Adrenergic Activity in Hypothalamus and Ovulation

Ao, Donoso; Mb, De Gutierrez Moyano

doi:10.3181/00379727-135-35110

Cited by 23 publications

(10 citation statements)

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“…These results are consis tent with the idea that noradrenergic activity is increased in the hypothalamus during proestrus [6,16], a time preparato ry for LH release and eventual ovulation. Thus, the findings of increased DBH levels during proestrus lend additional credence to the above-mentioned positive role of NE to 'transducer cells' [16] controlling LH secretion.…”

Section: Discussionsupporting

confidence: 76%

“…Donoso and De Gutierrez Moyano [6] have shown that there is a signifi cant increase in the turnover rate of hypothalamic NE in the rat during proestrus. Fluorescence histochemical methods [14] have also shown that in 4-and 5-day cycling rats the turnover of NE in parts of the median eminence are high on the afternoon of proestrus.…”

Section: Discussionmentioning

confidence: 99%

“…The neurotransmitter norepinephrine (NE) re ceived considerable attention because of its enhanced turn over in parts of the brain, particularly the hypothalamus, at a time when gonadotropins are secreted during proestrus [6,26] and because of its reported involvement in the preovula tory surge of luteinizing hormone (LH) [13], Central norad renergic neurons are also considered to be important in the mediation of the stimulatory feedback effects of estrogen and progesterone on LH and follicle-stimulating hormone release [11,12] and on the episodic release of LH in ovariectomized rats [7]. Of the diverse array of physiological and biochemical changes that are manifested with aging, a reduced reproduc tive capacity has been noted both in laboratory animals and in man [9,15,24], Given the role of central catecholamines, especially hypothalamic NE, in the regulation of pituitary gonadotropins, it has been speculated that the age-related decline in reproductive function may be caused by altered levels of hypothalamic catecholamines [17], A causal rela tionship between senescence and a reduced activity in the hypothalamic catecholaminergic system has also been sug gested from research by Finch [8] who demonstrated that in mice the hypothalamic capacity to convert precursors to NE is reduced with age.…”

mentioning

confidence: 99%

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Effects of Aging on the Activity of Hypothalamic Dopamine-Beta-Hydroxylase during Various Stages of the Estrous Cycle in C57BL/6 Mice

Banerji¹,

Parkening²,

Collins³

1982

Neuroendocrinology

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Hypothalamic dopamine-β-hydroxylase (DBH) activity and plasma luteinizing hormone (LH) concentrations were analyzed in female C57BL/6 mice aged 2–4, 7–8, 12–13, and 16–20 months at various times of the estrous cycle. Hypothalamic DBH levels were low during diestrus and metestrus in all age groups. In animals aged 2-4, 7-8, and 12–13 months DBH activities started to rise on the evening of proestrus, and the highest levels attained at 21:00 h were significantly greater than those found during the morning (11:00 h) of proestrus. In contrast, in 16- to 20-month-old mice the hypothalamic DBH activity did not show any significant proestrous rise. In this age group the highest levels of DBH were present at 24:00 h, but these were not significantly different from those found at 11:00, 18:00 or 21:00 h of proestrus. Plasma LH concentrations in all age groups began to increase at 18:00 h of proestrus and had reached their highest levels by 21:00 h of proestrus. The plasma LH concentrations at 21:00 h of proestrus were significantly higher when compared with those 3 h earlier in mice aged 2–4, 7–8, and 12–13 months; however, the LH values in 16- to 20-month-old mice were not significantly different when comparing these two time periods. These data are consistent with (1) the existing idea of an increased adrenergic activity in the rodent hypothalamus during the preovulatory proestrous period and (2) the hypothesis that a dysfunctioning female reproductive system in older rodents may result from a reduction in hypothalamic catecholaminergic activity. It is suggested from the experimental results that such a reduction in adrenergic activity in the mouse hypothalamus may be, at least in part, caused by a reduction in the levels of the norepinephrine-synthesizing enzyme, DBH.

