Biomedical subjects
Publications and source records attributed to H H Floch.
The metabolism of testosterone in the uropygial gland of the quail principally results in the production of 17 alpha, 5 beta derivatives. Moreover, an unusually small amount of testosterone is converted to 5 alpha-dihydrotestosterone. These results question the role played by intracellular 5 alpha-reduction in the response of the gland to testosterone stimulation.
Dibenzothiophene (DBT) was used as a model substrate of hepatic microsomal mixed-function oxidases. Liver microsomes from Aroclor-induced rats oxidatively transformed this substrate to DBT-5-oxide and subsequently to DBT-5-dioxide. These metabolites were identified by mass spectrometry after incubation of perdeuterated DBT. A simple and fast h.p.l.c. method for determination of the metabolites using u.v. detection at 225 nm is described. Optimal reaction conditions were determined. The apparent Km and the Vmax were, respectively, 85 microM and 8.25 nmol of DBT-5-oxide/min per mg protein. The effects of the inducers phenobarbitone, 3-methylcholanthrene and DBT itself on hepatic DBT-metabolizing activity in rats were determined. DBT, an important constituent of petroleum products, might serve as a useful substrate of aromatic hydrocarbon mono-oxygenase.
The effects of various quantities of Ba, Be, Ca, Cd, Co, Cu, Mg, Mn, Sr, Zn and EDTA on the formation of 5 alpha-reduced metabolites of testosterone (T) substrate and of 3 alpha-/3 beta-reduced metabolites of 5 alpha-dihydrotestosterone substrates by homogenates of 6 human hyperplastic prostate glands were studied in incubations at pH 7.4 with NADPH-generating system. Effects of these cations and EDTA on the VM and KM of the 5 alpha-reductase and 3 alpha-/3 beta-hydroxysteroid dehydrogenases (-HSD) were also measured. Quantities of 5 alpha-reduced T metabolites were significantly increased by Cd, Cu and Zn supplementations. These increments were shown to result from significant augmentations of the VM but no change in KM of the NADPH-dependent 5 alpha-reductase. Quantities of 3 alpha-reduced DHT metabolites were significantly decreased by Cd and Cu supplementations and resulted from an increase of the KM of the NADPH-dependent 3 alpha-HSD by Cd and both an increase of KM and a decrease of VM by Cu. Quantities of 3 beta-reduced DHT metabolites were significantly decreased by Cd and Cu supplementations. Increase of the KM of the NADPH-dependent 3 beta-HSD by Cd was found significant while Cu both increased the KM and decreased the VM of the enzyme. EDTA-related changes in 5 alpha-reductase activity were shown to result from the EDTA-induced decrease of the pH of the medium. No effect of EDTA was observed on the activities of both 3 alpha/3 beta-HSD.
Uropygial gland of quails was previously proved to have androgen receptors. The waxes secreted by this gland were shown to consist mainly of linear saturated fatty acids esterified by linear saturated diols. In adult male quails, the relative concentration of the C12 diol was found to be correlated to the androgen levels of the birds. Furthermore, in castrated quails implanted with testosterone propionate capsules, 6 days were required for the C12 diol to reach the level found in sexually active birds. These testosterone effects related to the C12 diol were nullified by cyproterone acetate administration. Consequently the C12 diol is a reliable specific marker for androgenicity in the quails' preen gland, a new and accurate model for the study of androgen action in sebaceous glands.
The uropygial gland of the quail, a sebaceous-like gland, has been proven to be androgen-dependent. Waxes secreted by this gland consist of fatty acids esterified by alkane-2,3-diols [12]. In castrated quails, the relative concentration of dodecane diol was enhanced after testosterone treatment; but 5 alpha-DHT could not evoke any increase in the relative concentration of dodecane diol. It is not possible from our present results to know if this lack of gland response to DHT administration is related to a high level of DHT metabolism in the gland cells or to a decreased affinity of the androgen receptor for DHT. However, because of the high similarity existing between uropygial gland of birds and mammalian sebaceous glands, these results give rise to the question of the true role of DHT in mammalian sebaceous glands.
