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In Vitro Effects of Estradiol, Testosterone, and Progesterone on 5‐Methoxyindole Content, Cyclic Adenosine 3′,5′‐Monophosphate Synthesis, and Norepinephrine Release in Different Parts of the Female Guinea Pig Pineal Complex
Author(s) -
Cardinali Daniel P.,
Vacas María I.,
Solveyra César González,
Sarmiento María I. Keller,
Vollrath Lutz
Publication year - 1986
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.1986.tb00757.x
Subject(s) - medicine , endocrinology , melatonin , guinea pig , adenosine , testosterone (patch) , biology , estrogen , stimulation , pinealocyte , hormone , cyclic adenosine monophosphate , chemistry , pineal gland , receptor
To examine the effects of estradiol, testosterone, or progesterone on cyclic adenosine 3′,5′‐monophosphate (AMP) accumulation, 5‐methoxyindole levels, and norepinephrine (NE) release by the female guinea pig pineal complex, samples of the deep, intermediate, or superficial portions of the complex were incubated in vitro with varied concentrations of either hormone. Exposure for 10 minutes to physiological amounts of estradiol (10 nM) or to 100 μM NE increased significantly cyclic AMP levels to the same extent in the three pineal regions. A maximal effect on cyclic AMP accumulation was observed at 100‐nM concentrations of estradiol, with a tendency to return to basal levels at 1–10 μM of estradiol. Only high concentrations of testosterone or progesterone (i. e., 1–10 μM) increased cyclic AMP accumulation in incubated guinea pig pineal fragments. At a 100‐nM concentration estradiol did not affect NE‐stimulated cyclic AMP accumulation in guinea pig pineal fragments. In samples of either pineal region incubated for 6 hours in TC 199 medium with 10 −7 M or greater concentrations of estradiol and analyzed for melatonin, 5‐methoxyindoleacetic acid, and 5‐methoxytryptophol by high‐pressure liquid chromatography with electrochemical detection, a significant increase of melatonin levels was found. Neither testosterone nor progesterone modified 5‐methoxyindole levels of incubated explants. K + ‐stimulated transmitter release from guinea pig pineal fragments previously incubated with 3 H‐NE was not affected by hormone exposure. These results suggest that physiological concentrations of estradiol may exert a postsynaptic stimulation of cyclic AMP and melatonin synthesis to the same extent in all three regions of the female guinea pig pineal complex.