SEX HORMONES IN FISH. PART II. THE OESTROGENS OF SCYLIORHINUS CANICULUS

Abstract

SUMMARY: Whole ovaries of the lesser spotted dogfish (Scyliorhinus caniculus) have been shown to contain oestradiol-17β and oestrone, each in a concentration of ca. 19 μg./kg., corresponding to approximately 0·8 μg./fish. The greater part (approximately 80%) of this material is localized within the eggs, the remainder being found in the ovarian tissue. The concentrations of oestradiol and oestrone in the eggs appear to be constant, independent of the size of egg, thus the amounts of these compounds in the egg increase as the egg matures. Free oestradiol-17β and oestrone have been found in blood plasma in respective concentrations of between 3 and 4 μg./l. and 0·5–1 μg./l.; protein-bound oestrone and oestradiol also appeared to be present, though in quantities too small for adequate characterization. No conjugated oestrogens could be detected. There is a significant difference between the ratios of oestradiol to oestrone in the eggs, ovarian tissue and blood plasma.