The interrenal gland in males of the cichlid fish Cichlasoma dimerus: relationship with stress and the establishment of social hierarchies.

In teleosts, cortisol is the primary glucocorticoid secreted by the steroidogenic cells of the interrenal gland and an increase in its plasma concentration is a frequent indicator of stress. Cortisol has been postulated as an endogenous mediator involved in the regulation of reproduction and aggression related to social dynamics. The cichlid fish Cichlasoma dimerus, is a monogamous species that exhibits complex social hierarchies; males appear in one of two basic alternative phenotypes: non-territorial and territorial males. In this work, we postulated as a general hypothesis that the morphometry of the interrenal gland cells and the plasma levels of cortisol and 11-ketotestosterone (11-KT) are related to the social rank in adult males of C. dimerus. First, the location and distribution of the interrenal gland with respect to its context - the kidney - was studied. Plasma levels of cortisol and 11-KT in territorial and non-territorial males were established by ELISA. Finally, a morphometric analysis of steroidogenic and chromaffin cells of the interrenal gland was performed. Results showed that the interrenal gland was exclusively located in the posterior portion of the cephalic kidney. Non-territorial males presented a greater nuclear area of their steroidogenic cells. Additionally, plasma cortisol and 11-KT levels were lower and higher, respectively, in territorial males. Finally, plasma cortisol levels positively correlated with the nuclear area of interrenal steroidogenic cells. Thus, the interrenal gland, by means of one of its products, cortisol, may be fulfilling an important role in the establishment of social hierarchies and their stability.

Interrenal responses to high ambient temperature in soft-shelled turtle, Lissemys punctata punctata.

An exposure to ambient temperature of 25 degrees C had no perceptible effect on interrenal function but further increase of temperature to 35 degrees C caused nuclear hypertrophy with increase of nuclear diameter, RNA concentration, acid phosphatase and alkaline phosphatase activities, accompanied by quantitative depletions of cholesterol (free, esterified and total) and ascorbic acid levels in the interrenal gland of the soft-shelled turtle Lissemys p. punctata. Similar manifestations of stimulation, except in the nucleus, were marked after exposure to 38 degrees C, but the degree of response in respect of esterified and free cholesterol levels was higher at 38 degrees C than at 35 degrees C. Moreover, withdrawal of 38 degrees C temperature and subsequently maintaining at 25 degrees C for 15 days showed reverse manifestations to those of 35 degrees C/38 degrees C, leading to a tendency towards normalcy. It is suggested that high a ambient temperature of 35 degrees C significantly stimulates interrenal function of Lissemys turtles, but further increase of 38 degrees C does not cause further overall stimulation, and withdrawal of higher temperature (38 degrees C) shows a tendency towards normalcy. It is also suggested that (a) high ambient temperature causes thermal stress, (b) it is reversible and (c) it acts on interrenal activity presumably via CRF-ACTH-axis in turtles.

[The direct activating effect of a nonapeptide neurohormone (vasotocin) on the thyroid and interrenal glands of sturgeons in in-vitro experiments]. / Neposredstvennoe aktiviruiushchee vliianie nonapeptidnogo neirogormona (vazototsina) na shchitovidnuiu i interrenalovuiu zhelezy osetrovykh ryb v opytakh in vitro.

An in-vitro effect of nonapeptide neurohormone vasotocin on thyroid and interrenal glands was studied in hybrid of Siberian and Lena sturgeons [correction of salmons] at light microscopy level using morphometric method. At a concentration of 0.1 and 1 nmol/l vasotocin was shown to exert undirectional stimulating effect on the thyroid and interrenal gland functions. In the presence of vasotocin at a concentration of 1 nmol/l in culture media the activity of glands is even more pronounced than under the influence of adenohypophyseal hormones, adrenocorticotropic (8 x 10 ng/ml) and thyrotropic (5 ng/ml).

Histophysiological studies on sex steroid induced changes in the interrenals of the male frog Rana cyanophlyctis (Schn.).

Administration (i.m.) of either estradiol-17 beta (0.5 microgram/frog) or progesterone (10 micrograms/frog) on alternate days for 15 days to adult male frogs induced the following changes in the interrenal cells: i) nuclear and cellular hypertrophy, ii) increase in the activity of delta 5-3 beta-hydroxy-steroid dehydrogenase and iii) decrease in sudanophilic lipid droplets. Treatment with testosterone propionate (100 micrograms/frog) dit not elicit marked changes in the above parameters. These results demonstrate that some sex steroids modify the interrenal gland steroidogenic activity in R. cyanophlyctis.

Histological observation of some of the endocrine glands in the sterile carp-funa hybrid (F1), with special reference to the hypophysis.

Some endocrine glands of the carp-funa hybrids were studied with a light microscope to elucidate their detailed structure and the possible causal factor of sterility in the males. Adult specimens of carp (Cyprinus carpio), gengoroh-buna (Carassius auratus cuvieri), and their hybrid (F1) were examined. The hybrid males are sterile as manifested by the failure of meiosis and seminomatous neoplasm in their testes. The hybrid females revealed well-developed ovaries, but their fertility was not tested. The hybrid hypophysis shows an intermediate condition between the parent species in the grade of ramification of the pars nervosa into the pars intermedia. Among seven types of granular cells demonstrated in the adenohypophysis, certain degenerative and anomalous changes are recognized only in the gonadotrophs of the hybrid hypophysis, especially in the female. These changes are discussed as a possible cause of sterility. A considerable amount of aldehyde fuchsin stainable neurosecretory material occurs in the cells of the nucleus preopticus and in the pars nervosa. The nucleus lateralis tuberis exhibits a histologically healthy condition.

Histological changes in Xenopus laevis Daudin adult specimens kept under dry conditions, then moved back to their natural aquatic environment. II. Skin, kidney and interrenal tissue.

Some cytological and histochemical characteristics of skin, the kidney and interrenal tissue were studied in Xenopus laevis adult specimens (1) kept in their natural aquatic environment; (2) gradually exposed to dry conditions under which they were kept one week; and (3) returned from the dry environment to water for 24 hr or a week. In the skin, the most relevant changes are those exhibited by epidermal "flask" cells. These cells are generally rather lean, tall and PAS-positive in "dry" animals and in those 24 hr after replacement in water, whereas in animals placed back in water for a week "flask" cells are often large and faintly stainable. In "dry" animals, the skin mucous glands look more emptied of secretion granules than in control animals kept in water or in "dry" specimens returned to water. Difference in the epidermis thickness or in its histochemically evidenced alkaline phosphatase activity were not observed between different groups. In the kidney a clearcut difference between animal groups was found in the glycogen content of the proximal convoluted tubules of the nephron. Glycogen level is very low in "dry" animals. These variations are tentatively ascribed to different degrees of electrolyte resorption. In the interrenal cells, the sudanophil material is scanty in "dry" animals, while it is much more abundant in those returned to water for 24 hr. Similar, though less pronounced, effects had been obtained in previous experiments of ours, in which some of the animals were kept out of water on moist moss, that is under less severe conditions of water deficiency than in the present experiments.

Histo-physiological studies on the interrenal gland of a catfish, Clarias batrachus (Linn.).

The effects of three drugs namely, reserpine, atropine, and adrenaline have been investigated on the interrenal gland of Clarias batrachus. All the drugs bring about lesser or greater degree of hypertrophy in the interrenal gland of this fish. Atropine exhibits more vigorous effect than reserpine and adrenaline.