotype with regard to the expression of monocyte-macrophage lineage (M theta) and Ia antigens as well as by their phagocytic capacity or the ability to produce glycosaminoglycans. In patients with non-inflammatory joint diseases, cells with the M theta + Ia+ (type I) phenotype constituted the majority of synoviocytes immediately adjacent to the joint cavity; cells with this phenotype were also scattered in the subsynovial tissue and in the perivascular regions. The fibroblastoid type III cells defined by the absence of both M theta and Ia antigens formed the major cell population in the subsynovial tissue in this patient group. In patients with rheumatoid arthritis, the Ia+ M theta + cells were present in a characteristic double configuration forming an intensely positive layer adjacent to the intra-articular space followed by an Ia- M theta - layer that again was succeeded by an intensely Ia+ M theta + layer. Large numbers of synoviocytes bearing M theta + Ia+ antigens were also demonstrated in the diffusely inflamed subsynovial tissue, in the perivascular regions as well as around and within lymphoid infiltrates.(ABSTRACT TRUNCATED AT 250 WORDS)

[Aneurysmal complication of a dacron vascular prosthesis]

Arterial prosthesis employed in the University Hospital Center, Homburg en Sarre, F.R.G. since 1972 have mainly consisted of knitted velvet dacron for internal insertion. Aneurysms at the site of anastomoses are a known complication and several cases have been observed, but no reports of aneurysms at the level of a prosthesis appear to have been published. This complication occurred twice in the same patient with a interval of fifteen months. Based on the results of experimental data, the question is raised as to whether this complication is the consequence of degradation of the dacron by monocytic elements.

Physicochemical analysis of glucocorticoid receptor in the immature pituitary gland: evidence for lability and aggregation of the heat-activated form

The present study was aimed at characterizing the deficiency of the glucocorticoid-receptor system in the immature pituitary gland of neonatal rats. Under conditions of both constant protein and DNA concentrations, [3H]dexamethasone binding to nuclei was significantly lower in the immature, compared with the mature, glands, despite the comparable density of receptor sites. Chromatography on DEAE-Sephacel columns revealed the failure of the neonatal receptor to form stable activated complexes, although the dissociation of tracer from binding sites, as well as the magnitude of receptor activation, remained closely similar to those found for the adult binder. Also, a striking observation was that the immature receptor exhibited the property of forming more than twice as much inactive aggregate as the mature component, when heat-activated in presence of KCl. It thus seems that development of full expression of glucocorticoid-binding activity in the pituitary involves qualitative changes of both the receptor molecules and the cytoplasmic environment, that tend to enhance stability of the activated form of the binder.

Hemophiliac knee: rehabilitation techniques

Hemophilia is an inherited bleeding disorder which produces its greatest morbidity in the musculoskeletal system. This article reviews current rehabilitation techniques for the hemophiliac knee--including restrictions of physical activity, external support, and corrective orthotic devices--reports our experience using aggressive strengthening techniques in 2 children, and compares the effectiveness of the 2 methods. It is the impression of the authors that strengthening, rather than immobilization, can bring about increased range of motion, increased strength, and decreased bleeding frequency.

[Localization diagnosis and differential diagnosis of postoperative intraperitoneal abscesses using 99m technetium-stannum-colloid-marked granulocytes]

Occult intraperitoneal abscesses are difficult to locate and dispose of. Therefore, a method of examination is needed that is specific, can be used at any time, is not expensive, and yields early results within 2-3 h. This seems possible with a new methods of examination. 99mTc-Sn colloid was used to label autologous polymorphonuclear leukocytes which, when reinjected, emigrate to the site of the suspected abscess. Standard scintigraphy localizes the labeled inflammatory cells. In 32 surgical patients, 34 scans were performed with good results (controlled by greyscale ultrasound); 17 (53.1%) scans represented intraperitoneal abscesses; 3 (9.4%) scans demonstrated true positive extra-abdominal inflammations.

