Adaptive morphogenesis of the adrenal glands of ducks in conditions of hyperthermia

It was found that under conditions of hyperthermia, morphofunctional changes develop in the interrenal part of the adrenal glands, indicating an increase in the functional activity of the gland. The study of ducks on the 5th day of hyperthermia revealed loosening and thickening of the adrenal gland capsule compared to the control. Significant hemodynamic disorders were noted: the phenomena of stasis and erythrocyte sludge in sharply expanded blood capillaries of the adrenal glands. It was found that on the 10th day of hyperthermia, hemodynamic disorders are progressive: the phenomena of sludge and red blood cell stasis are less pronounced, but parenchymal edema and a sharp expansion of sinusoid capillaries persist. Changes in interrenal cells (their high prismatic shape, cytoplasmic vacuolization, apical granularity) are also determined to characterize the high secretory activity of endocrinocytes. The found changes indicate the development of a stress reaction.

Nesfatin-1 stimulates the hypothalamus-pituitary-interrenal axis hormones in goldfish

Stress in vertebrates is mediated by the hypothalamus-pituitary-adrenal (in mammals)/interrenal (in fish) (HPA/I) axis, which produces the corticotropin-releasing factor (CRF), adrenocorticotropic hormone (ACTH), and corticosteroids, respectively. Nesfatin-1, a novel anorexigenic peptide encoded in the precursor nucleobindin-2 (NUCB2), is increasingly acknowledged as a peptide that influences the stress axis in mammals. The primary aim of this study was to characterize the putative effects of nesfatin-1 on the fish HPI axis, using goldfish ( Carassius auratus) as an animal model. Our results demonstrated that nucb2/nesfatin-1 transcript abundance was detected in the HPI tissues of goldfish, with most abundant expression in the pituitary. NUCB2/nesfatin-1-like immunoreactivity was found in the goldfish hypothalamus, pituitary, and interrenal cells of the head kidney. GPCR12, a putative receptor for nesfatin-1, was also detected in the pituitary and interrenal cells. NUCB2/nesfatin-1-like immunoreactivity was observed in ACTH-expressing pituitary corticotrophs. Acute netting and restraint stress upregulated nucb2/nesfatin-1 mRNA levels in the forebrain, hypothalamus, and pituitary, as well as crf and crf-r1 expression in the forebrain and hypothalamus. Intraperitoneal and intracerebroventricular administration of nesfatin-1 increased cortisol release and hypothalamic crf mRNA levels, respectively. Finally, we found that nesfatin-1 significantly stimulated ACTH secretion from dispersed pituitary cells in vitro. Collectively, our data provide the first evidence showing that nesfatin-1 is a stress responsive peptide, which modulates the stress axis hormones in fish.

Investigation of the Morphology of Adrenal Glands in Hens Kept in Two Different Housing Systems—A Pilot Study

It is difficult to objectively assess the chronic effects of housing systems on livestock and particularly on laying hens. However, this seems to be important in the context of animal welfare. Therefore, we conducted the present study in order to compare the effect of two different housing conditions, single cage (SC) and floor pen (FP), on the morphology of the adrenal gland. A higher amount of interrenal cells, which secrete stress hormones, can lead to a difference in the relation of adrenal and interrenal cells, which could be interpreted as an indication of chronic stress. For this purpose, adrenal glands were extracted, prepared, stained and examined by microscopy, and total area of the cut, total area of interrenal cells and total area of adrenal cells were measured. As a result, all laying hens had a higher percentage of interrenal cells than adrenal cells (FP: interrenal cells/adrenal cells = 78.37%/21.63%; SC: 80.00%/20.00%). The median of adrenal–interrenal ratio did not differ significantly (FP = 0.2503, SC = 0.2499), while the variation of the ratio between laying hens in FP and SC showed a slight tendency of a higher ratio in adrenal glands of FP (p < 0.0870). Body weight and adrenal–interrenal ratio were significantly negatively correlated in laying hens in FP (rS = −0.943, p < 0.0048) but not in SC (rS = −0.162, p = 0.7283). There was no significant correlation between body weight and total cell area for interrenal cells or adrenal cells. Body weight was significantly lower for laying hens kept in SC than for laying hens kept in FP (p < 0.0001). Due to the present results, it can be concluded that keeping laying hens in single cages can have a negative effect on body weight.

