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CHANGES IN THE MELANOPHOROTROPIC FUNCTION OF THE PITUITARY GLAND ACCOMPANYING BLINDNESS IN XENOPUS LAEVIS DAUDIN
Author(s) -
IMAI KATSUTOSHI,
TAKAHASHI HIROYA
Publication year - 1970
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1111/j.1440-169x.1971.00253.x
Subject(s) - xenopus , pars intermedia , chromatophore , biology , pituitary gland , hypophysectomy , medicine , melanophore , metamorphosis , endocrinology , blindness , anatomy , hormone , genetics , gene , larva , botany , optometry
A bstract A number of cases of blindness appeared among a group of cultured Xenopus laevis . The blind toads lacked eyeballs and optic nerves and were consistently dark in color. Similar anatomical changes in the head and pigmentation were produced experimentally by removing the eyeballs of tadpoles or young adult toads. The dark pigmentation of blind Xenopus : was shown to be due to the continuous release of MSH from the pars intermedia of the pituitary, since hypophysectomy led to the complete blanching of the dermal and epidermal melanophores. MSH activity in the pars intermedia of blind toads was extremely high in comparison with that of normal animals. No special difference with respect to the general growth and behaviour was found between normal and blind Xenopus , which suggests that the pituitary functions other than that of the pars intermedia are not affected by the state of the optic nerves. These observations suggest that the retrogressive degeneration of the optic nerves exerts a profound effect on the secretory activity of the pars intermedia via the hypothalamic controlling center.