Studies on the effect of iron overload on rat cortex synaptosomal membranes

Iron as ferrous ammonium sulfate was injected into the cerebral spinal fluid of rats. After three consecutive days of injection of 4 mumol of iron, the total iron content of brain cortex synaptosomes from the iron-treated animals was 2-fold higher than that from control animals receiving the saline vehicle only. Spin label studies of the synaptosomal membranes demonstrated that the lipid region of the membranes became more rigid and, in addition, the mobility of labeled SH groups of membrane proteins decreased after the iron treatment. The cholesterol content was significantly higher in iron-treated animals as compared to controls. Centrophenoxine pretreatment (100 mg/kg body weight daily for 6 weeks) diminished the iron effects. Synaptosomal membrane alterations observed after iron treatment were similar to changes observed previously during aging. This lends support to the notion that free-radical induced damage occurs in brain membranes with increasing age.

Heterozygosity in the Pi-system as a pathogenetic cofactor in chronic obstructive pulmonary disease (COPD)

A population (n = 526), consisting of employees with COPD, was compared with 2 control populations for the prevalence of Pi-phenotypes. In the patient group, the proportions of ZZ, SZ and MZ were significantly elevated. Among the patient population a prospective study was carried out to evaluate the role of alpha 1-antitrypsin deficiency as a cofactor in COPD. Severity of disease was estimated by standard pulmonary function tests, X-ray signs for emphysema and clinical assessment. Patients with ZZ, SZ and MZ were significantly worse than their MM partners. An influence of MS cannot be rejected. Phenotyping of all patients with COPD is advocated. Screening can also be by determining the ratio of alpha 1-antitrypsin and acid alpha 1-glycoprotein concentrations, which allowed detection of all ZZ, SZ, MZ and about 60% of the MS patients.

Tripeptide aldehyde protease inhibitors may depress in vitro prolactin and growth hormone release

The effects of novel nontoxic tripeptide aldehyde inhibitors of proteolytic enzymes were examined in order to investigate the possibility that serine-thiol protease(s) may be involved in PRL and GH secretion. Rat anterior pituitary cells maintained in culture for 7-8 days or freshly taken pituitary quarters were treated with BOC-DPhe-Pro-Arg-H (BOC-dPPA), DPhe-Pro-Arg-H (dPPA), BOC-DPhe-Leu-Lys-H (BOC-dPLL), or BOC-DPhe-Phe-Lys (BOC-dPPL). Newly synthetized [3H]PRL and [3H]GH as well as immunoreactive (i) hormones (iPRL, iGH) were measured in the incubation media and cell homogenates. Four hours of incubation in the presence of 0.1 mM dPPA resulted in a 30% decrease of [3H]PRL and iPRL release by cell cultures; the inhibition by BOC-dPPA was 60% and 48%, respectively. [3H]PRL biosynthesis was unchanged or slightly decreased. The effect of these tripeptide aldehydes on [3H]GH and iGH release was less pronounced but statistically significant. Pituitary quarters treated with 1.0 or 3.0 mM BOC-dPPA release 20% and 57% less [3H]PRL than the controls. In the same system BOC-dPPA in a 1.0 mM concentration did not effect GH secretion, and 3.0 mM BOC-dPPA inhibited [3H]GH output by 27%. Forty micromolars of BOC-dPPL decreased by 47%, 0.2 mM by 79%, and 1.0 mM by 94% [3H]PRL release from pituitary quarters. GH secretion was not influenced. A similar selectivity was observed when BOC-dPLL was used. It is clear that by serine-thiol protease inhibitors whose effects are sequence and dose dependent, PRL and GH release are decreased. The relative inhibiting potency on PRL release was BOC-dPPL greater than BOC-dPLL greater than BOC-dPPA greater than dPPA. The biosynthesis of [3H]PRL was reduced only in the presence of the highest tripeptide aldehyde concentrations or long (8 h) exposure, and only 1.0 mM Boc-dPPL reduced [3H]GH biosynthesis by 30%. The data suggest that proteolysis may be involved in the process of PRL and GH release and the enzyme(s) in question may be serine-thiol protease(s).

