Journal of Endocrinology and Reproduction

Anju Kurup ¹, A. V. Ramachandran ¹

Affiliations
1 Division of Developmental Biology, Department of Zoology, The M. S. University of Baroda, Vadodara – 390002, Gujarat, IN

Abstract

In order to evaluate the time-specific influence of pineal indoles on tail regeneration in lizards, melatonin (M), methoxytryptophol (ML) and methoxytryptamine (MT) were administered intraperitonealy to different groups of lizards at morning 7:00 hrs (m) or in the evening at 17:00 hrs (e). The Mm and MLe groups of lizards showed a delay in the attainment of various arbitrary stages of regeneration like wound healing, pre-blastema, blastema and initiation of growth while the Me and MLm groups of lizards showed hastened attainment. However, MTm and MTe treatments did not bring about any difference compared to the controls. The total length of tail regenerated and percentage replacement at the end of 30 days were significantly less in Mm and MLe groups of lizards. MTm and MTe treatments, however, did not affect the regeneration process. The results indicate that M and ML have opposite time-specific effects on regeneration, while MT has no effect. Apparently, M and ML are part of the photoperiodic and neuro-endocrine transduction mechanisms related to regenerative growth in lizards.

Keywords

Lizard, Melatonin, Methoxytryptamine, Methoxytryptophol, Regeneration.

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V. V. Nambiar ¹, I. Y. Bhatt ¹, P. A. Deshmukh ¹, R. R. Jape ¹, P. N. Jivani ¹, H. R. Kavale ¹, S. S. Prakashkar ¹, A. V. Ramachandran ¹

Affiliations
1 Division of Developmental and Reproductive Endocrinology, Department of Zoology, The Maharaja Sayajirao University of Baroda, Vadodara - 390 002, IN

Abstract

Epimorphic regeneration, as exemplified by lizard tail, involves the formation of regeneration blastema as a prerequisite for replacement growth. The formation of blastema is preceded by many regressive changes like tissue demolition, histolysis, inflammation, wound closure, dedifferentiation, cell migration and proliferation. The ECM components of a normal tail help maintain the differentiated state of the constituent heterogeneous tissue and tend to prevent cell migration and proliferation. Since the formation of a regeneration blastema involves many key cellular events like dedifferentiation, migration of dedifferentiated and other nomadic cells and cell proliferation, extensive reorganization of the extracellular matrix is likely to be a major event during post-autotomy period. To this end, total GAG content and gelatinase (MMP-2&9) activity were assayed during the first week post-caudal autotomy. The effect of MMP inhibition by doxycycline was also evaluated in terms of the number of days taken for wound closure and blastema formation as well as the length of detail regenerated at the end of twenty days from the time of initiation of growth. Significant progressive decrement in total GAG content up till 96 hours followed by a significant increment at 120 and 144 hours, together with a biphasic increment in gelatinase activity (first during 24-48 hours and second during 96-144 hours) have been recorded. The increased gelatinase activity and the decreased GAG content in the first 96 hours are suggestive of breakdown of proteoglycans and collagens (type IV, V, VII&X). The second phase of increase in GAG content is related with synthesis of hyaluronate, favoring dedifferentiation, proliferation and migration of cells. MMP inhibition by doxycycline significantly retarded tail regeneration. From these results it is concluded that ECM remodeling is crucial in the immediate post-autotomy period for the formation of an effective blastema and that MMPs play a crucial role in the same.

Keywords

ECM Remodeling, GAGs, Lizard, MMPs, Regeneration.

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Pradnya A. Deshmukh ¹, Isha Y. Bhatt ¹, Riddhi R. Jape ¹, Palak N. Jivani ¹, Hemangi R. Kavale ¹, Vandana V. Nambiar ¹, Sunny S. Prakashkar ¹, A. V. Ramachandran ¹

Affiliations
1 Division of Developmental and Reproductive Endocrinology, Department of Zoology, MS University of Baroda, Vadodara - 390 002, IN

