Female mammals are born with a lifetime's supply of oocytes individually enveloped in flattened epithelial cells to form primordial follicles. It is not clear how sufficient primordial follicles are maintained to sustain the reproductive lifespan, while providing an adequate supply of mature oocytes for ovulation. Locally produced growth factors are thought to be critical regulators of early fo...

BACKGROUND Human hair follicles are important for the renewal of new hairs and their development. The generation of induced pluripotent stem cells (iPSCs) from hair follicles is easy due to its accessibility and availability. The pluripotent cells derived from hair follicles not only have a higher tendency to re-differentiate into hair follicles, but are also more suited for growth in hair scal...

BACKGROUND Although both thyroid histology and serum concentrations of hormones are known to change with age, only a few reports exist on the relationship between the age-related structural and functional changes of the thyroid follicles in both mice and humans. Our objectives were to investigate age-related histological changes of the thyroid follicles and to determine whether these morphologi...

BACKGROUND In vitro follicle growth is a promising fertility preservation strategy in which ovarian follicles are cultured to produce mature and fertilization-competent oocytes. However, in primates, there has been limited success with in vitro follicle growth starting from primordial and primary follicles because adequate isolation methods and culture strategies have not been established. Unde...

Introduction: Genital system is important herd in animal's creation. It is necessary for animal reproduction. Mammal has two sex in genital system such as male and female in separated animals. Animal reproduction destroyed by disorder of genital system. In this case, animals cannot produce an animal similar to them. Finally it cause overthrow a species of animals. Methods: Histomorpholog...

Several lines of evidence indicate that retinoids, derivates of vitamin A, affect reproductive function in birds, however, the mechanism of their action in the ovary is still unknown. Therefore, the present study was designed (i) to show whether in the domestic hen 9-cis retinoic acid (9-cis RA), one of the retinoids, influences steroid secretion in vitro by white and yellow chicken ovarian fol...

The Fas antigen (Fas) is a cell surface receptor that may be involved in the initiation and progression of follicle cell apoptosis during atresia. Fas initiates apoptosis in sensitive cells after binding Fas ligand (FasL). Other experiments have shown that expression of Fas mRNA and responsiveness to Fas-mediated apoptosis vary in bovine granulosa and theca cells during follicle development. In...

This study was conducted to improve the yield of mature oocytes from in vitro-culture of ovarian primary follicles by optimizing follicle retrieval from neonatal mice of different ages. Primary follicles of 75 to 99 μm in diameter were collected daily from 7- to 14-day-old neonatal mice, and subsequently cultured in α-MEM medium. Number of primary follicles isolated, growth of the follicle duri...

This study aimed to determine the in vivo effect of silver nanoparticles (AgNPs) on concentration sex steroids (progesterone – P4, estradiol E2, testosterone T) and thyroid hormones (thyroxine T 4 , triiodothyronine 3 ) blood plasma as well messenger ribonucleic acid (mRNA) protein expression HSD3β, CYP17A1 CYP19A1 enzymes steroid hormone concentrations chicken ovarian follicles. AgNPs did not ...

Follicular growth is described as a continuum. It goes on at all times, at all ages, uninterrupted by pregnancy or other periods of non-ovulation. A distinction is made between the continuum at the beginning of follicular growth and events concerning the cyclicity at the end of follicular growth, i.e. ovulation. Follicles grow sequentially. Also large follicles continue to grow until they becom...