Verification of the membrane hypothesis of aging on the identified giant neurons of the snail Lymnaea stagnalis L. (Gastropoda, Pulmonata) by a combined application of intracellular electrophysiology and X-ray microanalysis

The validity of the membrane hypothesis of aging (Zs.-Nagy, 1978) was tested on identified giant neurons of the snail Lymnaea stagnalis L. by using a combination of intracellular microelectrophysiology and X-ray microanalysis of the intracellular water and electrolyte concentrations on the very same cells. The snails were taken from an inbred stock and divided into young, adult and old age groups (3, 12 and 24 mth, respectively). The giant neuron called LPa-2 from the left parietal ganglion was selected for the studies. The resting potential of the cell membrane was recorded by means of intracellular microelectrode technique. The very same cells were then explored by freeze fracture and analyzed by an energy dispersive bulk specimen method of X-ray microanalysis. The resting membrane potential displayed an age-dependent hyperpolarization, the intracellular water content decreased considerably and the intracellular potassium concentration increased almost 90% by old age. The relative passive permeability ratio for potassium (PK) and chloride (PCl) was calculated from the measured data by means of the Goldman-Hodgkin-Katz equation. Such calculations revealed that PK decreases nearly 50% with age causing the increase of the intracellular potassium content, and this is accompanied also by a significant decrease of the PCl. The results support the validity of the membrane hypothesis of aging and are in agreement with the general knowledge regarding the electrophysiological behaviour of the giant neurons of Gastropode snails.

[The role of splenectomy in the treatment of lymphomas of low malignancy]

The effect of splenectomy was studied in 30 patients with non-Hodgkin lymphoma of low malignancy. Severe bacterial infections occurred in 9 patients. Follow-up of the total group of 72 patients-years revealed one infection requiring hospitalization per eight patient-years. With chronic lymphatic leukaemia there was no difference in the incidence of severe infection between splenectomized and non-splenectomized patients. In 12 patients the splenectomy produced favourable results in that in some (8) cytostatic treatment was no longer required, while in others (4) the dose of cytostatic drugs could be reduced after several months without any medication. Survival rate was not influenced by splenectomy.

Various proteinase inhibitors decrease prolactin and growth hormone release by anterior pituitary cells

Proteinase inhibitors were tested for their ability to inhibit prolactin (PRL) and growth hormone (GH) release by cultured anterior pituitary cells of the rat. Inhibitors of microbial origin (chymostatin, elastatinal, leupeptin) had either no or a moderate effect on hormone release while some tripeptide aldehydes, especially those with lysine at their C terminus, inhibited markedly PRL and to a lesser extent GH release. Boc-DPhe-Phe-lysinal was the most effective on lactotrophs inhibiting PRL release more than 50% at 10(-4) M. The site(s) of action of tripeptide aldehydes remain to be elucidated.

The effects of various doses and various applications of heparin on the fat metabolism and on blood coagulation

Various effects of heparin were compared after intravenous infusion and after subcutaneous injection. Administration by the intravenous route causes a considerable amount of heparin to remain in circulation. A strong anticoagulant effect is thereby achieved, but also a diminution of the activity of antithrombin III, a decrease in platelet count and an increase in platelet aggregation. In addition, there is a considerable lipolytic effect. After subcutaneous injection heparin is mainly stored in the RES from where it is gradually released. This causes a much weaker effect on coagulation, on platelets, on antithrombin III and on lipid metabolism. The advantages and disadvantages of both routes of heparin administration are discussed.

Alterations in the molecular weight distribution of proteins in rat brain synaptosomes during aging and centrophenoxine treatment of old rats

Properly prepared membrane proteins of brain synaptosomes of 2-, 12- and 24-month-old CFY female rats were filtrated on a Sepharose 2B gel. The molecular weight distribution showed an age-dependence: there was a clear shift toward the higher molecular weights in the adult and old rats. The observed alterations reflect an increased cross-linking of the proteins during aging due most probably to the OH free radical damage of the cell components. Centrophenoxine treatment for 2 months reversed this phenomenon in the old animals: the high molecular weight fractions decreased and the lower ones increased in the treated animals as compared to the old, untreated rats. The results support the membrane hypothesis of aging and contribute to a better understanding of the biological effects of centrophenoxine.