Abstract

Epimorphic regeneration, as exemplified by lizard tail, involves the formation of regeneration blastema as a pre-requisite for replacement growth. The formation of blastema is preceded by many regressive changes like tissue demolition, histolysis, inflammation, wound closure, de-differentiation, cell migration and proliferation. Induction of signaling molecules would be crucial in the molecular biology of immediate post-autotomy period in providing the trigger for the initiation of regeneration. It is in this behest that the levels of the cAMP, cGMP and NO have been assayed during the first 72 hr post caudal-autotomy in the lizard Hemidactylus flaviviridis. The influence of exaggerated exogenous induction of NO as well as prolonged action of cGMP by the use of PDE5 inhibitor (sidenafil citrate) have also been evaluated in terms of the number of days taken to complete wound healing and form a blastema as well as the length of tail regenerated at the end of 20 days. cAMP-mediated PKA activation and downstream signaling cascades appear to be the principal mechanism as against cGMP-mediated mechanisms. Controlled NO generation appears to be of pivotal significance in minimizing apoptotic cell loss as substantiated by the reduced caspase 3 activity. Exaggerated induction of NO and prolongation of cGMP action appear to promote apoptotic cell loss resulting in retarded regenerative growth. It can be concluded from the present observations that cAMP- and PKA-mediated events occur first and that minimizing cell apoptosis by controlled NO generation is important in the formation of robust regeneration blastema.

Keywords

Apoptosis, Caspase 3, Lizard, Regeneration, Signaling Molecules.

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A. V. Ramachandran ¹, A. Kurup ¹

Affiliations
1 Division of Reproductive Endocrinology, Department of Zoology, The Maharaja Sayajirao University of Baroda, Vadodara - 390 002, IN

Abstract

Thyroid hormones have been implicated in the control of vertebrate appendage regeneration. In lizards, thyroid hormones have been reported to induce ependymal outgrowth and also exercise control over adaptive systemic metabolic activities. However, there have been no attempts to correlate the seasonal differences in regenerative performance with thyroid activity. The present study has evaluated the effect of induced thyroid hormone excess or deficiency (by T4 administration or methimazole treatment, respectively) on tail regeneration in H. flaviviridis on a seasonal basis in summer, monsoon and winter months. The experiments revealed a retardative influence of hypothyroidism in tail regeneration in both summer and winter months; however blastema formation occurred in the normal time course in the summer months. Hyperthyroidism induced by daily T4 administration, either systemically or in loco, hastened the formation of blastema and provided an early growth spurt but, ultimately, retarded regenerative growth in the summer months. However, T4 administration daily for the first 15 days and every other day thereafter favored a better regenerative growth. In contrast, during the monsoon months, both daily administration and administration every alternate day, either systemically or in loco, delayed blastema formation as well as retarded linear growth. Neither hypothyroidism nor hyperthyroidism exerted any influence on the sluggish performance characteristic of winter months. It is concluded that thyroid activity and thyroid hormone responsiveness vary on a seasonal basis with maximum activity at higher temperatures and minimal at lower temperatures. It can also be concluded that there is differential sensitivity to thyroid hormone during summer and monsoon seasons.

Keywords

Regeneration, Tail, Lizard, Thyroid, Season.

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R. V. Devkar ¹, D. S. Dandekar ¹, A. V. Ramachandran ¹

Affiliations
1 Division of Developmental Biology and Endocrinology : Poultry Section, Department of Zoology, M.S. University of Baroda, Vadodara 390 002, IN

Abstract

The pullets of Indian Rhode Island Red (RIR) breed of domestic fowl were reared under a step-down photoperiod of LD 18:6 (long photoperiod; LP) from day 1 to day 90 post-hatch, and then shifted to LD 12:12 (NLD), to assess its effect on growth kinetics of lymphoid and reproductive organs, and serum hormone profiles, the observations were made at 30,60 and 90 days and the results were compared with pullets reared under NLD alone. The weights of thyroid and ovary in LP chicks showed significant increment, whereas the weights of liver and lymphoid organs were identical to that of NLD chicks. The weights of adrenal and oviduct decreased significantly. In general, serum levels of T₃, T₄, corticosterone and progesterone tended to show a gradual decrement with age in NLD chicks, but the LP chicks showed a differential change marked by high T₃ and T₄ levels throughout and, increased corticosterone and decreased progesterone levels at 30 and 60 days. Long photoperiod seems to have an initial depressive, but later stimulatory effect on growth of thyroid, while it has an Inhibitory effect on adrenal. The histometric data of ovary suggest a stimulatory effect of light, indicated by increased number of follicles and decreased degree of follicular atresia. It is concluded from the present observations that exposure of chicks to LP has differential effects on growth kinetics and, a favourable influence on reproductive hormones suggesting inherent photosensitivity and, no setting in of photorefractoriness during this period.