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Section: Discussionsupporting

confidence: 76%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Effects of Aging on the Activity of Hypothalamic Dopamine-Beta-Hydroxylase during Various Stages of the Estrous Cycle in C57BL/6 Mice

Banerji¹,

Parkening²,

Collins³

1982

Neuroendocrinology

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“…However, there are many indications that when LH release is increased, as after castration [1,9], or during the proestrous surge of LH [2,8,16], NE is an important mediator of LH release. Our results suggest that this is also true of the stimulation of LH release by NAL.…”

Section: Discussionmentioning

confidence: 99%

Evidence for Hypothalamic Noradrenergic Involvement in Naloxone-Induced Stimulation of Luteinizing Hormone Release

et al. 1981

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A single injection of the opiate antagonist, naloxone (NAL), resulted in a fourfold increase in serum luteinizing hormone (LH) concentration 20 min after injection. To determine whether noradrenergic neurons were involved, male Sprague-Dawley rats were treated with α-methyl-p-tyrosine (α-MPT), phenoxybenzamine hydrochloride (PBH), or diethyl-dithiocarbamate (DDC), all anti-noradrenergic drugs. Reduction of hypothalamic norepinephrine synthesis by α-MPT or DDC, or blockade of the α-receptors by PBH, resulted in complete suppression of NAL-induced LH release. These results suggest that the NAL-induced increase in LH release is mediated in part via a hypothalamic noradrenergic mechanism.

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“…Turnover of hypothalamic NE is increased after gonadectomy [Anton-Tay and Wurtman, 1968;D onoso et al, 1969] and during proestrus [Donoso and G utierrez Moyano, 1970]. Furthermore, it has been reported that NE synthesis is greater in the hypothalami of ovariectomized rats than in the hypothalami of ovariectomized rats treated with gonadal steroids [Bapna et al, 1971].…”

mentioning

confidence: 99%

Evidence for Participation of a Catecholaminergic Mechanism in the Post-Castration Rise in Plasma Gonadotropins

Ojeda

McCann²

1973

Neuroendocrinology

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Orchidectomy produced a rise in plasma gonadotropin levels after 16 h, which was completely prevented by an intraperitoneal injection of DL-α-methyltyrosine (α-MT). When α-MT was injected 18 h after castration, a sharp fall in plasma LH, but not of FSH, followed. L-dihydroxyphenylalanine (l-DOPA) and dihydroxyphenylserine (DOPS) were given to restore catecholamine (CA) or norepinephrine (NE) synthesis, respectively. When given intraperitoneally 16 h after α-MT, the precursors did not alter LH levels; however, plasma FSH was significantly increased by either l-DOPA or DOPS. When α-MT was given 8 h after castration and precursors were injected 30 min later, l-DOPA increased both LH and FSH levels significantly 10 h after injections. When α-MT was injected 18 h after castration and precursors were injected 30 min later, DOPS prevented the fall in plasma LH, but l-DOPA was ineffective. The selective blockade of NE synthesis with diethyl dithiocarbamate (DDC) injected intraperitoneally 18 h after castration at two doses, 500 or 250 mg/kg, markedly decreased LH levels but did not alter plasma FSH. l-DOPA or DOPS, injected 30 min later, did not reverse the effect of the higher dose of DDC; however, when DOPS was injected 15 min after the lower dose of DDC, it partially prevented the decrease in plasma LH. Even at a dose of 200 mg/kg l-DOPA was ineffective. The selective blockade of DA receptors with Pimozide did not alter the rise in LH that follows orchidectomy, but partially blocked the rise of plasma

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Adrenergic Activity in Hypothalamus and Ovulation

Cited by 23 publications

References 0 publications

Effects of Aging on the Activity of Hypothalamic Dopamine-Beta-Hydroxylase during Various Stages of the Estrous Cycle in C57BL/6 Mice

Effects of Aging on the Activity of Hypothalamic Dopamine-Beta-Hydroxylase during Various Stages of the Estrous Cycle in C57BL/6 Mice

Evidence for Hypothalamic Noradrenergic Involvement in Naloxone-Induced Stimulation of Luteinizing Hormone Release

Evidence for Participation of a Catecholaminergic Mechanism in the Post-Castration Rise in Plasma Gonadotropins

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