Hypertrehalosemic hormone in a cockroach: molecular cloning and expression

Hypertrehalosemic hormone (HTH) is a neuropeptide in the adipokinetic hormone/red pigment-concentrating hormone (AKH/RPCH) family that stimulates the synthesis of trehalose, the main blood sugar of many insects. The preproHTH of the cockroach Blaberus discoidalis was cloned from the corpora cardiaca (CC), the endocrine source for HTH, and the deduced sequence and organization of preproHTH were compared with other AKH/RPCH precursors. PreproHTH mRNA was determined to be approximately 0.5 kb in length as predicted by DNA sequence analysis. Northern blot analysis of the CC, ventral nerve cord, brain and fat body detected HTH-mRNA only in the CC. Levels of the HTH transcript in the CC were determined according to age, gender and mating. The HTH message was most abundant in the CC during the first several days of adult life in both sexes, then declined by 50% and were stable. HTH-mRNA levels in the CC did not respond to mating.