354
UNIT 3
Organ Systems
D. Cui
Interstitial (Leydig) cell
Interstitial (Leydig) cell
Interstitial (Leydig) cell
Hypothalamus
Inhibin (–)
Activin (+)
FSH (+)
)
(gonadotrophs
LH (+)
()
gonadotrophs
(–)
(–)
GnRH (+) LH
GnRH (+) FSH
Pituitary gland
Increases
concentration
of testosterone
Inhibin & activin
hormones
ABP
Sertoli cell
Sertoli cell
Sertoli cell
Sertoli cell
Sertoli cell
Sertoli cell
(+)
Inhibits female organ
development
Anti-Müllerian
hormone
Promotes
spermatogenesis
Supports development of
male sex organs and
maintains male sexual
characteristics;
promotes spermatogenesis
(+)
Testosterone
Figure 18-8.
Hormone regulation involving the testicular cells (interstitial cells of Leydig and Sertoli cells).
H&E,
3
1,005
The preoptic nucleus in the hypothalamus secretes
gonadotropin-releasing hormone (GnRH)
, which stimulates the pituitary gland
to produce and release
luteinizing hormone (LH)
and
FSH
. Secretion of
testosterone
by the
interstitial cells of Leydig
is stimulated
by the
LH
produced by the
gonadotrophs
in the
adenohypophysis
of the pituitary gland. An excessive level of
testosterone
sends
negative feedback to the hypothalamus to inhibit production of
GnRH
, resulting in decreased secretion of LH in the pituitary gland.
Sertoli cells
that release
ABP
are stimulated by
FSH
, which stimulates production of the
ABP
. Sertoli cells also secrete
anti-Müllerian
hormone
as well as
inhibin
and
activin hormones
. The
inhibin hormone
suppresses and
activin hormone
stimulates the production
of GnRH, which infl uences FSH production by the gonadotrophs in the adenohypophysis of the pituitary gland.
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