Hemolymph proteins and reproduction in Periplaneta americana: the nature of conjugated proteins and the effect of cardiac-allatectomy on protein metabolism
1. The nature and behavior of the conjugated proteins in the hemolymph of adult female Periplaneta americana (L.) have been studied in relation to the ovarian cycle, using disc electrophoresis in polyacrylamide gel and various staining procedures. It is shown that there may be not only a change in the relative concentration of the different protein fractions with oocyte growth, but also differences in their chemical composition. Fraction 3 and the female fraction 4, which represent the major proteins in the blood, appear to serve as carriers of lipids to the ovaries, besides most likely providing proteinaceous yolk precursors to the same. Fractionations made with ovarian homogenates seem to indicate that the lipids and sugars bound to such proteins may become freed at entry into the ovary. 2. Cardiac-allatectomy has been found to result in a pronounced accumulation of proteins in the blood, and also in changes in their chemical composition. In such animals there is a tendency with aging for the loss of lipid prosthetic groups and for several of the fractions including the major proteins to stain preferentially for carbohydrates. This effect could be reversed by the implantation of fresh cardiacum-allatum complexes taken from adult females. It is suggested that in cardiac-allatectomized females there is probably a bilateral arrest of lipid and protein metabolism, and that the vitellogenic proteins already synthesized. but not utilized by the ovary, become converted into glycoproteins. 3. Fractionation studies on fat body homogenates of females in different stages of ovarian activity appear to indicate that in Periplaneta americana none of the soluble lipo- or glycoproteins, including the female fraction, is as such synthesized or stored in the fat body
