As embryonic development proceeds, numerous organs need to coil, bend or fold in order to establish their final shape. Generally, this occurs so as to maximise the surface area for absorption or secretory functions (e.g., in the small and large intestines, kidney or epididymis); however, mechanisms of bending and shaping also occur in other structures, notably the midbrain–hindbrain boundary in some teleost fish models such as zebrafish. In this review, we will examine known genetic and molecular factors that operate to pattern complex, coiled structures, with a primary focus on the epididymis as an excellent model organ to examine coiling. We will also discuss genetic mechanisms involving coiling in the seminiferous tubules and intestine to establish the final form and function of these coiled structures in the mature organism.

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Crucial Convolution: Genetic and Molecular Mechanisms of Coiling during Epididymis Formation and Development in Embryogenesis

Effects of testosterone on skin structure and factors related to androgen conversion and binding in Hetian sheep

Progress in research on the reproductive function in the sand rat (Psammomys obesus): A review.

The article focuses on the data from Russian and foreign literature on the morphofunctional characteristics of the appendage of the testis in humans and mammalian animals. In the appendage of the testis, the head, body and tail are isolated. The head is formed by the efferent ductules, then they pass into the duct of the appendage forming the body and tail of the appendage. The epithelial cell classification in the appendage is debatable, which is due to both different methodological approaches and species differences in the epithelial lining of the testis appendage in different species. Species differences in the morphofunctional organization of the epithelium of the appendage of the testis are insignificant, this manifests the principle of parallelism in the evolutionary dynamics of the appendage epithelium. The appendage of the testis is a hormone-dependent organ, androgens play a leading role in regulating the development and functioning of the appendage; in addition, estrogens and prolactin take a significant part in regulating the appendage activity. Morphological equivalents of the negative influence of various damaging factors are basically similar, which evidences the presence of a nonspecific mechanism of reaction to the action of adverse factors formed during evolution. Despite a significant number of studies related to the morphology of the testis appendage, many aspects of morphofunctional, molecular and biochemical transformations occurring in the testis appendage still remain poorly understood and require further in-depth study. There are also insufficient number of comparative studies, and studies investigating the appendage of the testis of animals of natural biocenosis.

Khammar Farida

Papers

Androgen and estrogen receptors immunolocalization in the sand rat (Psammomys Obesus) cauda epididymis