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Biomedical subjects

P De Moor

Publications and source records attributed to P De Moor.

At least 19 recordsLinked to original sources
PubMed1979

Changes in some lipid variables in obese women during the early days of fasting.

Adult obese human subjects with a normal or slightly disturbed oral glucose tolerance test, were submitted to a 7-day fast. Initial serum triglyceride levels were inversely related to the Intralipid fractional removal rate, reflecting the close dependency of triglyceridemia on clearance efficiency; the correlation was less significant on the 5th day of fasting. The direction of the change in triglycerides during fasting was clearly related to the prefast triglyceride levels, the groups of patients with a lower level showing an increase, the group with a higher level showing a decrease. Changes in triglyceridemia were inversely related to fractional removal rate; changes in lipid clearing from plasma, however, could not explain the direction of changes in triglyceridemia in all subjects investigated. The group of patients responding to fasting with a decrease in triglyceridemia had a lower mean initial serum cholesterol value and their serum cholesterol levels showed a less prolonged increase during fasting than the other groups of patients.

Adult↗
PubMed1979

Localisation of the NADPH delta 4-3-keto steroid-5 alpha-oxidoreductase in the rat ovary.

The 5 alpha-reductase activity was localised on the stromal comportment of the rat ovary. The 5 alpha-reductase activity in stromal tissue decreased from 27.3 +/- 2.9 ng/hr/mg protein in rats 20 days old, to 13.4 +/- 1.2 ng/hr/mg protein in rats 30 days old and to 7.1 +/- 1.0 ng/hr/mg protein in adult rats. During the oestrous cycle no significant variations in enzyme activity could be demonstrated.

3-Hydroxysteroid Dehydrogenases↗
PubMed1978

The heterogeneity of human Gc-globulin.

Gc-globulin or group-specific component, also known as the vitamin D-binding protein, was investigated by the combined use of electrofocusing and immunofixation. Serum of the Gc 2-2 type was found to contain a single protein band whereas serum of the Gc 1-1 type shows two bands with a lower isoelectric point. The Gc 1-2 type contains all three bands known as Gc-2 (pI 5.10), Gc-1Slow (pI 5.03), and Gc-1Fast (pI 4.95). Each apoprotein shows an anodal shift of about 0.07 pH unit after incubation with an excess of 25-hydroxycholecalciferol. After treatment with sialidase Gc-1Fast focuses in the position of Gc-1Slow, whereas the position of Gc-2 remains unchanged.

Alpha-Globulins↗
PubMed1978

Purification and characterisation of prostatic binding protein and its subunits.

The prostatic binding protein, previously described in rat ventral prostate, was isolated. The purified protein binds pregnenolone with an affinity of 1.2 X 10(6) M-1 and contains an average of 0.84 binding site per molecular. Its carbohydrate content is 3.2%. Its Mr, estimated by gel filtration, is 51 000 but in the presence of 6 M guanidine hydrochloride or 0.1% dodecylsulfate it dissociates into two subunits (S and F), which can be separated by polyacrylamide gel electrophoresis or by chromatography on hydroxyapatite. The Mr of these subunits is about 17 000, when estimated by gel filtration in 6 M guanidine hydrochloride, or 19 000 for subunit F and 20 000 for subunit S, when measured by dodecylsulfate/polyacrylamide gel electrophoresis. Their isoelectric points, estimated by isoelectric focusing in 8 M urea, are 4.6 for subunit F and 4.9 for subunit S. Prostatic binding protein and both subunits have a very similar amino acid composition. Upon reduction of disulfide bridges each subunit dissociates further into two components: one of these components is the same in both subunits.

Amino Acids↗
PubMed1978

Immunochemical measurement of the vitamin D-binding protein in rat serum.

The vitamin D-binding protein (DBP) was measured in rat serum using a single radial immunodiffusion technique. Normal serum levels at birth (74 +/- 11 mg/liter, mean +/- SD) were lower than during the last day of fetal life (130 +/- 14 mg/liter) and much lower than in adult rats. A marked sex difference in DBP occurred after puberty: male values (656 +/- 52 mg/liter) were significantly higher than female values (472 +/- 46 mg/liter). The sex difference could be abolished by either adult gonadectomy or transpharyngeal hypophysectomy. Implantation of a pituitary gland under the renal capsule in hypophysectomized male rats further decreased the DBP concentration, suggesting that PRL suppresses the DBP level. A similar decrease was also observed at the end of pregnancy and during lactation. Administration of androgens to either normal female or gonadectomized male rats increased their DBP concentration to the normal adult male level. The serum levels of total 25-hydroxyvitamin D did not fluctuate according to the concentration of DBP, indicating that the concentration of "free 25-hydroxyvitamin D" is not regulated at a constant level.

