Annual and daily serum aldosterone and catecholamine patterns in males of the Italian crested newt, Triturus carnifex (Amphibia, Urodela).

Abstract The present work studied the annual and daily aldosterone, norepinephrine and epinephrine patterns in the newt Triturus carnifex. The annual variations of the serum aldosterone were evaluated every month by radioimmunoassay, from September to July; the daily variations of this hormone were evaluated in the months of January, April, July and November. Aldosterone levels were low from September to November (lowest value 187.23 ± 19.7 pg/ml in November), increased in December, remained high until March and peaked in April (587.25 ± 58.2 pg/ml). In May, the levels decreased and remained steady until July. Considering the daily aldosterone pattern, in all the examined months, serum aldosterone levels were lowest at 5:00 am (lowest value 162.51 ± 17.4 pg/ml in November) and peaked at 5:00 pm (maximal value 2075.00 ± 213.00 pg/ml in April). As regards the annual catecholamine pattern as measured by HPLC, serum norepinephrine levels were low from September to November (lowest value 541.13 ± 39.8 pg/ml in September), increased in December, peaked in January (1457.03 ± 106.97 pg/ml) and remained high in February. In March, the levels decreased and remained steady until June, then decreased in July. Serum epinephrine levels increased from September to November, decreased in December and remained low until February. In March, the levels increased and peaked in April (721.55 ± 49.91 pg/ml), then decreased (lowest value 140.00 ± 10.0 pg/ml in June) and remained steady until July. Considering the daily catecholamines levels, in all the examined months, there were no daily variations among serum norepinephrine levels. Otherwise, serum epinephrine levels were always lowest at 5:00 am (lowest value 100.77 ± 9.9 pg/ml in January) and peaked at 11:00 pm (maximal value 3831.05 ± 211.5 pg/ml in November). The annual and daily aldosterone and catecholamine patterns appear correlated to the metabolic activity of this species.