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Biomedical subjects

J Fishman

Publications and source records attributed to J Fishman.

At least 217 records · Page 12Linked to original sources
PubMed1968

Estradiol metabolism in cirrhosis.

Abnormal estrogen metabolism has been found in cirrhosis after administration of intravenous tracers of estradiol-(3)H to 6 patients and 23 healthy controls. The major abnormalities observed involved estrogen metabolites other than the 3 "classic" ones, i.e., estrone (E1), estradiol (E2), and estriol (E3). Urinary recovery of radioactivity was regularly elevated in the patients, to an average of 71% of the dose compared to 51% in normals. This is considered to reflect the component of intrahepatic cholestasis in cirrhosis. The per cent dose recovered as urinary glucosiduronates (42%) was normal in cirrhotics in contrast to impaired glucuronidation of cortisol metabolites in this disease. E1 and E2 were present in normal amounts, and E3 was slightly elevated to 21% of the extract compared to 14% in controls. There were strikingly decreased excretion of 2-hydroxyestrone (3% compared with normal 20%) and 2-methoxyestrone (2% compared with 5%) and increased excretion of 16alpha-hydroxyestrone (12% compared with normal 6%). Thus cirrhosis, too, is characterized by the reciprocal relationship between decreased 2-hydroxylation and increased 16alpha-hydroxylation previously described in hypothyroidism and male breast cancer. However, unlike these latter, the increase of 16alpha-hydroxy metabolites was less than the decrease of 2-hydroxy metabolites. The data indicate clearcut impairment of 2-hydroxylation, suggestive impairment of 16alpha-hydroxylation, and a definite depression of the reaction 16alpha-hydroxyestrone-->estriol, the latter finding so far unique to cirrhosis. Demonstration of abnormal peripheral metabolism of estrogen in cirrhosis provides a new approach to the origin of the hyperestrogenic syndrome in this disease.

Journal Article↗
PubMed1967

Penetration of sugars across the blood-brain barrier.

1. A cerebral perfusion method was used to measure the net uptake of arabinose from the circulatory system in cats.2. There was found to be discrimination between the optical isomers of this substance, with apparently greater uptake of the (-)-form.3. The uptake process was highly temperature dependent, with a Q(10) of 3.0.4. The uptake of arabinose was partially inhibited by 1 mM ouabain perfused concurrently. It was not significantly inhibited by dinitrophenol or phlorrhizin.5. Glucose inhibited competitively the uptake of (-)-arabinose.6. We conclude that the mechanism involved is of the carrier-mediated or of the active transport type, and that at least part of it is shared with glucose and probably other sugars.

Animals↗