Effects of isolation, handling and novelty on the pituitary--adrenal response in the mouse

Male Swiss strain mice were individually- or group-housed for four weeks. Basal corticosterone levels did not differ with the type of housing, providing no support for the suggestion that the condition of the individually-housed mouse is stressful. Plasma corticosterone levels also were determined for mice which had been either left undisturbed or exposed to new cages which differed from their home cages by varying degrees. There were elevations in mean plasma corticosterone levels corresponding to the degree of difference between the home cage and the new cage. This finding supports the suggestion that changes in 11-OHCS levels are sensitive measures of environmental changes. Mice forced to remain in novel places exhibited higher plasma corticoid concentrations than animals which were given the opportunity to move freely between familiar and novel places. Corticoid values, as well as neurophysiological and behavioral responses, suggested that the stress induced by forced exploration might be due to the fact that animals are prevented from freely regulating their exposure to novel places rather than to novelty per se.

Evidence for a possible dopaminergic control of pituitary alpha-MSH during ontogenesis in mice

This study was aimed at determining the alpha-MSH and ACTH contents of the neurointermediate lobe (NIL) of the mouse hypophysis during ontogenesis, as well as the ability of the gland, incubated in a perfusion system, to respond to dopamine (DA) and high potassium (K+). We showed that: (1) the NIL content of alpha-MSH exhibited a biphasic pattern of evolution, characterized by a dramatic increase appearing between postnatal days 3 and 5. By contrast, NIL ACTH content followed a completely different pattern of evolution; (2) both DA and high K+ reversibly inhibited MSH release from superfused NIL, the latter effect being more pronounced with the use of pituitaries from 7-day-old than from 1-day-old mice; (3) the inhibitory influence of high K+ was impaired by haloperidol pretreatment. From these data, as well as from morphological observations, it appears that functional DA receptors seem to be present on melanotrophs of the developing hypophysis in mice and that the increase in alpha-MSH in IL cells observed shortly after birth may result from the onset of inhibitory influence exerted by dopaminergic innervation on hormonal secretion. This view, however, does not preclude possible effects of other hypothalamic releasing and/or inhibiting factors.

Modulation by transcortin-like binding sites of uptake and distribution of glucocorticoids by dispersed pituitary cells

The influence of transcortin-like (TL) binding sites on uptake and distribution of glucocorticoids by dispersed pituitary cells was investigated. TL material, which combines corticosterone (CORT), but not dexamethasone (DEX), was previously found to be present on cell membranes and in cytosol of hypophysis. Exposure of cells at 0 degrees brought about striking differences in steroid binding, as labeled CORT was taken up more rapidly and to a significantly greater extent than DEX. This resulted from a higher concentration of binding sites and not from a difference in binding affinity. At 25 and 37 degrees, while the same relationship was apparent during the early events of steroid interaction with the cell, binding of DEX increased gradually with incubation time and finally exceeded that of the natural steroid. Also, time-course studies on nuclear translocation showed a biphasic pattern, which closely paralleled that of whole-cell binding. Interestingly, treatment of rats with transcortin antiserum caused a decrement of pituitary TL sites, as well as of CORT translocation. We conclude that the TL binder, which is probably of plasma origin, may be actively involved in the process of uptake and cellular distribution of corticosteroids in the pituitary gland.

Glucocorticoid binding and control ACTH secretion

This report attempts to summarize the present state of knowledge concerning interaction of glucocorticoids with brain and pituitary receptors, in relation to induction of specific biological effects. It examines the properties of the receptors, emphasizing the fact that transcortin-like binding molecules are present on the cell membrane in the pituitary gland. Also, it considers the functional aspects of the mechanism of action of steroids, including control, occupancy and heterogeneity of binding sites, as well as correlation with regulation of ACTH release.

