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R. Yadav ¹, C. Haldar ¹, L. K. Pandey ²

Affiliations
1 Pineal research Lab., Department of Zoology, Banaras Hindu University, Varanasi – 221 005, IN
2 Department of Obstetrics and Gynecology, Institute of Medical Sciences, Banaras Hindu University, Varanasi – 221 005, IN

Abstract

There is lack of basic information about peripheral melatonin level and its relationship with gestational hormones i.e., estrogens and progesterone, in human females. The present study addressed this issue and aimed to find the relationship between the levels of melatonin and estrogen and progesterone during different weeks of gestation, during parturition and during post-partum. The data suggest that there is a definite ratio of melatonin with both the steroids hormons before and during gestation as well as post-partum. An inverse relationship between the levels of estrogen and melatonin was observed in non-pregnant and post-partum women, while a direct relationship was observed during gestation. These two different types of hormonal relationships might be essential for maintenance of pregnancy. The inverse relationship of melatonin with progesterone during parturition may serve as a signal for parturition.

Keywords

Melatonin, Estradiol, Progesterone, Gestation, Parturition, Post-Partum.

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S. Rai ¹, C. Haldar ¹

Affiliations
1 Pineal Research Lab, Reproductive Biology Unit, Department of Zoology, Banaras Hindu University, Varanasi- 221 005, IN

Abstract

The significance of annual variation in metabolic (thyroxine) and chronobiotic (melatonin) hormones in relation to immune adaptation of the Indian palm squirrel was investigated. The squirrel is summer breeder and, hence, remains healthy during reproductively active phase (Feb - Aug) when melatonin level is low and thyroxine level is high. Our data show that the circulating levels of melatonin (MEL) and thyroxine (T₄) have their respective annual rhythms, which are inversely related. Thyroxine level is low during the winter months (Sep-Jan) when metabolic activity of this rodent is also low. During this period melatonin level is high because of the short photoperiod and the squirrels indicate poor reproductive activity, with low gonadal steroids, which could be due to high circulating melatonin. The immune parameters also present an annual rhythmicity, which is parallel with circulating melatonin level, but inversely related to thyroxine level. This suggests that the metabolic hormone, thyroxine, and the chronobiotic hormone, melatonin, might be responsible for maintenance of the immune system to adapt the rodent for the rigors of the seasonal environmental changes.

Keywords

Annual Variation, Immune Parameters, Melatonin, Squirrel, Thyroxine.

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C. Haldar ¹, S. S. Singh ¹

Affiliations
1 Pineal Research Laboratory, Department of Zoology, Banaras Hindu University, Varanasi-221005, IN

Abstract

Birds (n general have not been frequently examined for the immunological influences of melatonin or pineal gland, as it has been potentially noted with the mammals including human being. There are only few reports suggesting that melatonin may play some role in the development and function of the immune system in the birds. The diurnal pattern of the melatonin synthesis is the same In almost all vertebrate groups so far examined, though differences exist in structure or anatomy of the pineal gland and seasonal variation in the peripheral melatonin level. Since functional relationship between neuroendocrine pineal gland and immune systems appears as to be diverse, it is logical that immunomodulatory effects of melatonin may be different in different seasons. The seasonal variation In melatonin level has been proved to improve the status of Immunity in seasonal tropical birds to bear the natural challenges. The level of peripheral melatonin minimizes some inflammatory diseases and sudden death syndrome in some poultry birds. The effect of melatonin also depends upon the phases of the inflammatory reaction/process. Pinealectomy in birds demonstrated functional interrelationship between the development of pineal gland, ontogeny of the melatonin secretion and immune system and/or neuroendocrine network. Bursectomy could influence the diurnal rhythm of melatonin and may abolish the effect of immunization on serum melatonin level. Specificities of avian immune system may be, however, very useful for understanding numerous phylogenetic and evolutionary mysteries. In this way a reciprocal functional connection between the avain immune system and the pineal gland seems to exist, but the mechanisms involved in maintaining the immune status by melatonin in avain group Is still not clear and needs to be elucidated.

Keywords

Birds, Immunity, Melatonin, Pineal, Reproduction.

