Search PubMed⌕ Search

Biomedical subjects

H C Ford

Publications and source records attributed to H C Ford.

64 records · Page 4Linked to original sources
PubMed1979

Circannual variation and genetic regulation of hepatic testosterone hydroxylase activities in inbred strains of mice.

Hydroxylation of testosterone by hepatic microsomes at positions 6 alpha, 6 beta, 7 alpha, 15 alpha, and 16 alpha has been studied in C57BL/6J, 129/J, and A/J mice. Differences in hydroxylase activities between the C57BL/6J and A/J strains and between the C57BL/6J and 129/J strains were investigated using standard genetic breeding protocols. In the C57BL/6J X A/J line, 6 alpha- and 7 alpha-hydroxylase activity appeared to be under polygenic control in both sexes, as did 15 alpha-hydroxylase activity in females. The lack of 16 alpha-hydroxylase activity observed in 129/J females behaved as a recessive, autosomal, single locus, sex-limited trait. In several instances, the level of hydroxylase activity at one position appeared to be affected by the level of hydroxylase activity at a second position; however, no clear-cut pattern was discerned. Over a period of a year, a remarkable cycle in total hydroxylase activity for all mice was observed; the average activity was greatest in December and least in April.

Animals↗
PubMed1975

Hydroxylation of testosterone at carbons 1, 2, 6, 7, 15 and 16 by the hepatic microsomal fraction from adult female C57BL/6J mice.

The metabolism of a mixture of [4-14C]- and [7 beta-2H]testosterone by the hepatic microsomal fraction from adult femal C57BL/6J mice has been investigated. The following metabolites were identified by their mass spectra and by their retention times on gas chromatography on one or two phases: 1epsilon-, 2beta-, 6alpha-, 6beta-, 7alpha-, 15alpha-, 15beta-, 16alpha- and 16beta-hydroxytestosterone; 6alpha-, 6beta- and 7alpha-hydroxy-4-androstene-3,17-dione; and 4-androstene-3,17-dione. A compound tentatively identified as 6- or 7-oxotestosterone was also isolated. 17beta-Hydroxy-4,6-androstadien-3-one, 17beta-hydroxy-1,4-androstadien-3-one and 4,6-androstadiene-3,17-dione were identified but are considered to arise non-enzymatically from 7alpha-hydroxytestosterone, 1epsilon-hydroxytestosterone and 7alpha-hydroxy-4-androstene-3,17-dione, respectively.

Acclimatization↗
PubMed1971

Studies on an extract of rat testicular microsomal fraction that catalyses the transformation of progesterone into 17-hydroxyprogesterone and androgens.

The supernatant obtained by centrifugation of Triton N-101-treated freeze-dried rat testicular microsomal fraction at 105000g(av.) for 2h transformed progesterone into testosterone via 17-hydroxypregn-4-ene-3,20-dione and androst-4-ene-3,17-dione. Hydroxylation at C-17 of 3beta-hydroxypregn-5-en-20-one and deoxycorticosterone was not observed. Non-haem iron protein, cytochrome P-450 and material with NADPH dehydrogenase activity were precipitated by 40% saturation of the supernatant with ammonium sulphate; however, it was not possible to establish the participation of these substances in the 17alpha-hydroxylase and side-chain-cleavage activities also present in the precipitate. The results of gel-filtration chromatography indicated that the Triton N-101 extract consisted primarily of a suspension of small particles of microsomes and that the progesterone 17-hydroxylase and the 17-hydroxypregn-4-ene-3,20-dione side-chain-cleavage enzyme were not in true solution.

Androgens↗
PubMedDate not supplied

Proteins of human placental microvilli: I. Cytoskeletal proteins.

Microvilli isolated from the syncytiotrophoblast surface of the human term placenta were separated into two fractions, one of which contained microvilli lacking a visible cytoskeleton on electron microscopy. One- and two-dimensional electrophoresis showed that a number of proteins were present in reduced amounts in the fraction lacking a visible core structure. The possibility that these proteins were cytoskeletal components was investigated by further electrophoretic studies in conjunction with 125I labelling of proteins of intact and disrupted microvillous vesicles, digestion of external proteins with immobilized, insoluble trypsin, and selective solubilization of plasma membrane proteins by Triton X-100. From the results of these studies, eight proteins of molecular weights 103 000, 80 000, 70 000, 69 000, 43 000, 36 000, 25 000 and 18 000 were tentatively assigned to the cytoskeleton. The differences between our findings for the cytoskeletal proteins of human placental microvilli and the results reported by others for the well-studied cytoskeletal proteins of the intestinal microvilli of the rat are likely to reflect differences in structure and function of the microvilli from the two sources.

Calmodulin↗
PubMedDate not supplied

Proteins of human placental microvilli: II. Identification and topology of the plasma membrane proteins.

We have investigated the location of proteins in the transverse plane of the plasma membrane of microvilli isolated from the syncytiotrophoblast layer of the human term placenta. Microvillous proteins were labelled with 125I under reaction conditions where those proteins exposed on the maternal-facing surface of the microvilli were most heavily labelled. The proteins were then solubilized and subjected to one- and two-dimensional electrophoresis followed by protein staining and autoradiography. More than 65 proteins, differing in molecular weight or isoelectric point or both, were identified, and these were classified into three groups: weakly, moderately heavily, and heavily labelled. The microvilli were in the form of intact vesicles that were correctly orientated ('right-side out'). Thus the extent of labelling of each protein could be used as an indication of the extent of its exposure on the maternal-facing surface of the microvilli. Human serum albumin was present on the surface of the isolated, washed microvilli, but was probably a contaminant originating from maternal blood.

Alkaline Phosphatase↗