Development of a radioimmunoassay for European eel growth hormone and application to the study of silvering and experimental fasting.
A specific and sensitive homologous radioimmunoassay for eel (Anguilla anguilla L.) growth hormone (angGH) has been developed. The antiserum, raised against purified angGH and used at 1:20,000 final dilution, did not cross-react with eel prolactin or thyrotropin, carp gonadotropin II, bovine GH, or serum from hypophysectornized eel. The inhibition curves for eel pituitary extracts and serum were parallel to that of angGH standard. The ED50 value was between 1 and 2 ng/tube and the recovery of purified angGH added to the serum was about 100%. In immunocytochemical studies, the antiserum, used at 1:1000 dilution, specifically labeled the somatotrophs in the pituitaries of the glass, yellow, and silver eels. The GH contents were determined in the pituitaries of glass, yellow, and silver eels and in the serum at the yellow and silver stages. GH variations during the transformation of the yellow to silver eel were examined. The results indicated a decrease in GH production between the yellow and the silver eels, possibly related to the cessation of growth at the silver stage. In contrast to the situation in the naturally fasting silver eel, submitting yellow eels to 3 months of starvation (experimental fasting) greatly increased GH production. This suggests a variation in the regulation of GH according to the type of fasting (natural or experimental) and/or the stage of the fish (yellow or silver).
Marchelidon
J
J
Muséum National d'Histoire Naturelle, URA CNRS No. 90, Paris, France.
Schmitz
M
M
Houdebine
L M
LM
Vidal
B
B
Le Belle
N
N
Dufour
S
S
D000811:Anguilla / Q000097:blood / Q000254:growth & development / Q000378:metabolism*; D000818:Animals; D003429:Cross Reactions; D004305:Dose-Response Relationship, Drug; D005215:Fasting / Q000502:physiology; D005260:Female; D013006:Growth Hormone / Q000032:analysis* / Q000097:blood / Q000302:isolation & purification; D007016:Hypophysectomy; D007150:Immunohistochemistry / Q000379:methods; D010903:Pituitary Gland, Anterior / Q000737:chemistry / Q000648:ultrastructure*; D011863:Radioimmunoassay / Q000379:methods*; D012680:Sensitivity and Specificity; D013972:Thyrotropin / Q000032:analysis
D013972:Thyrotropin; D013006:Growth Hormone