Radioimmunoassay of 3α-hydroxy-5α-pregnan-20-one in rat and human plasma

Purdy, Robert H.; Moore, Perry H.; Rao, P. Nageswara; Hagino, Nobuyoshi; Yamaguchi, Tatsumi; Schmidt, Peter J.; Rubinow, David R.; Morrow, A. Leslie; Paul, Steven M.

doi:10.1016/0039-128x(90)90031-6

Cited by 199 publications

(128 citation statements)

References 29 publications

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“…During late diestrus, the PAG circuitry becomes intrinsically more excitable due to a reduction in ongoing GABAergic tone, which is linked to upregulation of a4, b1, and d GABA A receptor subunits on GABAergic neurons (Brack and Lovick 2007;Lovick et al, 2005;Griffiths and Lovick 2005a). These neuronal changes are linked with the fall in brain levels of progesterone and hence allopregnanolone, the major neuroactive metabolite of progesterone (Butcher et al, 1975;Purdy et al, 1990). Withdrawal from dosing with exogenous progesterone also evoked upregulation of a4, b1, and d GABA A receptor subunits (Griffiths and Lovick, 2005b), suggesting that the natural fall in progesterone levels that occurs during late diestrus is the trigger for the functional changes within the circuitry in the PAG.…”

Section: Discussionmentioning

confidence: 99%

Differential Activation of the Periaqueductal Gray by Mild Anxiogenic Stress at Different Stages of the Estrous Cycle in Female Rats

Devall¹,

Lovick²

2010

Neuropsychopharmacol

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The effect of acute exposure to mild anxiogenic stress on cutaneous nociceptive threshold was investigated in female Wistar rats at different stages of the estrous cycle. Baseline tail flick latencies did not change significantly during the cycle. However after brief exposure to vibration stress (4 Hz for 5 min), rats in late diestrus, but not at other cycle stages, developed a hyperalgesia (decrease in tail flick latency). Animals in late diestrus revealed a more than fivefold increase in the density of Fos-like immunoreactive nuclei in the dorsolateral, lateral, and ventrolateral columns in the caudal half of the periaqueductal gray matter (PAG). There was no change in the density of Fos-like immunoreactive nuclei in the PAG in rats in estrus and early diestrus, although rats in proestrus showed a smaller (50%) but significant increase. Rats undergoing withdrawal from a progesterone dosing regimen (5 mg/kg i.p. twice daily for 6 days) designed to mimic the fall in progesterone that occurs naturally during late diestrus, exhibited a stress-induced hyperalgesia that was similar to animals in late diestrus and a significant increase in Fos-positive cells in the PAG. We suggest that falling levels of progesterone during late diestrus may be a predisposing factor for the development of stress-induced hyperalgesia, which is linked to differential activation of descending pain control circuits in the PAG. Similar changes in women, when progesterone levels fall during the late luteal phase of the menstrual cycle, may contribute to the development of premenstrual symptoms that include increased anxiety and hyperalgesia.

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Section: Discussionmentioning

confidence: 99%

Differential Activation of the Periaqueductal Gray by Mild Anxiogenic Stress at Different Stages of the Estrous Cycle in Female Rats

Devall¹,

Lovick²

2010

Neuropsychopharmacol

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“…Allopregnanolone and related neurosteroids have been commonly analyzed by sensitive radioimmunoassay, gas chromatography, and mass spectrometry assays (Purdy et al, 1990;Bicikova et al, 1995;Griffiths et al, 1999;Chatman et al, 1999;Kim et al, 2000). Many studies describe derivatization for the trace analysis of neurosteroids by mass spectrometry (Cheney et al, 1995;Lierre et al, 2000;Higashi et al, 2005).…”

Section: Analysis Of Neurosteroidsmentioning

confidence: 99%

Mass spectrometric assay and physiological–pharmacological activity of androgenic neurosteroids

Reddy¹

2008

Neurochemistry International

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Steroid hormones play a key role in the pathophysiology of several brain disorders. Testosterone modulates neuronal excitability, but the underlying mechanisms are obscure. There is emerging evidence that testosterone-derived "androgenic neurosteroids", 3α-androstanediol and 17β-estradiol, mediate the testosterone effects on neural excitability and seizure susceptibility. Testosterone undergoes metabolism to neurosteroids via two distinct pathways. Aromatization of the A-ring converts testosterone into 17β-estradiol. Reduction of testosterone by 5α-reductase generates 5α-dihydrotestosterone, which is then converted to 3α-androstanediol, a powerful GABA A receptormodulating neurosteroid with anticonvulsant properties. Although the 3α-androstanediol is an emerging neurosteroid in the brain, there is no specific and sensitive assay for determination of 3α-androstanediol in biological samples. This article describes the development and validation of mass spectrometric assay of 3α-androstanediol, and the molecular mechanisms underlying the testosterone modulation of seizure susceptibility. A liquid chromatography-tandem mass spectrometry assay to measure 3α-androstanediol is validated with excellent linearity, specificity, sensitivity, and reproducibility. Testosterone modulation of seizure susceptibility is demonstrated to occur through its conversion to neurosteroids with "anticonvulsant" and "proconvulsant" actions and hence the net effect of testosterone on neural excitability and seizure activity depends on the levels of distinct testosterone metabolites. The proconvulsant effect of testosterone is associated with increases in plasma 17β-estradiol concentrations. The 5α-reduced metabolites of testosterone, 5α-dihydrotestosterone and 3α-androstanediol, had powerful anticonvulsant activity. Overall, the testosterone-derived neurosteroids 3α-androstanediol and 17β-estradiol could contribute to the net cellular actions of testosterone in the brain. Because 3α-androstanediol is a potent positive allosteric modulator of GABA A receptors, it could serve as an endogenous neuromodulator of neuronal excitability in men. The 3α-androstanediol assay is an important tool in this area because of the growing interest in the potential to use adjuvant aromatase inhibitor therapy to improve treatment of epilepsy.

