Puromycin: A potent metabolic effect independent of protein synthesis

SynopsisThe effects of cholera enterotoxin (CET) on the male gonad was investigated using testis slices of the rat.CET stimulated adenylate cyclase activity of the interstitial tissue of the rat testis, increased cyclic AMP (cAMP) production and testosterone release from the interstitial tissue in vitro, thus mimicking effects of LH and human chorionic gonadotropin (hCG). CET also stimulated adenylate cyclase activity of the seminiferous tubules and increased cAMP production, whereas hCG did not exhibit such an effect.The stimulatory effect of CET on adenylate cyclase activity of the rat testis occurred with a lag time of about 30 min, reached the maximum level after 2-hr incubation and continued over 6 hr. Testosterone release by CET was observed within 1-to 2-hr incubation, when the increase in cAMP was already demonstrated.The steroidogenic effect of CET was enhanced at low concentration (1 mM) of theophylline and inhibited at high concentration (20mM) of theophylline. Protein synthesis inhibitors (puromycin and cycloheximide) abolished these steroidogenic effect completely, but not cAMP production.Tracer studies of active site(s) of CET in testicular steroidogenesis revealed that the stimulation of testosterone synthesis by CET was, like hCG, due to the stimulation of the conversion of cholesterol to testosterone.These results suggest that CET stimulates the adenylate cyclase/cAMP system of the interstitial tissue (probably of Leydig cells) and stimulates testosterone synthesis from cholesterol, and that once the adenylate cyclase of Leydig cells has been stimulated, the biosynthetic pathway leading to testosterone is quite similar to that caused by gonadotropins (LH and hCG), although the activation mechanism of adenylate cyclase seems to be different each other.

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“…This would be reasonably understood, wheno ne takes into account that puromycin is also a phosphodiesterase inhibitor (Appleman and Kemp, 1966).…”

Section: Discussionmentioning

confidence: 99%

Gonadotropic effects of cholera enterotoxin in the rat testis slices: Stimulation of adenylate cyclase activity and testosterone synthesis from cholesterol.

Sato

Ohsawa

1977

Endocrinol Japon

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“…Thus the major site olf action of chloramphenicol on processes in storage tissute disks is probably via oxidative phosphorylation (22) and not via protein synthesis as has been assumed previously (9,18,30,37). The specificity of action of 2 othler commonly used antibiotics has been recently questioned, namely actinomycin D (20), and pulromvcin (2).…”

Section: Discussionmentioning

confidence: 99%

Activation of Protein Synthesis by Microsomes from Aging Beet Disks

Ellis

MacDonald²

1967

Plant Physiol.

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Suimmary. Microsomal fractions isolated from sterile, aged disks of red beetrool Jncorporate leucine into protein when supplemented with the supernatant fraction, ATP, GTP, and KCl; the incorporation is sensitive to RNase and is not duLe to 'bacteria. Thle nicrosomal activity is inhibited by puromycin and cycloheximide but is virtually insensitive to both D-threo and L-threo-chloramphenicol, as predicted from physiological studies.Microsomes isolated from fresh disks have much lower incorporatin;g ability than those from disks aged for I or 2 days; maximal activity occurs wihen the rate of protein synthesis by the intact disks is highest. The low activitv of fractions from ifiresh disks .s attributable to a deficiency in the microsomal fraction and not to the supernatant fraction; it is not due to a dissocialble inihibitor. The RNA content of the microsomal fraction increases with aging and so the increase in incorporating ability may 'be due to a synthesis of messenger RNA induced by slicing, rather than to an activation of 'preexisting messenger. These results support the view that the aging phenomenon involves a derepression of gene activity.

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“…For this reason, similar experiments were carried out using puromycin which has also been shown to inhibit phosphodiesterase [1]. As before, supernatants were obtained from 24-hour MML cultures (2 X 10°/ml).…”

Section: Effect On the Migration Of Purified Polymorphs Of MML Culturmentioning

confidence: 99%

Effects of Theophylline on Capillary Tube Leucocyte Migration

Stevenson¹,

Gray²,

Lucie³

1979

Int Arch Allergy Immunol

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Theophylline stimulates the capillary tube migration of human peripheral blood mixed leucocytes. Minor stimulation of polymorph migration is produced directly by theophylline and dibutyryl cyclic AMP, but polymorph migration is markedly stimulated by mononuclear leucocyte culture supernatants to which theophylline has been added. These results suggest that polymorph migration is stimulated when intracellular cyclic AMP increases, and that mononuclear leucocytes produce a potential migration stimulator whose activity is enhanced by theophylline.

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Puromycin: A potent metabolic effect independent of protein synthesis

Cited by 98 publications

References 10 publications

Gonadotropic effects of cholera enterotoxin in the rat testis slices: Stimulation of adenylate cyclase activity and testosterone synthesis from cholesterol.

Gonadotropic effects of cholera enterotoxin in the rat testis slices: Stimulation of adenylate cyclase activity and testosterone synthesis from cholesterol.

Activation of Protein Synthesis by Microsomes from Aging Beet Disks

Effects of Theophylline on Capillary Tube Leucocyte Migration

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