Effects of ionic strength on the activity of superoxide dismutase in vitro

Changes in superoxide dismutase (SOD) activity were studied in vitro at increasing NaCl or KCl concentrations. SOD activity was measured using two different systems of superoxide radical generation: pyrogallol autoxidation, and xanthine-xanthine oxidase reaction. Pyrogallol autoxidation was directly measured by spectrophotometry, whereas in the second case cytochrome c reduction was followed at 550 nm. The inhibition of SOD on those parameters was taken as measure of SOD activity. Increasing concentrations of NaCl and KCI significantly increased the rate of pyrogallol autoxidation. The inhibitory effect of SOD significantly decreased under the influence of these salts and followed an exponential curve. The two salts studied resulted in essentially identical changes in SOD activity. Increasing concentrations of NaCl and KCl decreased the rate of cytochrome c reduction in the xanthine-xanthine oxidase system. When correcting the results for these primary effects, SOD activity also displayed in this system an exponential decay with increasing salt concentrations. The results are interpreted in terms of the known charge distribution pattern on the surface of the SOD molecule, and of the age-dependent increase of the intracellular potassium and sodium concentrations in the postmitotic cells.

Electron spin resonance spectroscopic demonstration of the hydroxyl free radical scavenger properties of dimethylaminoethanol in spin trapping experiments confirming the molecular basis for the biological effects of centrophenoxine

The ADP-Fe(II)-H2O2 system generates OH free radicals which can be trapped by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) thus yielding a measurable signal by electron spin resonance spectroscopy. The amount of DMPO-OH spin adduct formed under certain conditions decreased considerably, if dimethylaminoethanol (DMAE), p-chlorophenoxyacetic acid (PCPA) or centrophenoxine (CPH) were present in comparable concentrations to that of DMPO. It has been demonstrated that such an effect cannot be attributed to any interference of the tested compounds with the Fe(II) and its oxidability by H2O2. The reaction of DMAE with OH free radicals was demonstrated also by using other spin traps. These spin traps reacted with OH free radicals either not at all (phenyl-tert-butylnitrone, PBN) or only to a slight extent (alfa-pyridyl-l-oxide-N-tert-butylnitrone, 4-POBN). DMAE was also a competitive OH free radical scavenger with proline and hydroxyproline, both of which have recently been shown to react with OH free radicals to form nitroxyl free radicals. On the basis of the experimental results, the OH free radical scavenger property of DMAE can be regarded as firmly established. This result supports the molecular mechanism proposed for the explanation of the anti-aging effects of CPH in terms of the membrane hypothesis of aging.

Hydroxyl free radical reactions with amino acids and proteins studied by electron spin resonance spectroscopy and spin-trapping

It has recently been shown that Fe(I) complexes of ADP or ATP generate OH radicals with H2O2 in a Fenton-type reaction. The OH radicals can be detected by using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap in electron spin resonance spectroscopy. All the biologically occurring amino acids, some related compounds and several proteins (histone, bovine serum albumin, collagen) were tested as OH radical scavengers against DMPO. The tested compounds competed with DMPO in trapping OH radicals to various extents as shown by the decrease of signal intensity of DMPO-OH spin-adduct. The tested compounds did not oxidize Fe(II) itself, with the only exception being tyrosine, as revealed by properly designed ferrozine reaction. Some of the amino acids reacted also with the DMPO-OH spin-adduct to a certain extent, whereas others did not. The formation of carbon centered organic radicals of the amino acids could be detected under the influence of OH radicals by using the spin traps phenyl-tert-butylnitrone (PBN) and alpha-pyridyl-1-oxide-N-tert-butylnitrone (4-POBN). The proteins, however, did not react with these spin traps. One can conclude that the amino acids and proteins can be targets of OH radical damage even in vivo, and such phenomena may be of importance in the deterioration of the conformation of proteins, e.g., during aging or in some pathological processes.

Formation of long-lived hydroxyl free radical adducts of proline and hydroxyproline in a Fenton reaction

Proline and hydroxyproline when exposed to the hydroxyl free radical generating system of ADP-Fe(II)-H2O2 yielded long-lived free radicals. An analysis of the electron paramagnetic resonance spectra of the long-lived hydroxyl free radical adducts of proline and hydroxyproline is consistent with a free electron on a nitroxyl group interacting with the nitrogen atom as well as with three separate protons. In the case of proline, nitroxide formation was observed under the influence of tert-butyl-hydroperoxide, giving a similar EPR spectrum (Lin, J.S., Tom, T.C. and Olcott, H.S. (1974) J. Agr. Food Chem. 22, 526-528); however, the hydroxyl free radical adduct of hydroxyproline has not been described yet. In the case of the proline nitroxide radical, two of the three protons involved interact with the free electron equivalently. The coupling constants for the hydroxyl free radical adduct of proline are AN = 1.58 mT, AH1 beta = AH2 beta = 2.13 mT, AH3 beta = 1.77 mT and for hydroxyproline are AN = 1.54 mT, AH1 beta = 2.56 mT, AH2 beta = 2.03 and AH3 beta = 1.51. The data are consistent with the amine nitrogen of proline and hydroxyproline being oxidized to a nitroxyl group and the free electron of the nitroxyl interacting with the beta-protons of these amino acid hydroxyl free radical adducts.

