Steroid production by the normal opossum (Didelphis virginiana) adrenal in vitro

Brownell, Katharine A.; Beck, R. R.; Besch, Paige K.

doi:10.1016/0016-6480(67)90054-8

Cited by 10 publications

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“…The finding that echidna adrenals produce aldosterone underlines the essential similarity of adrenal cortical function in this species which survives adrenalectomy, compared with most other mammalia which do not. The American opossum provides a parallel case, since it, too, may survive adrenalectomy (Silvette & Britton, 1936;Britton & Silvette, 1937;Hartman, Smith & Lewis, 1943) and produces a full complement of adrenal cortical steroids (Brownell, Beck & Besch, 1967;Johnston, Davis & Hartroft, 1967). Although the capacity to produce aldosterone was shown in the present experiments, Reid (1971) demonstrated renin activity only in echidnas that were sodium depleted.…”

Section: Resultscontrasting

confidence: 49%

Biosynthesis of Adrenocortical Steroids by Monotremes: Echidna (Tachyglossus Aculeatus) and Platypus (Ornithorhynchus Anatinus)

Weiss¹

1973

Journal of Endocrinology

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The formation of corticosteroids from [14C]pregnenolone or [14C]progesterone by platypus and echidna adrenal homogenates was studied. Corticosteroids were assayed in the peripheral blood plasma of the platypus. In the platypus nine labelled conversion products were identified. The combined yields of cortisol and cortisone averaged 70 % and the combined yields of corticosterone and 11-dehydrocorticosterone averaged 14%. Aldosterone was identified in each experiment in yields below 0\m=.\1 %. In the echidna ten labelled conversion products were identified. Those in highest yield were 11-deoxycorticosterone and 11-deoxycortisol which contained, respectively, an average of 35 and 11% of the added substrate. The yield of corticosterone was always less than 1% and that of cortisol was consistently lower. Aldosterone was identified in all cases in yields below 0\m=.\05%.The yields of total 11\g=b\-hydroxylated conversion products from platypus adrenal exceeded 80%, whereas they were below 1 % from glands of male echidnas and 7 % from female echidna.The yield\p=m-\time curves for labelled conversion products from [ 14C] \ x=r eq-\ pregnenolone indicated that the biosynthetic pathways of corticosteroid production by the monotreme adrenal are similar to those in eutherian mammals.From stored endogenous precursors of a platypus adrenal incubated for 30 min, corticosteroids were formed in the following amounts (per 100 mg adrenal): cortisone, 5\m=.\1\g=m\g;cortisol, 1\m=.\3\g=m\g;11-dehydrocorticosterone, 1\m=.\5 \g=m\g. In the peripheral plasma of platypus the concentration of combined cortisol and cortisone was 14\g=m\g/100ml and the combined corticosterone and 11-dehydrocorticosterone was 1\m=.\8 \g=m\g. The mean ratio of adrenal weight (mg) to body weight (kg) was 39\m=.\5in the echidna and 257 in the platypus. The marked contrast in adrenocortical biosynthetic capacity of the two monotremes is discussed and a comparison of the results is made in relation to higher mammals.

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