Hormonal control of tanning in the American cockroach: Changes in blood cell permeability during ecdysis

Abstract

The content of diuretic hormone (DH), antidiuretic hormone (ADH), and tanning hormone (bursicon) in the haemolymph have been determined for several periods during the moulting process in Periplaneta americana. ADH builds up immediately prior to the ecdysis and causes the blood volume to increase. DH and bursicon rise simultaneously after the ecdysis which results in a dramatic decrease in blood volume. Further investigations have shown that blood cell permeability to tyrosine is enhanced by post-ecdysis blood and by partially purified hormone preparations. From these data (and from separation procedures which indicate a similar molecular weight for DH and bursicon) it is postulated that DH and tanning hormone may be analogous. Tanning hormone or DH may serve the function of increasing the blood cell permeability to tyrosine and thus allowing the subsequent formation of N-acetyl dopamine.