Age-dependent decrease of the passive Rb+ and K+ permeability of the nerve cell membranes in rat brain cortex as revealed by in vivo measurement of the Rb+ discrimination ratio

Young, adult and old male CFY rats (2, 12 and 24 mth of age, respectively) were treated with a daily dose of 30 mg RbCl/100 g body weight, in form of aqueous solution injected intraperitoneally for 14 days. A considerable part of the intracellular K+-content of the body was replaced by Rb+ during this treatment. After cessation of the RbCl injections, a relative steady state came into being in each age group, called Rb+-release period. During this period Rb+ and K+ contents of the blood serum and the cisternal CSF were measured by atomic absorption spectrophotometry, and of the intracellular space of brain cortical cells by energy-dispersive X-ray microanalysis. Ultrastructural features of the brain cortex were also checked by transmission electron microscopy. For X-ray microanalysis, the L-line of Rb at 1.694 keV energy was used at 10 kV accelerating voltage in a scanning electron microscope equipped with an EDAX System F. Rb+ and K+ concentrations were obtained for the cellular dry mass and converted into wet concentrations on the basis of intracellular water contents known from former experiments. Rb+-replacement of K+ did not cause any ultrastructural alteration in the brain cortex. However, the Rb+ accumulation displayed a very significant age-dependent increase: at the beginning of release, adult and old rats had 32.6 and 44.7 mM Rb+ in their intracellular water as against the 8.6 mM found in the young group, and similar proportional difference persisted during 20 days of the release. Rb+ discrimination ratios (DR) calculated either for the blood or the CSF displayed very considerable age-dependent increase: the values of the adult and old groups were 191 and 242% of the young one, indicating that the passive Rb+ (and K+) permeability of the nerve cell membrane decreases throughout the life span of rats. These results give further support to the membrane hypothesis of aging.

Inhibition of growth hormone and prolactin secretion by a serine proteinase inhibitor

The action of the tripeptide aldehyde t-butyloxycarbonyl-DPhe-Pro-Arg-H (boc-fPR-H), belonging to a family of serine proteinase inhibitors, on the release of immunoreactive prolactin (iPRL) and growth hormone (iGH) has been studied. In rat anterior pituitary cell cultures and pituitary quarters 1 mM boc-fPR-H inhibited basal iPRL and iGH release. Thyroliberin-induced iPRL release by cultured cells was also markedly inhibited with a concomitant accumulation of intra-cellular iPRL. During the short- and long-term exposure of cells to boc-fPR-H there no changes in total cell protein contents and in activities of some lysosomal marker enzymes. A wide scale of unchanged parameters characteristic for cellular metabolism indicated that the tripeptide aldehyde has no cytotoxic effect. The marked inhibition of basal as well as stimulated hormone release in the presence of the enzyme inhibitor might suggest that at least a portion of the hormones is released via a proteolytic enzyme-dependent process.

Correlation of malignancy with the intracellular Na+:K+ ratio in human thyroid tumors

Energy-dispersive X-ray microanalysis was applied on human intraoperative biopsy materials of different thyroid tumors. To ensure suitability of these tissue pieces for quantitative microanalysis in freeze-fractured, freeze-dried bulk specimens, sampling was carried out with strictly defined criteria. Benign adenomas and differentiated and anaplastic carcinomas were selected for the studies on the basis of pathohistological investigations of the same specimen. The results of the tumor cells were compared to those obtained in apparently normal human epithelial cells. The number of normal cells analyzed was 349, whereas in the tumors 408, 423, and 891 cells were measured in the benign, differentiated, and anaplastic groups, respectively. Intracellular monovalent contents were calculated as percentage of cell dry mass; then, Na+:K+ molar ratios were calculated for each cell individually. Due mostly to the increase of Na+ content, the distribution histograms of the Na+:K+ molar ratio show an increase in the number of cells with a higher Na+:K+ ratio with increasing malignancy of the tumors studied. The differences proved to be statistically highly significant by the chi 2 test. Thus, in human thyroid, increasing malignancy is associated with increasing intracellular Na+:K+ ratio. The results give further support to the theory of C. D. Cone (J. Theor. Biol., 30: 151-181, 1971) according to which the sustained depolarization of the cell membrane results in an increased rate of cell division.

