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Histochemistry of the a cell neurosecretory material in the milkweed bug, Oncopeltus fasciatus dallas (heteroptera: Lygaeidae), with a discussion of the neurosecretory material/carrier substance problem

1966; Elsevier BV; Volume: 6; Issue: 3 Linguagem: Inglês

10.1016/s0016-6480(66)80027-8

1095-6840

Berit Schreiner,

Insect and Arachnid Ecology and Behavior

Neurosecretory cells (A cells) of the pars intercerebralis and their neurosecretory material have been investigated histochemically in virgin adult females of the milkweed bug, Oncopeltus fasciatus Dallas. Freeze-drying with subsequent embedding in a water-soluble wax (carbowax, polyethylene glycol) as well as conventional fixatives with embedding in paraffin has been employed. The results show that the neurosecretory material is probably not soluble in alcohol. The alcohol, however, renders the stainable part of the neurosecretory material soluble in water. It has not been possible to demonstrate any content of carbohydrates or lipids. The histochemical results suggest that the neurosecretory material is a protein rich in cysteine or cystine, although it has not been possible to split the protein with pepsin or trypsin. Theories about the concept of the connection between a carrier substance and the active hormone(s) are discussed, and a hypothesis is proposed where the hormone(s) are considered to be a “coating” on the carrier substance.