In vitro activation of insect prothoracic glands by the prothoracicotropic hormone (original) (raw)
Related papers
A monoclonal antibody to the insect prothoracicotropic hormone
The Journal of neuroscience : the official journal of the Society for Neuroscience, 1988
The prothoracicotropic hormone (PTTH) is an insect cerebral peptide that stimulates the prothoracic glands to produce the steroid hormone ecdysone thus initiating molting and metamorphosis. "Big" PTTH, one of several molecular forms of the neurohormone, was isolated from brains of the tobacco hornworm Manduca sexta, and fractionated by high-pressure liquid chromatography (HPLC) for use in antibody production. A murine polyclonal antiserum and a monoclonal antibody (MAb) have been generated using this highly purified preparation of big PTTH. Antisera and hybridoma supernatants were screened with an indirect, brain whole-mount immunocytological assay, and antibody specificity was confirmed by immunocytological, ELISA, and functional criteria. In brain whole-mount preparations, the MAb (A2H5) and antiserum specifically immunostained the lateral protocerebral neurosecretory cells (L-NSC III), the prothoracicotropes, which produce PTTH. This immunostaining was blocked by preads...
Proceedings of the National Academy of Sciences, 1979
The distribution of prothoracicotropic hormone in the pupal brain of Manduca sexta has been determined by an in vitro assay for prothoracic gland activation. Prothoracicotropic activity was observed in both the brain and retrocerebral complex, but predominantly in the dorosolateral regions of the protocerebrum. Of the two groups of neurosecretory cells present in this area of the brain, only the two lateral type III neurosecretory cells exhibited significant prothoracicotropic hormone activity. Further analysis revealed that the neurohormone was localized in only one of the two type III cells, suggesting that a single neurosecretory cell in each hemisphere is the source of the hormone at the stage examined (day 0). Prothoracicotropic hormone activity was detected in both the corpora allata and the corpora cardiaca, but the corpora allata contained 2 to 9 times the activity of the corpora cardiaca, depending on developmental stage. The significantly higher level of activity in the co...
Journal of Insect Physiology, 1995
Fluctuations in hemolymph ecdysteroid titer are part of a complex mechanism that regulates pupal-adult development. The amount of ecdysteroid produced in z&-o by prothoracic glands from female Lymantria dispar (L.) (Lepidoptera: Lymantriidae) pupae and pharate adults, as well as the competency of these glands to respond to a prothoracicotropic hormone (PTTH) stimulus in uitro, each correspond temporally with hemolymph ecdysteroid titers. Based on studies of gland kinetics and dose-responses to brain extract using prothoracic glands from different female pupal and pharate adult ages, an in vitro bioassay for the quantification of PTTH activity was developed using glands from day 2 females incubated without stimulus for 1 h followed by a 3 h incubation with stimulus. Only extracts of brains and corpora allata from pupae and pharate adults possess a PTTH factor. This factor is heat stable and can be separated on high performance size exclusion chromatography into two molecular sizes of 13.75 and 3.2 kDa. Ecdysone and 3-dehydroecdysone are produced in vitro by prothoracic glands from all ages of female L.. dispar pupae and pharate adults tested. The amount of ecdysone produced by these glands exceeds that of 3-dehydroecdysone production after 4 h of incubation.
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2012
Prothoracicotropic hormone (PTTH) is a brain neurohormone that has been studied for over 80 years. The only known target of PTTH is the prothoracic glands (PGs) of larvae, which synthesize the insect molting hormones (ecdysteroids) and a massive literature exists on this axis. The PGs degenerate around the time of adult emergence, yet presence of PTTH has been reported in the brains of several adult insects. Using an in vitro bioassay system, we confirm that PTTH is present in the adult female brain of Rhodnius prolixus. The material is electrophoretically, immunologically and biologically indistinguishable from larval PTTH. The amount of PTTH in the brain shows a daily rhythm during egg development. We show that brains in vitro release PTTH with a daily rhythm over this period of time. PTTH is released at each scotophase. This is the first report that PTTH is released from the adult brain and functions as a hormone, inviting explanation of its function. Larval PTTH is also known to be released with a daily rhythm, and the clock in the brain controls both larval and adult rhythms. The potential significance of rhythmic PTTH release in female adults is discussed in relation to the regulation of ecdysteroids, egg development and the concept of internal temporal order.
Journal of Insect Physiology, 1992
The prothoracicotropic hormone (PTTH) was extracted from brains of the fruit fly, Drosophila melanogaster, partially purified and characterized by chromatography and electrophoresis. In vitro bioassays of the fractions obtained from chromatography revealed the existence of at least two forms of PTTH, a large form (14-17 kDa: "big PTTH") and a small form (3-5 kDa: "small PTTH"). The neural extract was able to stimulate ring glands to secrete ecdysone in a dose-dependent manner in vitro. Moreover, when incubated with imaginal wing discs, the extract specifically stimulated the synthesis of the heat-shock protein 83. This observation suggests that PTTH may have a hormonal role beyond its well-known function in the control of ecdysone secretion within the neuro-endocrine axis of brain and prothoracic glands.
The Biology of the Prothoracicotropic Hormone Peptidergic Neurons in an Insect
Integrative and Comparative Biology, 1993
SYNOPSIS. The prothoracicotropic hormone and the cerebral peptidergic neurons that produce it have traditionally been thought to have the singular function of acting as a primary effector of insect postembryonic development. Recent investigations of this neuroendocrine axis in the tobacco hornworm, Manduca sexta, are leading to a new view that these peptidergic neurons and their peptide phenotypes may be multifunctional. They may act in different ways depending upon the animal's developmental stage and site of phenotype release. The possibility for this functional diversity of the prothoracicotropic hormone is possibly even greater due to multiple neuronal sites of peptide expression within the central nervous system. Similarly, the L-NSC III may have more functions due to the expression of multiple peptide phenotypes. The data, thus far, have not enabled us to identify additional physiological roles for the peptide, but they have provided insight into the experimental approaches that might be effective in resolving these functions.