Corpus allatum and corpus cardiacu regulation of long hyaline gland protein synthesis in the male grasshopper, Melanoplus sanguinipes

Abstract

Rates of accumulation of, and radiolabel incorporation into, the major secretory product of the long hyaline gland, a glycoprotein LHPI, were used to examine the role of the corpus allatum (CA) and corpus cardiacum (CC) in the regulation of protein synthesis in the accessory reproductive gland of the male grasshopper, Melanoplus sanguinipes. Incorporation of [ 35S]methionine into LHPI in vitro indicated that LHPI was an endogenous long hyaline gland protein, whose in vivo synthesis in allatectomized animals was stimulated by topical application of juvenile hormone (JH) III. This response was not dependent on the presence of the extrinsic lobe of the CC, the CC/brain complex, or on continued feeding and suggests a direct effect of JH on the gland. Severance of the nervi corporis allati I and II reduced accumulation of LHPI but unilateral CA removal did not, perhaps because of a compensatory activation of the remaining CA. Normal postcopulatory stimulation of LHPI accumulation was abolished by allatectomy. These results suggest that the physiological level of JH may regulate LHPI synthesis. Corpus cardiacum effects were small in comparison to those of the CA; they were evident only in cardiacectomized animals that were allatectomized also and exerted over prolonged periods when the animals continued to feed. Endocrine manipulations produced no qualitative changes in long hyaline gland LHPI immunoreactive protein, only quantitative ones.