Exogenous melatonin may act as a reproductive-phase dependent modulator of the relationship in morphology between pineal and adrenal cortex in male Blossomheaded parakeet (Psittacula cyanocephala) and Indian Weaver bird (Ploceus philippinus)
TL;DR: It is suggested that melatonin can act as a reproductive‐phase dependent modulator of the pineal gland and adrenal cortex in these birds.
Abstract: The influence of melatonin, at a daily dose of 250 μg/100 g b.w. for ten consecutive days on morphological parameters of the pineal and adrenal cortex was investigated in two diverse avian species, Blossomheaded parakeet (Psittacula cyanocephala) and Indian Weaver bird (Ploceus philippinus). The results suggest that melatonin administered during the breeding phase caused stimulation of the adrenal cortex as evidenced from the significant increase in adrenocortical cord width and nuclear size in both avian species. However, the pineal gland in both species remained unaltered during this phase. On the contrary, melatonin given during the non‐breeding phase failed to alter the adrenal cortex but stimulated the pineal gland activity as evidenced from the significant increase in pinealocyte nuclear diameter in both species alike. It is suggested that melatonin can act as a reproductive‐phase dependent modulator of the pineal gland and adrenal cortex in these birds.
Citations
More filters
TL;DR: Both the selective impairment of nocturnal melatonin secretion, and the reduction of hypothalamo-pituitary-adrenal (HPA) sensitivity to steroid feedback might be considered as markers of aging brain.
Abstract: The study of the neuroendocrine changes occurring in aging may give information about the CNS functions, and also explain the impaired plasticity of the aged organism. In 16 elderly women and in 14 young controls, the circadian rhythms of plasma melatonin, GH, PRL, ACTH and cortisol, and of oral temperature were simultaneously studied. The plasma cortisol circadian rhythm was also evaluated after DXM administration (1 mg orally at 23:00). The circadian profile of all the bioperiodic functions evaluated was clearly flattened in elderly subjects, and an impairment of the hormonal nocturnal secretion of GH, PRL and melatonin was apparent in elderly subjects when compared to young controls. The plasma ACTH levels throughout the 24-hour cycle were significantly higher in elderly than in young subjects. The cortisol circadian profile exhibited significantly higher values in the evening- and night-time in elderly subjects, compared to young controls; the cortisol nadir values were significantly age-related. A reduction of the sensitivity to DXM inhibition occurred in the elderly group. Both the selective impairment of nocturnal melatonin secretion, and the reduction of hypothalamo-pituitary-adrenal (HPA) sensitivity to steroid feedback might be considered as markers of aging brain. The neuroendocrine alterations of physiological aging may be ascribable to both the structural and neurochemical changes occurring in the CNS.
36 citations
01 Dec 2009
TL;DR: It is concluded, that a mutual relationship between the pineal and the thyroid gland karyomorphological and functional parameters in response to corticoids and an antiadrenal agent in post pubertal male rat (Rattus rattus) is indicated.
Abstract: The relationship between pineal and thyroid in response to the adrenocortical modulation is poorly understood. In the present study post pubertal male rats were treated with natural and synthetic corticoids and an antiadrenal agent mitotane. Hydroxycortisone was administered at a dose of 4 mg / 100 g b.w., dexamethasone 2 mg / 100 g b.w. and mitotane 3 mg / 100 g b.w. for fifteen consecutive days. Our data revealed that both the corticoids, hydroxycorticosterone and dexamethasone induced hyperactivity of pineal and thyrofollicular cell morphology. The functional relation between the cells of the pineal parenchyma and thyroid follicles were noted. Similar results were induced by mitotane, an antiadrenal agent. It is concluded, that our present study indicates a mutual relationship between the pineal and the thyroid gland karyomorphological and functional parameters in response to corticoids and an antiadrenal agent in post pubertal male rat (Rattus rattus).
8 citations
Cites background from "Exogenous melatonin may act as a re..."
...…size (Quay, 1976; Chakraborty and Maiti, 1981; Maiti and Chakraborty, 1980; Diehl et al., 1984; Sahu and Chakraborty, 1983, 1986; Chaudhuri and Maiti, 1989; Hira et al., 1989; Martinez Soriano et al., 1990; Chakraborty, 1993, 1994; Chakraborty et al., 1981, 1992; Ganguli et al., 1998, 2001)....
[...]
