Immunocytochemistry of gonadotropic cells in the pituitary of some teleost species

GENERAL

AND

COMPARATIVE

ENDOCRINOLOGY

lmmunocytochemistry

50,

252-260 (1983)

of Gonadotropic Cells in the Pituitary Some Teleost Species

M. OLIVEREAUANDY. Laboratoire de Physiologie de I’lnstitut Oc+anographique, and *Laboratory of Reproductive Biology, National

of

NAGAHAMA*

195 rue Saint-Jacques, Institute for Basic Biology,

F-75005 Paris, France, Okazaki, Japan 444

Accepted July 12, 1982 An antiserum (anti-sGTH) raised against salmon gonadotropin (SG-GlOO) was tested on pituitary sections of Sarotherodon mossambicus. Carassius auratus, Anguilia anguilla (intact and estradiol-treated to induce the development of the gonadotropic (GTH) cells), Salmo trutta fario, and a protandric marine teleost (Sarpa salpa, Sparidae). Using an immunoenzymologic technique, anti-sGTH stained GTH and thyrotropic (TSH) cells in the species studied. Anti-sGTH stained the granulated GTH cells in S. truttafario and S. salpa; the vacuolated cells remained faintly stained or unlabeled in most cases. The results are discussed in the light of cytological, ultrastructural, and biochemical data which suggest that two forms of GTH cells may be present in some teleost pituitaries.

Immunocytochemical techniques have been used to identify various cell types in the teleost pituitary (cf. Foll&ius et al., 1978). Using antibodies against mammalian gonadotropin, i.e., anti-ovine LH or anti-HCG, gonadotrophs (GTH cells) have been identified in the pituitary of some salmonid fishes (McKeown and Van Overbeeke, 1971: Olivereau, 1978). In contrast, negative results were obtained with anti/3-LH in S. furio, S. gairdneri, and Oncorhynchus tshawytscha (Olivereau, 1978) and with anti-ovine FSH or porcine-FSH in 0. nerka (McKeown and Van Overbeeke, 1971). The specificity of these results is questionable as mammalian and piscine gonadotropins (GTH) show differences in their chemical composition (BurzawaGCrard and Fontaine, 1972). More specific labeling has been obtained by using antisera to teleost GTH such as anti-carp GTH (Billard et al., 1971; Goos and Van Oordt, 1975; Peute and De Bruyn, 1976; Ekengren et al., 1978a-c) and antisalmon GTH (Ekengren et al., 1978a-c; Lindahl, 1980; Van Putten et al., 1981). In these studies, however, thyrotrophs (TSH cells) were labeled in some cases. An anti252 001~6480/83 $1.50 Copyright @ 1983 by Academic Press, Inc. All rights of reproduction in any form reserved.

body against p-subunit of the carp GTH has been reported to be very specific for the GTH cells of Xiphophorus maculatus (Schreibman and Margolis-Kazan, 1979). The present study describes the immunocytological distribution of GTH in the pituitary gland of several teleosts using an anti-salmon GTH (Crim et al., 1973). Results obtained on trout and eel pituitaries have been published in abstract form (Olivereau and Nagahama, 1982). MATERIALS

AND METHODS

An anti-salmon gonadotropin (sGTH), prepared with salmon GTH (SG-GlOO) was kindly donated by L. W. Crim (Memorial University of Newfoundland). It was used at a dilution of l/50. The inhibition test was performed by using antiserum saturated with SGGlOO. Control reactions were also carried out with nonimmune serum. Both tests gave negative results. Animals. Five species of teleosts were used in this study. Sexually maturing tilapia, S. mossambicus, weighing 30-40 g were raised and maintained in holding cages in a freshwater pond at the University of California, Berkeley. Sexually immature or maturing goldfish, C. auratus, weighing 11- 16 g were kept in recirculating tap water at 14 or 24” under a natural photoperiod at the Institute for Basic Biology in Okazaki. They were killed in early July. Female silver eels, A. anguilla, were kept at 21” in fresh water under a 12 hr photoperiod; some eels were treated with