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“…The DHP (X-947) and 3α,5α-THP antibodies (#921412-5, purchased from Dr. Robert Purdy, Veterans Medical Affairs, La Jolla, CA), were used in a 1:5000 dilution, typically bind between 40% and 60% of [ 3 H] 3α,5α-THP [33], and bound 51% in the present study. The DHP antibody cross-reacts with 3α,5α-THP (100%), 5α-pregnan-3,20-dione (50%), 4-pregnen-3α-ol-20-one (50%), and P 4 (17%) [47]. The 3α,5α-THP antibody cross-reacts with 3α-hydroxypregn-4en-20-one (84%) and DHP (11%) and its β isomer (7%), P 4 (6%), and pregnenolone (<2%) [47,48].…”

Section: Set-up and Incubation Of Radioimmunoassays-mentioning

confidence: 99%

“…The DHP antibody cross-reacts with 3α,5α-THP (100%), 5α-pregnan-3,20-dione (50%), 4-pregnen-3α-ol-20-one (50%), and P 4 (17%) [47]. The 3α,5α-THP antibody cross-reacts with 3α-hydroxypregn-4en-20-one (84%) and DHP (11%) and its β isomer (7%), P 4 (6%), and pregnenolone (<2%) [47,48].…”

Section: Set-up and Incubation Of Radioimmunoassays-mentioning

confidence: 99%

Infusions of 3α,5α-THP to the VTA enhance exploratory, anti-anxiety, social, and sexual behavior and increase levels of 3α,5α-THP in midbrain, hippocampus, diencephalon, and cortex of female rats

Frye

Rhodes

2008

Behavioural Brain Research

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Abstract17β-Estradiol (E 2 ) and progesterone (P 4 ) influence the onset and duration of sexual behavior and are also associated with changes in behaviors that may contribute to mating, such as exploration, anxiety, and social behaviors (socio-sexual behaviors). In the midbrain ventral tegmental area (VTA), the P 4 metabolite, 5α-pregnan-3α-ol-20-one (3α,5α-THP), modulates lordosis of E 2 -primed rodents; 3α,5α-THP can also influence anxiety and social behaviors. To examine if 3α,5α-THP in the VTA mediates socio-sexual behaviors, we infused 3α,5α-THP to the VTA of diestrous and proestrous rats. As expected, proestrous, compared to diestrous, rats showed more exploratory (open field), anxiolytic (elevated plus maze), pro-social (partner preference, social interaction), and sexual (paced mating) behavior and had increased E 2 , P 4 , dihydroprogesterone (DHP), and 3α,5α-THP in serum, midbrain, hippocampus, diencephalon, and cortex. Infusions of 3α,5α-THP to the VTA, but not control sites, such as the substantia nigra (SN) or central grey (CG), of diestrous rats produced behavioral and endocrine effects akin to that of proestrous rats and increased DHP and 3α,5α-THP levels in midbrain, hippocampus, and diencephalon. Levels of DHP and 3α,5α-THP, but neither E 2 nor P 4 concentrations, in midbrain, hippocampus, diencephalon, and/or cortex were positively correlated with socio-sexual behaviors. Thus, 3α,5α-THP infusions to the VTA, but not SN or CG, can enhance socio-sexual behaviors and increase levels in midbrain, hippocampus, and diencephalon.

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Radioimmunoassay of 3α-hydroxy-5α-pregnan-20-one in rat and human plasma

Cited by 199 publications

References 29 publications

Differential Activation of the Periaqueductal Gray by Mild Anxiogenic Stress at Different Stages of the Estrous Cycle in Female Rats

Differential Activation of the Periaqueductal Gray by Mild Anxiogenic Stress at Different Stages of the Estrous Cycle in Female Rats

Mass spectrometric assay and physiological–pharmacological activity of androgenic neurosteroids

Infusions of 3α,5α-THP to the VTA enhance exploratory, anti-anxiety, social, and sexual behavior and increase levels of 3α,5α-THP in midbrain, hippocampus, diencephalon, and cortex of female rats

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