Isolation, Amino Acid Sequence and Action of Guinea-Pig Acth on Aldosterone Production by Glomerulosa Cells

Smith, A. Ian; Wallace, CA; Moritz, Robert L.; Simpson, Richard J.; Schmauk-White, L.B.; Woodcock, Elizabeth A.; Funder, J. W.

doi:10.1677/joe.0.115r005

Cited by 17 publications

(3 citation statements)

References 15 publications

(15 reference statements)

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“…The structure of guinea-pig ACTH has been determined at both the level of protein (Smith et al 1987) and mRNA (Keightley et al 1991). In guinea-pig ACTH, alanine is substituted for proline at position 24.…”

Section: Resultsmentioning

confidence: 99%

“…In guinea-pig ACTH, alanine is substituted for proline at position 24. Initial studies indicate that this distinct form of ACTH represents a super-agonist at the adrenal cortex (Smith et al 1987). However, a recent study has reinvestigated the actions of guinea-pig ACTH at the adrenal cortex and concludes that no such super-agonist properties exist (Robinson et al 1995).…”

Section: Resultsmentioning

confidence: 99%

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Adrenocortical Response Profiles to Corticotrophin‐Releasing Hormone and Adrenocorticotrophin Challenge in the Chronically Catheterized Adult Guinea‐Pig

Liu

Matthews

1999

Experimental Physiology

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summaryThe guinea-pig has been used extensively to investigate adrenal steroidogenesis. However, very little is known about adrenocortical responses to corticotrophin-releasing hormone (CRH) and adrenocorticotrophin (ACTH) in this species, in vivo. In the present study, we have developed a stress-free sampling system, in the chronically catheterized adult guinea-pig, that has allowed us to investigate basal and activated adrenocortical activity. Indwelling carotid artery and jugular vein catheters were surgically implanted into female guinea-pigs (n = 5). Each animal was treated with vehicle, human CRH (0·2 or 2 ìg kg¢) and ACTH1-24 (0·2 or 2 ìg kg¢), and serial plasma samples removed for analysis of ACTH and cortisol concentrations by radioimmunoassay. There was no effect of serial sampling on pituitary-adrenocortical activity, indicating that the animals remain in an unstressed state. Basal plasma ACTH and cortisol concentrations were 703·9 ± 24·5 pg ml¢ and 117·9 ± 5·2 ng ml¢, respectively. Both CRH and ACTH significantly increased adrenocortical activity in a dose-dependent manner. ACTH (2 ìg kg¢) was the most potent activator leading to plasma cortisol concentrations of 647 ± 116 ng ml¢. In conclusion, we have shown that basal plasma cortisol concentrations in the guinea-pig are low compared to those obtained in previous studies by cardiac puncture or following decapitation. However, plasma ACTH concentrations are high compared to other species. We have also shown that human CRH and ACTH1-24 act as potent activators of the guinea-pig pituitary-adrenocortical axis,

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Adrenocortical Response Profiles to Corticotrophin‐Releasing Hormone and Adrenocorticotrophin Challenge in the Chronically Catheterized Adult Guinea‐Pig

Liu

Matthews

1999

Experimental Physiology

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“…There are numerous anomalies in the guinea pig endocrine system, as recently reviewed by Keightley & Fuller (1996). With regard to the pituitary-adrenal axis, guinea pig adrenocorticotrophin has increased biopotency (Smith et al 1987), plasma levels of cortisol are very high (Claman 1972) and the affinity of cortisol to cortisol-binding globulin (CBG) is weak (Westphal 1967), while its affinity to the GC receptor is low (Kraft et al 1979). The MC receptor of the guinea pig, however, shows no difference from that of other species (Myles & Funder 1994).…”

mentioning

confidence: 99%

Evidence for isoforms of 11β-hydroxysteroid dehydrogenase in the liver and kidney of the guinea pig

Quinkler

Kosmale²,

Bähr³

et al. 1997

Journal of Endocrinology

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In the human and in rodents like the rat and mouse, the liver enzyme 11 beta-hydroxysteroid dehydrogenase type I (11 beta-HSD-I) is a functional oxidoreductase preferring NADP+/NADPH as cosubstrate, while the renal isoenzyme (11 beta-HSD-II) prefers NAD+ as cosubstrate, and seems to be a pure oxidase and protects the tubular, mineralocorticoid (MC) receptor from occupancy by cortisol and corticosterone. We studied the enzyme kinetics of 11 beta-HSDs in kidney and liver microsomes of the guinea pig, a species whose zoological classification is still a matter of debate. With a fixed concentration of 10(-6) mol/l cortisol, liver and kidney microsomes preferred NAD+ to NADP+ (10(-3) mol/l) for the conversion to cortisone. Kidney microsomes converted cortisol to cortisone with K(m) values of 0.64 mumol/l and 9.8 mumol/l with NAD+ and NADP+ as cosubstrates respectively. The reduction of cortisone to cortisol was slow with kidney microsomes, but could be markedly enhanced by adding an NADH/NADPH regenerating system: with NADPH as preferred cosubstrate, the approximate K(m) was 7.2 mumol/l. This indicated the existence of both isoenzymes in the guinea pig kidney. Liver microsomes oxidized cortisol to cortisone with similar K(m) and Vmax values for NAD+ to NADP+ as cosubstrates (K(m) of 4.3 mumol/l and 5.0 mumol/l respectively). The NAD+ preference for the oxidation of 10(-6) mol/l cortisol described above may be due to a second, NAD(+)-preferring 11 beta-HSD with a K(m) of 1.4 mumol/l. In contrast to the kidney, liver microsomes actively converted cortisone to cortisol with a preference for NADPH (K(m): 1.2 mumol/l; Vmax: 467 nmol/min per mg protein). Thus, the main liver enzyme is similar to the oxidoreductase of other species (11 beta-HSD-I) and is also present in the kidney, while the main kidney enzyme is clearly NAD(+)-preferring. This kidney enzyme (analogous to 11 beta-HSD-II of other species) seems to be suitable for the protection of the MC receptor from the high free plasma cortisol levels of the guinea pig.

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Peptide and Protein Hormones

König

2000

Ullmann's Encyclopedia of Industrial Chemistry

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Isolation, Amino Acid Sequence and Action of Guinea-Pig Acth on Aldosterone Production by Glomerulosa Cells

Cited by 17 publications

References 15 publications

Adrenocortical Response Profiles to Corticotrophin‐Releasing Hormone and Adrenocorticotrophin Challenge in the Chronically Catheterized Adult Guinea‐Pig

Adrenocortical Response Profiles to Corticotrophin‐Releasing Hormone and Adrenocorticotrophin Challenge in the Chronically Catheterized Adult Guinea‐Pig

Evidence for isoforms of 11β-hydroxysteroid dehydrogenase in the liver and kidney of the guinea pig

Peptide and Protein Hormones

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