Adrenal Steroid Secretion in the Tasmanian Devil (Sarcophilus Harisii) and the Eastern Native Cat (Dasyurus Viverrinus). A Comparison of Adrenocortical Activity of Different Australian Marsupials

Abstract

Adrenal venous and peripheral blood was collected from three Tasmanian devils and three Eastern native cats. Ten \g=D\4-3-oxosteroids were identified in the adrenal venous blood of the devils and nine from the native cats. Cortisol was the major steroid and its maximum corticotrophin (ACTH) stimulated secretion rate averaged 61 \g=m\g/h/100mg adrenal in devils and 36 \ g=m\ g in cats. The cortisol : corticosterone ratio in two devils and two cats was approx. 2\m=.\5and 5, respectively. Aldosterone secretion rates in devils ranged from 0\m=.\06 to 0\m=.\12 \ g=m\ g/ h/ 100mg adrenal and in cats from 0\m=.\12to 0\m=.\93, the response to ACTH varied in different animals. 21-Deoxycortisol was found in all animals, it increased during ACTH stimulation (maximum range in devils: 8\m=.\5-19\m=.\5 \g=m\g/h/100mg adrenal, and 0\m=.\6-5\m=.\4in cats). Another unusual steroid isolated from adrenal venous blood was identified as 17\g=a\-hydroxy-20\g=b\-dihydroprogesterone. Its rate of secretion was higher in devils (range approx. 2-6 \g=m\g/h/100mg adrenal). No relationship was found between adrenal blood flow and corticosteroid secretion. In the peripheral blood plasma only cortisol and corticosterone were identified. The female of both species had a significantly higher concentration of cortisol ofthe order of 7 \g=m\g/100 ml plasma. The combined adrenal weights/ kg body weight averaged 168 mg/kg in the devils and 132 mg in the cats. Since all three Superfamilies of Australian marsupials have now been investigated a comparison of the results obtained from seven representative species is made and they are also considered in relation to eutherian mammals.

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

“…The criteria for identification were the same as described previously (Weiss & McDonald, 1967;Weiss & Richards, 1971). Cortisone was present at a concentration of 8-2 fig/100 ml blood plasma, cortisol at 5-4/ig/100 ml, and the combined corticosterone and 11-dehydrocorticosterone at 1-8/ig/lOO ml.…”

“…From the platypus adrenal incubated without addition of substrate three steroids were identified, using the previous identification procedures (Weiss & Richards, 1971). The amounts of these steroids produced after 30 min of incubation per 100 mg adrenal tissue were: cortisone, 5-1 fig; cortisol, 1-3 fig and 11-dehydrocorticosterone, [1][2][3][4][5] fig.…”

“…In two echidnas (El and E4) and one platypus (P2), aldosterone was estimated by the double isotope derivative method of Kliman & Peterson (1960) with some modi¬ fications as described by Weiss & Richards (1971).…”

“…Yields lower than 0-1% are approximations only. Pro¬ cedures for identification and measurement of the steroids isolated from peripheral blood and from endogenous adrenal tissue stores of the platypus were the same as previously described (Weiss & Richards, 1971). …”

Non-invasive assessment of stress in captive numbats, Myrmecobius fasciatus (Mammalia: Marsupialia), using faecal cortisol measurement

“…Cortisol rather than corticosterone was measured in the numbat faeces because cortisol is the major GC found in the blood of most marsupials [16] and cortisol is the main GC secreted by dasyurids (the marsupial taxa mostly closely related to the numbat) [30]. Cortisol concentrations were analyzed in duplicate using microtiter EIA plate procedures previously reported for this steroid [31].…”