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Biomedical subjects

I Bădescu

Publications and source records attributed to I Bădescu.

At least 19 recordsLinked to original sources
PubMed1993

Redox capacity of the pineal gland in rats. Effect of castration.

The day/night cycle-induced effects, and the effect of castration on pineal oxidative potential in rats, were studied herein. Experiments were made in adult and castrated Wistar rats kept under normal light conditions during winter (on December and January). Castration was performed 72 hrs before sacrification. Groups of 6 intact or castrated animals were sacrificed at 4 hr-intervals during 24 hrs (the day/night cycle). Blood and pineal were then taken. Peroxides and total pineal antioxidants in plasma and pineal homogenate were assessed by chemiluminescence. The results obtained prove that photoperiod is involved in the organism oxidative potential, and that pineal is involved in the diurnal rhythm of this potential. Pineal peroxide and antioxidative concentrations show circadian variations with minimum and maximal values during the day or the night, which are also reflected at the plasma level. In the first half of the morning are registered increased peroxide and decreased antioxidative levels while at night the diagrams are reversed. As compared to the intact group, in the castrated one antioxidants and peroxides maintain their biorhythms but their concentrations are significantly changed. The diagram of pineal peroxides in the castrated group is situated above that of the intact one, with statistically significant differences only at midday (12:00). Taking into account the antioxidative characteristics of melatonin, one can suppose that maximum pineal antioxidative levels during the night might be due to maximum concentrations of nocturnal melatonin. The significant increase in peroxide concentration and the decrease in antioxidants after castration would partly explain the physiologic status of the elderly with decreased melatonin production and increased oxidative processes.

Animals↗
PubMed1992

Total and free amino acids in the "Crinofizin" pineal extract.

In order to establish the chemical nature of Crinofizin, a protidic extract obtained from bovine pineal, the amino acids content was analysed using two analytic programs: one for biologic fluids, the other for protein hydrolysates. The results showed that the pineal extract contains besides the common protein amino acids reported earlier, others, rare in proteins, such as hydroxyproline, hydroxylysine and 1-methylhistidine as well as non-protein amino acids. From among the latter, the alpha-aminoadipic acid, beta- alanine, O-cysteine, are found only in a bound form, and are detected only by hydrolysis. Other amino acids, such as taurine, glutamine, citruline are present only in free form whereas the alpha-amino-n-butyric acid, GABA, ethanolamine and ornithine are present in both forms, free or bound. The paper discusses the physiologic significance of some amino acids.

Amino Acids↗
PubMed1991

Purification and physico-chemical characterization of the antigonadotropic fractions obtained by ultrafiltration from the pineal extract.

In order to isolate the antigonadotropic factor from a pineal extract prepared from bovine pineals the authors first applied ultrafiltration, which yielded three fractions: F1 greater than 10 kDa, 1 kDa less than less than F2 less than 10 kDa, and F3 less than 1 kDa. Examination of the biologic activity showed that only F1 and F2 have a statistically significant antigonadotropic activity. Ion exchange chromatography of F1 yielded two subfractions: one, F11, which was not retained, and another one, F12, which was retained by the exchanger. Both subfractions showed biologic activity. While F11 is closer to F2 less than 10 kDa, F12 has a molecular weight around 13.7 kDa, as resulted after applying the SDS-PAGE procedure. The F1 fraction has a proteic content of 903 micrograms/ml, F11 = 308 micrograms/ml and F12 = 247 micrograms/ml. Amino acids assay showed that the F12 subfraction has the same composition as F1 and the F11 subfraction also has free amino acids which indicates a process of adsorption of small molecules on large molecules. The F2 less than 10 kDa fraction, biologically active, has a proteic content of 433 micrograms/ml and an amino acids composition similar to F11 except for cysteine and methionine. The F3 less than 1 kDa fraction with a proteic content of 79 micrograms/ml having an amino acid composition in which prevails the glutamic acid shows poor antigonadotropic activity. The results of this study, as well as the fact that the antigonadotropic activity is concentrated in fractions both above and under 10 kDa, suggests at least two hypotheses: either that the pineal antigonadotropic factor exists under various molecular forms in which the activity is preserved, or that the antigonadotropic factor is a peptide with strong aggregation properties as demonstrated in our study.

Amino Acids↗
PubMed1991

Melatonin involvement in oxidative processes.

The fact that the pineal gland, by its melatonin (MT) production, responds to environmental light variations (the day-night cycle), being also a modulator of the body adaptation to these conditions, may lead to the assumption of its involvement in the body oxidative processes. The redox capacity of melatonin was followed-up in vitro by the chemiluminescence phenomenon. The system generating chemiluminescence as well as free radicals was made up of luminol and H2O2. Incubation of melatonin in doses of 0.08-0.5 microM/ml with the generating system showed that in doses under 0.25 microM/ml melatonin has a pro-oxidative effect while in doses above this value it has an antioxidative effect. The diagram of the results shows the answer specific to a modulator. The study of the correlation between the dose of melatonin with highest pro-oxidative properties and the various peroxide concentrations in the generating system showed that melatonin gets antioxidative properties with the increase in peroxide concentrations (less than 8 mM/ml). In the presence of a hypothalamic homogenate, which is a stimulant of the chemiluminescence-generating system (PXI = 16), melatonin has a dose-dependent antioxidative effect. Similar results were also obtained by adding tryptophan--a free radicals acceptor (PXI = 0.1) and the substrate in melatonin synthesis to the reaction medium. Melatonin in low concentrations (greater than 0.1 microM/ml) has an antioxidative effect while in higher doses it has a dose-dependent pro-oxidative effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1978

Anti-LH and FSH activity of melatonin-free pineal extract.

