Biomedical subjects

T Singtripop

Publications and source records attributed to T Singtripop.

8 recordsLinked to original sources

PubMed2001

Decrease in the number of sperm associated with decreased blood testosterone levels in male rats treated with extracts from seven plants consumed by natives of northern Thailand.

Natives of northern Thailand believe that certain plants preserved in alcohol provide sexual elevation although there is no scientific proof. To ascertain whether those plants have any biological effects on reproductive activity, we administered the extracts from seven kinds of plants to male rats. Treatments with these extracts resulted in a decrease in the number of sperm associated with decreased serum testosterone levels and an elevation of serum prolactin levels. The circulating levels of follicle stimulating hormone were only slightly affected by all extracts, although some extracts significantly decreased the luteinizing hormone levels. Thus, the extracts may contain a biologically active substance such as phytoestrogen and lead to a hormonal imbalance.

Journal Article↗

PubMed1993

Suppression of spontaneous development of uterine adenomyosis by a Chinese herbal medicine, keishi-bukuryo-gan, in mice.

Keishi-bukuryo-gan (KBG) is a traditional Chinese herbal remedy and has been used for the treatment of gynecological disorders, such as hypermenorrhea, dysmenorrhea, and infertility. The effects of KBG on the development of uterine adenomyosis, which is characterized by an abnormal growth of glands and stroma into and beyond the smooth muscle layers of the uterus, were examined in an experimental animal model using the SHN strain of mice. Mice fed handmade chow containing relatively high doses of KBG (0.5% and 1%) showed a significantly lower incidence of adenomyosis and lower activity of thymidylate synthetase (TS) in the uteri than mice fed control handmade chow containing no KBG. The long-term exposure to KBG between 25 and 120 days of age hardly affected the estrous cycle, food intake and body weight. However, mice provided with chow containing a low dose of KBG (0.1%) showed no difference in the incidence of adenomyosis as compared with the controls. The inhibitory effects of the high doses of KBG were nullified by pituitary isografting, which has been proved to enhance the development of adenomyosis. The present mouse data support the view in humans that the oral administration of KBG is a useful tool for the treatment of uterine adenomyosis.

Animals↗

PubMed1992

Suppression of the development of uterine adenomyosis by danazol treatment in mice.

Inhibitory effects of danazol, an isoxazol derivative of synthetic steroid 17 alpha-ethinyl-testosterone, on the development of uterine adenomyosis, a pathological disorder of endometrial tissue defined as the presence of endometrial glands and stroma in the myometrium, were investigated in mice of SHN strain. Mice treated with 0.5 microgram danazol for 5 weeks during 4-9 weeks of age and killed at 21 weeks of age showed significantly lower incidence of the spontaneous development of adenomyosis than the age-matched intact control mice. The inhibitory effects of danazol were also evident in mice bearing pituitary isografts which were effective in inducing an early and a high incidence of adenomyosis. Furthermore, the treatment with danazol resulted in the decrease of serum levels of luteinizing hormone (LH) and prolactin (PRL) associated with hypofunction of ovaries and persistent diestrus. These results support the usefulness of danazol for the clinical treatment of gynecological disorders except for hypofunction of ovaries.

Animals↗

PubMed1992

Increase of DNA synthesis in uterine adenomyosis in mice with ectopic pituitary isograft.

Ectopic pituitary isografts (EPI) have been found to induce a high incidence of uterine adenomyosis in SHN mice. All the SHN mice given EPI in the right uterus at 40 days of age developed uterine adenomyosis, and more than 80% of mice showed the genesis of subserosal nodules, an advanced state of adenomyosis, 65 days after EPI. Activities of both thymidylate synthetase and thymidine kinase, i.e. DNA-synthesizing enzymes in de novo and salvage pathways of pyrimidine metabolism, respectively, were significantly increased in EPI-induced uterine adenomyosis to approximately 2-fold those in normal control uteri. Bromodeoxyuridine-immunoreactive cells were regarded as the cells in S phase, and the number in the endometrial epithelium and stroma in EPI-induced uterine adenomyosis was more than 1.5-fold that in normal control uteri. EPI may affect the genesis of uterine adenomyosis generally, but not locally, because there were no differences between the right uterus with EPI and the left without EPI in the incidence of adenomyosis, histology or DNA-synthesizing enzyme activities.

