Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was initiated to detect possible changes in beta-endorphin (beta-EP) levels of the hypothalamus, anterior pituitary gland, and peripheral blood of rats after ovariectomy and estrogen administration. Attempts were also made to determine the correlation between peripheral and central levels of beta-EP. Twenty-six Sprague-Dawley rats were decapitated. Nine had intact ovaries (Gr. INT), and 17 were ovariectomized 3 weeks before they were killed. Nine of the ovariectomized rats received estradiol benzoate (EB) (Gr. EB) and the other 8 received peanut oil (Gr. OVX) prior to the decapitation. A beta-EP radioimmunoassay was used to analyze homogenates of the hypothalamus and anterior pituitary, and peripheral blood. In the hypothalamus, beta-EP levels were significantly lower in Gr. INT and Gr. EB than in Gr. OVX. In the pituitary gland and peripheral blood, beta-EP levels were significantly higher in Gr. INT than in Gr. OVX. Pituitary beta-EP levels did not vary between Gr. OVX and Gr. EB, although beta-EP levels in peripheral blood were significantly higher in Gr. EB than in Gr. OVX. No significant correlations were noted in beta-EP levels between the hypothalamus, pituitary gland, and peripheral blood in either Gr. INT, Gr. OVX, or Gr. EB. It appears that EB exerts different effects on beta-EP levels in the hypothalamus, anterior pituitary gland, and peripheral blood, and that beta-EP levels in these regions may be independent of one another.
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PMID:Effect of ovariectomy and estrogen replacement on hypothalamic, pituitary and peripheral blood beta-endorphin levels in the rat. 176 67

A dramatic late-gestation increase in fetal plasma cortisol concentrations is critical for the timing of parturition in the sheep. This increase appears to depend upon an intact hypothalamo-pituitary unit and is characterised by increasing responsiveness of the fetal adrenal gland to ACTH. ACTH has been postulated as the critical determinant of the late-gestation cortisol increase; however, recent evidence has suggested that other factors, including the ACTH precursor, pro-opiomelanocortin, may also be involved. To further define the role of ACTH in determining the timing of parturition and the responsiveness of the fetal adrenal gland, intact (INT/ACTH) and hypophysectomised (HX/ACTH) fetuses received a continuous infusion of ACTH(1-24) from the time of surgery (approximately 115 days gestational age (GA)) at a rate we have previously shown to generate normal fetal cortisol concentrations and term parturition in HX fetuses. A third group of saline-infused intact fetuses (INT/SAL) served as the control group. Adrenal responsiveness was assessed by cortisol responses to ACTH(1-24) challenges at 120, 130 and 140 days GA. There were no differences between the three groups of fetuses in the timing of parturition, the late-gestation increase in cortisol concentrations or the size of the adrenal cortex. In both INT/SAL and INT/ACTH fetuses, there were significant increases in basal immunoreactive-ACTH concentrations with advancing GA, although no such increase was observed in HX/ACTH fetuses. The proportion of total ACTH immunoreactivity present in low molecular weight (LMW) forms in INT/ACTH fetuses was greater than that in INT/SAL fetuses, while the level of LMW ACTH in HX/ACTH fetuses was intermediate. Both ACTH(1-24)-infused groups of fetuses had dramatically enhanced adrenal responsiveness to ACTH(1-24) at all GAs tested when compared with INT/SAL fetuses and there was a correlation (in rank order) between the proportion of LMW ACTH immunoreactivity and adrenal responsiveness. From these observations it appears that there is a separate regulation of adrenal responsiveness from basal cortisol concentrations and that an increase in basal cortisol concentrations can occur in the absence of an increase in basal ACTH concentrations. Furthermore, an increase in adrenal responsiveness does not appear to predict the timing of parturition nor basal cortisol concentrations. Taken together with previous studies it appears that ACTH plays an essential role in maintaining the growth of the fetal adrenal and enhancing its responsiveness, but a late-gestation increase in ACTH concentrations is not required to regulate basal cortisol concentrations or the timing of parturition.
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PMID:Studies on the role of ACTH in the regulation of adrenal responsiveness and the timing of parturition in the ovine fetus. 977 59

Administration of amphetamine (AMPH) can induce symptoms of psychosis in humans and locomotor sensitization in rats; in contrast, withdrawal from a period of AMPH intake is most often associated with symptoms of human endogenous depression. The aim of this study was to determine whether AMPH withdrawal produces a depressive-like state in rats. The present study examined the effects of withdrawal from an escalating-dose AMPH schedule (ESC; three daily injections over 6 days, 1-5 mg/kg, i.p.) and an intermittent-dose AMPH schedule (INT; one daily injection over 6 days, 1.5 mg/kg, i.p.) on animals' performance in three behavioral paradigms related to depression: the Porsolt swim test, the learned helplessness assay and operant responding for sucrose on a progressive ratio schedule. ESC and INT AMPH withdrawal had no effect on any of these tests or on stress responsiveness as measured by increased plasma levels of corticosterone (CORT) and adrenocorticotropin following the swim test, although basal CORT levels were higher in AMPH-withdrawn animals compared to controls. Finally, we confirmed the presence of locomotor sensitization for both AMPH schedules after 30 days of withdrawal. Our results suggest that the ability of AMPH withdrawal to produce symptoms of depression may not be evident in all behavioral screens for depressive symptoms in the rat.
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PMID:Amphetamine withdrawal does not produce a depressive-like state in rats as measured by three behavioral tests. 1257 77