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N. H. Mohan ¹, R. S. Srivastava ¹, C. Haldar ²

Affiliations
1 Department of Veterinary Physiology, College of Veterinary Science and AH NDUAT, Faizabad 224 229, IN
2 Department of Zoology, BHU, Varanasi, Division of Physiology and Climatology, Indian Veterinary Research Institute, Izatnagar 243 122, UP, IN

Abstract

The pineal gland is reported to contain several proteins and peptides, which are having role in reproduction. The present study was undertaken with an objective to assess whether pineal gland extracts and ovarian follicular fluid proteins have any antigenic similarity. Extracts were prepared in normal saline from caprine pineal glands obtained from local abattoir at the time of slaughter. The ovarian follicular fluid was obtained from the ovaries collected along with pineal glands.

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S. Rai ¹, S. S. Singh ¹, C. Haldar ¹

Affiliations
1 Pineal research Lab, Reproductive Biology Unit, Department of Zoology, BHU, Varanasi-221 005, IN

Abstract

The immune system was believed until recently, to be closely integrated with other physiological circuits such as the central nervous and neuroendocrine system of which pineal is a integral constituent (Gupta 1990). A lot of in vivo and in vitro studies have been performed to explain the immunoregulatory role of melatonin but till date there is very less report, available in the laboratory animals in this context. The present study was undertaken to elucidate the immunoregulatory role of pineal melatonin together with IL-1, i.e. synergic effect (IL-1 produced by LPS induced peritoneal macrophages) on the spleenocyte and thymocyte proliferation of the spleen and thymus respectively of F. pennanti. IL-1 is well known to induce proliferation of lymphocytes in rodents (Durum et ai, 1985; Mannel et al., 1985). This capacity of IL-1 has been utilized in its wisely used bioassay (Gearing et al., 1985).

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R. Tripathi ¹, C. Haldar ¹, R. Yadav ¹

Affiliations
1 Department of Zoology, Banaras Hindu University, Varanasi-221005, IN

Abstract

Phosphorylation of thymidine, a key step in pyrimdine salvage pathway involved in DNA synthesis is catalyzed by Deoxythymidine kinase [Thymidine kinase (TK)-ATP: thymidine 5'-Phosphotransferase, EC: 2.7.1.21]. Several authors correlated changes in TK activity and ³H-Thymidine incorporation into DNA of various tissues or with cell divisions or under influence of EGF (Lewinski et al., 1997) and found that the relationship was a proportional one (Kahn et al, 1980; Zieve 1985).

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S. Dubey ¹, C. Haldar ²

Affiliations
1 Department of Zoology, Udai Pratap College, Varanasi, IN
2 Centre of advanced study, Department of Zoology, Banaras Hindu University, Varanasi-221 005, IN

Abstract

The Harderian glands are large orbital glands present in most vertebrates and are known to produce lipid, porphyrins, (precursor of haem)&indole amines. Sex hormones play an important role in the clinical expression of several porphyriasis. Some form of this disease are more common in women than in men and may be exacerbated during menstrual cycle and pregnancy, suggesting an involvement of some pregnancy associated hormones in modulation of this disease. However, no proofs are available in literature for occurrence of porphyriasis in rodents.

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C. Haldar ¹, R. Yadav ¹

Affiliations
1 Pineal Research Lab, Department of Zoology, Banaras Hindu University, Varanasi - 221005, IN