...…diminished nuclear size (Quay, 1976; Maiti and Chakraborty, 1980; Chakraborty and Maiti, 1981; Diehl et al., 1984; Sahu and Chakraborty, 1983, 1986; Chakraborty, 1993, 1994; Ganguli et al., 1998, 2001). studies related to humans, bilateral adrenalectomy with or without glucocorticoid replacement…...
[...]
TL;DR: It was concluded that in male post-pubertal mice both pineal and adrenal glands show antagonistic response towards estradiol and testosterone administration, and although tamoxifen showed estrogen agonistic behaviour, flutamide conversely induced pineal - adrenal cytophysiological stimulation.
Abstract: In the present investigation steroid hormones, estradiol and testosterone and non-steroidal antihormones, tamoxifen and flutamide induced responsiveness in pineal and adrenal karyomorphology and cell proliferation activity was studied in post pubertal male mice (Mus musculus). Estradiol was injected at a dose of 5µg, testosterone 100 µg, tamoxifen 500 µg and flutamide 2 mg per 100 gm body weight administered intramuscularly in all cases for ten consecutive days. Control mice were similarly injected with oil vehicle 0.3 ml of peanut oil intramuscularly for same duration. The results indicated that except testosterone, all other treatments with estradiol, tamoxifen and flutamide caused significant hyperactivity of both the pineal and the adrenal gland associated with significantly increased cell proliferation activity. On the contrary testosterone administration was inhibitory to pineal - adrenal karyometric and mitotic incidence values. It was concluded that in male post pubertal mice both pineal and adrenal shows antagonistic response towards estradiol and testosterone administration. Although tamoxifen showed estrogen agonistic behaviour, flutamide on the reverse induced pineal and adrenal cytophysiological stimulation. Such stimulatory response was antagonistic to the inhibitory response shown by pineal and adrenal karyomorphology and cell proliferation following testosterone administration.
4 citations
Cites background or methods from "Exogenous melatonin may act as a re..."
...In all cases, pineal (Quay 1976; Chakraborty 1981, 1993, 1994; Chakraborty & Maiti 1981; Chakraborty et al. 1981, 1982, 1994; Maiti & Chakraborty 1982; Diehl et al. 1984; Sahu & Chakraborty 1983, 1986; Chaudhuri & Maiti 1989; Hira et al. 1989; Martinez Soriano et al. 1990; Bandyopadhyay et al.…...
[...]
...…1989; Hira et al. 1989; Martinez Soriano et al. 1990; Bandyopadhyay et al. 2000) and adrenal (Miller 1954; Maitra & Chakraborty 1983; Maitra 1987; Chakraborty 1994) cytological studies were made from mid-sagittal paraffin section of 5 µm thickness, stained with haematoxylin-eosin and observed…...
[...]
...2000) and adrenal (Miller 1954; Maitra & Chakraborty 1983; Maitra 1987; Chakraborty 1994) cytological studies were made from mid-sagittal paraffin section of 5 μm thickness, stained with haematoxylin-eosin and observed under oil immersion (15 ocular x 100 objective)....
[...]
Journal Article•
TL;DR: It is indicated that methimazole induced chemical hypothyroidism inhibits pineal gland activity in both mammals and birds.
Abstract: In the present investigation, influence of experimentally induced hypothyroidism on pineal karyomorphology was studied in three different species of animals – post pubertal male mice (Mus musculus), adult male rats (Rattus rattus) and neonatal male chicks (Gallus domesticus). Twenty-two animals of each species group were used, divided into two sets of experimental groups, Group A the control group and the other Group B the treated group. In Group A, eleven control animals of each species were given normal pelleted feed and normal drinking water ad libitum. In GroupB, the adult male mice (N=11), rats (N=11) and chicks (N=11) were supplied with normal pelleted feed and methimazole dissolved in drinking water (at a dose of 1 gm/l). After expiry of the experimental period of fifteen consecutive days each set of control and treated animals were divided into two groups and killed by etherisation. In the first set of control (N=6) and treated (N=6) experiments, animals were considered for histological studies. The second set of control (N=5) and treated (N=5) experiments, animals were considered for T4 assay. Present data reveal that methimazole caused a significant reduction reaching about detection value of serum T4 (μg/dl) levels in all the three species of animals. Such hypothyroid animals showed inhibition of the pineal gland activity as seen from significantly decreased pinealocyte nuclear diameter (μm) in all three species of animals, along with an increased pinealocyte nuclear density per microscopic field in mice and rats. Our study indicates that methimazole induced chemical hypothyroidism inhibits pineal gland activity in both mammals and birds.