[Vasopressin and "CRF" in the regulation of ACTH secretion by the anterior and intermediate lobes of the pituitary gland (author's transl)]

The aim of this review was to summarize the present state of knowledge concerning the mode of action of vasopressin (VP) and the putative corticotropin releasing factor (CRF) on ACTH secretion from the anterior and intermediate lobes of the pituitary gland. In vitro data show that although both CRF and VP enhanced release of anterior pituitary ACTH, the pattern of hormonal release, based on kinetical and dose-dependent studies, appeared to be different. Also, the effect of VP most probably was mediated by specific putative receptor sites. In contrast, VP was found not to alter ACTH secretion from the intermediate lobe; that secretion seems to be regulated by CRF-like material and neurotransmitters. The importance of VP as a corticotropin agent is discussed.

Ontogenesis of glucocorticoid receptors in anterior pituitary gland: transient dissociation among cytroplasmic receptor density, nuclear uptake, and regulation of corticotropic activity

The present investigation was undertaken to define the developmental pattern of glucocorticoid binding to the anterior pituitary gland and ascertain whether that binding correlated to modulation of corticotropin-releasing factor-induced release of ACTH. Scatchard analysis of data revealed the presence in cytosol (besides classical receptor sites interacting with both [3H]dexamethasone and [3H]corticosterone) of a transcortin-like component binding only the natural steroid. Whereas the number of sites of the former binder was not significantly altered during maturation and remained close to the adult value (276 +/- 12 fmol/mg protein), that of the latter declined dramatically after birth and rose again after postnatal day 10. The apparent Kd, however, remained unchanged. Transfer of te [3H]dexamethasone-receptor complex to nuclei of pituitary cells from neonates 2-6 days of age was found to be 20% that of adults despite the presence of comparable concentrations of receptor sites. Mixing experiments carried out with cytosol and nuclear fractions from different origins pointed to the cytoplasmic compartment as being implicated in this discrepancy. It was not until after postnatal day 10 that nuclear transfer reached mature levels. Although the extent of nuclear uptake and the magnitude of inhibition of ACTH secretion, as judged by means of a perifusion system, correlated well in hypophyses from 10- to 30-day-old neonates and adults, steroid binding and induction of biological response at earlier time points were less closely related. The results indicate the existence during development of a transient dissociation between cytosol and nuclear binding of corticosteroids by the anterior pituitary as well as between the latter process and blockade of ACTH release. These data are discussed in connection with the postnatal period nonresponse to stress. (Endocrinology 108: 591, 1981)

Thermosensitivity of the membrane potential of normal and simian virus 40-transformed hamster lymphocytes

The effects of temperature in the fever range (37-42 degrees) on the membrane potentials of normal and simian virus 40-transformed hamster lymphocytes were analyzed. The transmembrane distributions of radiolabeled triphenylmethylphosphonium and thiocyanate were measured, and they provide upper and lower limits for the normal cell membrane potential at 37 degrees of -48 +/- 6 (S.D.) and -31 +/- 5 mV and for the tumor cells, -36 +/- 4 and -19 +/- 2 mV. The mitochondrial contribution to the triphenylmethylphosphonium-measured membrane potential, 5 to 10 mV for both splenocytes and simian virus 40-transformed lymphocytes, was estimated by utilizing antimycin A and carbonylcyanide-m-chlorophenylhydrazone to inhibit generation of a mitochondrial membrane potential. Incubation for 1 to 2 hr at 38-42 degrees resulted in a 6- to 15-mV depolarization of normal cells and a 2- to 6-mV hyperpolarization of tumor cells. Both depolarization and hyperpolarization were fully reversible by subsequent incubation at 37 degrees and insensitive to antimycin A and carbonyl-cyanide-m-chlorophenylhydrazone. The membrane potential of normal splenocytes when measured with triphenylmethylphosphonium at 37 degrees was depolarized by 35% with 1 mM ouabain and thermally induced depolarization was blocked. The membrane potential of tumor cells at 37 degrees was insensitive to ouabain; however, the hyperpolarization at 40 degrees was inhibited. The membrane potential of normal lymphocytes stimulated with phytohemagglutinin was depolarized relative to that of nonstimulated control cells and assumed the thermal response characteristics of tumor cells.