The effects of neurotransmitters and other cellular modulators and factors on hypothalamic and anterior pituitary Δ 4 -steroid (progesterone) 5α-reductase activity
A number of diverse biological compounds involved in the regulation of the hypothalamo-hypophyseal-ovarian axis have been examined for effects on the conversion of 3H-progesterone to 3H-5α-dihydro-progesterone and 3H-3α-hydroxy-5α-pregnan-20-one by female rat hypothalamus and/or anterior pituitary....
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Published in | Steroids Vol. 36; no. 3; pp. 305 - 320 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Inc
01.09.1980
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Subjects | |
Online Access | Get full text |
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Summary: | A number of diverse biological compounds involved in the regulation of the hypothalamo-hypophyseal-ovarian axis have been examined for effects on the conversion of
3H-progesterone to
3H-5α-dihydro-progesterone and
3H-3α-hydroxy-5α-pregnan-20-one by female rat hypothalamus and/or anterior pituitary. Broken cell preparations were incubated with
3H-progesterone and NADPH, and product 5α-reduced progestins were quantitated by reverse isotopic dilution analysis. Progesterone 5α-reductase activity was reduced up to 50% in the presence of 10
−2 to 10
−3
M
serotonin in both preparations. At 10
−3 M, various indoles including n-acetylserotonin, melatonin, 5-methoxytryptamine, 5-methoxytryptophol, and 5-hydroxyindole acetic acid decreased by 10 to 30% 5α-reduced product formation. At 10
−2
M
, carbamylcholine and norepinephrine were without effect, while 10
−2
M
dopamine reduced by 20% the 5α-reduction of progesterone only in pituitary homogenates. The LHRH protease inhibitor bacitracin (2 × 10
−3
M
) decreased by 10 to 40% progesterone 5α-reductase activity in both tissues. By itself, LHRH did not affect the 5α-reduction of progesterone nor did it potentiate the bacitracin effect. In the presence of 1 n
M
ATP, 100 μ
M
cAMP and 100 μ
M
cGMP increased 5α-reduced product formation in the hypothalamus by 19 and 14%. The gonadotropins LH and FSH and the prostaglandins E
1, E
2, F
1α, and F
2α were without effect. Thus, these results and others indicate that a number of cellular components and other factors can affect the
in vitro
5α-reduction of progesterone in broken cell preparations. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0039-128X 1878-5867 |
DOI: | 10.1016/0039-128X(80)90005-7 |