Tanaka S, Okuda T
Department of Insect Physiology and Behavior, National Institute of Sericultural and Entomological Science, 1-2, Ohwashi, Tsukuba, Ibaraki, Japan
J Insect Physiol. 1997 Jul;43(7):635-641. doi: 10.1016/s0022-1910(97)00023-1.
The hemolymph juvenile hormone (JH) titer in sexually immature female adults of Locusta migratoria (Ibaraki strain, Japan) was lower than in sexually mature females; nevertheless, JH synthetic activity by the corpora allata (CA) in vitro was considerably higher in immature females than in sexually mature females ([Okuda et al., 1996]). We carried out experiments to explain this contradiction. The CA activity of sexually immature female adults was very low when the CA were incubated as a complex together with the corpora cardiaca (CC) and brain. When the same complex was assayed after cutting the nerve cord connecting the CC and CA (NCA1), JH synthesis by the CA was enhanced tenfold. When this pair of CA was incubated in fresh medium without the CC and brain, JH synthesis was further increased. Therefore, the higher in-vitro JH production by CA from immature female adults was the result of isolation of the CA from the brain and CC. A methanolic extract of brain-CC complexes contained a factor that inhibited JH synthetic activity by CA in vitro in both immature and mature insects, and this inhibition was reversible. The factor was heat-resistant but lost allatostatic activity after pronase digestion. These results indicate that the allatostatic factor is probably a heat-stable peptide.
日本伊贺崎品系未成熟成年雌性飞蝗的血淋巴保幼激素（JH）滴度低于成熟雌性；然而，未成熟雌性体内咽侧体（CA）的JH合成活性在体外却显著高于成熟雌性（[奥田等人，1996年]）。我们进行了实验来解释这一矛盾现象。当CA与心侧体（CC）和脑作为一个复合体一起孵育时，未成熟成年雌性的CA活性非常低。当切断连接CC和CA的神经索（NCA1）后对同一复合体进行检测时，CA的JH合成增强了十倍。当这对CA在没有CC和脑的新鲜培养基中孵育时，JH合成进一步增加。因此，未成熟成年雌性的CA在体外产生更高的JH是CA与脑和CC分离的结果。脑 - CC复合体的甲醇提取物含有一种因子，该因子在体外对未成熟和成熟昆虫的CA的JH合成活性均有抑制作用，且这种抑制是可逆的。该因子耐热，但经链霉蛋白酶消化后失去了保幼激素抑制活性。这些结果表明，保幼激素抑制因子可能是一种热稳定肽。
