Mention the difference between male germ cells and sertoli cells?
Answers
Answer:
germ cells and sertoli cells?
Explanation:
SERTOLI CELLS ARE REQUIRED FOR GERM CELL
DEVELOPMENT
The descriptive morphology has been informative, and
these morphological data coupled with some endocrine
physiology have led to an important and apparently simple
axiom; i.e., spermatogenesis in higher vertebrates is dependent on the functions of Sertoli cells. The concept of a
basic requirement for Sertoli cells is most strongly supported by two important sets of experimental findings. First,
the endocrine regulation of spermatogenesis is a result of
hormone action on Sertoli cells (for a review see [14]). Second, the function and efficiency of Sertoli cells appear to
be limiting to germ cell numbers. Evidence for and challenges to these findings are discussed below.
Our current understanding of the primary endocrine
regulation of spermatogenesis is outlined in Figure 1. Few
investigators would question the roles of FSH and testosterone as the primary regulators of spermatogenesis. There
is still considerable discussion about the relative importance of FSH in the fully adult male nonseasonal breeding
rodent [15]. In some of these rodent species, the role of
FSH in the prepubertal animal appears to be transferred to
testosterone in the adult. The fundamental notions that FSH
is rk of
a need for an androgen receptor in germ cells. Second, the
common vole lacks the X-chromosome in all spermatogonia or advanced germ cells. It follows that spermatogenesis
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critical biological importance must deal with the contrary
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studies on three interesting animal models in which the
size of the testis and the spermatogenic output was manipulated by changing the number of Sertoli cells. First, Orth
et al. [27] inhibited the proliferation of Sertoli cells during
testicular development and produced rats with smaller testes.
Second, propylthiouracil was used to inhibit thyroid hormone action during development, and this treatment resulted in rats with larger than normal testes [28]. Third,
hemicastration of developing boars at the appropriate age
resulted in increased proliferation of Sertoli cells and larger
than normal testes [29]. In all three of these animal models,
the ratio of spermatids to Sertoli cells remained relatively
constant. The obvious conclusion is that the number of germ
cells appears to be directly related to the number of Sertoli
cells and probably to their synthetic capability.
THE FUNCTION OF SERTOLI CELLS
What do Sertoli cells do that makes them necessary for
germ cell development in higher vertebrates? What is their
role in spermatogenesis? It appears that during development Sertoli cells play a role in the formation of the testis
[30]. This developmental role is currently under investigation and probably involves the expression of a number of
The general experimental approach to identify these
specific products made by Sertoli cells has been to isolate
and characterize the products present in cultured Sertoli
cells or in the spent medium of cultured Sertoli cells. More
recently, the availability of numerous antisera and cDNA
probes has allowed for quick screens of histological sections using immunohistochemistry and/or in situ hybridization. Additional factors continue to be added to the catalog of potentially important products of Sertoli cells, but
information about the identity of these products has not
often provided insight into their biological functions. There
has also been a tendency to extrapolate results from the
tt Adluminal Compartment
and proteases and protease inhibitors. Secretion may occur specifically to
the adluminal or basal compartment or to both. The type, amount, and
direction of secretion may be influenced by stage of testicular development, endocrine status of animal, and stage of cycle of seminiferous epithelium.
culture system directly to a Sertoli cell function without
testing the extrapolation in vivo. The concept that Sertoli
cells metabolize glucose to lactate and pyruvate as a form
of pre-digestion for the eventual use by germ cells arose
because of the capability of cultured Sertoli cells to produce lactate and the inefficient use of glucose by cultured
germ cells [33-38]. However, many types of cells in culture
produce lactate, some produce more than do Sertoli cells,
and direct proof of this potentially important physiological
event is lacking and experimentally difficult to obtain [39].
Sertoli cells dedicate a reasonably large percentage of
their protein synthesis to the synthesis and secretion of glycoproteins [40]. The glycoproteins secreted by the Sertoli
cells can be placed in several categories according to their
known biochemical properties (Fig. 2). The first category