Keywords

Chick Ovary, Corticosterone, Growth Kinetics, Lymphoid Organs, Photoperiod, Progesterone, Thyroid Hormones.

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B. P. Thakkar ¹, A. V. Ramachandran ¹

Affiliations
1 Division of Reproductive Biology and Endocrinology, Department of Zoology, M. S. University of Baroda, Vadodara Gujarat, IN

Abstract

Rat neonates have been exposed to melatonin by i.p. injection of 40(19 melatonin/animal/day daily in the evening at 16:30 hrs from day 0 to day 21. The preweaning hypeimelatonemia did not significantly influence either adult body weight or ovarian weight. The estrogen titre was reduced and progesterone titre increased in melatonin treated rats. Increased thyroid weight and elevated thyroid hormones levels were also recorded. The primordial and primary follicles were more in number with significantly lesser atretic follicles of all developmental stages. The first litter size was significantly greater (lit 3 vs 8 ± 2) in melatonin treated rats compared to controls. These results are interpreted in terms of protective action of neonatal melatonin against follicular apoptosis either directly or indirectly through thyroid hormones.

Keywords

Follicular Apoptosis, Melatonin, Progesterone, Thyroid Hormone.

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R. V. Devkar ¹, C. S. Patel ¹, A. V. Ramachandran ²

Affiliations
1 Zoology Division, Department of Biology, Bahuddin Science College, Junagadh, Gujarat, IN
2 Division of Avian Endocrinology, Department of Zoology, M.S. University of Baroda, Vadodara 390 002, IN

Abstract

Possible impact of pineal indoles (Melatonin-M; Methoxytryptophol-ML; Methoxytryptamine-MT) and pCPA on carbohydrate metabolism in terms of hepatic and muscle glycogen contents, hepatic phosphorylase and G-6-Pase on blood glucose level and pancreatic islet functions have been studied in the feral pigeons, Columba livia during the recrudescent phase.

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Khushali Upadhyay ¹, Foram Patel ¹, A. V. Ramachandran ², Elizabeth Robin ¹, Darshee Baxi ¹

Affiliations
1 Division of Biomedical and Life-Science, School of Science, Navrachana University, Vadodara − 391410, Gujarat, IN
2 School of Science, Navrachana University, Vadodara − 391410, Gujarat, IN

Abstract

Breast cancer is one of the most prevalent forms of cancers in women around the world. Owing to its biochemical variation and complexity, treatment with chemotherapy and/or radiotherapy is very complicated and often results in adverse side effects. This article reviews the widely practiced chemotherapeutic drugs, their modes of actions and side effects. The several breast cancer therapeutic approaches based on medicinal plants, hormones, nutritional supplements and/or some advanced drug delivery systems that may lead to faster recovery are also reviewed.

Keywords

Alternative Therapy, Breast Cancer Therapy, Chemotherapeutics.

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Ansarullah ¹, A. V. Ramachandran ²

Affiliations
1 The Jackson Laboratory, Bar Harbor, 04609, Maine, US
2 School of Science, Navrachana University, Vadodara 391410, Gujarat, IN

Abstract

The decline in functional β-cell mass and β-cell dysfunction causes diabetes. Pancreatic β-cells play a fundamental role in controlling the glucose milieu, and β-cells of diabetic patients poorly respond to glucose. The mechanism underlying the pathology of impaired β-cell function is a unique challenge. This concise review summarizes the identity of β-cells during the progression and established diabetes. Understanding β-cell heterogeneity and the dynamic functional state during health and disease progression would be important for designing diabetes therapeutics to restore the β-cell mass by cellreplacement or regeneration approaches.

Keywords

β-Cell Dedifferentiation, β-Cell Dysfunction, β-Cell Identity.

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