Indomethacin inhibits ovarian PGE secretion and gonadotropin-induced ovulation in a reptile (Anolis carolinensis)

Effect of GnRH agonist (deslorelin) on reproductive activity in captive female veiled chameleons (Chamaeleo calyptratus)

Eighteen 5 months old veiled chameleon females (Chamaeleo calyptratus) were used in the study. Seven females received subcutaneous implants with gonadotropin-releasing hormone agonist (GnRH) deslorelin acetate whereas eleven females were used as control animals without any implants. Females were kept in five terraria, in groups of four females (in 3 terraria) and groups of three females (in 2 terraria), respectively. A minimum of one female with GnRH implants was present in each terrarium. They were kept under standard husbandry conditions. Females of both groups (females with GnRH and controls, respectively) were monitored for three years. No differences between females with GnRH implants and females without GnRH implants were observed with respect to the presence of large ovarian follicles, number of eggs/female, or number of clutches/female. GnRH implants did not prevent spontaneous reproductive activity in any of the 7 females with implants. Ovariectomy was performed in 8 females (4 females with GnRH implants and 4 control females). Ten females (3 females with GnRH implants and 7 control females) had to be euthanised. In 17 of 18 female veiled chameleons of this study histologic examination revealed heterophilic granulomatous oophoritis. The use of GnRH agonist implants did not prove to be an appropriate method for the control of reproductive function in captive female veiled chameleons.

Modulators of Bufo arenarum ovulation

In this study we investigated ovulation in vitro using ovary samples from Bufo arenarum with respect to their response to stimulation with homologous pituitary homogenate (HPH) or with progesterone and prostaglandins (PGF2α and PGE1) as intermediates of pituitary action. Ovary samples were obtained from animals captured during the breeding period. Our results demonstrate that the ovulatory response to all different inducers was dose dependent, the highest percentage of ovulated oocytes being obtained with HPH treatment. An important increase in the ovulatory response was obtained by the association of PGF2α with either HPH or progesterone at suboptimal doses, indicating that this prostaglandin induced a synergistic potentiating effect. Incubation with cyclooxygenase inhibitors (indomethacin or diclofenac sodium) produced a significant decrease in the ovulation induced by HPH, demonstrating that prostaglandins are involved in the action of the pituitary gland in this process. According to our results, PGE1 not only had no participation in the ovulatory process, but also produced an inhibitory effect on ovulation induced by HPH treatment.

Uterine motility in the reptileAnolis carolinensis: interactive effects of tension, prostaglandins, calcium, and vasotocin

Uteri of Anolis carolinensis exhibited spontaneous rhythmic contractions in vitro. Addition of arginine vasotocin (AVT) caused an immediate, strong, tonic contraction followed by rhythmic contractions with the same frequency as spontaneous contractions but of a greater amplitude. At low tension (1.5 g) the AVT-induced tonic contraction was blocked by low dose of indomethacin, suggesting that it is influenced by calcium rather than prostaglandins (PGs). An increase in tension (from 1.5 to 15 g) reduced the duration of the AVT-induced tonic contraction; this stretch-induced decrease was also blocked by indomethacin. Stretch also decreased the duration of the rhythmic contractions, but this stretch effect was not inhibited by indomethacin. The rest interval between rhythmic contractions was decreased by PGF2alpha and PGE2, and indomethacin or stretch blocked these PG effects. Indomethacin, AVT, or stretch alone did not affect PGF2alpha secretion from AVT-treated uteri. Stretch also reduced PGF2alpha secretion from AVT-treated uteri, an effect inhibited by indomethacin.

Immunohistochemical localization of PGF2 alpha receptor in the rat ovary

As a step towards understanding the role of prostaglandin F2 alpha (PGF2 alpha) in ovarian function, a rabbit antiserum against purified PGF2 alpha receptor (PGF2 alpha-R) was produced. This report details the use of this antiserum in immunohistochemical staining of ovaries of non-pregnant and pregnant rats to ascertain which cell types, in vivo, possess PGF2 alpha-R. In non-pregnant rats, three ovarian cell subpopulations contain immunoreactive PGF2 alpha-R. These include: a subpopulation of the cells found in corpora lutea, a subpopulation of the thecal cells surrounding secondary and mature (Graafian) follicles, and a subpopulation of primary and secondary interstitial cells. The ovarian tissues and cell types in which immunoreactive PGF2 alpha-R cannot be demonstrated include: the serosa overlying the ovary and its vessels, the coelomic epithelium and its underlying cortical stroma, medullary stroma and vessels, granulosa cells of primary, secondary and mature follicles, the oocyte, and the blood vessels and stroma within corpora lutea. PGF2 alpha-R immunohistochemical staining of corpora lutea from non-pregnant animals was examined both prior to the start of luteolysis and during luteolysis. During luteolysis, cells undergoing apoptosis stained for the presence of PGF2 alpha-R. PGF2 alpha-R immunohistochemical staining was also examined in corpora lutea during pregnancy and until 4 days postpartum. The major findings here were the apparent large increase in staining intensity of granulosa-lutein cells during pregnancy, and the loss of PGF2 alpha-R immunopositivity of the granulosa-lutein cells during the postpartum period. In summary, three ovarian cell subpopulations, all of which can secrete steroids, possess immunoreactive PGF2 alpha-R.