Alterations of the synaptosomal membrane 'microviscosity' in the brain cortex of rats during aging and centrophenoxine treatment

Synaptosomal and myelin fractions were isolated from the brain cortex of young, adult and old male CFY rats (2, 12 and 24 mth, respectively). The purity of the fractions was tested by transmission electron microscopy and marker enzyme assays. The cholesterol content of the fractions was also determined. Samples of the fractions were labelled with diphenylhexatriene (DPH) and the fluorescence anisotropy (r) of the label was measured at various optical densities. The values of r extrapolated to zero optical density were compared in the age groups and used for calculating the 'microviscosity' of the membranes. The 'microviscosity' of synaptosomal membranes displayed a significant age-dependent increase: from 2.3 +/- 0.02 (SD) in the young group it increased to 2.6 +/- 0.03 poise by the age of 24 mth at 37 degrees C. Most of this increase occurred between the adult and old age. The cholesterol content of the synaptosomes also increased significantly during aging. Centrophenoxine (CPH)-treatment with 100 mg/kg body weight daily dose for 2 mth was able to reverse the age-dependent alterations of both the membrane 'microviscosity' and the cholesterol content in the synaptosomes: the values returned nearly to the adult level. The results obtained are interpreted in terms of the membrane hypothesis of aging attributing to primary role to the free-radical induced membrane damage in cellular aging.

Microfluorimetric and X-ray microanalytic studies on the DNA content and Na+:K+ ratios of the cell nuclei in various types of thyroid tumors

Parallel studies were performed using microfluorimetric DNA determination and X-ray microanalysis on the same thyroid biopsy material to compare the intranuclear DNA and monovalent electrolyte contents (Na+, K+, Cl-). Samples were taken from apparently healthy, adenomatous, and cancerous parts of human thyroid glands removed surgically. The time interval was less than 1 min. The tissues were classified by the pathologist into four main classes: 1) Normal thyroid tissue; 2) benign adenomas; 3) differentiated (follicular and papillary) carcinomas; and 4) anaplastic cancers. The results revealed that the level of aneuploidization showed an increase parallel with the malignancy of the studied tumor. At the same time, a similar tendency was found in the average values of the intranuclear Na+:K+ ratios. The results obtained in this way confirm the possibility that the electric properties of the cell membrane, that is the sustained membrane depolarization, may have a role in the regulation of DNA synthesis and in mitogenesis. These results may offer new diagnostic and/or therapeutic possibilities.

Is there a direct correlation between the activities of various lysosomal enzymes and prolactin secretion in the rat anterior pituitary?

The degree of endocrine activity by rat pituitary lactotrophs was manipulated and the lysosomal involvement in the release and intracellular degradation of PRL was monitored by concomitant assays of acid phosphatase, beta-glucuronidase, dipeptidyl peptidases I and II, and nonspecific esterases in the anterior lobe. The in vitro release of PRL by cell cultures was inhibited by 0.5 or 1.5 microM bromocriptine during 24 or 72 h of incubation and by 0.75 microM for 4 h. Long term treatment caused a 40% reduction in the total PRL content of cells and media; however, after 4 h of bromocriptine treatment, no reduction in PRL content was found. TRH (10 ng/ml) in medium for 4 h increased PRL release, whereas it produced intracellular hormone depletion. In vitro treatment of anterior lobes of diestrous rats with 1 microM dopamine decreased PRL release by 50%. No changes in lysosomal enzyme activities were observed after the inhibition of release or stimulation of the in vitro secretion of PRL. Haloperidol (2.5 mg/kg BW) caused a 90% increase in serum PRL concentrations in diestrous rats 1 h after sc injection. alpha-Methyl-p-tyrosine (200 mg/kg BW, ip) stimulated in vivo PRL secretion, monitored 1, 4, and 24 h after drug administration. The administration of 100 micrograms/rat bromocriptine for 3 consecutive days, a single dose of 100 micrograms/rat polyestradiol phosphate, and their combination resulted in the expected changes in PRL production in female rats. These in vivo treatments failed to alter lysosomal enzyme activities in the anterior pituitary. These findings suggest that the release, intracellular accumulation, or depletion of PRL occurred without concomitant changes in lysosomal enzyme activity in the anterior pituitary. We suggest that the system of lysosome-dependent hormone degradation may involve more specific enzymes than those monitored to date.