Abstract

The pineal gland, the transducer of several environmental cues through its hormone, melatonin, is known to play a critical role in the reproduction of several seasonally breeding mammals. The role of pineal gland in the control of male reproduction is already established beyond doubt. The logical hypothesis that the pineal gland would be involved in the aspects of female reproduction, particularly gestation, embryonic development and fetal growth, has been tested in a few seasonally breeding mammals and this paper reviews the outcome as of now. Evidence for establishment of an inverse relationship before pregnancy followed by moderately high activity with a positive correlation during pregnancy and a sudden increase in pineal activity during parturition has been produced, which suggests that high melatonin level has something to do with parturition or early abortion. The pineal gland perhaps maintains the normal physiology during gestation and post-parturition periods. This is further reflected in the prolactin levels of fetal sheep which is modulated by the photoperiod experienced by the mother during gestation. Maternal photoperiodic exposures during gestation and lactation periods alter the neonatal growth and sexual maturation of the Indian palm squirrel via the maternal transfer of photoperiodic information through the pineal gland, as aspect known as "pineal programming". The primary source of melatonin for the fetus is the maternal pineal gland, which is transferred across the placenta during conception and, later after parturition, through the milk, which suggests that a maternally generated melatonin rhythm would be expressed in fetal cerebrospinal fluid as well as in the circulation. Further, maternal melatonin is necessary for normal somatic growth and postnatal development of reproductive organs of the offspring. Melatonin ultimately affects reproductive activity by modulating hypothalamic neuroendocrine circuits whose activity is necessary for gonadal function. The influence of melatonin on reproductive development begins during the prenatal period and extends into the postnatal life. Photoperiodic information, mediated via the pineal gland may be important for maintaining gestational physiology as well as postpartum recovery in female rodents. Further, melatonin has been shown to play adaptive role in the maintenance of delayed embryonic development in bats. Correlation between a developmental decline in melatonin levels and the timing of puberty in humans led to the speculation that melatonin regulates the timing of puberty in the human. These studies on the influence of melatonin on gestation indicate two major inferences viz., melatonin could be one of the major hormones establishing homeostasis during gestation since any disturbance in the level of melatonin causes abortion, and melatonin is one of the hormones of great adaptive significance for embryonic diapause.

Keywords

Embryonic Growth, Gestation, Melatonin, Photoperiod, Pineal Gland, Puberty.

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S. Lahiri ¹, S. Rai ¹, C. Haldar ¹

Affiliations
1 Pineal Research Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221 005, IN

Abstract

Endogenous melatonin is involved in regulation of reproductive function of the photoperiodic species. A circannual rhythmicity of the pineal gland in relation to reproduction has been observed in a tropical seasonally breeding mammal, Funambulus pennanti. A trade-off relation is known to exist between melatonin and the gonadal steroids. In vitro suppression of splenocyte proliferation by testosterone and the reversal of this effect by melatonin supplementation have already been reported. Melatonin receptors have been detected in the lymphoid tissues by binding of 2-[¹²⁵I] iodomelatonin to splenocytes and thymocytes. We analyzed the presence of melatonin receptor adopting Western blot technique. We found that MTl receptor protein, one of the variants of melatonin receptor, is expressed in both the thymus and spleen tissue and the expression is suppressed by testosterone treatment. This substantiates the direct immunomodulatory role of melatonin. To find the significance of steroid toxicity at molecular level, particularly testosterone, it is important to study its effect on the expression pattern of these receptors.

Keywords

Melatonin, Melatonin Receptor, Spleen, Steroid, Testosterone, Thymus.

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C. Haldar

Abstract

As per the provision of the Clause No. 64 of the Memorandum and Article of The Association, the 85th Annual General Meeting for the financial year 2004-2005 will be held on June 29, 2005 at 6-30 p.m. to discuss the following agenda (Venue: lA- 11 Salt Lake City, Kolkata - 700 097).

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V. K. Verma , S. K. Yadav , C. Haldar , R. K. Tripathi

Abstract

As a transducer of the environmental factors the pineal gland, together with the metabolically active thyroid gland, plays a major role in control of reproduction during different times of the year, in response to the changing environmental conditions of the tropical zone unlike in the temperate zone. Our avian model P. asiatica is a long day breeder. It is reproductively active during summer and quiescent during winter months. In this study we investigated the role of thyroid gland super-imposed by melatonin in the regulation of the annual male reproduction in this bird. The metabolically active thyroid gland presented a functional parallelism with the testicular activity suggesting that thyroid hormone is essential for reproductive activity and related metabolic energy for avian species. Our data also suggest an inhibitory effect of melatonin on thyroid gland function [weight, thyroxine (T3/T4) level and thymidine kinase activity, THK] both during active and inactive phases of the reproductive cycle. However, this inhibitory effect was less evident during the active phase. The low level of melatonin during the reproductively active phase might be due to long days of summer which prevented the birds from being hyperthyroidic. Therefore, we suggest that the level of melatonin serves as a physiological check to control the seasonal reproductive activities of gonads and thyroid which synergistically play most important physiological roles in energy metabolism of these seasonally breeding bird P. asiatica.

Keywords

Bird, Environmental Factors, Melatonin, Reproduction, Thyroid.

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