The Pineal Gland: Basic Implications and Clinical Correlations

Preslock, James P.

doi:10.1210/edrv-5-2-282

Cited by 82 publications

(12 citation statements)

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“…The day-nicht differences in melatonin levels noted in this study are not unexpected since this is a com mon phenomenon noted in all animals stud ied to date [19,20], including the female rab bit [21 ]. An unexpected finding was the corre spondence between high levels of melatonin at a time when the prepubertal levels of go nadotropins decreased several-fold ( fig.…”

Section: Discussionsupporting

confidence: 62%

Light-Related Melatonin Changes in Pituitary Response to Gonadotropin-Releasing Hormone during Sexual Development in the Female Rabbit

Younglai¹,

Todoroff²,

Foster³

et al. 1992

Biological Signals

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Melatonin levels in the blood of female rabbits were determined from the time of weaning to adulthood in a longitudinal study. Blood samples were taken at 3 h after light onset and 1 h after dark onset and plasma was analysed for melatonin, LH and FSH by radioimmunoassay procedures. The animals were sacrificed on days 25, 32, 39, 51, 72, 91 and 120 days of life and pituitaries removed for in vitro incubation of slices to determine their response to GnRH. Circulating melatonin levels were significantly higher in the dark compared to the light phase and peaked on days 72 and 91 when gonadotropin levels were at a nadir. Melatonin levels on day 120 were lower than those on any other day examined. Basal secretion of LH and FSH by pituitary slices in vitro increased several-fold from day 25 of age to days 51–91 and then decreased by day 120. The pituitary gonadotropin responsiveness to GnRH in vitro was also different: while LH generally increased, FSH accumulation remained constant after GnRH stimulation. These data suggest that the female rabbit pituitary undergoes changes in sensitivity to GnRH during sexual maturation and that the pineal gland may play a role in this process.

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Section: Discussionsupporting

confidence: 62%

Light-Related Melatonin Changes in Pituitary Response to Gonadotropin-Releasing Hormone during Sexual Development in the Female Rabbit

Younglai¹,

Todoroff²,

Foster³

et al. 1992

Biological Signals

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“…On the other hand, there is good evi dence that the pineal gland is implicated in the regulation of the neurosecretory activity of the hypothalamo-hypophysial system through the release of indoles, in particular melatonin [27]. Whether the presence of ANF binding sites in pinealocytes may predict a role for ANF in the modula tion of pineal function remains to be determined.…”

Section: Discussionmentioning

confidence: 99%

Radioautographic Localization of <sup>125</sup>I-Atrial Natriuretic Factor Binding Sites in the Brain

et al. 1986

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Rats were injected through the carotid artery (cephalad direction) with 18.9 µCi of either ¹²⁵I-Arg 101-Tyr 126 atrial natriuretic factor alone or together with an excess of unlabeled hormone. At 2 min after injection, all rats were fixed in vivo by perfusion and serial sections of the whole brain were processed for light microscope radioautography. The radioautographic reaction produced by ¹²⁵I-atrial natriuretic factor alone was localized in all circumventricular organs (except the subcommissural organ), the smooth muscle cells and endothelial cells of arteries, arterioles, veins, venules, the endothelial cells of intraparenchymal capillaries and the epithelial cells of the choroid plexus. In rats which received ¹²⁵I-atrial natriuretic factor plus an excess of unlabeled hormone, the radioautographic reaction was reduced by 70–90%. Binding sites are thus localized in regions of the brain, some of them involved in the central monitoring of blood pressure and osmolarity. In addition, the presence of binding sites in the cerebral vasculature and in the epithelium of the choroid plexus suggests that circulating ANF may play a role in the control of cerebral blood flow and in the production of vertebrospinal fluid.

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“…Light intensity, registered via the retino-hypothalamic projections underlie the rhythmic biphasic nature of melatonin secretion. Information about light intensity is transferred via the retino-hypothalamic tract to the suprachiasmatic nuclei of the hypothalamus, from where im pulses, transmitted via the superior cervical ganglion, con trol the secretory activity of the pineal gland [9,10].The exact function of melatonin is as yet speculative but several effects of melatonin have been described. Several …”

mentioning

confidence: 99%

“…Several endocrine abnormalities such as disturbances in corticoid secretion [11], aldosterone secretion [10], growth hormone secretion [12], insulin secretion [13,14], reproductive steroid levels [15] and the secretion of thyroid hormones [16], are in some way linked to abnormal levels of plasma melatonin. It is suggested that the pineal gland may modulate the release of pituitary hormones through an inhibitory effect on en zyme activity, mitotic rate and cell proliferation [10], A regulatory feedback mechanism between pineal activity and hypophyseal activity is suggested by the observation of pineal atrophy following hypophysectomy in experimental animals. The role of a pineal secretion, most probably melatonin, as an inhibitory modulator of anterior pituitary function, is propagated by some.…”

mentioning

confidence: 99%

Melatonin in Chronic Renal Failure

Viljoen

Steyn

Rensburg

et al. 1992

Nephron

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The melatonin status of patients in end-stage chronic renal failure (CRF) was evaluated by the determination of daytime plasma melatonin levels and by the investigation of the circadian rhythmicity of melatonin secretion. A significant increase in plasma melatonin concentration was found in all CRF patient groups investigated, i.e. CRF patients on conservative treatment (CT; n = 48), CRF patients on maintenance haemodialysis treatment (HD; n = 39) and CRF patients on peritoneal dialysis (PD; n = 32). Successful transplantation led to a marked reduction in plasma melatonin levels. The circadian rhythm of melatonin secretion would appear to be suppressed in CRF as the nocturnal secretory surge was absent in all HD patients and in 80% of the posttransplantation patients studied.

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The Pineal Gland: Basic Implications and Clinical Correlations

Cited by 82 publications

References 0 publications

Light-Related Melatonin Changes in Pituitary Response to Gonadotropin-Releasing Hormone during Sexual Development in the Female Rabbit

Light-Related Melatonin Changes in Pituitary Response to Gonadotropin-Releasing Hormone during Sexual Development in the Female Rabbit

Radioautographic Localization of <sup>125</sup>I-Atrial Natriuretic Factor Binding Sites in the Brain

Melatonin in Chronic Renal Failure

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