Induction of luteal regression in the marmoset monkey (Callithrix jacchus) by a gonadotrophin-releasing hormone antagonist and the effects on subsequent follicular development

Abstract

Doses of 100 or 200 micrograms of a novel GnRH antagonist ([N-acetyl-D beta Na11-D-pCl-Phe2-D-Phe3-D-Arg6-Phe7-Arg8-D-Ala10]NH2 GnRH) (4 animals/dose) were administered on Days 10/11 of the luteal phase and induced a marked suppression of circulating bioactive LH and progesterone concentrations within 1 day of treatment (P less than 0.01). Thereafter, progesterone concentrations remained low or undetectable until after the next ovulation. Similar results were obtained when 200 micrograms antagonist were given on Days 5/6 of the luteal phase (N = 4). The interval from injection of antagonist (200 micrograms but not 100 micrograms) to ovulation (based on a rise in progesterone above 10 ng/ml) was significantly longer than that from prostaglandin-induced luteal regression to ovulation in control cycles (N = 4/treatment) (range, 13-15 days after antagonist vs 8-10 days after prostaglandin, P less than 0.01). This delay of 4-5 days was equivalent to the duration for which LH concentrations were significantly suppressed by 200 micrograms antagonist when administered to ovariectomized animals (N = 3). Corpus luteum function during the cycle after GnRH antagonist treatment appeared normal according to the pattern of circulating progesterone. These results show that corpus luteum function and preovulatory follicular development in the marmoset monkey are dependent on pituitary gonadotrophin secretion.

Development of a modified artificial insemination technique combining penile vibration stimulation and the swim-up method in the common marmoset

“…The ovarian cycles of the seven females were monitored by determining plasma PRG concentrations [17,18]. Briefly, a 0.2-mL aliquot of blood was collected from the femoral vein using a heparinized syringe every week for 10 weeks.…”

Multimodal Oestrus Advertisement in a Small Nocturnal Prosimian, Microcebus murinus

“…The plasma was prediluted (1:15) in progesterone buffer (2.42 g trishydroxymethylaminomethane + 23.3 g NaCl +1g BSA fraction V in 1l Aqua bidest, pH 7.5) and stored at -20°C until further analysis. Plasma progesterone concentrations were quantified by an enzyme immunoassay (previously described in [18,19]). Intraassay variance was <7% and interassay variance <10%.…”

Behavioral discrimination between circumgenital odor from peri-ovulatory dominant and anovulatory female common marmosets (Callithrix jacchus)

“…The blood withdrawal procedure included capture, sampling, delivery of a fruit drink and return to the home cage, and took no more than 5 minutes per animal. Concentrations of plasma progesterone were determined using an enzyme-linked immunoabsorbent technique, modified from a heterologous enzyme immunoassay [described by Sauer et al, 1986], and concentrations of bioactive LH were measured in an in vitro bioassay using testosterone production from mouse leydig cells [Abbott et al, 1988;Hodges et al, 1988]. Intra-assay coefficients of variation for low and high pools were 5.2 % and 4.7 %, respectively, and interassay coefficients of variation were 6.4% (low Q.C.)…”