Animals↗

PubMed1991

Animal model of uterine adenomyosis: is prolactin a potent inducer of adenomyosis in mice?

Uterine adenomyosis is a benign lesion but a serious disease for women, because the symptoms are characterized by abnormal bleeding, pain, cramps, and sterility. Thus elucidation of the mechanisms involved in the development of the disease would contribute to improved management and treatment and prophylaxis of this lesion. A mouse model, in which ectopic pituitary isografting is associated with an increase in the plasma level of prolactin, is useful for a rapid and frequent induction of uterine adenomyosis and can be used to study the origin of this lesion.

Animals↗

PubMed1991

Development of uterine adenomyosis after treatment with dopamine antagonists in mice.

Development of uterine adenomyosis was studied in SHN mice treated with psychotherapeutic drugs, sulpiride and perphenazine, and gastroenteric drug, metoclopramide, which act as dopamine antagonists to increase prolactin release from the pituitary gland. Administration of these drugs twice daily for 40-70 or 40-90 days of age induced an elevation in serum level of prolactin. Furthermore, the treated mice showed a prolongation of metestrous plus diestrous phase and a high incidence of uterine adenomyosis compared with vehicle-treated control mice. These results indicate that hyperprolactinemia produced by continuous treatment with psychotherapeutic and gastroenteric drugs is responsible for the occurrence of irregular estrous cycles and the genesis of uterine adenomyosis in mice.

Animals↗

PubMedDate not supplied

Juvenile hormone-mediated termination of larval diapause in the bamboo borer, Omphisa fuscidentalis.

Larvae of the bamboo borer, Omphisa fuscidentalis are in diapause for more than nine months (Singtripop, T., Wanichaneewa, S., Tsuzuki, S., Sakurai, S. 1999. Larval growth and diapause in a tropical moth, Omphisa fuscidentalis Hampson. Zool. Sci. 16, 725-733). To examine the endocrine mechanisms underlying this larval diapause, we assayed the responsiveness of the diapausing larvae to 20-hydroxyecdysone (20E) and a juvenile hormone analogue (JHA: S-methoprene). 20E injection caused the larvae to halt movement, followed by deposition of a pupal cuticle. Topical application of JHA induced pupation in a dose-dependent manner. JHA also induced pupation of the larvae whose brains were removed before JHA application. In those larvae, the prothoracic glands became active and competent to respond to brain extracts within seven days after JHA treatment, and the hemolymph ecdysteroid concentration began to increase 12 days after JHA application. These results indicate that JHA stimulates the prothoracic glands of diapausing Omphisa larvae, terminating larval diapause, in contrast with previous findings that JH inhibits the brain-prothoracic gland axis and thus maintains the larval diapause. Current results therefore suggest a novel regulatory mechanism for larval diapause in this species.

Animals↗

PubMedDate not supplied

Age-related changes in gonadotropin, prolactin and growth hormone levels with reference to the development of uterine adenomyosis in female SHN mice.

The patterns of serum FSH, LH, PRL and GH levels in SHN mice were determined by radioimmunoassay between 1 and 12 months of age. In addition, the incidence of spontaneous development of uterine adenomyosis and mammary tumor was also studied for 12 months. Serum FSH level increased gradually with age while the level of LH was almost constant during the observation period. On the other hand, concentrations of PRL and GH significantly increased with age. The present data showed that the development of adenomyosis and mammary tumor rapidly increased after 6 and 9 months of age, respectively. Pituitary grafting at 30 days of age resulted in a high incidence of adenomyosis after 6 months of age. There were no significant differences in FSH and LH levels between mice with and without pituitary grafting. However, pituitary grafting resulted in the increase in PRL and GH levels compared with age-matched controls. These findings altogether suggest that the spontaneous development of adenomyosis in SHN mice may be related to the elevation in PRL and GH levels as a function of age.

Aging↗