3 citations
Cites background from "Exogenous melatonin may act as a re..."
...…et al., 1984; Sahu and Chakraborty, 1983, 1986; Hira et al., 1989; Peschke t al., 1989; Martinez Soriano et al., 1990; Chakraborty et al., 1993; Chakraborty, 1981, 1993, 1994; Chakraborty and Sarkar, 1994; Ganguli et al., 1998, Bandopadhyay and Chakraborty, 2010, Sinha et al., 2010, Sinha and…...
[...]
...…et al., 1984; Sahu and Chakraborty, 1983, 1986; Hira et al., 1989; Peschke et al., 1989; Martinez Soriano et al., 1990; Chakraborty et al., 1993; Chakraborty, 1981, 1993, 1994; Chakraborty and Sarkar, 1994; Ganguli et al., 1998; Bandopadhyay and Chakraborty, 2010; Sinha et al., 2010; Sinha and…...
[...]
01 Jan 2014
TL;DR: It is shown that exogenous melatonin induced disparate changes in pineal and thyroid gland activity in these neonatal chicks, whereas pineal gland showed an overall stimulation; in contrast,melatonin induced thorough inhibition of thyroid cytophysiomorphology and hormonal milieu compared to control group of neonatal chick (Gallus domesticus).
Abstract: A composite study including pineal and thyroid cell morphology, hormonal analysis and function in response to exogenous melatonin administration awaits in depth investigation in any bird. To investigate the pineal and thyroid responsiveness to exogenous melatonin from combined morphological and hormonal studies in neonatal chicks – two groups, each with eleven chicks were used as control (C) and treated with melatonin (M) at a dose of 100 µg.100 g body weight for fifteen consecutive days. The treatment with melatonin induced stimulation of pineal karyomorphology as evidenced from significantly increased nuclear diameter in the melatonin treated group. On the contrary, melatonin used inhibition of thyroidal activity as evidenced by significantly decreased values of thyroid nuclear diameter, thyrofollicular epithelial height, diameter and D/N activity associated with significantly decreased T4 values in neonatal male chicks. Our study thus shows that exogenous melatonin induced disparate changes in pineal and thyroid gland activity in these neonatal chicks, whereas pineal gland showed an overall stimulation; in contrast, melatonin induced thorough inhibition of thyroid cytophysiomorphology and hormonal milieu compared to control group of neonatal chick (Gallus domesticus)
3 citations
Cites background or methods or result from "Exogenous melatonin may act as a re..."
...Our current studies lend support to the contention that in addition to alterations in pineal biochemistry [8,11,16,74-77] and pineal induced physiological activities [76,77] also seems to serve as a target organ for exogenously administered indoleamine....
[...]
...An active phase is characterized by increased pinealocyte nuclear size indicating stimulation of synthesis activity, whereas an inhibitory phase is characterized by decreased nuclear size suggestive of inhibition of gland cells [8-9, 43-66] ....
[...]
...Reports about the stimulatory action of the indoleamine on pinealocyte morphology [8,11] , pineal ultrastructural components [12] and serotonin secretion [14] confirm our foregoing observations, revealing melatonin to have a stimulatory action on the pineal gland activity....
[...]
...An active phase is characterized by increased pinealocyte nuclear size indicating stimulation of synthesis activity, whereas an inhibitory phase is characterized by decreased nuclear size suggestive of inhibition of gland cells [8,9,43-49] ....
[...]
...Additionally a number of reports substantiate the present findings, in as much as melatonin’s ability to stimulate pineal morphological and ultrastructural features [8,11-12,21-22,78] and enhance the biochemical and hormonal activity of the pineal gland [16,17,19,20] ....
[...]
References
More filters
TL;DR: It is indicated that chronic daily injections of melatonin can depress reproductive function in hamsters and that the effectiveness of the injections is dependent upon the time of day at which they are administered.
