ISSN:
1095-8649
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Levels of androgens and oestradiol in dogfish, Scyliorhinus canicula, plasma, measured by radioimmunoassay, decrease markedly after ovariectomy (OVX). The magnitude and latency of these responses varies according to length of captivity preceding the operation and the time of year at which ovariectomy is performed. Androgens are cleared more rapidly than oestradiol from plasma following OVX, and levels of both steroids are reduced after laparotomy (LAP) in November but not in March. An extract of ventral lobes of the dogfish pituitary induces a significant increase in the circulating androgen levels in LAP fish but not in OVX fish, indicating that the ovary is the major site of androgen production in response to stimulation by dogfish gonadotrophin. Intramuscular injections of oestradiol benzoate (2.5 mg per fish) into LAP fish produce a significant reduction in the gonadotrophin content of the pituitary ventral lobe, measured in the quail testicular cell bioassay, when compared to LAP and unoperated controls. However, no significant changes in the gonadotrophin content of the ventral lobe were seen five days after OVX in June.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1095-8649.1982.tb02834.x
