Knowledge of the mechanism of estrogen biosynthesis and of the enzyme or enzymes involved in it is critical to an understanding of this essential biotransformation and to its rational control in diseases where estrogen formation needs to be limited. We will study the aromatization of androgens from several directions. The nature of the three oxidative steps participating in the process will be explored using novel specifically labeled substrates which allow examination both of the initial two hydroxylations at C-19 and the terminal hydroxylation leading to aromatization. Experimental evidence supports the 2Beta carbon as the site of the final hydroxylation, but other observations cast doubt on that location. Experiments are proposed to resolve the difficulty and to define the nature of the terminal enzymatic step in estrogen biosynthesis. The nature of estrogen biosynthesis. The nature of estrogen biosynthesis will be studied in tissues other than the placenta including the ovaries, testes, brain and other non-gonadal sites. Evidence has already been obtained that the process is different in the ovaries and brain and new tools will be used to probe the mechanism of aromatization in these tissues and to study the role of pituitary hormones and other agents in its control. New affinity media and specific radiolabeled irreversible ligands will be used to purify and separate the placental aromatase complex into its catalytic components. Immunocytochemical and autoradiographic methods will be used to study the localization of the enzymes in the various sites or aromatization. Information obtained in these studies will be used in the modification of the already synthesized new high affinity inhibitors of estrogen biosynthesis to generate new categories of those agents which will be expected to exhibit high in vivo potency in diminishing estrogenic levels in diseases such as breast cancer and prostatic hyperplasia and in controlling reproductive processes.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
2R01HD018350-04
Application #
3315384
Study Section
Biochemical Endocrinology Study Section (BCE)
Project Start
1984-02-01
Project End
1990-01-31
Budget Start
1987-02-01
Budget End
1988-01-31
Support Year
4
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Rockefeller University
Department
Type
Graduate Schools
DUNS #
071037113
City
New York
State
NY
Country
United States
Zip Code
10065
Miyairi, S; Sugita, O; Sassa, S et al. (1988) Aromatization and 19-hydroxylation of androgens by rat brain cytochrome P-450. Biochem Biophys Res Commun 150:311-5
Norton, B I; Miyairi, S; Fishman, J (1988) 19-Hydroxylation of androgens by rat granulosa cells. Endocrinology 122:1047-52
Fishman, J; Hahn, E F (1987) The nature of the final oxidative step in the aromatization sequence. Steroids 50:339-45
Michnovicz, J J; Hahn, E F; Fishman, J (1987) 19-Hydroxylation and aromatization of androgens in the developing rat brain. Endocrinology 121:1209-14
Stone, N N; Fair, W R; Fishman, J (1986) Estrogen formation in human prostatic tissue from patients with and without benign prostatic hyperplasia. Prostate 9:311-8
Miyairi, S; Fishman, J (1986) 3-Methylene-substituted androgens as novel aromatization inhibitors. Evidence of a requirement for C-3 oxygen in C-19 hydroxylations. J Biol Chem 261:6772-7
Hahn, E F; Fishman, J (1985) Stereochemistry of 1,2-hydrogen loss during aromatization in the brain. J Steroid Biochem 22:597-600
Hahn, E F; Miyairi, S; Fishman, J (1985) 19-Hydroxylation of androgens in the rat brain. Proc Natl Acad Sci U S A 82:2728-30