Studies on teleost corpuscles of Stannius: Physiological and biochemical aspects of synthesis and release of hypocalcin in trout, goldfish and eel

Hypercalcemia (induced by CaCl₂-injection or seawater exposure of the fish) reduced the hypocalcin content of corpuscles of Stannius (CS) in trout, goldfish and eel; concomitantly the synthetic activity of CS of hypercalcemic fish, as determined in vitro, was enhanced. The monomeric forms of prohypocalcin and of hypocalcin of trout and goldfish are 32 and 28 kDA M_r glycoprotein species respectively; those of the eel are 2 kDa bigger, viz. 34 and 30 kDa respectively. Moreover, eel CS produce in vitro an enigmatic 70 kDa glycoprotein with affinity for concanavalin-A. It is concluded that plasma calcium levels control storage and synthesis rates of hypocalcin in the CS.