IMMUNOCYTOCHEMISTRY estradiol-17P (E2, Sigma) according to the methods previously described (Olivereau and Olivereau, 1979) to induce the differentiation and development of the GTH cells. Trout, S. trutln furio, were raised and kept at a commercial fishery (France) under natural conditions. They were collected at different stages of sexual maturation (Billard et al., 1978) through the courtesy of Dr. Billard and Dr. Breton (University of Rennes). Specimens of a marine teleost, S. (Boops) snlpu (Saupe), at various stages of sexual maturation, collected in the vicinity of Monaco, were kindly provided by Mrs. Malo-Michble (University of Nice). Histology and immunocytochemistry. All pituitaries were fixed in sublimated Bouin-Hollande solution, apart from some goldfish pituitaries which were fixed in aqueous Bouin fixative. Paraffin sections were cut at 4 or 5 pm thickness. Sections were treated with the antiserum and then with the peroxidase-antiperoxidase technique according to Nakane (1970). They were mounted with Canada balsam. Adjacent sections were stained with Herlant’s tetrachrome to confirm the nature of the labeled GTH and TSH cells. Detailed immunocytochemical techniques have been described elsewhere (Nagahama er al., 1981).

RESULTS

Anti-sGTH bound to both GTH and TSH cells of all the pituitaries used in the present study, although tilapia TSH cells were not present in the sections tested. (a) Goldfish. In the goldfish, GTH cells are restricted to the proximal pars distalis (PPD). They are polygonal in shape and often contain coarse granules and some large globules. Granules and globules are labeled (Fig. 1). Immunoreaction was much more intense in the globular GTH cells of the gravid goldfish kept at 14” than in those of fish kept at 24”, although GTH cells are smaller in size in fish maintained at a low temperature. Typical TSH cells, mainly located in the rostra1 pars distalis (RPD) (Olivereau, 1962), were also labeled. (b) Tilupia . Tilapia GTH cells are found in the ventral part of the PPD and usually contain large vacuoles, some of which exceed one-half of the cell area; TSH cells form a small group of cells in the mid-dorsal region of the pituitary (Bern el al., 1974). GTH cells clearly reacted with the anti-

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sGTH, the vacuolar content being always negative (Fig. 2). (c) Eel. In the PPD, GTH cells of untreated eels were poorly differentiated and showed no immunoreaction; TSH cells located in the RPD were strongly labeled (Fig. 3). After E2 treatment, enlarged and heavily granulated GTH cells are abundant in the PPD (Olivereau and Olivereau, 1979). They reacted strongly, as did some large GTH cells situated in the RPD (Fig. 4). The large globules often seen in GTH cells were never labeled with this antiserum (Fig. 6). In contrast, the labeling was much reduced in enlarged TSH cells (Fig. 5), in agreement with their stimulation and degranulation after E2 treatment (Olivereau et al., 1981b). (d) Trout. In the trout, immunoreaction was mainly restricted to the elongated cells located in the ventral and lateral regions of the PPD; these cells often invade the RPD (Fig. 7). They contain coarse granules and stain intensely with anilin blue, PAS, Alcian blue, and aldehyde -fuchsin. Their cell bodies were often located in the middle of the glandular cords; they make contact with the basal lamina through a thin pedicle whose ending is often enlarged and more granulated (Fig. 8). This cell type increases in number before and during the spawning period. Pituitary and plasma levels of GTH increase simultaneously (Billard et al., 1978). A second type, presumed to be gonadotropic, is more rounded in shape. It contains fine granules and is unstained or very faintly stained with PAS, Alcian blue, and aldehyde-fuchsin. These cells are located more dorsally in the PPD and often contact the neurohypophysis. In the spring and summer, these cells are well granulated; however, their labeling was faint and sometimes doubtful or absent and was always much lighter than that of the coarsely granulated cell type which is much smaller and less active at this time of the year. In prespawning and spawning fish, these cells

