Summary
In the normal male rat pituitary tritiated thymidine labeled mainly STH cells (somatotrophs), no labeled prolactin cell was found. Following estradiol treatment for 21 days tritiated thymidine labeled mainly prolactin cells (mammotrophs). To determine the origin of these mammotrophs tritiated thymidine was given before the estradiol treatment started, thus labeling many somatotrophs. After 21 days of estradiol, out of 42 labeled cells, 14 were mammotrophs and 13 were somatotrophs; these results suggest that there might be a true transformation of somatotrophs into mammotrophs under the influence of estradiol or that there exist two types of somatotrophs: 1) a committed somatotroph which is not transformed by estrogen treatment, and 2) an uncommitted mammosomatotroph, which under normal conditions bears the features of a somatotroph, but which transforms into a mammotroph under the influence of estradiol.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Chen, C. L., Meites, J.: Effects of estrogen and progesterone on serum and pituitary prolactin levels in ovariectomized rats. Endocrinology 86, 503–505 (1970)
Farquhar, M. G., Rinehart, J.: Electron microscopic studies of the anterior pituitary gland of castrate rats. Endocrinology 54, 516–541 (1954)
Hedinger, C. E., Farquhar, M. G.: Elektronenmikroskopische Untersuchungen von zwei Typen acidophiler Hypophysenvorderlappenzellen bei der Ratte. Schweiz. Z. allg. Path. 20, 766–768 (1957)
Hymer, W. C., McShan, W. H., Christiansen, R. G.: Electron microscopic studies of anterior pituitary glands from lactating and estrogen-treated rats. Endocrinology 69, 81–90 (1961)
Kurosumi, K.: Functional classification of cell types of the anterior pituitary gland accomplished by electron microscopy. Arch. histol. jap. 29, 329–362 (1968)
Lloyd, H. M., Meares, J. D., Jacobi, J.: Secretory and mitotic response of male rat pituitary gland to repeated doses of oestrogen. Int. J. Cancer 11, 90–94 (1973a)
Lloyd, M. H., Meares, J. D., Jacobi, J.: Early effects of stilboestrol on growth hormone and prolactin secretion and on pituitary mitotic activity in the male rat. J. Endocr. 58, 227–231 (1973b)
Lloyd, H. M., Meares, J. D., Thomas, F. J.: Duration and nature of altered pituitary function in the male rat after a single large dose of estrogen. Hormone Metab. Res. 4, 392–395 (1972)
Moriarty, G. C.: Adenohypophysis: ultrastructural cytochemistry. J. Histochem. Cytochem. 21, 855–894 (1973)
Moriarty, G. C., Halmi, N. S.: Electron microscopic study of the adrenocorticotropin producing cell with the use of unlabeled antibody and the soluble peroxidase-antiperoxidase complex. J. Histochem. Cytochem. 20, 590–603 (1972)
Nakane, P. K.: Classifications of anterior pituitary cell types with immunoenzyme histochemistry. J. Histochem. Cytochem. 18, 9–20 (1970)
Pasteels, J. L.: Etude expérimentale des cellules responsables de la sécrétion de prolactine chez les mammifères. Rapport. Coll. Int. CNRS, Paris, Cytologie de l'Adénohypophyse, 137–148 (1963)
Schelin, U., Lundin, P. M.: An electron microscopic study of normal and neoplastic acidophil cells of the rat pituitary. Acta endocr. (Kbh.) 67, 29–39 (1971)
Schelin, U., Lundin, P. M., Bartholdson, L.: Light and electron microscopic studies on an autonomous stilbestrol-induced pituitary tumor in rats. Endocrinology 75, 893–900 (1964)
Shiino, M., Williams, G., Rennels, E. G.: Ultrastructural observation of pituitary release of prolactin in the rat by suckling stimulus. Endocrinology 90, 176–187 (1972)
Siperstein, E. R., Allison, V. F.: Fine structure of the cells responsible for secretion of adrenocorticotrophin in the adrenalectomized rat. Endocrinology 76, 70–79 (1965)
Siperstein, E. R., Miller, K. J.: Further cytophysiologic evidence for the identity of the cells that produce adrenocorticotrophic hormone. Endocrinology 86, 451–486 (1970)
Smith, R. E., Farquhar, M. G.: Lysosome function in the regulation of the secretory process in cells of the anterior pituitary gland. J. Cell Biol. 31, 319–347 (1966)
Stratmann, I. E., Ezrin, C., Kovacs, K., Sellers, A. E.: Effect of TRH (Thyrotropin-Releasing Hormone) on the fine structure and replication of TSH and prolactin cells in the rat. Z. Zellforsch. 145, 23–37 (1973)
Stratmann, I. E., Ezrin, C., Sellers, E. A., Simon, G. T.: The origin of thyroidectomy cells as revealed by high resolution radioautography. Endocrinology 90, 728–734 (1972)
Author information
Authors and Affiliations
Additional information
This work was supported by grants MA-552 and MT-2701 from the Medical Research Council of Canada. The authors wish to thank Dr. G. M. Brown, Clarke Institute of Psychiatry, University of Toronto, for the radioimmunoassays of growth hormone and prolactin. Reagents for both radioimmunoassays were kindly provided by the National Institute of Arthritis and Metabolic Diseases, through the Rat Pituitary Hormone Distribution Program. — We are also thankful to Dr. L. Endrenyi, Department of Pharmacology, University of Toronto, for the statistical analysis of our data.
Fellow of the Medical Research Council of Canada.
Rights and permissions
About this article
Cite this article
Stratmann, I.E., Ezrin, C. & Sellers, E.A. Estrogen-induced transformation of somatotrophs into mammotrophs in the rat. Cell Tissue Res. 152, 229–238 (1974). https://doi.org/10.1007/BF00224697
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF00224697