We have known for over 30 years that minoxidil stimulates hair growth, yet our understanding of its mechanism of action on the hair follicle is very limited. In animal studies, topical minoxidil shortens telogen, causing premature entry of resting hair follicles into anagen, and it probably has a similar action in humans. Minoxidil may also cause prolongation of anagen and increases hair follic...

Although hormonal regulation of ovarian follicle development has been extensively investigated, most studies concentrate on the development of early antral follicles to the preovulatory stage, leading to the successful use of exogenous FSH for infertility treatment. Accumulating data indicate that preantral follicles are under stringent regulation by FSH and local intraovarian factors, thus pro...

Adult rat pelage follicle dermal papilla cells induced follicle neogenesis and external hair growth when associated with adult footpad skin epidermis. They thus demonstrated a capacity to completely change the structural arrangement and gene expression of adult epidermis--an ability previously undocumented for cultured adult cells. Isolation chambers ensured that de novo follicle formation must...

The hair follicle produces a terminally differentiated keratinized end product, the hair shaft, that is eventually shed. The follicle undergoes cyclical regeneration with at least 10 different epithelial and mesenchymal cell lineages. Hair is formed by rapidly proliferating matrix keratinocytes in the bulb located at the base of the growing (anagen) follicle. The duration of anagen varies great...

This study evaluated the consistency of manual and automated measurements of monodominant follicle diameter with different follicle size in infertile patients. Transvaginal two-dimensional (2D) ultrasound and SonoAVC (Sonography-based Automated Volume Calculation) were both performed in 226 infertile patients with monodominant follicle growth. 2D diameters were separately compared with SonoAVC-...

Two critical processes in ovarian biology are the assembly of the primordial follicles early in development and then the subsequent development and transition of the primordial follicle to the primary follicle. These processes directly effect the number of oocytes available to a female throughout her reproductive life. Once the pool of primordial follicles is depleted a series of physiological ...

In vitro ovarian follicle culture provides a tool to investigate folliculogenesis, and may one day provide women with fertility-preservation options. The application of tissue engineering principles to ovarian follicle maturation may enable the creation of controllable microenvironments that will coordinate the growth of the multiple cellular compartments within the follicle. Three-dimensional ...

The pesticide methoxychlor (MXC) is a reproductive toxicant that targets antral follicles of the mammalian ovary. Cytochrome P450 enzymes metabolize MXC to mono-OH MXC (1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane [mono-OH]) and bis-OH MXC (1,1,1-trichloro-2,2-bis(4-hydroxyphenyl)ethane [HPTE]), two compounds that are proposed to be more toxic than the parent compound, can inte...

Whatever the stage of the cycle, follicles of various sizes are apparent on the surface of the ovary of sheep. No evidence of waves of follicular growth at fixed-time intervals has been found during the luteal phase, and growth probably occurs at random until the follicle attains a size of 4 to 7 mm. This shows that follicles can enlarge under a wide range of hormonal levels. The recruitment of...

Activins have been implicated as important regulating factors for many reproductive processes. The aim of this study was to determine the effect of activin A on the development of ovine preantral follicles in vitro. Mechanically isolated preantral follicles (161 +/- 2 microm) were cultured for 6 days in the presence of human recombinant activin A (0, 10 and 100 ng/ml). Half of the medium was re...