Search Results

You are looking at 1 - 4 of 4 items for

  • Author: M. J. Sauer x
  • All content x
Clear All Modify Search
Free access

M. J. Sauer

Introduction

The capacity of the conceptus to synthesize a variety of hormones has been established for many years (Klopper & Diczfalusy, 1969; Davies & Ryan, 1972; Fuchs & Klopper, 1977). It has been demonstrated that the embryo is able to influence maternal functions before and during the implantation or attachment period (De Feo, 1967; Heald, 1976; Perry, Heap, Burton & Gadsby, 1976) although the means by which it secures its continued existence and development at this time are only now becoming clear. The objective of this review is to discuss aspects of embryonic and uterine development during the pre- and peri-implantation period in relation to the hormonal exchanges believed to occur at this time. The main emphasis is placed on embryonic hormones, particularly steroids, in relation to the influence of hormones on preimplantation embryonic development, maternal recognition of pregnancy and hormonal involvement in the implantation process.

Free access

M. J. Sauer, J. A. Foulkes, A. Worsfold, and B. A. Morris

Summary. A simple direct-addition microtitre plate enzymeimmunoassay (EIA) for progesterone in whole milk is described. The assay used antiserum raised against 11α-hydroxyprogesterone 11-hemisuccinate (progesterone 11-hemisuccinate) and a heterologous label prepared by conjugation of 11α-hydroxyprogesterone 11-glucuronide (progesterone 11-glucuronide) with alkaline phosphatase using an active ester procedure. The sensitivity, analytical recovery, linearity of response and precision of the assay compared favourably with radioimmunoassay (RIA). Results from EIA of milk samples were compared with determinations made after isolation of progesterone by HPLC (r = 0·910). Milk samples (200) were assayed by RIA at both the Milk Marketing Board and the Cattle Breeding Centre and the results were correlated with EIA performed at the Cattle Breeding Centre (r = 0·890 and r = 0·833 respectively). Calving data were obtained from a further 110 cows for which the milk progesterone EIA had provided a pregnancy test 24 days after AI; 46 cows were correctly identified as non-pregnant and 58 as pregnant and there were 4 false positive and 2 inconclusive results.

Free access

G Rahimi, E Isachenko, H Sauer, M Wartenberg, V Isachenko, J Hescheler, P Mallmann, and F Nawroth

At present, the long-term culture of ovarian tissue is problematic. The aim of this study was to measure apoptosis in long-term cultures of human ovarian tissue. Biopsies of human ovaries were cultured for 6 weeks. Samples were taken weekly for histological investigation. The apoptotic cells were marked with anti-caspase 3. Simultaneous to this experiment, other tissue samples were preincubated for 3 h with 1 micromol staurosporine l(-1), an inducer of apoptosis, and apoptosis was compared among samples. Furthermore, the proportion of lethal cells was determined weekly. After 6 weeks, 99% of the tissue samples showed an intact structure. They expanded in all directions on the floor of the multi-wells to form a monolayer. Apoptotic cells could be marked only sporadically (16.3 +/- 5.9 fluorescence (counts per 3600 microm(2))) after 6 weeks. After preincubation with staurosporine after the same period of culture, the proportion of apoptotic cells was significantly increased compared with that in untreated control samples (66.8 +/- 14.5 versus 16.3 +/- 5.9%, respectively; P < 0.05). Under the same experimental conditions, the proportion of lethal cells was 3.6 +/- 0.9, 3.9 +/- 2.1 and 5.2 +/- 1.5% for weeks 1, 3 and 6, respectively. After preincubation with 1 micromol staurosporine l(-1), the proportion of pyknotic cells after 6 weeks of culture was significantly higher (37.2 +/- 4.4%) than that in control samples (3.95 +/- 2.05%; P < 0.05). No significant increase in apoptosis in cultured human ovarian tissue after 6 weeks was observed compared with control tissues on day 1. These results indicate that under optimal culture conditions it is possible to cultivate human ovarian tissue long term. The influence of long-term culture on hormone synthesis and follicle maturity will be investigated further.

Free access

J. K. Hodges, D. I. Green, P. G. Cottingham, M. J. Sauer, C. Edwards, and S. L. Lightman

Summary. Doses of 100 or 200 μg of a novel GnRH antagonist ([N-acetyl-dβNall-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 < 0·01). Thereafter, progesterone concentrations remained low or undetectable until after the next ovulation. Similar results were obtained when 200 μg antagonist were given on Days 5/6 of the luteal phase (N = 4). The interval from injection of antagonist (200 pg but not 100 μg 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 < 0·01). This delay of 4–5 days was equivalent to the duration for which LH concentrations were significantly suppressed by 200 μg 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.

Keywords: GnRH antagonist; monkey; corpus luteum