§5.211 CARBOHYDRATE METABOLISM 191 



et al, 1950). It is clear that an increase in blood-sugar, or hypcr- 

 glycaemia, is produced in these crustaceans as a result of stress, 

 very much as in mammals, as long as the sinus gland has its 

 innervation intact; the converse experiment of injecting sinus 

 gland extract raises the blood-sugar content as much as 400 per 

 cent in Callinectes (Abramowitz et al, 1944). The comparable 

 effect of excitement or pain in inducing hyperglycaemia in 

 Callinectes (but not in the less pugnacious Astaciis) was shown by 

 injecting plain saline ; this produced as great a rise in blood-sugars 

 as injections of adrenaline, but in either case the effect could be 

 almost completely inhibited by cutting the nerve to the sinus gland. 



Injection of an eyestalk extract, not identified more exactly, 

 increases blood-sugars in a number of other Crustacea, including 

 the freshwater shrimps, Paratya and Palaemon (Nagano, 1951). 

 An eyestalk hormone also increases the concentration of glucose in 

 the blood, and apparently decreases its utilization in the tissues of 

 two species of spiny lobsters, Panulirus (Scheer and Scheer, 1951). 

 However, since C^^ when used to label injected glucose, does not 

 reappear in the respiratory CO 2 during the following 24 hr, but 

 30 per cent of it can eventually be recovered from the skeleton, it 

 seems that glucose must be mainly concerned in chitin formation. 

 It is therefore arguable that the hormone of the eyestalks w^hich 

 increases blood-sugars should not be considered as comparable 

 with the diabetogenic hormones of vertebrates. 



The hormone secreted from the sinus gland is presumably a 

 neurosecretion derived as usual from either the brain or the 

 ganglionic-X-organ ; but the exact origin has not yet been decided. 

 There appears to be direct nervous control of the release of the 

 diabetogenic hormone, with no intervention of any endocrino- 

 kinetic hormone. 



Insecta. Reduction in blood-sugar follows the removal of the 

 CORPORA ALLATA in the stick insect, Carausius (= Dtxippus; 

 L'Helias, 1955), indicating a diabetogenic function for their 

 secretion. 



There appears to be no direct evidence of the corpora allata 

 being controlled by a hormone from the brain in this case, any 

 more than there is in relation to oxygen consumption. 



Vertebrata. Recent information on diabetogenic hormones m 



