This dissertation, "Studies on Endocrine and Metabolic Changes in the Japanese Eel (anguilla Japonica) Following Induced Sexual Maturation" by Lai-man, Annie, Cheung, 張麗雯, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thisis entitled 'Studies on endocrine and attabolic changes in ths Japanese eel (Artguilla japonic a} following induced sexual ttturatiori' subraitted by Annie Cheung Lai Man for the digriNi of Doctor of Philosophy at the University of Hong Kong in Nov**ber, 1913. Fisting sals and feaale eels were injected Hith huaan chorionic fenatiotropin CHC0), saion gonadotropin (S8A-8TH), crude saloon pituitary extract, testottarone, n-ketotestoitercne, and Bstradiol-i7 DEGREES, Tht gontdal rssponses to hormonal treatwent were cooparBd. Metabolic aodificatians and histological changes in the pituitary and th* Ittraius corpuslcs in ralation to gonadal development were studied. HC8 trsataent inducsd full ttsticular saturation in intact and hypophyssctoniztd tilt within five Mtaks with the gonadoDtic Indies* (081) reaching 7.13 and 2.20 rtsptctivsly. Salmon pituitary axtract and 8QA-9TH stinulatsd speraatogtntie to ths iptritocyte stags. In -femala csls, HC8 and 8SA-BTH raised 83! up to 5 in five weeks. The treatment induced vitellogenesis and the development of zona radiata and granulosa cells. Hypophysectoiy reduced the ovarian response. Androgtns had very little effects on gonadal development while estradiol had no effects. In raale aela with 881 exceeding 10, testis protein, fat andcalciua contents increased by 87-, 72- and 41-fold respectively compared with the control group, Increases in blood glucose, sarua *-ai8in0 acid and calciUM concentrations Here detected. In HCB-treated feaale eels Kith BSI in excess o-f 2, vitel logentsis Mas accompanied by 3-, 9.4- and 4.8-fold elevations in ovary protein, fat and ctlciua contents respectively, -Berut lipid, free fatty acid and calclue levels increased significantly. In both sexes, gonadal davelopasnt Mas supported initially by cataboiisH of liver glycogen, then by sobilintion of Metabolite* froM the gut and white Muscle. Within the saie tiee span, utilization of reserves MIS More extensive in Rale eels than in feaale eels due to larger gonad size. Although both iature nail eels and partially mature ftaale eels exhibited declines in gut weight, and white muscle lipid and protein contents, feeale eels did not seen to utilize gut lipid. The white outcle Bass served as the aain source of energy for gonadal Maturation. During sexual Maturation, liver weight increased is t result of fatty infiltration particularly in the Male eels. Increased Metabolic and catabolic activities during gonadtl Maturation led to augaented oxygen consusption rate in Mile eels. Aneonia excretion rate Hhich renained IOM during tetticular developaent (due to nitrogen conservation) Mas elevated at the completion of spernatogenesis. During induced Maturation, the eels Mobilized their bone calciuM to the developing gonads. The corpuscles of Stannius, which showed distinct hypertrophy during gonadal Maturation, Has probably involved. Hypophysectosy attenuated tht cutabolic responses in salt and fetale till during induced aturation. Bonadal naturation was accoBpaniad by progressive increases in size and nuaber of gonadotropie cells in the pituitary. In -ale eels, degranulation of these gonadotropic cells was observed at the final stages of maturity. Endogenous gonadotropin thus released night contribute to the development of the gonads, Estradiol also had itiaulatory effect en pituitary gonadotropic cells, In the study, re...