The effect of primycin on the intracellular monovalent ion and water contents of rat hepatocytes as revealed by energy dispersive X-ray microanalysis and interference microscopy

Using energy-dispersive X-ray microanalytic and interference microscopic techniques, the intracellular concentration of the monovalent ions (Na+, K+, Cl+) as well as the intracytoplasmic and intracellular water contents were studied in normal and adrenalectomized rat hepatocytes with and without primycin treatment. Although primycin influenced significantly only the intracellular potassium content of the adrenalectomized group, it exerted a marked influence on the intranuclear water content in both the normal and adrenalectomized rats. The intranuclear water content increased significantly in the primycin-treated animals. The conclusion is drawn that the increased level of hydration of the nuclear substances reflects a 'decondensation' of the chromatin which on the other hand, may represent the basis for the various effects of primycin on the induction of certain hepatic enzymes.

In vivo studies on the age-dependent decrease of the rates of total and mRNA synthesis in the brain cortex of rats

The membrane hypothesis of aging (Zs.-Nagy, I., 1978, J. Theor. Biol. 75, 189-195) attributes the primary role in cellular aging to an age-dependent decrease of the passive potassium permeability of the cell membrane which is due most probably to free-radical damage of the membrane components. As a consequence, the intracellular and intranuclear ionic strength increases resulting in a condensation of the chromatin and a slowing down of the synthetic processes performed by the nucleus. In this concept it was of importance to reveal whether the rates of total and mRNA synthesis display any age-dependent alteration parallel with the change of membrane permeability of the brain nerve cells. Experiments were performed using tritiated uridine incorporation measurements and suitable preparation techniques in young, adult and old rats (1.5, 13 and 25 mth of age, respectively). Comparisons of the incorporation rates revealed a very considerable decrease in the rate of synthesis of both the total and polyadenylated RNA (polyA + RNA) between the ages of 13 and 26 mth. The old animals displayed only about 55 and 67% of the rate of synthesis for the 2 classes of RNA, respectively, as compared to the young and adult rats, if the results are expressed as dpm/mg RNA. However, the decreases are even more pronounced (34 and 41%) if the results are expressed on a dry weight basis. The results obtained are compatible with the membrane hypothesis of aging.

Restoration of pituitary prolactin synthesis and release by the administration of morphine to rats bearing a transplanted prolactin-secreting tumor

Rats bearing transplanted prolactin-secreting tumors are known to have very high prolactin levels in the serum, reduced hypothalamic opiate concentrations, increasing hypothalamic dopamine synthesis and increased hypophyseal portal blood dopamine levels. Further, it has been shown that incubation in 3H-leucine of anterior pituitary glands from these tumor-bearing rats demonstrates a marked inhibition of 3H-prolactin synthesis and release. Using rats with the prolactin-secreting tumor MtTW15, we have found that 4 days of continuous administration of either morphine sulfate 1.44 mg daily or haloperidol 0.11 mg daily using and osmotic infusion pump caused a significant increase in the synthesis and release of 3H-prolactin from incubated pituitary gland compared to untreated tumor-bearing animals. Morphine may reduce hypothalamic dopamine release, whereas haloperidol is a direct dopamine receptor antagonist in achieving these effects.

In vivo effects of vitamin E deficiency on the intracellular monovalent electrolyte concentrations in brain and liver of rat. An energy dispersive X-ray microanalytic study

Vitamin E is known to play a protective role for cell membranes against free-radical attacks. Vitamin E deficiency causes a rapid macroscopic ageing of rats. On the other hand, during normal ageing, cell membranes undergo functional alterations resulting in an increased intracellular potassium concentration in brain and liver cells. Therefore, is was of interest to study whether vitamin E deficiency produces similar alterations in young rats. Female Wistar rats were fed with a vitamin E deficient diet from 1 month of age for 10 months. The parietal brain cortex and the liver were analyzed by means of a quantitative energy dispersive X-ray microanalytic method using a JEOL JSM-35C-EDAX-711-NOVA-3 system. Monovalent electrolyte contents as well as the water content of the cells were determined in 5 treated and 5 control animals. Water content was measured by analyzing the potassium content in aqueous, frozen state, and again in the dry mass of the cells. On the basis of these data, a computer program calculated the water proportions. Average values for 200 or more cells of each organ per group revealed a significant increase in the intracellular potassium content of the brain cells, whereas the sodium and chloride contents increased to a much lower extent. There was a 2.6% loss of intracellular water in the brain cells in the vitamin E deficient group. The liver monovalent ions and water content remained unchanged. The results obtained are discussed in terms of the membrane hypothesis of ageing.

