Release of cyclic AMP and progesterone from the isolated perfused luteal ovary of the PMSG treated rat

Abstract

A model for in vitro perfusion of the isolated rat ovary was developed. In the luteinized ovaries of PMSG treated rats the relationship between perfusion flow and progesterone production was evaluated. A positive correlation was found indicating that a high blood flow rate may be necessary for an optimal secretion of progesterone from the fully developed corpus luteum in the rat. Also the effects of a continuous exposure of LH on ovarian cyclic AMP and progesterone release was studied. A rapid and sustained increase in both cyclic AMP and progesterone release was seen and this release tended to have episodic pattern with elevations occurring at intervals between 30 and 90 min following LH. Experiments in several species (rabbit, Janson & Albrecht 1975; guinea-pig, Hossainetal. 1979; rat, Pang & Behrman 1979) have indicated that the fully functional corpus luteum (CL) receives more than 80% of the total ovarian flow. Furthermore, these studies show that the CL is one of the most abundantly perfused tissues in the body. The lack of a significant number of arterio-venous shunts within the CL (Janson et al. 1983) indicates that the luteal flow is a capillary flow. The functional sig¬ nificance of its high magnitude still remains ob¬ scure. Since the main function of the CL is produc¬ tion of progesterone it may be speculated to which extent this production rate is dependent on a high luteal flow. Recent investigations in vivo in the rabbit strongly indicate a positive correlation be¬ tween the blood flow and progesterone production in the fully developed CL (Janson et al. 1981). In these experiments, the luteal blood flow was meas¬ ured indirectly with radioactive microspheres and was correlated to the release of progesterone into the ovarian vein.In the search for a simplified model for direct studies of the relationship between capillary flow and progesterone synthesis we have developed an in vitro perfusion model of the isolated rat ovary. The additional aim of the present study was to evaluate this perfusion model from a morphologi¬ cal and functional point of view. Material and MethodsAnimaL· Immature female rats of the Sprague-Dawley strain (Anticimex Ltd., Sweden) were housed under controlled conditions with 14 h light and 10 h dark and fed a standard diet of pellets and water ad libitum. In the morning of day 26 of life the rats were given a single dose of 8 to 10 IU pregnant mare serum gonadotrophin (PMSG, Sigma Co., USA) sc. This resulted in an endo¬ genous LH surge 2 days later and ovulation on the morning of the next day (for references, see Khan 1979). The mean weight of the unperfused ovary was 23 mg and the mean number of CL was 8. Perfusions were carried out 5 days after spontaneous ovulation. Surgical techniqueThe animals were anaesthetized with sodium pentobarbitone (Mebumal vet., ACO, Sweden), 40 mg/kg, ip. The abdomen was opened through a midline incision and the gut covering the lumbar aorta was cut free and put aside. Following ligation of the renal vessels on both sides, the kidneys were rem...

Histamine induces ovulation in the isolated perfused rat ovary

“…Albumin serves as a carrier protein for steroids and counteracts the formation of oedema and preserves the morphology in the ovary (Cajander et al, 1984). Since the oedema, the ovarian morphology, and the steroid release is the same for 2% and 4% BSA (Sogn et al, 1984) the present experiments were performed with the lower concentration of BSA.…”

“…The surgical technique for isolation of the ovaries was that described in detail by Koos, Jaccarino, Magarti & LeMaire (1984) and Sogn, Abrahamsson & Janson (1984).…”

Seven days ex vivo perfusion of whole ewe ovaries with follicular maturation and oocyte retrieval: towards the development of an alternative fertility preservation method

“…This study demonstrated successful harvesting of oocytes and to our knowledge, this is the longest ex vivo perfusion time (7 days) described to date for ewe ovaries. A number of studies have been performed on ovarian tissue perfusion from rodents (Koos et al 1984;Sogn et al 1984;Brännström et al 1987;Brännström and Flaherty 1995), rabbit (Lambertsen et al 1976;Hamada et al 1977Hamada et al , 1979Kobayashi et al 1981a), sheep (Wallin et al 2009;Milenkovic et al 2011b;Maffei et al 2016) and also from human tissue (Stähler et al 1974;Abrahamsson et al 1990;Milenkovic et al 2011a;McLaughlin et al 2018). However, a complete follicular development in vitro with subsequent oocyte maturation and live offspring has only been successful in rodent models (Eppig and Schroeder 1989;O'Brien et al 2003).…”

Cellular localization of ovarian histamine, its cyclic variations, and histaminergic effects on ovulation in the rat ovary perfused in vitro

“…After opening the ovarian bursa to expose the follicles, the ovary-vessel preparation was transferred to the perfusion apparatus. Further details of the surgical procedure have been described elsewhere (Koos et al, 1984;Sogn et al, 1984).…”