Linked Life Data

9202401

Source:http://linkedlifedata.com/resource/pubmed/id/9202401

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1997-8-11
pubmed:abstractText
The formation of the 5alpha-reduced metabolites of testosterone (T) and of progesterone (P) is a very active process in the brain, since the enzyme 5alpha-reductase (5alpha-R) is present in almost any central nervous system (CNS) structure. A particularly elevated 5alpha-R activity has been shown in myelin sheaths. Two isoforms of the enzyme have been cloned, with different localisation as well as different biochemical properties. The present study was performed to determine whether both isoforms of the 5alpha-R, or only one of them, are/is responsible for the enzymatic activity observed in myelin. Kinetic analyses have been performed on purified myelin membranes prepared from the male or female rat brain, using both T and P as substrates. The 5alpha-R present appears to possess a pH optimum at basic values. The Vmax values obtained in the Lineweaver-Burk analysis were comparable in male and female preparations independently on whether T or P were used as the substrates, suggesting that a single enzymatic form is present in all samples examined; the Km obtained using [14C]T (Km: male 1.14 microM; female 1.46 microM) or [14C]P (Km: male 0.5 microM; female 0.64 microM) as substrates, were in good agreement with those obtained for the recombinant type 1 isoform. These data suggest that the type 1 isoform is the most relevant 5alpha-R present in myelin. To confirm this, a new polyclonal antibody was raised against the type 1 5alpha-R enzymatic protein, and used in immunohistochemical studies. The experiments were performed on the optic nerve, a myelinated structure very rich in 5alpha-R activity and the results clearly indicated the presence of a specific type 1 enzyme immunoreactivity in the myelin sheaths of axons.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0303-7207
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
129
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
181-90
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Identification of type 1 5alpha-reductase in myelin membranes of male and female rat brain.
pubmed:affiliation
Istituto di Endocrinologia, Università degli Studi di Milano, Italy. poletti@isfunix.farma.unimi.it
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't