Summary
In normal pars distalis of Rana temporaria, a gradient of activity of the P.A.S.-positive cells is always present. In animals, with complete and permanent interruption of all nervous pathways to the median eminence and hypophysis and without disturbance of the normal blood supply of the hypophysis, a subtotal disappearance of the gradient of activity occurred and the total activity of the P.A.S.-cells of the pars distalis was lowered. The activity of the P.A.S.-positive cells regressed in a typical way, suggesting a humoral mechanism.
In animals with marked regeneration of the interrupted nerve fibres, a normal gradient of activity was present. From these and previous experiments, it is concluded that the gradient of activity of the P.A.S.-positive cells of the pars distalis of Rana temporaria is largely dependent on the A.F.-negative fibres of the median eminence, not originating from the magnocellular neurosecretory preoptic nuclei. It is suggested that these nerve fibres exert their influence on the activity of the P.A.S.-positive cells via substances released in the blood capillaries of the median eminence.
The gradient of activity and its variations are mainly related to the gonadotropic function of the pars distalis.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Diepen, R.: Der Hypothalamus. In: Handbuch d. mikroskopischen Anatomie des Menschen, Bd. IV, Teil 7, Berlin-Göttingen-Heidelberg: Springer 1962.
Dierickx, K.: The total extirpation of the preoptic magnocellular nucleus of Rana temporaria. Arch. int. Pharmacodyn. 143, 268–275 (1963a).
—: A gradient of activity in the hypophysis in relation with the vascularization. Naturwissenschaften 50, 574 (1963b).
—: The structure and activity of the hypophysis of Rana temporaria in normal and in experimental conditions. Z. Zellforsch. 61, 920–939 (1964a).
—: The nerve fibres controlling the gonadotropic activity of the hypophysis of Rana temporaria. Z. Zellforsch. 63, 938–949 (1964b).
Fortier, C.: Hypothalamic control of anterior pituitary. In: Comparative Endocrinology, vol. 1, p. 1–24. New York: Academic Press 1963.
Guillemin, R.: Sur la nature des substances hypothalamiques qui contrôlent la sécrétion des hormones antéhypophysaires. J. Physiol. (Paris) 55, 7–44 (1963).
Igarashi, M., and S. M. McCann: A hypothalamic follicle stimulating hormone-releasing factor. Endocrinology 74, 446–452 (1964).
Lison, L.: Histochimie et Cytochimie Animales. Paris: Gauthier-Villars 1960.
Nikitovitch-Winer, M. B.: Induction of ovulation in rats by direct intrapituitary infusion of median eminence extracts. Endocrinology 70, 350–358 (1962).
Pearse, A. G. E.: Histochemistry, p. 228–248. London: J. A. Churchill Ltd. 1960.
Schiavi, R., M. Jutisz, E. Sakiz, and R. Guillemin: Stimulation of ovulation by purified L.H.-releasing factor (L.R.F.) in animals rendered anovulatory by hypothalamic lesion. Proc. Soc. exp. Biol. (N. Y.) 114, 426–429 (1963).
Szentágothai, J., B. Flerkö, B. Mess, and B. Halász: Hypothalamic control of the anterior pituitary, p. 1–330. Budapest: Adadémiai Kiadó 1962.
Van Oordt, P. G. W. J.: Cell types in the pars distalis of the amphibian pituitary. In: Cytologie de l'adenohypophyse. No 128, pp. 301–314. Ed. du Centre National de la recherche scientifique (1963).
Author information
Authors and Affiliations
Additional information
I am indebted to miss M. T. Bakeeff and miss C. Everaert who were so kind to check the karyometric results.
Rights and permissions
About this article
Cite this article
Dierickx, K. A gradient of activity in the hypophysis of Rana temporaria . Zeitschrift für Zellforschung 65, 514–520 (1965). https://doi.org/10.1007/BF00337065
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00337065