FIG. 1. Goldfish (proximal pars distalis). GTH cells are labeled with anti-sGTH. STH cells (S) are unlabeled. x 300. FIG. 2. Tilapia (proximal pars distalis). Large GTH cells react with the anti-sGTH, the vacuole content is not labeled. x300. FIG. 3. Eel (rostra1 pars distalis). TSH cells are stained with the anti-sGTH. They are scattered among follicles of prolactin cells (P). x325. FIG. 4. Estradiol-treated eel (40 days). The proximal pars distalis contains numerous large GTH cells heavily labeled. Neurohypophysis (N). x350. FIG. 5. Estradiol-treated eel (40 days). TSH cells are enlarged and often less reactive than in untreated eels. x325. FIG. 6. Estradiol-treated eel (80 days). In GTH cells, granules are labeled with the anti-sGTH; no large globules react. x930. 254

FIGS. 7- 10. Pars distalis of female trout killed before spawning (begining and end of November). Labeling of the GTH cells with the anti-sGTH. FIG. 7. GTH cells infiltrate among prolactin cells showing a follicular organization (F). GTH cells are mainly located in the proximal pars distalis. x 150. FIG. 8. Some densely granulated GTH cells have elongated pedicles (arrow head) reaching the neurohypophysial strands. Globular cells (arrows) remain unlabeled. x575. FIG. 9. Heterogeneity of the labeling of the GTH cells. x350. FIG. 10. Large vacuolar GTH cells, which contain very little glycoproteins, show a faint or doubtful labeling in some cytoplasmic areas. More elongated granular GTH cells are clearly labeled. Neurohypophysis (N). x930. 255

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11 and 12. Pituitary of Sarpa salpa labeled with the anti-sGTH. 11. TSH cells located among prolactin and ACTH cells are immunoreactive. Neurohypophysis (N). x350. FIG. 12. Mature male. Well-granulated GTH cells are heavily labeled. Islets of vacuolar GTH cells are unreactive. X350. FIGS. FIG.

became vacuolated and were unlabeled or only very faintly labeled (Figs. 9 and 10). (e) Saupe. In the RPD, islets of TSH cells were labeled with anti-sGTH (Fig. 11). Changes occurring in the GTH cells and gonads in protandric males and in females were previously described (Malo-Michble, 1977, 1978). In juvenile saupes, granulated GTH cells reacted faintly to this antiserum. In protandric males near spermiation (October), two types of GTH cells were recognizable, granulated GTH cells and highly vacuolated ones. The former cells reacted strongly (Fig. 12), but the latter did not show any immunoreaction, apart from a very faint and rarely observed reaction of the cytoplasmic strands surrounding the vacuoles. In previtellogenic females, collected in January, the cells with coarse granules displayed a moderate immunoreaction. During vitellogenesis (August), the intense labeling was restricted to the granular cell type. A similar staining was

observed in mature females just prior to spawning (October); the labeling was less intense in females having atretic oocytes. In spent females (December), in which ovarian recrudescence has commenced, the intensity of the reaction was variable, but was still restricted to the granular cell type, suggesting that cells at this stage are variably granulated. Vacuolated cells or cells with a pale cytoplasm did not react. As a rule, granulated cells formed compact masses among large areas of vacuolated cells; the two cell types were rarely intermingled. The cells of the pars intermedia did not react with the antibody, except in Sarpa in which GTH cells sometimes formed a more or less complete mantle around the caudal end of the pituitary. In the nucleus preopticus of the trout and the eel, some neurons in the magnocellular area reacted to the anti-sGTH, a similar labeling being also detectable in the neurohypophysis; labeling of the pericarya