The influence of melatonin (MEL)-free pineal extract on luteinizing hormone (LH) and follicle stimulating hormone (FSH) was studied comparatively with that of MEL. Administration of pineal extract to rats, 3 days running, was found to induce a statistically significant decrease of serum LH and FSH. This effect was also demonstrated by the biological tests used, namely, a decrease in weight of both rat ventral prostate (anti-LH activity) and mouse uterus (anti-FSH activity). MEL administered for 3 days, in doses of 1 microgram/day in the ventral prostate weight test or of 10 microgram in the uterine weight test, failed to induce comparable effects. The identity of the pineal substances responsible for the anti-gonadotropic activity of the pineal gland is discussed.

Animals↗
PubMedDate not supplied

Comparative study of the effects of melatonin-free pineal extract and melatonin on biochemical and hormonal parameters in the rats.

A melatonin-free pineal extract administered to rats in doses of 2 ml/day/animal along 12 days, induced a statistically significant drop in urinary 17 KS, cholesterolemia, hepatic, adrenal and testicular cholesterol. The dose of 1 microgram melatonin/day/animal did not alter these biochemical indices. This dose administered for 3 days did not affect the serum level and testicular concentration of testosterone, unlike the pineal extract which lowered significantly serum and testicular testosterone. Unlike the pineal extract administration of melatonin in doses of 10 micrograms/day/animal along 3 days had no effect on DNA, RNA and testicular proteins. Administration of the pineal extract lowered significantly serum LH and FSH after 3 days whereas melatonin in doses of 50 micrograms/day/animal did not have a similar effect. Furthermore, while the pineal extract inhibited the post-castration elevation of LH and FSH, melatonin in doses of 50 micrograms/day/animal had no effect. The same difference was noted with rats under GnRH stimulation: the pineal extract inhibited the pituitary response to GnRH whereas melatonin did not. The authors conclude that the effects produced by the pineal extract are not mediated by melatonin.

17-Ketosteroids↗
PubMedDate not supplied

Effect of pineal treatment on testicular biochemical parameters under basal conditions and after stimulation with HCG in the rat.

The effect of a melatonin-free pineal extract on sialic and ascorbic acid, nucleic acids (DNA RNA), proteins, total, free and esterified cholesterol in the rat testis under basal conditions and after stimulation with HCG was followed up. The pineal extract induced a decrease in sialic and ascorbic acid, total and esterified cholesterol, but it increased the proteins and RNA after 3 days of treatment, under basal conditions. The decrease in RNA and proteins was noticed after 30 days of treatment. Administration of HCG increased the sialic and ascorbic acids and decreased the total and esterified cholesterol, proteins and DNA without affecting RNA and free cholesterol in the testicular tissue. Concomitant administration of HCG and pineal extract showed that the pineal treatment corrected partially and sometimes completely the increasing or decreasing effect produced by HCG on the biochemical indices studied. The decrease in testicular esterified cholesterol the latter associated with androgen hormone synthesis, brings into discussion the role of the pineal gland in testicular testosteronogenesis, as the same pineal extract also caused a decrease in testosterone. The authors also discuss the regulating role of the pineal gland on some testicular biochemical indices.

Animals↗
PubMedDate not supplied

Effect of pineal treatment on rat HDL-cholesterol under basal conditions and under stimulation with HCG.

The effect of the pineal extract and that of two fractions, f1 and f2, one above, the other 10,000 daltons obtained by ultrafiltration of the extract, on HDL-cholesterol as well as on cholesterolemia and testosterone, under basal conditions and under exogenous HCG stimulation was followed up. Under basal conditions, the pineal extract induced a statistically significant decrease in the 3 biochemical indices, an effect which was also recorded with the two fractions, with the difference that the effect of f2 is more intense and significant as compared to f1, whereas the effect of the pineal extract appears more intense than that of the fractions. Under exogenous HCG stimulation, the pineal extract and less the fractions, partly inhibited the lowering effect of HCG on cholesterol and the rising effect of this hormone on testosterone. The role of the equilibrating agent of the pineal extract on HDL-cholesterol, cholesterolemia and testosterone, is discussed.

Animals↗
PubMedDate not supplied

Decrease in high-density lipoprotein cholesterol after administration of melatonin-free pineal extract in the rat.

The work was focused on the effect of the pineal extract on HDL-cholesterol alongside the effect of the same extract on serum cholesterol and testosterone in the rat under basal conditions. HDL-cholesterol is utilized in the rat, preferentially by the Leydig cells for steroidogenesis. Administration of melatonin-free pineal extract, in doses of 2 ml/day/animal along 3, 6 and 12 days caused a statistically significant decrease in HDL-cholesterol of 19, 21 and 20%, respectively. The same depressor effect occurred 4 hr following a unique injection of pineal extract (-25%, p less than 0.001). Cholesterolemia decreased significantly alongside with HDL-cholesterol (14, 18, and 16% after 3, 6 and 12 days and 18% after 4 hr). The effect of the pineal extract on testosterone tested in only two experiments was to depress it significantly by 43% after 4 hr and 45% after 6 days of treatment. The decrease in testosterone level following the decrease of its major precursor, cholesterol, is discussed.

Animals↗