The role of thyroid gland on oxidative and intermediary metabolism has been unequivocally confirmed in different classes of sub-mammalian groups employing radiolabel incorporation studies and hormone receptor assay, besides the effect on enzyme activities. His group has recently confirmed the long term and short-term effects of both T3 and T2 on lipid metabolism through C14 acetate incorporation studies to suggest a biological role for T2 which was considered inactive. The role of thyroid hormones on metabolism in fish was confirmed by demonstrating binding affinity for T3 by hepatic cells in a teleost. The different mechanisms of action of thyroid hormones have also been suggested using metabolic inhibitors. Besides thyroid hormones, they have investigated the effects of growth hormone and prolactin on lipid metabolism in a teleost, Anabas recently. Very recently, they have studied the non-genomic effects of steroids on enzymes of osmoregulation in a teleost Oreochromis mossambicus, employing the inhibitors of protein synthesis both in vivo and in vitro mutually substantiating each other. This has helped them to add one more dimension to steroid action in sub-mammalian vertebrates, probably first of its kind of a study. Having established the role of thyroid hormones in metabolism, and that metabolism generates reactive oxygen species (ROS), their current emphasis is on hormonal regulation of ROS quenching in a teleost model. This is envisaged to establish the mechanism of homeostasis in this group.

Studies on Biodiversity and reproductive physiology
Further, they we revisiting the studies on spermatogenesis in caecilian amphibian pioneered by Seshachar several decades ago with modern tools of staining and EM. The initial results on spermatogenesis and spermateleosis are highly encouraging. We also intend to create a gene library for the different extant caecilian species to help future systematic biologists to compare and confirm their studies. This study is done with collaboration of Natural History Museum, London and Bharatidasan University, Tiruchirapally.

Natural products as therapeutic agents                     
Studies on natural products are underway to investigate the biological activity of Stevia rebaudiana, anatural calorie free sweetener and Curcumin longa, a broad-spectrum anti-cancer agent. The differential effects of curcumin and biochemical mechanism of protection is yet to be completely understood in various animal models besides cell lines. They are also probing into the combinations of natural plant compounds which may have preventive and therapeutic applications against the environmental induced tumors.

The significance of these results can be implicated in relation against the induction of tumors in various target organs. Classification of chemopreventive effects of curcumin by its potency, mode of action, and selectivity is expected to contribute to the design of the next generation of Curcumin research. The project on Stevia rebaudiana is expected to contribute significantly to the elucidation of the role of dried Stevia leaves and purified diterpenoid glycosides as a non-caloric sweetener in food stuffs. The results should be of major significance to the people all over the world, especially to those who are suffering from diabetes. The detailed study on the reproductive toxicity may contribute to find out, whether the aqueous Stevia extracts and its purified active compounds have any contraceptive value.

Reactive oxygen species and amphibian metamorphosis
Amphibian metamorphosis is a model system for study of comparative biochemistry and cellular differentiation since it illustrates a series of remarkable biochemical and structural adaptations. This system bears strong similarities to postembryonic development in mammals. Metamorphosis, a developmental phenomenon, involves extensive organ remodeling consisting of growth and development of some as well as regression of others. Fuelling this complex process requires co-ordinated regulation of all aspects of energy metabolism. Among vertebrates, amphibians provide the most fruitful material for the study of development. Reactive oxygen species (ROS) like superoxide, hydrogen peroxide, and hydroxyl radicals are implicated in many ways with stressful conditions: as primary elicitors, as products and propagators of oxidative damage, or as signal molecules initiating defense or adaptation. Relatively few studies have been done to estimate antioxidant enzyme profile during metamorphosis. A link between ROS and metamorphosis has not been established till date. Future research will be necessary to establish the link between ROS & TH-signaling within the metamorphic signaling architecture. We hypothesize that the interaction between hormonal signals and ROS with specific components of cell death pathways orchestrates these two divergent developmental programs, thereby leading to the successful formation of adult tissues and organs.