IMMUNOCYTOCHEMISTRY

in the nucleus lateralis tuberis was not observed. DISCUSSION

The antibodies to the sGTH crossreacted with both GTH and TSH cells in all species tested in this study in which TSH cells were present. These results agree with those obtained with anti-carp GTH which reveals both GTH and TSH cells of the carp (Billard et al., 1971), Brachydunio rerio, Anoptichthys jordani, and X. helleri (Goos and Van Oordt, 1975), Mollienisia latipinna (Goos et al., 1976), and with anti-sGTH in Rutilus rutilus (Ekengren et al., 1978a). The labeling of GTH and TSH cells often reported is probably related to the common o-subunit whose antibodies stain both cell types in mammalian species. A more specific labeling of Xiphophorus GTH cells was obtained with the p-subunit antiserum of carp GTH (Schreibman and MargolisKazan, 1979; Margolis-Kazan et al., 1979). GTH cells are more heavily labeled in goldfish kept at 14” than in those kept at 24” in July. Pituitary GTH content is also higher in goldfish kept for 3 months at 12” in the spring compared to fish kept at 20 and 30” (Gillet and Biilard, 1981). Cytological studies (Cook and Van Overbeeke, 1972; Olivereau, 1976; Ueda and Takahashi, 1977; Malo-Michelle, 1978; Shjkhuis, 1978; Ueda and Hirashima, 1979; Ueda, 1980; Leatherland and Sonstegard, 1980) suggest that there are two separate GTH cells in certain teleosts reacting differently to gonadectomy or various hormonal treatments (Simon and Reinboth, 1974; Ueda and Takahashi, 1980). Only globular GTH cells were stained with anti-HCG in S. gairdneri, S. furio, and 0. tshawytscha (Olivereau, 1978) and with anti-sGTH in S. fario and Sarpa. Antibodies against flounder maturational GTH reacted with PAS-staining cells at the anterior margin of the flounder PPD, whereas antivitellogenic GTH stained certain cells

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of the peripheral PPD (Burton et al., 1981). Biochemical data also suggest the existence of two GTH in the pituitaries of salmon, carp, winter flounder, and American plaice (Idler and Ng, 1979; Ng and Idler, 1978a, b, 1979; Ng et al., 1980). The labeling of the large globules in the GTH cells of goldfish may suggest that these globules contain some hormone. A similar suggestion, supported by radioimmunoassay data, has been made for the globules in the GTH cells of S. gairdneri (Peute et al., 1978). The large globules of EZtreated eels (Olivereau and Chambolle, 1978) do not stain with anti-sGTH. The significance of these globules is further complicated by the localization of acid phosphatase in the secretory granules and to a lesser extent, the globules of S. gairdneri (cf. Van Oordt, 1979). This author suggested that globules are large storage granules, in accordance with Peute et al. (1978) and Leunissen et al. (1980). In the pars intermedia (PI), the p-subunit antiserum of carp GTH cross-reacted with the PAS-positive cells of Xiphophorus even in neonatal fish (Schreibman et al., 1980); absorption with various concentrations of GTH did not selectively extinguish the immunoreaction. Furthermore, these PASpositive cells react with anti-LH-RH (luteinizing hormone-releasing hormone) (Schreibman et (11.) 1979; Margohs-Kazan et ul., 1979, 1981). This finding is surprising. The PAS-positive PI cells of Gambusia (Kah, 1978) and the eel (Olivereau et al., 1981a) have ultrastructural characteristics very different from those of typical GTH cells, appear involved in calcium regulation in the goldfish (Olivereau et al., 1980a, b, 1982) and eel (Olivereau and Olivereau, 1982a, b) and are not related to sexual maturation. In some other species they react to the background color (Ball and Batten, 1981). Anti-human TSH reacts only with the TSH cells in Xiphophorus (Margolis-Kazan