Focal nodular hyperplasia of the liver and hepatic cell adenoma in women on oral contraceptives

The article reports on the respective occurrence of focal nodular hyperplasia and hepatic cell adenoma in the liver of two women on oral contraceptives. The hepatic cell adenoma showed serious vascular lesions, including peliosis hepatis. Both tumors were removed surgically, and the patients are well. A possible relationship between oral contraception and benign hepatic tumor genesis is discussed under consideration of the pertinent literary data.

On the role of cross-linking of cellular proteins in aging

Water-insoluble protein fractions increase in the brain cortical tissue and liver of rats during aging in both sexes. This suggests a possible increase in the cross-linking of proteins which may be due to the formation of, for example, hydroxyl free radicals during several metabolic processes. In vivo application of centrophenoxine causes a reversal of this phenomenon in old rats. In vitro experiments show that the generation of hydroxyl free radicals by chemical systems like homolysis of H2O2 by redox coupling with Fe2+ leads to Fe3+ conversion, results in the cross-linking of bovine serum albumin and the mixed proteins of liver or brain homogenates of young rats. The cross-linked proteins have a very much increased molecular weight, they become mostly insoluble even in 6 M urea. Dimethylaminoethanol, the effective part of the centrophenoxine molecules, is able to diminish the extent of cross-linking, acting most probably as a free-radical scavenger. The results are discussed in terms of the "membrane hypothesis of aging". A molecular basis is proposed for the anti-aging effect of centrophenoxine.

Effect of antiestrogens on pituitary prolactin production in normal and pituitary tumor-bearing rats

Administration of the antiestrogen tamoxifen to normal Buffalo female rats caused a 45% reduction (p less than 0.01) in 3H-prolactin synthesis and release in vitro. Radioimmunoassayable prolactin in incubated glands and medium also decreased significantly. Similar results were observed in Wistar-Furth animals except for in vitro radioimmunoassayable prolactin, which decreased less markedly (by 33%, p less than 0.01). Serum prolactin concentration in treated rats was unchanged. Tamoxifen did not affect the extremely high serum prolactin concentration in rats bearing mammotropic tumors. It further reduced in vitro synthesis of radioactive prolactin but not of the radioimmunoassayable hormone. No interaction between antiestrogens and the dopamine agonist bromocriptine was observed. These observations suggest that the nonsteroidal antiestrogens decrease the synthesis of prolactin but have little effect on release of the hormone. Tamoxifen inhibits growth of transplantable mammotropic tumors MtTW15 and 7315a potently without altering tumor prolactin production. In vivo treatment of adult female rats with tamoxifen did not affect in vitro synthesis and release of radioactive growth hormone, but reversed the elevated growth hormone production of rats bearing 7315a tumors.

Major metabolic pathways and hormone production in unstimulated monolayer cultures of the rat anterior pituitary

In cell cultures derived from anterior pituitary glands of rats, enzyme activities of cell homogenates and hormone (GH, PRL, LH, and FSH) content of the culture media were measured. Sex differences in enzyme activities representing major metabolic pathways (citrate cycles, pentose cycles, and glycolysis) were demonstrated both in freshly dispersed cells and in 8-day-old cultures; in cultures of both sexes enzyme activities increased during cultivation. In cultures derived from female rats, cell protein doubled by the 12th day and remained constant for up to the 24th day in culture, whereas enzyme activities showed changes suggesting that cell metabolism shifted to anaerobic glycolysis during cultivation. In the culture media the presence of four pituitary hormones was demonstrated for as long as 3 weeks of cultivation with variable secretion dynamics; the release of gonadotropic hormones diminished gradually whereas that of GH remained constant and PRL levels increased with time. These results indicate that under strictly defined culture conditions pituitary cells may function in spite of profound metabolic changes.