Immunoreactivity in pituitary gonadotropes and hypothalamic vasopressinergic neurons for the monoclonal antibody INO.

The monoclonal antibody INO (inhibitor of neurite outgrowth) has been shown to bind to a complex of laminin and a heparan sulfate proteoglycan and to block the action of this complex in promoting neurite outgrowth. We now report that the same antibody binds to cytoplasmic constituents in rat adenohypophyseal gonadotropes, as well as to vasopressinergic neurons in the hypothalamus and their terminals in the neurohypophysis. INO immunoreactivity in fixed sections of pituitary does not colocalize with the immunoreactive laminin in blood vessels and glandular basement membranes, although when unfixed tissue is washed in buffer prior to fixation, the INO immunoreactivity appears in these laminin-rich structures. These observations suggest similarities between the INO hypophyseal antigen and the neurite-promoting proteoglycan complex characterized in conditioned media. Presence of this complex in specific neurosecretory cell types suggests that it is involved with specific secretory products with function yet to be determined.

[Possibilities and value of immunofluorescence in the diagnosis of endocrine diseases]. / Möglichkeiten und Stellenwert der Immunfluoreszenz in der Diagnostik endokriner Erkrankungen.

The indirect immunofluorescence (IFL) test is the method of choice for the detection of new organ-specific autoantibodies. It is also the standard method of detection of antibodies to pancreatic islet cells, adrenal cortex, and steroid-producing cells in gonads and placenta. A positive test is the essential diagnostic step to find out the etiology of some endocrine diseases, but the significance of this method varies in different organs. There is as yet no substitute for the IFL test in the determination of single cell antibodies within organs e.g. antibodies to endocrine cells of the pituitary and the gut. In some clinical situations it is advisable to look for the complement-fixing ability of cytoplasmic autoantibodies using the CF-IFL test and for scientific investigation the IFL test can be applied when looking for antigens on the surface of cells in suspension or culture.

[Hypothalamic influence on differentiation of the immunoreactive ACTH beta-LPH, alpha- and beta-endorphin containing cells in adenohypophysial primordia of rat fetus in organ culture (author's transl)]. / Influence de l'hypothalamus sur la différenciation des cellules présentant une immunoréactivité de type ACTH, beta-LPH (beta-lipotropine), alpha- et beta-endorphines dans les ébauches antéhypophysaires de foetus de rat en culture organotypique.

Adenohypophysial primordia were isolated in rat fetuses from day 12.5 to day 15.5 of gestation. The organ culture employed for maintenance of the primordia was made up according to Watanabe et al. (1973). The fixation of primordia in Bouin Hollande's solution was performed after 9, 8, 7 or 6 days of culture when the normal duration of pregnancy was achieved. The cultivated primordia were immunologically studied using different antisera: anti-alpha(17-39)ACTH, anti-beta(1-24)ACTH, anti-beta-LPH, anti-alpha and anti-beta-endorphins, with immunoperoxidase or immunofluorescence techniques, including control experiments of the specificity of the antisera. A similar study was performed on pituitaries removed from normal rat fetuses from day 16.5 of gestation and each day up to birth, and fixated immediately. In vivo the first cells reacting with all the antisera used in this study were observed on day 16.5 of gestation; their number increased during gestation (Fig. 1 A, B and C). Immunoreactive cells with the different antisera could be detected in primordia isolated on day 12.5 of gestation after 9 days of culture. Numerous groups of cells were observed in primordia of older fetuses (Fig. 2 A and B). These data indicate that the corticotropic cells in rat fetuses could start to be differentiated without stimuli from the hypothalamus since primordia were isolated before the appearance of this cell type in normal rat fetuses and before the differentiation of the hypothalamus. The presence of ACTH and other peptides such as beta-LPH or beta-endorphin would support the hypothesis of a common precursor in this cell type existing early in gestation. Similar results were obtained in human fetuses.