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la Carpe Cyprinus carpio. C.R. Acad. Sci. Paris, and Schreibman, 1980) and in S. salar Ser. D 272, 981-983. (Fridberg et al., 1981). In contrast, antiB., Fostier, A., Jalabert, B., and bovine TSH immunoreacts with both GTH Billard,We&R.,C.Breton, (1978). Endocrine control of the teleost and TSH cells in 0. tshawytscha, as does reproductive cycle and its relation to external an antiserum against HCG (Olivereau and factors: Salmonid and cyprinid models. In “Comparative Endocrinology” (P. J. Gaillard and H. H. Bugnon, unpublished data). Some caution Boer eds.), pp. 37-48. ElseviedNorth-Holland, is necessary before interpreting these findAmsterdam. ings since some species specificity of TSH Burton, M. P., Idler, D. R., and Ng, T. B. (1981). The has been suggested (Fontaine, 1969). immunofluorescent location of teleost gonadotroIn control and EZtreated eels, the intenpins and thyrotropins in flounder pituitary. Gen. Comp. Endocrinol. 43, 135- 147. sity of labeling of TSH cells with anti-sGTH agrees with the granular content of the cells Burzawa-Gerard, E., and Fontaine, Y. A. (1972). The gonadotropins of lower vertebrates. Gen. Comp. and seems to reflect accurately the horEndocrinol. Suppl. 3, 715-728. mone content according to the histological Cook, H., and Van Overbeeke, A. P. (1972). Uland biochemical studies (Olivereau et al., trastructure of the pituitary gland (pars distalis) in sockeye salmon (Oncorhynchus nerka) during 198 lb). Methyltestosterone stimulates gonad maturation. Z. Zellforsch. 130, 338-350. thyroid activity in Oryzias latipes (NishiL. W., Meyer, R. K., and Donaldson, E. M. kawa, 1976). However, it may reduce TSH Crim,(1973). Radioimmunoassay estimates of plasma release according to Goos ef al. (1976) as gonadotropin levels in the spawning pink salmon. it increases the immunofluorescence of Gen. Comp. Endocrinol. 21, 69-76. TSH cells of Mollienisia latipinna and sup- Crim, L. W., and Evans, D. M. (1980). LH-RH stimulated gonadotropin release from the rainbow presses that of GTH cells. trout pituitary gland: an in vitro assay for detecThe presence of GTH-like immunoreaction of teleost gonadotropin releasing factor(s). tive material in the preoptic area of eels and Gen. Comp. Encrinol. 40, 283-290. trouts must be viewed with considerable Ekengren, B., Lindahl, K., and Fridberg, G. (1978a). Immunocytology and innervation of the gonadocaution, in agreement with the statement tropic cells in the teleost fish Rutilus r&us. Acta made by Crim and Evans (1980).

ACKNOWLEDGMENTS The assistance of J. Olivereau (CNRS) in the preparation of the manuscript is gratefully acknowledged. This work was supported by special funds for cooperative research provided by the National Institute for Basic Biology (Japan).

REFERENCES Ball, J. N., and Batten, T. F. C. (1981). Pituitary and melanophore responses to background in Poecilia latipinna (Teleostei): Role of the pars intermedia PAS cell. Gen. Comp. Endocrinol. 44, 233-248. Bern, H. A., Nishioka, R. S., and Nagahama, Y. (1974). The relationship between nerve fibers and adenohypophysial cell types in the cichlid teleost Tilapia mossambica. In “Recherches Biologiques Contemporaines” (L. ANY ed.), Manfred Gabe Memorial Vol., pp. 179- 194. Vagner, Nancy. Billard, R., Breton, B., and Dubois, M. P. (1971). Immunocytologie et histochimie des cellules gonadotropes et thyreotropes hypophysaires chez