Loss of Cyp11c1 causes delayed spermatogenesis due to the absence of 11-ketotestosterone

The impacts of androgens and glucocorticoids on spermatogenesis have intrigued scientists for decades. 11β-hydroxylase, encoded by cyp11c1, is the key enzyme involved in the synthesis of 11-ketotestosterone and cortisol, the major androgen and glucocorticoid in fish, respectively. In the present study, a Cyp11c1 antibody was produced. Western blot and immunohistochemistry showed that Cyp11c1 was predominantly expressed in the testicular Leydig cells and head kidney interrenal cells. A mutant line of cyp11c1 was established by CRISPR/Cas9. Homozygous mutation of cyp11c1 caused a sharp decrease of serum cortisol and 11-ketotestosterone, and a delay in spermatogenesis which could be rescued by exogenous 11-ketotestosterone or testosterone, but not cortisol treatment. Intriguingly, this spermatogenesis restored spontaneously, indicating compensatory effects of other androgenic steroids. In addition, loss of Cyp11c1 led to undersized testes with a smaller efferent duct and disordered spermatogenic cysts in adult males. However, a small amount of viable sperm was produced. Taken together, our results demonstrate that cyp11c1 is important for testicular development, especially for the initiation and proper progression of spermatogenesis. 11-ketotestosterone is the most efficient androgen in tilapia.

Transgenerational hypocortisolism and behavioral disruption are induced by the antidepressant fluoxetine in male zebrafish Danio rerio

The global prevalence of depression is high during childbearing. Due to the associated risks to the mother and baby, the selective serotonin reuptake inhibitor fluoxetine (FLX) is often the first line of treatment. Given that FLX readily crosses the placenta, a fetus may be susceptible to the disruptive effects of FLX during this highly plastic stage of development. Here, we demonstrate that a 6-day FLX exposure to a fetus-relevant concentration at a critical developmental stage suppresses cortisol levels in the adult zebrafish (F0). This effect persists for three consecutive generations in the unexposed descendants (F1 to F3) without diminution and is more pronounced in males. We also show that the in vivo cortisol response of the interrenal (fish “adrenal”) to an i.p. injection of adrenocorticotropic hormone was also reduced in the males from the F0 and F3 FLX lineages. Transcriptomic profiling of the whole kidney containing the interrenal cells revealed that early FLX exposure significantly modified numerous pathways closely associated with cortisol synthesis in the male adults from the F0 and F3 generations. We also show that the low cortisol levels are linked to significantly reduced exploratory behaviors in adult males from the F0 to F2 FLX lineages. This may be a cause for concern given the high prescription rates of FLX to pregnant women and the potential long-term negative impacts on humans exposed to these therapeutic drugs.

Cytology of the Pituitary Gonadotrophs, Histological Characteristics of Interrenal and Chromaffin Cells in Relation to Testicular Activities in Mystus Vittatus (Siluriformes, Bagridae) During Growth, Maturation and Spawning Phases

The histological changes observed in the pituitary corticotrophs, gonadotrophs, adrenocortical tissues and testicular cells in M. vittatus (Bloch, 1794) have been studies during growth, maturation and spawning phases. The studies based on the changes observed in the cell types, shape and size of the cells of the adrenocortical tissues, testes and the overall percentage of gonadotroph (GTH) and thyrotroph (TSH) cells of the pituitary. However, during growth phase, in proximal pars distalis (PPD) the considerable increment of GTH and TSH have been observed having intense aniline blue stain. The corticotrophs (ACTH) also showed significant accumulation of fuchsinophilic cytoplasmic granules. The cytoplasmic features and the architecture of the interrenal cells were well coincident with the increase of different spermatogenic cells. During the maturation phase dense granulation in the GTH and TSH cells appeared to be concomitant with the spermiation. The amount of cytoplasmic granules of the interrenal cells increased than chromaffin cells and was well coincidence with the increase of spermatids and spermatozoa. The hyperactive and vacuolated features of the interrenal cells during spawning phase appeared to be concomitant with the final process of spermiation.

Manipulation of Interrenal Cell Function in Developing Zebrafish Using Genetically Targeted Ablation and an Optogenetic Tool

Zebrafish offer an opportunity to study conserved mechanisms underlying the ontogeny and physiology of the hypothalamic-pituitary-adrenal/interrenal axis. As the final effector of the hypothalamic-pituitary-adrenal/interrenal axis, glucocorticoids exert both rapid and long-term regulatory functions. To elucidate their specific effects in zebrafish, transgenic approaches are necessary to complement pharmacological studies. Here, we report a robust approach to specifically manipulate endogenous concentrations of cortisol by targeting heterologous proteins to interrenal cells using a promoter element of the steroidogenic acute regulatory protein. To test this approach, we first used this regulatory region to generate a transgenic line expressing the bacterial nitroreductase protein, which allows conditional targeted ablation of interrenal cells. We demonstrate that this line can be used to specifically ablate interrenal cells, drastically reducing both basal and stress-induced cortisol concentrations. Next, we coupled this regulatory region to an optogenetic actuator, Beggiatoa photoactivated adenylyl cyclase, to increase endogenous cortisol concentrations in a blue light-dependent manner. Thus, our approach allows specific manipulations of steroidogenic interrenal cell activity for studying the effects of both hypo- and hypercortisolemia in zebrafish.