Comparison of Steroidogenic Effects of cAMP and dbcAMP in the Rat Adrenal Gland1 1

Pearlmutter, A. Frances; Rapino, Eloise; Saffran, Murray

doi:10.1210/endo-92-3-679

Cited by 21 publications

(7 citation statements)

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“…Within lmin of adding ACTH an increase of about 50 % in protein kinase activity was observed and-this stimulation was maximal within 2 min. This increased protein kinase activity was apparent well before the onset of steroidogenesis, since previous studies in this and other systems in vitro have shown that there is a delay'ofabout 3 min after ACTH addition before any steroidogenic increase is discernible (Richardson & Schulster, 1972;Pearlmutter et al, 1973). Increased protein kinase activity was observed even though the concentration of cyclic AMP in non-stimulated adrenal cells has been estimated to be 0.3pM (Richardson et al, 1973); a concentration higher than that needed to activate fully partially purified adrenal cytosol protein kinase (Gill & Garren, 1970).…”

Section: Resultsmentioning

confidence: 58%

The role of protein kinase activation in the control of steroidogenesis by adrenocorticotrophic hormone in the adrenal cortex

Richardson

Schulster

1973

Biochemical Journal

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A method has been developed for investigation of the effect of adrenocorticotrophic hormone (ACTH) on the state of activation of a cyclic AMP-dependent protein kinase within cells of the adrenal cortex. Enzyme activity was measured in terms of the quantity of (32)P transferred from [gamma-(32)P]ATP to histone under conditions in which bound cyclic AMP did not dissociate from the regulatory subunit of the protein kinase ACTH (1x10(-2)i.u./ml) caused a rapid and complete activation of the cyclic AMP-dependent protein kinase activity within 2min of hormone addition to the isolated cells. In response to a range of ACTH concentrations a sigmoid log dose-response curve for protein kinase activation was obtained, with half-maximal stimulation attained at about 1x10(-3)i.u./ml. However, some low doses of ACTH that elicited a marked (but submaximal) steroidogenic response failed to cause a clear stimulation of protein kinase activity in isolated adrenal cells. Theophylline (2mm) potentiated the effect of ACTH on protein kinase activity. The results implicate an important role for protein kinase in ACTH action on the adrenocortical cell.

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Section: Resultsmentioning

confidence: 58%

The role of protein kinase activation in the control of steroidogenesis by adrenocorticotrophic hormone in the adrenal cortex

Richardson

Schulster

1973

Biochemical Journal

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“…However, a number of informative studies have been carried out by using intact adrenals in vivo (Beaven et al, 1964;Garren et al, 1965) or superfused adrenals or adrenal quarters in vitro (Schulster et al, 1970;Grahame-Smith et al, 1967;Pearlmutter et al, 1973). For example, Grahame-Smith et al (1967) reported that ACTH caused an increase in cyclic AMP concentrations in adrenal quarters after 1 min, whereas an increased steroid output was apparent after 2min.…”

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confidence: 99%

Measurement of the dynamics of stimulation and inhibition of steroidogenesis in isolated rat adrenal cells by using column perfusion

Lowry¹,

McMartin²

1974

Biochemical Journal

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Isolated adrenal cells were perfused in a small column by using Bio-Gel polyacrylamide beads as an inert supporting matrix, and the time-course of the response to various stimuli was observed by measuring fluorogenic 11-hydroxycorticosteroids in the effluent. A small but significant response was observed 1 min after stimulation with physiological concentrations of ACTH (adrenocorticotrophin), but the response did not start to build up rapidly for 3-4min and eventually reached a plateau after 9-10min. A similar pattern of events was observed for the decay of the steroid output on removal of ACTH. ACTH analogues, including one with a long duration of action in vivo, were found to produce responses with similar kinetics. However, cyclic AMP caused a more rapid increase in steroidogenesis and its effects were more short-lived after withdrawal. If, as present evidence suggests, cyclic AMP is produced rapidly after ACTH stimulation the delayed build-up of the steroidogenic response to ACTH would indicate that cyclic AMP may not be the intracellular mediator. When inhibitors were applied during ACTH stimulation, aminoglutethimide, which blocks mitochondrial conversion of cholesterol into pregnenolone (3beta-hydroxypregn-5-en-20-one), caused a rapid fall in steroid output (1 min), whereas cycloheximide took longer to achieve its full effect. Nevertheless, the response had fallen by 50% in 2 min, indicating a much shorter half-life than that previously reported for the labile protein implicated in steroidogenesis. In addition the rapid response to cyclic AMP makes it unlikely that steroid production is induced as a result of initiation of protein synthesis. This suggests that the labile protein plays an obligatory but permissive role in the development of the response. Column perfusion has proved to be a simple technique which can readily yield accurate data on responses of cells to stimulants and inhibitors.

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“…'Caution must therefore be used in the interpretation of experiments, using addition of cAMP or derivatives of this nucleotide to isolated ovaries, a conclusion which in principle can be drawn also from experiments on other in vitro systems, e.g. the thyroid (Burke et al 1971) and the adrenals (Pearlmutter et a!. 1973).…”

Section: Discussionmentioning

confidence: 99%

Comparison between Effects of Cyclic AMP, Dibutyryl Cyclic AMP and Luteinizing Hormone on Ovarian Glycolysis

Herlitz

Hamberger

Ahrén

1974

Acta Physiologica Scandinavica

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HERLITZ, H., L. HAMBERGER and K. AH&.N. Comparison between effects of cyclic AMP, dibutyryl cyclic AMP and luteinizing hormone on ovarian glycolysis. Acta physiol. scand. 1974. 92. 181-194. Prepubertal rat ovaries were incubated in medium containing 5.5 mM glucose and various concentrations of cyclic AMP (CAMP) and dibutyryl cyclic AMP (dbcAMP). Glucose uptake and lactic acid production were stimulated in presence of 5 mM CAMP. The effect was less pronounced with higher concentrations, and 25 mM cAMP inhibited ovarian glycolysis compared to control ovaries. A biphasic effect was also obtained with dbcAMP: a dosedependent increase with lower concentrations (0.1-5 mM) and smaller effects with higher concentrations. Luteinizing hormone ( L H ) stimulates ovarian glycolysis with a linear doseresponse relationship over an extremely wide range of concentrations (Hamberger and AhrCn 1967). The stimulatory actions of dbcAMP and L H on ovarian glycolysis were augmented by low concentrations of aminophylline (0.5-1 mM). No additive effects were seen when L H and dbcAMP were used together in maximal stimulatory concentrations. LH, cAMP and dbcAMP were also compared as to their lipolytic actions on the ovary. Lipolysis as judged by glycerol release was markedly enhanced by dbcAMP while the two other substances had only marginal effects. When bovine serum albumin (acceptor for fatty acids) was present in the medium, the dose-response curve of the effect of dbcAMP on ovarian glycolysis was dramatically changed, indicating an interaction between the lipolytic and the glycolytic effects of this compound.

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Comparison of Steroidogenic Effects of cAMP and dbcAMP in the Rat Adrenal Gland1 1

Cited by 21 publications

References 0 publications

The role of protein kinase activation in the control of steroidogenesis by adrenocorticotrophic hormone in the adrenal cortex

The role of protein kinase activation in the control of steroidogenesis by adrenocorticotrophic hormone in the adrenal cortex

Measurement of the dynamics of stimulation and inhibition of steroidogenesis in isolated rat adrenal cells by using column perfusion

Comparison between Effects of Cyclic AMP, Dibutyryl Cyclic AMP and Luteinizing Hormone on Ovarian Glycolysis

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