Zool. 59, 12.5-133. Ekengren, B., Peute, J., and Fridberg, G. (1978b). The distribution and nature of gonadotropic cells in the rostra1 pars distalis of the Atlantic salmon, Salmo salar. Ann. Biol. Anim. Bioch. Biophys. 18, 799-804. Ekengren, B., Peute, J., and Fridberg, G. (1978~). Gonadotropic cells in the Atlantic salmon, Salmo salar. An experimental immunocytological, electron microscopical study. Cell Tissue Res. 191, 187-203. Follenius, E., Doerr-Schott, J., and Dubois, M. P. (1978); Immunocytology of pituitary cells from teleost fishes. Int. Rev. Cytol. 54, 193-223. Fontaine, Y. A. (1969). La sptcificite zoologique des proteines hypophysaires capables de stimuler la thyrdide. Acfa Endocrinol. 60, Suppl. 136, l- 154. Fridberg, G., Lindahl, K., and Ekengren, B. (1981). The thyrotropic cell in the Atlantic salmon, Salmo salar. Acta Zool. 62, 43-51. Giiet, G., and Billard, R. (1981). Effets de la temperature, de la photoperiode et des niveaux alimentaires sur la gonadotropine plasmatique et hypophysaire et la gametogenese du Poisson

IMMUNOCYTOCHEMISTRY

rouge. Cah. Lab. Hydrobiol. Montereau 11, 41-48. Goos, H. J. T., and Van Oordt, P. G. W. J. (1975). Cross-reaction of rabbit anti-carp gonadotrophin globulin with gonadotrophic hormone of some teleost fish as tested by immunofluorescence. J. Endocrinol. 64, 45P. Goos, H. J. T., Seldenrijk, R., and Peute, J. (1976). The gonadotrophic cells in the pituitary of the black molly, Mollienisia latipinna, and other teleosts, identifted by the immunofluorescence technique in normal and androgen-treated animals. Cell

Tissue

Res.

167, 211-219.

Idler, D. R., and Ng, T. B. (1979). Studies on two types of gonadotropins from both salmon and carp pituitaries. Gen. Comp. Endocrinol. 38,421-440. Kah, 0. (1978). “Etude des correlations hypothalmohypophysaires chez Gambusia sp. (Poecilidae vivipare). Contr6le de la fonction gonadotrope par la technique de greffes.” These 3e cycle, Univ. Bordeaux, pp. l- 107. Leatherland, J. F., and Sonstegard, R. A. (1980). Seasonal changes in thyroid hyperplasia, serum thyroid hormone and lipid concentrations, and pituitary gland structure in lake Ontario coho salmon, Oncorhynchus kisutch Walbaum and a comparison with coho salmon from lakes Michigan and Erie. J. Fish Biol. 16, 539-562. Leunissen, J. L. M., Leeuw, A. M. de, Peute, J., and Elbers, P. F. (1980). Morphology of a few cell types in the pituitary gland of the rainbow trout (Salmo gairdneri) and immunocytochemistry of gonadotropic hormone-producing cells as revealed by cryo-ultramicrotomy. Ultramicr. 5, 109. Lindahl, K. (1980). The gonadotropic cell in Parr, precocious parr male and smolt of the Atlantic salmon, Salmo salar. An immunocytological, lightand electron microscopical study. Acta Zoo/. 61, 117-125. McKeown, B. A., and Van Overbeeke, A. P. (1971). Immunohistochemical identification of pituitary hormone producing cells in the sockeye salmon (Oncorhynchus nerka, Walbaum). Z. Zellforsch. 112, 350-362.

Malo-Michele, M. (1977). Contribution a l’etude histologique de la gonade, en particulier de l’ovaire, chez la Saupe, Boops salpa (L.) (Teleosteen, Sparidae). Donnees nouvelles sur son type d’hermaphrodisme. Invest. Pesqu. 41, 165- 183. Malo-Michble, M. (1978). Evolution des cellules gonadotropes de Boops salpa L. (Teleosteen Sparidae) au tours de la spermatogenese. Ann. Biol. Anim. Bioch. Biophys. 18, 911-915. Margolis-Kazan, H., Peute, J., Schreibman, M. P., and Halpern, L. R. (1979). Ultrastructural localization of immunoreactive gonadotropin (GTH) and luteinizing hormone -releasing hormone

OF TELEOST

GTH

(LH-RH) Amer.

259

CELLS

in the pituitary gland of the platytish.

Zool.

19, 852.

