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Journal of Experimental Biology, Vol 66, Issue 1 255-266, Copyright © 1977 by Company of Biologists
JOURNAL ARTICLES |
D Gibbs and LM Riddiford
1. A new method for the assay of insect prothoracicotropic hormone (PTTH) is described, using fourth instar larvae of Manduca sexta. Larvae neck-ligated at a critical time to prevent release of PTTH from the head fail to undergo the next larval moult. Such ligated larvae moult to fifth instar larvae or larval-pupal intermediates after injection of brain homogenates from Manduca larvae, pupae or pharate adults. The degree of response is proportional to the concentration of brain homogenate injected. 2. The source of PTTH in the pupal brain is the dorsal region of the protocerebrum containing the lateral neurosecretory cells. Microhomogennates of single pieces of brain showed activity with this method. 3. PTTH activity in partially purified extracts is water soluable, stable to boiling for 10 min, and is destroyed by Pronase or trypsin.
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W. Bollenbacher, E. Katahira, M O'Brien, L. Gilbert, M. Thomas, N Agui, and A. Baumhover Insect prothoracicotropic hormone: evidence for two molecular forms Science, June 15, 1984; 224(4654): 1243 - 1245. [Abstract] [PDF] |
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