Neurophysin biosynthesis in vitro in oat cell carcinoma of the lung with ectopic vasopressin production.

Abstract

A B S T R A CAfter short labeling periods, most ofthe radioactivity resided in 20K species, which plateaued after 1 h, whereas 10K neurophysin progressively increased in its height. When cells were chased with unlabeled cysteine after the exposure to a short pulse of labeling, 20K neurophysin peak gradually decreased with an apparent initial half-life of 1 h. In contrast, the label in 10K neurophysin steadily increased, which exceeded the former by 3 h of chase. Analysis of 20K neurophysin in cell extract by isoelectric focusing on polyacrylamide gel demonstrated that it was principally composed of a protein with an apparent isoelectric point (pI) of 5.7.

Direct effects of catecholamines, thyrotropin-releasing hormone, and somatostatin on growth hormone and prolactin secretion from adenomatous and nonadenomatous human pituitary cells in culture.

“…Extraction and immunoprecipitation of GH were conducted according to the general method described by Mains and Eipper (26) for adrenocorticotropic hormone with a modification (27). Cells were frozen and thawed several times on dry ice and homogenized in 0.6 ml of 0.01 N NaOH (28) with a Teflon pestle.…”

[D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P, a potent bombesin antagonist in murine Swiss 3T3 cells, inhibits the growth of human small cell lung cancer cells in vitro

“…They can stimulate the growth of SCLC cells in vitro (23,24) and may act as autocrine growth factors (2,25). The dilutional hyponatraemic syndrome, which commonly complicates SCLC, is associated with ectopic production of vasopressin (26,27). Thus, the identification of more potent antagonists, which recognize the receptors for both peptides, could be of considerable interest in future clinical approaches to the treatment of SCLC.…”

Acetylcholine Receptors in Small Cell Carcinomas

“…Several neuronal markers have been found previously in SCC. These include the neuronal isozymes of enolase (Tapia et al, 1981) and creatine kinase (Gazdar et a]., 1981), neuronal-type intermediate filaments ( L e h t o et al., 1983), and numerous peptide hormones (Szabo et al, 1980;Wood et al, 1981;Yamaji et al, 1981). SCC also express antigens shared by neural crest-derived cells in the peripheral nervous system (Bell e t al., 1976).…”