Margolis-Kazan, H., and Schreibman, M. P. (1980). Immunocytochemical demonstration of crossreactivity between fish and human pituitary hormones. Amer. Zool. 20, 829. Margolis-Kazan, H., Peute, J., Schreibman, M. P., and Halpern, L. R. (1981). Ultrastructural localization of gonadotropin and luteinizing hormone releasing hormones in the pituitary gland of a teleost fish (the platyfish). J. Exp. Zool. 215,9!102. Nagahama, Y., Olivereau, M., Farmer, S. W., Nishioka, R. S., and Bern, H. A. (1981). Immunocytochemical identification of the prolactinand growth hormone-secreting cells in the teleost pituitary with antisera to tilapia prolactin and growth hormone. Gen. Comp. Endocrinol. 44, 389-395. Nakane, P. K. (1970). Classifications of anterior pituitary cell types with immunoenzyme histochemistry. J. Histochem. Cytochem. 18, 9-20. Ng, T. B., and Idler, D. R. (1978a). “Big” and “little” forms of plaice vitellogenic and maturational hormones. Gen. Camp. Endocrinol. 34, 408-420. Ng, T. B., and Idler, D. R. (1978b). A vitellogenic hormone with a large and small form from salmon pituitaries. Gen. Comp. Endocrinol. 35, 189-195. Ng, T. B., and Idler, D. R. (1979). Studies on two types of gonadotropins from both American plaice and winter flounder pituitaries. Gen. Comp. Endocrinol. 38, 410-420. Ng, T. B., Idler, D. R., and Burton, M. P. (1980). Effects of teleost gonadotropins and their antibodies on gonadal histology in winter flounder. Gen. Comp.

Endocrinol.

42, 355-364.

Nishikawa, K. (1976). Influence of methyltestosterone on the thyroid gland of the medaka, Oryzias lutipes.

Bull.

Fat.

Fish.

Hokkaido

Univ.

27,

121-128. Olivereau, M. (1962). Cytologie de l’hypophyse du Cyprin (Carassius auratus L.). C. R. Acad. Sci. Paris

255,

2007-2009.

Olivereau, M. (1976). Les cellules gonadotropes hypophysaires du Saumon de 1’AtJantique: Unicite ou dualite? Gen. Comp. Endocrinol. 28, 82-95. Olivereau, M. (1978). Les cellules gonadotropes chez les Salmonides. Ann. Biol. Anim. Bioch. Biophys. 18, 793-798.

Olivereau, M., Aimar, C., and Olivereau, J. M. (1980a). Response of the teleost pituitary (goldfish, eel) to deionized water. Cell Tissue Res. 208, 389-404. Olivereau, M., Aimar, C., and Olivereau, J. M. (1980b). PAS-positive cells of the pars intermedia are calcium sensitive in the goldfish maintained in

260

OLIVEREAU

AND NAGAHAMA

an hyposmotic milieu. Cell Tissue Res. 212, 29-38. Olivereau, M., and Chambolle, P. (1978). Ultrastructure des cellules gonadotropes de l’Anguille normale et apres injection d’oestradiol. C.R. Acad. Sci. Paris, Ser. D 287, 1409-1412. Olivereau, M., Chambolle, P., and Dubourg, P. (1981a). Ultrastructural changes in the calciumsensitive (PAS-positive) cells of the pars intermedia of the eel kept in deionized water and hyperosmotic environments. Cell Tissue Res. 219, 9-26. Olivereau, M., Leloup, J., De Luze, A., and Olivereau, J. (1981b). Effet de l’oestradiol sur l’axe hypophyso-thyroidien de 1’Anguille. Gen. Comp.

Endocrinol.

43, 352-363.

Olivereau, M. and Nagahama, Y. ( 1982). Immunological study of eel and trout gonadotrophs. Gen. Comp.

Endocrinol.

46, 365.