Abstract: Hamsters were maintained on a long photoperiod (14L:10D) and were injected once daily with melatonin (10-25 mug) or sesame oil. Males which received melatonin during the afternoon (e.g., 6.5-13.75 h after lights-on) showed regressed testes and decreased levels of serum LH and FSH after several weeks of treatment. Injections of the oil vehicle or injections of melatonin given in the morning (3 h after lights-on) had no detectable effect on testicular size or on serum gonadotropins. Females which received melatonin during the afternoon became acyclic after several weeks of treatment and showed a diurnal pattern of LH secretion. The acyclic females required 4-6 weeks to resume estrous cyclicity following termination of the melatonin injections. The effects of melatonin on gonadal function and on serum gonadotropin concentrations in both sexes were similar to the previously observed effects of prolonged exposure to short photoperiods. These results indicate that chronic daily injections of melatonin can depress reproductive function in hamsters and that the effectiveness of the injections is dependent upon the time of day at which they are administered.
419 citations
TL;DR: The results indicate that daily MEL injections are capable of suppressing reproductive physiology in male hamsters, but only when the indole is injected late in the light period, in this case, 13 h after light on.
Abstract: The daily s.c. injection of 25 µg melatonin (MEL) in oil into adult male hamsters at 7 p.m. (lights on 6 a.m. to 8 p.m.) for 50 days caused involution of the testes, coagulation of
168 citations
TL;DR: Giving the extract of a protein-free bovine pineal extract to intact animals caused effects varying with the dose, which reversed changes in ovarian hypertrophy, pituitary hyperTrophy, and adrenalhypertrophy.
Abstract: Fifty-four 26-day-old female rats of the CD strain were divided into four groups of 10 or 11 each, i.e. 1) controls; 2) animals given 0.3 ml of a protein-free bovine pineal extract daily intraperitoneally for 28 days; 3) sham-operated animals; 4) pinealectomized animals. In a second experiment two groups of six each were divided into a ) control animals given a diet restricted with respect to Na, K and phosphate, and b) animals on the same diet, given 1.0 ml/day of the pineal extract. Pinealectomy caused ovarian hypertrophy ( P < .001), pituitary hypertrophy ( P < .001), and adrenal hypertrophy ( P < .05). The extract reversed these changes. Giving the extract to intact animals caused effects varying with the dose. The dose of 0.3 ml given daily caused gonadal atrophy ( P < .05), pituitary atrophy ( P < .001) and insignificant adrenal activity. The dose of 1.0 ml caused further gonadal atrophy ( P < .001) and significant adrenal atrophy ( P < .05).
126 citations
TL;DR: Melatonin reversed adrenal hypertrophy in male mice and caused adrenal hypotrophy, by itself, and augmented adrenal enlargement due to castration in males, but only the portion ofhypertrophy due to pinealectomy was reversed by melatonin.
Abstract: Pinealectomy produced adrenal hypertrophy in male mice. Melatonin not only reversed this effect, but also caused adrenal hypotrophy, by itself. Pinealectomy also augmented adrenal enlargement due to castration in males, but only the portion of hypertrophy due to pinealectomy was reversed by melatonin. Unilateral adrenalectomy was followed by adrenal enlargement 3 days later in males and females. This effect was reversed in males by melatonin, and in females by melatonin, 5-hydroxy-tryptamine, N-acetyl-5-hydroxytryptamine, 5-hydroxytryptophol, 5-methoxytryptophol, and 5-hydroxyindoleacetic acid; less so by 6-hydroxymelatonin; and not at all by 5-hydroxytryptophan or 5-methoxyindoleacetic acid (administered in single doses of 100 µg on the day of operation). Castration gave rise to increased adrenal weight in males, which was not significantly counteracted by melatonin. Adrenals were enlarged in males subjected to an ambient temperature of 5 °C for 4 h on each of 3 successive days, with no amelioration in adrenal weight response when
76 citations
TL;DR: Data indicate that the pineal itself is a target organ for exogenously administered melatonin, compatible with a generalized organ's activation.
Abstract: Melatonin administration or exposure of rats to darkness for two weeks induced comparable changes in pineal ultrastructure, compatible with a generalized organ's activation. These include an increased number of ribosomes, procentrioles and microtubules, prominent nucleoli and Golgi apparatus, and annulate lamellae. Melatonin treatment resulted in a dose-dependent increase of hydroxyindole-O-methyl transferase and serotonin-N-acetyltransferase activities. In addition it increased by 85% the colchicine binding capacity of pineal homogenates, an estimation of the microtubule protein content of the gland. Pineal norepinephrine turnover was not affected by melatonin treatment. These data indicate that the pineal itself is a target organ for exogenously administered melatonin.
67 citations