Here are the abstracts. The first sheds light on the possible mechanism of the second abstract.
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Nippon Yakurigaku Zasshi. 2002 Mar;119(3):167-74. Related Articles, Links
[Hair growth effect of minoxidil]
[Article in Japanese]
Otomo S.
Pharmacological Evaluation Laboratory, Taisho Pharmaceutical Co., Ltd., 403, Yoshino-cho 1-chome, Saitama-shi, Saitama 330-8530, Japan.
The length and size of hair are depend on the anagen term in it’s hair cycle. It has been reported that the some cell growth factors, such as VEGF, FGF-5S, IGF-1 and KGF, induce the proliferation of cells in the matrix, dermal papilla and dermal papillary vascular system and increase the amount of extra cellular matrix in dermal papilla and then maintain follicles in the anagen phase. On the other hand, negative factors, like FGF-5, thrombospondin, or still unknown ones, terminate the anagen phase. If the negative factors become dominant against cell proliferation factors according to fulfilling some time set by the biological clock for hair follicles, TGF beta induced in the matrix tissues evokes apoptosis of matrix cells and shifts the follicles from anagen to catagen. Androgenetic alopecia is caused by miniaturizing of hair follicles located in the frontal or crown part of scalp and are hereditarily more sensitive to androgen. In their hair cycles, the androgen shortens the anagen phase of follicles and shifts them to the catagen phase earlier than usual. The mode of action of hair growth effect of minoxidil is not completely elucidated, but the most plausible explanation proposed here is that minoxidil works as a sulfonylurea receptor (SUR) activator and prolongs the anagen phase of hair follicles in the following manner: minoxidil (1) induces cell growth factors such as VEGF, HGF, IGF-1 and potentiates HGF and IGF-1 actions by the activation of uncoupled SUR on the plasma membrane of dermal papilla cells, (2) inhibits of TGF beta induced apoptosis of hair matrix cells by opening the Kir 6.0 channel pore coupled with SUR on the mitochondrial inner membrane, and (3) dilates hair follicle arteries and increases blood flow in dermal papilla by opening the Kir 6.0 channel pore coupled with SUR on the plasma membrane of vascular smooth muscle cells.
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: J Am Acad Dermatol. 2003 Jun;48(6):962-5. Related Articles, Links
Pseudoacromegaly induced by the long-term use of minoxidil.
Nguyen KH, Marks JG Jr.
Department of Dermatology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA.
Acromegaly is an endocrine disorder caused by chronic excessive growth hormone secretion from the anterior pituitary gland. Significant disfiguring changes occur as a result of bone, cartilage, and soft tissue hypertrophy, including the thickening of the skin, coarsening of facial features, and cutis verticis gyrata. Pseudoacromegaly, on the other hand, is the presence of similar acromegaloid features in the absence of elevated growth hormone or insulin-like growth factor levels. We present a patient with pseudoacromegaly that resulted from the long-term use of minoxidil at an unusually high dose. This is the first case report of pseudoacromegaly as a side effect of minoxidil use.
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J Urol. 1991 Jul;146(1):50-3. Related Articles, Links Minoxidil versus nitroglycerin: a prospective double-blind controlled trial in transcutaneous erection facilitation for organic impotence.
Cavallini G.
Department of Urology, Hospital of Adria, Veneto, Italy.
A new type of topically applied drug (minoxidil) to facilitate erection is presented. Minoxidil acts directly on arterial smooth muscles via relaxation. This drug (1 ml. Of a 2% solution) was studied under strict laboratory conditions in a double-blind controlled trial on 33 patients (4 with neurogenic plus arterial, 10 with neurogenic and 19 with arterial impotence) and compared to placebo and nitroglycerin (2.5 gm. Of a 10% ointment). The application sites were the penile shaft (nitroglycerin) or glans penis (minoxidil and placebo). Increases in diameter and rigidity were measured with the RigiScan device and arterial flow was evaluated by conventional Doppler sonography. Side effects were considered as well. This drug proved to be more active than nitroglycerin and placebo in increasing diameter, rigidity and arterial flow of the penis. The highest activity proved to occur in neurogenically impotent patients. Fewer side effects also were found with minoxidil than with nitroglycerin. For these reasons minoxidil is proposed as a long-term therapeutic agent for organic impotence