摘要：

Of twenty five silver male eels injected with high doses of radioiodine (I 131), complete thyroid destruction was achieved in only four. In the pituitary there was hypertrophy and hyperplasia of thyrotropic cells which became completely degranulated and vacuolated. Nuclear and nucleolar hypertrophy occurred simultaneously. Erythrosinophilic cells were stimulated and partly degranulated; their prolactinic function is discussed. Both of these cell types are localized in the rostral region of the pars distalis of the teleost pituitary. The orange G-positive cells and the still undifferentiated gonadotropic cells located in the caudal region of the pars distalis were not modified by radiothyroidectomy. These reactions are compared with data collected from other species. The validity of the nomenclature applied to regions of the fish pituitary, when based only on histology or topographical anatomy, appears questionable. It seems worthwhile, considering histochemical and electron microscope studies, to adopt a terminology consistent with that in higher vertebrates. It is the pars distalis of the teleost hypophysis which is homologous to the mammalian anterior lobe or pars distalis, and contains the various adenohypophyseal hormones already identified by cytophysiology, histochemistry, or bioassay.

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