Olivereau, M., and Olivereau, J. (1979). Effect of estradiol-17a on the liver, gonad and pituitary cytology of freshwater female eels. Cell Tissue Res. 199, 431-454. Olivereau, M., and Olivereau, J. (1982a). Calciumsensitive cells of the pars intermedia and osmotic balance in the eel. I. Responses to changes of the environmental calcium. Cell Tissue Res. 222, 231-241. Olivereau, M., and Olivereau, J. (1982b). Calciumsensitive cells of the pars intermedia and osmotic balance in the eel. II. Response to calcium-free sea water. Cell Tissue Res. 225, 487-496. Olivereau, M., Olivereau, J. M., and Aimar, C. (1982). Responses of the calcium-sensitive cells (pars intermedia) of the goldfish adapted to diluted sea water with different calcium and magnesium contents. Cell Tissue Res. 225, 497-505. Peute, J., and De Bruyn, M. G. A. (1976). Effect of methyl-testosterone on the gonadotropic cells of the black molly, Mollienisia latipinna, an immunofluorescence and electron microscopical study. Gen.

Comp.

Endocrinol.

29, 262.

Peute, J., Goos, H. J. T., De Bruyn, M. G. A., and Van Oordt, P. G. W. J. (1978). Gonadotropic cells of the rainbow trout pituitary during the annual cycle. Ultrastructure and hormone content. Ann. Biol. Anim. Bioch. Biophys. 18, 905-910. Schreibman, M. P., Halpem, L. R., Goos, H. J. T., and Margolis-Kazan, H. (1979). Identification of luteinizing hormone-releasing hormone (LH-

RI-I) in the brain and pituitary gland of a fish by immunocytochemistry.J. Exp. Zool. 210,153160. Schreibman, M. P., and Margolis-Kazan, H. (1979). The immunocytochemical localization of gonadotropin, its subunits, and thyrotropin in the teleost, Xiphophorus

maculatus.

Gen.

Comp.

Endocrinol.

39, 467-474. Schreibman, M. P., Margolis-Kazan, H., and Halpern, L. R. (1980). LH-RH and gonadotropin in neonatal platyfish (Xiphophorus maculatus) Amer.

Zool.

20, 729.

Simon, N., and Reinboth, R. (1974). Adenohypophyse und Hypothalamus. Histophysiologische Untersuchungen bei Lepomis (Centrarchidae). Advan. Anat. Embryol. Cell Biol. 48, l-82. Slijkhuis, H. (1978). Ultrastructural evidence for two types of gonadotropic cells in the pituitary gland of the male three-spined stickleback, Gasterosteus

aculeatus.

Gen.

Comp.

Endocrinol.

36,

639-641. Ueda, H. (1980). Changes of two types of pituitary gonadotrophs in white-spotted char, Salvelinus leucomaenis, during gonadal development. Bull. Fat. Fish. Hokkaido Univ. 31, l-15. Ueda, H., and Hirashima, T. (1979). On two different types of putative gonadotrophs in the pituitary gland of the masu salmon, Oncorhynchus masou. Annot. Zool. Japon 52, 114-124. Ueda, H., and Takahashi, H. (1977). Promotion of ovarian maturation accompanied with ovulation and changes of pituitary gonadotrophs after ovulation in the loach, Misgurnus anguillicaudatus, treated with clomiphene citrate. Bull. Fat. Fish. Hokkaido Univ. 28, 106-117. Ueda, H., and Takahashi, H. (1980). Responses of two different types of pituitary gonadotrophs in the loach, Misgurnus anguillicaudatus, to gonadectomy and to exogenous sex steroids. Gen. Comp. Endocrinol.

40, 463-472.

Van Oordt, P. G. W. J. (1979). A typology of the gnathostome adenohypophysis with some emphasis on its gonadotropic function. Basic Appl. Histochem. 23, 187-202. Van Putten, L. J. A., Peute, J., Van Oordt, P. G. W. J., Goos, H. J. T., and Breton, B. (1981). Glycoprotein gonadotropin in the plasma and its cellular origin in the adenohypophysis of sham-operated and ovariectomized rainbow trout, Salmo

gairdneri.

Cell

Tissue

Res.

218,

439-448.