Volume Number 5 ‖ Issue Number 3 ‖ Year 2020 ‖Page Number 15 WORLD JOURNAL OF BIOLOGY AND BIOTECHNOLOGY Phosphocalcemic responses of vitamin D3 administered intact or hypophysectomized Heteropneustes fossilis maintained either in artificial freshwater or calcium deficient freshwater Ajay Kumar, Abhishek Kumar, ManiRam Prasad, Chandra Prakash, Sunil Kumar Srivastav Department of Zoology, D.D.U. Gorakhpur University, Gorakhpur, India, 273009. Authors’ Contribution Kumar, A performed the experiments; A. Kumar wrote and format the manuscript; M. Prasad and C. Prakash analyzed the data and S. K. conceived and designed experiments. Article History * Corresponding email address: abhisheksriwastava@yahoo.co.in Digital Object Identifier (DOI): https://doi.org/10.33865/wjb.005.03.0332 Received: 17 April 2020, Revised: 26 June 2020, Accepted: 27 July 2020, Published Online: 25 August 2020 ABSTRACT The serum calcium level of vehicle injected fish (group-A) exhibits no alteration throughout the experiment. Vitamin D3 administration to fish Heteropneustes fossilis exhibited hypercalcemia from day 3 to day 7 (group-B). However hypophysectomized and vehicle injected fish showed hypocalcemia from day 3 to day 7 (group-C). While hypophysectomized and vitamin D3 injected fish exhibited hypercalcemia on day 3 till the end of experiment (group -D). The serum phosphate of group A fishes is unaltered throughout experiment. The phosphate level of vitamin D3 treated fish (group-B) exhibits hyperphosphatemia from day 3 to day 7. In group C fishes exhibited a significant decrease in phosphate level throughout the experiment. While the group D fishes showed hyperphosphatemia from day 3 to day 7. In group E fishes the serum calcium level remains unaffected up to day 3 the level decreases on day 5 to day 7. In group F fishes showed hypercalcemia from day 3 to day 7. In group H fishes a progressive decrease in serum calcium level is noticed on day 3 to day 7. The group H fishes shows increase in the serum calcium level from day 3 to day 7. The serum phosphate level of group E fishes showed a decrease from day 3 to day 5. The phosphate level increases from day 3 to day 7 in group F fishes. The phosphate level exhibited a decrease from day 3 to day 7 (group G). The phosphate level increases from day 5 to day 7 of group H fishes. Keywords: Hypophysectomy, vitamin D3, serum calcium, serum phosphate, Heteropneustes fossilis. NTRODUCTION: A large fraction of calcium within cell is sequestered in mitochondria and endoplasmic reticulum. The intracellular free calcium concentrations fluctuate greatly, from roughly 100 nm to greater than 1 µm, due to release from cellular stores or influx from extra- cellular fluid. These fluctuations are integral to calcium’s role in intracellular signaling, enzyme activation and muscle contraction. Roughly half of the calcium in blood is bound to proteins. A vast majority of body’s calcium resides in bone. Within bone 99% of calcium is tied up in the mineral phase, and the remaining 1% can be rapidly exchanged. In teleosts about 99% of total calcium pool is incorporated into the skeleton and dermal scales as calcium phosphate and to a little extent as calcium carbonate (Flik et al., 1986). Numerous studies on fish calcium physiology (Bonga and Pang, 1991; Flik and Verbost, 1993; Riccardi, 1999) have established that calcium, particularly the ionic calcium is a crucial factor in a wide variety of processes, including neuronal excitability, membrane permeability, muscle contraction, cell division, adhesion of one cell to another, hormone release and mineralization of bone tissue. In contrast to terrestrial vertebrates, fish have access to unlimited supply of calcium through external environment. Moreover, the skeleton and dermal scales, important for shape, armor, structure and muscle attachment, serve a role as reservoirs for calcium as well. The external calcium in fish is taken up via gill and the intestinal tract. Extracellular calcium concentrations are thus maintained at a relatively constant level and many endocrine systems play an important role in calcium metabolism throughout the vertebrate classes. In fish this regulation is accomplished by calcium regulating hormones acting upon target organs, thus affecting uptake, excretion and turnover of internal calcium stores. The main role of Vitamin D is to provide the mineral balance. It regulates the metabolism and absorption of minerals and determines serum calcium and phosphorus levels. In vertebrates, the vitamin D endocrine system is a major regulator of calcium and phosphate homeostasis (Norman et al., 2002). Liver and fat stores large quantity of vitamin D in fishes. That is why fish are an important dietary source of vitamin D. Vitamin D is not synthesized by fish and are fully dependent on dietary source (Lock et al., 2010). Fish absorb vitamin D directly from their diet (Dusso et al., 2011). Uptill 1970s it was considered that the fish accumulate vitamin D but not metabolize vitamin D. But now it is clear that the fish have a vitamin D endocrine system with similar function like mammals (Lock et al., 2010). 1, 25 (OH)2 D3 (calcitriol), an active metabolite of vitamin D3 exerts its hypercalcemic effects through high affinity vitamin D3 receptor (Lock et al., 2010). Calcitriol plays a role in fish calcium metabolism by stimulation of intestinal calcium absorption and is a key factor in bone formation (Haga et al., 2004); the effects of calcitriol can be considered hypercalcaemic in mammals and fish alike. BJECTIVES: The objective of the present study is to investigate the Phosphocalcemic responses of vitamin D3 administered intact or hypophysectomized Heteropneustes fossilis maintained either in artificial freshwater or calcium deficient freshwater. ATERIALS AND METHODS: Area of study: Adult specimens of Heteropneustes fossilis (bw 27-36g) were procured locally and acclimatized to the laboratory conditions for one week (temp 22-26⁰C) An initial sampling of blood was collected (from 10 fish) before the start of the experiment (zero hour). Then they were divided into following groups and given following treatments: Group A: This group received daily intraperitoneal injection of vehicle (0.1 mL of 96% ethanol /100g bw) and kept in artificial I O M ISSN (Online) = 2522-6754 ISSN (Print) = 2522-6746 www.sciplatform.com Research Manuscript