Theca of follicle
Encyclopedia
The theca folliculi comprise a layer of the ovarian follicle
s. They appear as the follicles become tertiary follicles.
The theca are divided into two layers, the theca interna
and the theca externa
.
The theca interna is responsible for the production of androstenedione
, and indirectly the production of 17β estradiol
, also called E2, by supplying the neighboring granulosa cells with androstenedione
that with the help of the enzyme aromatase
can be used as a substrate for this type of estradiol
.
Ovarian follicle
Ovarian follicles are the basic units of female reproductive biology, each of which is composed of roughly spherical aggregations of cells found in the ovary. They contain a single oocyte . These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single...
s. They appear as the follicles become tertiary follicles.
The theca are divided into two layers, the theca interna
Theca interna
Theca interna cells express receptors for luteinizing hormone to produce androstenedione, which via a few steps, gives the granulosa the precursor for estrogen manufacturing....
and the theca externa
Theca externa
The theca externa is the outer layers of the theca folliculi. They contain smooth muscle and abundant collagen. During ovulation, the surge in luteinizing hormone increases cAMP which increases progesterone and PGF2α production. The PGF2α induces the contraction of the smooth muscle cells of the...
.
The theca interna is responsible for the production of androstenedione
Androstenedione
Androstenedione is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol.-Synthesis:Androstenedione is the common precursor of male and female sex...
, and indirectly the production of 17β estradiol
Estradiol
Estradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...
, also called E2, by supplying the neighboring granulosa cells with androstenedione
Androstenedione
Androstenedione is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol.-Synthesis:Androstenedione is the common precursor of male and female sex...
that with the help of the enzyme aromatase
Aromatase
Aromatase is an enzyme responsible for a key step in the biosynthesis of estrogens. It is a member of the cytochrome P450 superfamily , which are monooxygenases that catalyze many reactions involved in steroidogenesis. In particular, aromatase is responsible for the aromatization of androgens into...
can be used as a substrate for this type of estradiol
Estradiol
Estradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...
.