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Biomedical subjects

P de Moor

Publications and source records attributed to P de Moor.

12 recordsLinked to original sources
PubMed1979

Stimulation effect of neurotransmitters on the aromatization of testosterone by Sertoli cell-enriched cultures.

The aromatization of testosterone has been studied in Sertoli cell-enriched cultures derived from 19-day-old rats. It was found that, besides dbcAMP and FSH, several neurotransmitters have a stimulatory effect. At a concentration of 10(-5) M, the strongest effects were noted with L-isoproterenol, L-norepinephrine, L-epinephrine and D,L-synephrine. Some stimulation was observed with dopamine, whereas histamine, melatonin and serotonin as well as acetylcholine and pilocarpine were ineffective. Experiments with alpha- and beta-adrenergic antagonists suggest that beta 2- and maybe also alpha-receptors are involved. The same maximal level of stimulation was generally observed for dbcAMP, FSH and isoproterenol. No further increase in activity was obtained with combinations of these compounds. It is concluded that adrenergic agonists may play a role in testicular development and function.

Animals↗
PubMed1977

The measurement of the vitamin D-binding protein in human serum.

The concentration of the vitamin D-binding protein was measured in human serum by single radial immunodiffusion. Normal serum concentrations were slightly higher in normal women than in normal men. No race-related difference was found between white people from Belgium and black people from Zaire. Lower concentrations were found in cord serum and in patients with cirrhosis of the liver. Increased serum levels were observed during pregnancy or during the intake of estro-progestogens. The serum level of the vitamin D-binding protein was not altered in various diseases of calcium metabolism (primary osteoporosis, primary and secondary hyperparathyroidism, rickets, osteomalacia or vitamin D intoxication). No correlation was found between serum levels of 25-hydroxy vitamin D and those of its binding protein. From these data the following conclusions can be drawn: 1) The serum concentration of the vitamin D-binding protein (about 6.10(-6)M) largely exceeds the normal serum concentration of 25-hydroxy vitamin D (about 4.10(-8)M), so that this protein is normally for less than 1% saturated, 2) Normal serum levels of the vitamin D-binding protein were observed in several diseases of calcium metabolism, and 3) The free concentration of 25-hydroxyvitamin D is not regulated at a constant level.

Adult↗
PubMed1977

Concentration of transcortin in the pregnant rat and its foetuses.

The concentration of transcortin in serum from foetal, neonatal, pregnant and lactating rats was measured by a single radial immunodiffusion method. A decrease in transcortin concentration in sera from foetuses and pregnant rats occurred starting on days 19 and 20 of pregnancy respectively. A more pronounced fall in transcortin concentration in foetal and maternal serum was observed after treating pregnant rats with dexamethasone. These results suggest that corticosterone may be responsible for the observed changes in transcortin concentration.

Age Factors↗
PubMed1976

The transport of vitamin D in the serum of primates.

"Transcalciferin" (the serum transport protein for cholecalciferol and related substances) of two New World monkeys, Cebus apella and Cebus albifrons, was found to be immunologically identical with the transcalciferin of other monkeys and partially with that of man. In contrast with the alpha-globulin mobility of the transcalciferin of other primates, the transcalciferin of cebus monkey has the electrophoretic mobility of albumin. Most of the serum 25-hydroxycholecalciferol was precipitable with isolated monospecific anti-(human transcalciferin) gamma-globulins but not with anti-(human albumin) gamma-globulins. These results indicate that the transport of 25-hydroxycholecalciferol in the cebus monkey is not due to albumin itself but to transcalciferin with the electrophoretic mobility of albumin. Similar variants of transcalciferin also exist in man.

Animals↗
PubMedDate not supplied

Variations in the capacity of the steroid binding beta globulin (SBbetaG) in plasma from normal young twins.

The capacity of human plasma to bind specifically dihydrotestosterone (DHTBC) has been determined in normal monozygotic and dizygotic twins less than 20 years old. The total variation in DHTBC was analysed by stepwise multiple regression, combined with variance analysis, applied to the pair sums in DHTBC, body height and body weight, as well as to age. A significant part of the variation in DHTBC was explained. Due to the strong interwining between body weight, body height and age in growing children it was impossible to make out which one of the latter variable contributed most to the negative correlation which was observed. Previous studies in adults did, however, show that only body weight and not body height or age correlated negatively with DHTBC. By doing the same calculations for the within-pair differences in DHTBC, body height and body weight it was hoped to delineate the within-family part of the environmental variation in DHTBC. Body weight and body height did, however, not offer any significant explanation as to this part of the variation in DHTBC. The upper limit of heritability (h2) for DHTBC was estimated by comparing intraclass-correlation coefficients in monozygotic and dizygotic twins. According to the method used to calculate the latter intraclass-correlation coefficients h2 estimates for DHTBC of 0.774 and 0.960 were arrived at. However, due to the rather small number of dizygotic twins available the confidence limits of these estimates were rather large.

Adolescent↗