The reaction of the preoptic nucleus of Xenopus laevis tadpoles to osmotic stimulation. A fluorescence microscopical investigation

Histochemical and immunohistochemical properties of the CRF-granules and other "Gomori-positive" substances of the rat

In adrenalectomized rats, histochemical and immunohistochemical properties of the following secretion products have been investigated: 1. CRF-granules in the outer layer of the median eminence; 2. neurosecretory material (NSM) in the supraoptico-hypophysial system of the hypothalamus; 3. secretory granules in the TSH-cells of the anterior lobe of the hypophysis; 4. secretory granules in the ependymal cells of the subcommissural organ (SCO); 5. beta-cell-granules in the islets of Langerhans in the pancreas. All these substances are characterized by their stainability with the so-called "Gomori method". The experiments have included studies into: a) the extractability of the substances by various solvents; b) the digestability of the substances by pepsin or trypsin; c) their histochemically detectable content of disulfide groups, arginine and periodic acid-Schiff (PAS) reactive carbohydrates; d) their reaction with porcine-neurophysin-II-antibodies. All substances exhibited a positive reaction for disulfide groups. Based on their solubility properties, their resistance to pepsin or trypsin, their respective content of PAS-reactive carbohydrates and their failure to react with anti-neurophysin serum the "Gomori-positive" granules in TSH-, SCO- and pancreatic beta-cells can be distinguished from one another and from CRF- and neurosecretory granules. In contrast, CRF-granules and NSM showed identical properties. Taking into consideration data from the biochemical and histochemical literature, the present findings suggest that CRF-granules and NSM consist of closely related biochemical substances.

Autoradiographic localization of hormone-concentrating cells in the brain of an amphibian, Xenopus laevis. II. Estradiol

Autoradiographic techniques for light microscopic examination of sex steroid retention were applied to the brains of male and female Xenopus laevis, and anuran amphibian, after 3H-estradiol administration. Estrogen was concentrated by cells in three telencephalic areas (the ventral striatum, the ventral-lateral septum and the amygdala), the anterior preoptic area, the ventral thalamus, the ventral infundibular nucleus, and in the torus semicircularis. The anterior preoptic area and the ventral infundibular nucleus contained the greatest number of labelled cells. The topography of estrogen-concentrating cells was the same in male and female brains. This fact and comparisons of 3H-estradiol with 3H-testosterone retention in Xenopus suggest that the sex steroid itself, and not the genetic sex of Xenopus determines the pattern of uptake by cells in the brain. The distribution of hormone-concentrating cells in Xenopus has many similarities to that found in birds and mammals. Preoptic, hypothalamic (tuberal), limbic forebrain and specific mesencephalic sites in all these forms contain labelled cells following radioactive sex steroid administration. Findings in Xenopus add to the argument for a phylogenetically stable system of hormone-concentrating nerve cells in limbic, hypothalamic and mesencephalic structures.