ISSN:
1420-9071
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The kinetics of prothoracicotropic hormone (PTTH) activation of pupal prothoracic glands (PG) of the cabbage army worm,Mamestra brassicae, and silkworm,Bombyx mori, were determined in vitro. Activation was assessed by comparing the increase in the rate of ecdysone synthesis by one member of a PG pair incubated with a PTTH preparation from pupal brains with the basal rate of synthesis of the other PG incubated without PTTH. A time course of ecdysone synthesis revealed thatBombyx PTTH extract activatedBombyx PG, andMamestra PTTH extract activatedMamestra PG. Dose responses of activation ofBombyx andMamestra PG by their respective PTTH were saturable and were indicative of neurohormonal activation. TheBombyx PG were half-maximally activated (A50) by far less PTTH thanMamestra PG, 0.34 and 0.91 brain equivalents, respectively. Heterologous dose response of activation studies, in which PTTH and PG fromMamestra, Bombyx and the tobacco hornworm,Manduca sexta, were assayed for interspecific PG sensitivity and PTTH specificity, revealed cross-reactivity among the three PTTH-PG axes, withManduca PG being more sensitive to the PTTH of the other species andBombyx PTTH being the most effective in activating the PG of the other two species.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01989764
