Circulating inhibin and testosterone during sexual maturation and reproductive seasonality of captive male killer whales (Orcinus orca)

The present study aimed to investigate the reproductive biology of male killer whales. Changes in the concentrations of two circulating testicular hormones, inhibin and testosterone, were monitored during sexual maturation of two male Type 1 Eastern Northern Atlantic killer whales over a period of 20 years. The two killer whales grew rapidly at the pubertal stage and reached a plateau at the age of 23 and 20 years, respectively, after which growth slowed down. In the younger male, circulating inhibin was higher in the juvenile than in the pubertal and mature stages; whereas circulating testosterone exhibited the opposite trend. The pubertal period was estimated to last approximately 5 years, from 12 to 17 years of age. In the elder male, circulating testosterone was high from the onset of this study (12 years of age), when the animal also sired successfully for the first time. This finding shows that the male killer whale is possible to sire even if it is not socially matured, if there is opportunity for copulation. During the mature stage, both animals exhibited significantly higher circulating testosterone concentrations in spring compared to autumn and winter; whereas no seasonal change was observed for circulating inhibin. These results clearly demonstrate that the male killer whale is a seasonal breeder, even though it is fertile throughout the year. This is the first study to elucidate the inhibin concentration and secretory source in the male killer whale

Liver elasticity measurement before and after biliary drainage in patients with obstructive jaundice : a prospective cohort studya prospective cohort study

Background: Obstructive jaundice has been reported to influence liver elasticity, independent of liver fibrosis. The aim of our prospective study was to evaluate the changes in liver elasticity, before and after biliary drainage, in patients with obstructive jaundice, and to evaluate the correlation between elasticity measures and serum markers of liver fibrosis. Methods: This is a prospective cohort study of 20 patients with obstructive jaundice. Liver elasticity was assessed by Transient Elastography (TE) and Virtual Touch (TM) Quantification (VTQ). Serum total bilirubin (T-Bil) level was measured before biliary drainage (Day 0), with measures repeated at 2 days (Day 2) and 7 days (Day 7) after biliary drainage. Serum levels of the following markers of liver fibrosis were also obtained on Day 0 and Day 7: hyaluronic acid (HA), procollagen-III-peptide (P-III-P). Results: T-Bil, TE, and VTQ for the left (VTQ-L) and right (VTQ-R) lobes of the liver were all elevated before biliary drainage, with respective levels, measured at Day 0, of 11.9 +/- 1.5 mg/dl, 12.1 +/- 0.9 kPa, 2.23 +/- 0.10 m/s, and 1.85 +/- 0. 10 m/s. All values decreased on Day 7 after drainage: T-Bil, 4.7 +/- 1.0 mg/dl (P < 0.001); TE, 7.6 +/- 0.6 kPa (P < 0.001); VTQ-L, 1.53 +/- 0.08 m/s (P < 0.001); and VTQ-R, 1.30 +/- 0.05 m/s (P < 0.001). Similar changes were observed in serum markers of liver fibrosis. Liver elasticity measures correlated with serum levels of T-Bil, P-III-P, and HA (r = 0.35-0.67, P < 0.001). Conclusions: This study confirmed decreases in liver elasticity, measured by TE and VTQ, after biliary drainage. Measures of liver elasticity correlated to levels of T-Bil and serum markers of liver fibrosis. (UMIN ID: UMIN00001284313)