Age Factors↗
PubMed1978

Secretion of prostatic binding protein by rat ventral prostate: influence of age and androgen.

Rat ventral prostate of adult male rats contain a large amount of prostatic binding protein (PBP). Immunological evidence indicates that this protein is a specific secretion product of this gland. The amount and concentration of PBP in ventral prostate show marked changes as a function of age. PBP is low but detectable (0.009 and 0.002 U/mg prostate) in 5- and 10-day-old rats and increases thereafter in a biphasic way to adult levels (0.619 U/mg prostate). After castration of PBP drops to 0.054 U/mg prostate after 10 days and 0.030 U/mg prostate after 21 days. The concentration of PBP returns to precastration levels after 2 weeks of androgen treatment. Estradiol and progesterone are ineffective in this respect. The antiandrogen, cyproterone acetate, counteracts the stimulatory effect of testosterone propionate.

Aging↗
PubMed1978

Relationship between the pituitary gland and gonadal steroids: involvement of a hypophysial factor in reduced alpha 2u-globulin and increased transcortin concentrations in rat serum.

Evidence is presented that the level of alpha 2u-globulin in the serum of male rats depends, at least in part, on neonatal androgens. After castration of adult animals the concentration of this protein falls but remains measurable, whereas in intact or ovariectomized female rats alpha 2u-globulin cannot be detected. Moreover, alpha 2u-globulin is found in adult male and female rats gonadectomized at birth and treated with a single injection of testosterone propionate immediately thereafter. The mechanism by which neonatal androgens increase the concentration of alpha 2u-globulin has been investigated. Transplantation of a supplementary pituitary gland under the renal capsule of male rats resulted in reduced levels of alpha 2u-globulin and increased levels of transcortin. The changes discussed here were observed only in those animals in which the transplant was functional and they were amplified or reversed by modulators of prolactin secretion such as oestrogens or bromocriptine respectively. The hypothesis is advanced that neonatal androgens stimulate the production of a hypothalamic inhibitory factor that controls the secretion of prolactin, or another hypophysial hormone subjected to similar neuroendocrine control. Measurements in gonadectomized animals and in rats receiving both oestradiol benzoate and bromocriptine indicate that, besides these pituitary-mediated effects, both oestrogens and androgens exert direct effects on the level of alpha 2u-globulin.

Alpha-Globulins↗
PubMed1977

Prostatic binding protein. A steriod-binding protein secreted by rat prostate.

Rat prostatic cytosol contains a high concentration of a prostatic binding protein with peculiar steroid-binding properties. Indeed, in spite of a relatively low affinity, charcoal adsorption can be used for its measurement. Furthermore, the binding is not specific for particular steroids and increases very strongly after delipidation. In delipidated cytosol the concentration of the binding site is 3.1 micronmol/g protein and the apparent affinity for pregenolone 1.7 X 10(6) M-1. The high concentration of prostatic binding protein in prostatic fluid shows that this substance is secreted by the prostate. Prostatic binding protein has the following physicochemical characteristics: it is precipitated by ammonium sulfate between 50 and 70% saturation; the elution position from a Sephadex G-100 column corresponds to a molecular weight of 51000; it sediments in sucrose density gradients at 3.7 S and is eluted from DEAE-cellulose columns at about 0.25 M KCl. On polyacrylamide gel electrophoresis the binding activity coincides with the major cytosolic protein band. This band has the same mobility as serum albumin in 7% gels, but a higher mobility in more concentrated gels.

Animals↗
PubMed1977

Binding of 25-hydroxycholecalciferol in tissues.

Evidence is presented that the 5.8 S 25-hydroxycholecalciferol-binding protein found in the cytosols of all nucleated rat tissues is formed from two macromolecular substances: a heat-stable 4.1 S 25-hydroxycholecalciferol-binding protein which behaves identically with the serum 25-hydroxycholecalciferol-binding protein, and a cytosolic heat-labile protein which appears to sediment around 4 S and does not show binding properties for 25-hydroxycholecalciferol. The 5.8 S complex is formed in vitro by incubating cytosols with appropriate amounts of serum. The complex is dissociated by heating, leaving the serum 25-hydroxycholecalciferol-binding protein. Complex formation also occurred with serum 25-hydroxycholecalciferol-binding proteins from other species. The widespread occurrence of the 4 S cytosolic component raises the possibility that the high affinity binding proteins for 25-hydroxycholecalciferol observed in nucleated tissues are largely the result of plasma contamination.

Animals↗