Role of L-thyroxine, hydrocortisone and progesterone in regulation of blood volume in a fresh-water air-breathing fish, Clarias batrachus (Linn.).

Effect of hormones on the blood volume of Clarias batrachus were ascertained and it was observed L-thyroxine and progesterone decrease, while hydrocortisone increases the total and relative blood volumes. The ratio of plasma to corpuscular volume is increased by the intraperitoneal injection of L-thyroxine, hydrocortisone and progesterone (higher dose only), thus indicating the regulation of blood volume under the complex control of homeostasis.