Explore the source record for details and available documents.
The uropygial gland of the male quail is a sebaceous-like, androgen-dependent structure. The waxes secreted by this gland consist of fatty acids esterified by alkane-2,3-diols. In adult male quail the relative concentrations of all fatty acids were not affected by castration and testosterone treatment; but in contrast, the relative concentration of dodecane diol was found to be correlated with the androgen levels. In castrated quail administration of testosterone induced an increase in the dodecane diol percentage which was blocked by protein-synthesis inhibitors. Furthermore, the effects of testosterone were found to be neutralized by the administration of cyproterone acetate. Consequently it may be stated that the relative concentration of dodecane diol is indeed a very good marker for androgenicity in the uropygial gland of the male quail. This experimental model seems well suited for evaluating the stimulators and inhibitors of the activity of the sebaceous gland.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
DNA polymerase alpha and beta activities were studied and compared in the cloacal gland and the uropygial gland (sebaceous-like gland) taken from castrated quails after testosterone administration. In the cloacal gland, testosterone induced an important increase in DNA polymerase alpha while DNA polymerase beta was not found to be altered. In the uropygial gland, testosterone induced a cyclic variation of DNA polymerase alpha activity which may relate to the holocrine function of this gland.
5 alpha-DHT is bound with a high affinity (Kd = 0.8 nM) and a limited capacity (80 fmol/mg proteins) in the cytosol of the preen gland of quails, an analogue of sebaceous glands. The complex can be precipitated by protamin-sulfate and is sedimented in the 8 S region after ultra-centrifugation in a sucrose gradient. The occurrence of this binding that exhibits the main properties of an androgen receptor, supports the use of the preen gland of quails as a tool for the study of the mechanism of action of androgens in birds and as a model for the study of the androgen control of sebaceous-like glands.
In the rabbit, the metabolic clearance rate (MCR) was found to be higher for corticosterone than for cortisol. At the same time corticosterone, aldosterone and 11-dehydrocorticosterone showed similar MCR while cortisone ranged at intermediate levels between cortisol and corticosterone. The relative binding affinity of transcortin to the corticosteroids, as calculated by an in vitro technique, decreased progressively from cortisol, to cortisone, then to corticosterone, then 11-dehydrocorticosterone and, finally to aldosterone. The occurrence of antibodies in plasma, induced against aldosterone, corticosterone or even cortisone resulted in a marked decrease in the MCR of the corresponding steroid, to the level measured in controls for cortisol. We deduced that, in rabbits: (1) the MCR of a corticosteroid is clearly connected with its binding to a specific protein; (2) in spite of the relatively high binding affinity of transcortin for corticosterone as compared to other species it nevertheless appears unable to significantly protect the steroid against peripheral metabolism; (3) a very effective protection is however, induced, by raising a specific antibody with a high binding affinity for corticosterone.
Zinc, magnesium and copper concentrations were measured in homogenates of 20 human prostates with benign hyperplasia and a significant direct relationship between zinc and magnesium contents was found. Activities of the testosterone-5 alpha-reductase in the same homogenates were not significantly changed according to the concentrations of the three metals but activities of the 3 alpha- and 3 beta-hydroxysteroid dehydrogenases were inversely related with the zinc concentrations of the tissue preparations. This inverse relationship may explain the known increased 5 alpha-dihydrotestosterone content in prostatic tissues with high zinc concentrations.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A close correlation was evidenced between the length of a silastic capsule filled with testosterone propionate and the resulting plasma concentrations in testosterone in castrated male Quail. 5 days after the beginning of the treatment, testosterone induced in the spleen glands a conspicuous increase in total RNA, DNA and protein contents.
Phthalic acid esters are among the most frequently encountered pollutants in biological extracts. They are very often detected in biological analysis using gas chromatography. Even using high resolution glass capillary columns, the identification of some of these esters remains difficult. In this paper the mass spectral fragmentation of a large number of phthalic acid esters is presented. Some criteria for the identification of the type of isomerism on the aromatic ring and the identification of the ester functions are also presented.