Biomedical subjects

J K Hodges

Publications and source records attributed to J K Hodges.

At least 73 records · Page 4Linked to original sources

PubMed1987

Early implantation and embryonic development of the baboon: stages 5, 6 and 7.

Implantation stages of the olive baboon, Papio cynocephalus anubis, showing embryonic development equivalent to Carnegie stages 5, 6 and 7 of development, were collected by hysterotomy and examined histologically. The younger specimens (stage 5) consisted of a thick trophoblastic plate composed of cytotrophoblast and syncytiotrophoblast with multiple small clefts, and a bilaminar disk embryo with a small slit-like amniotic cavity. An epithelial plaque response was present in the uterine epithelium immediately peripheral to the implantation site, within an area of pronounced uterine edema. The bilaminar embryonic disk consisted of columnar epiblast cells underlying the amniotic cavity, and thickened visceral endodermal cells that form part of the yolk sac. The slightly further developed placenta (stage 6) consisted predominantly of cytotrophoblast including primary villi and syncytiotrophoblast lining large spaces containing maternal blood. Secondary placental villi were present in the oldest group (stage 7), and there was modest decidualization of the uterine stroma. An epithelial plaque response persisted, but varied in extent. The sequence of events in early development in the baboon is similar to that in the rhesus monkey insofar as blood space formation and endometrial responses are concerned. However, the plaque response is not so great as in the rhesus; there is no secondary placenta, and the decidual response is slightly more extensive.

Animals↗

PubMed1987

Controlled ovulation in the marmoset monkey (Callithrix jacchus) with human chorionic gonadotropin following prostaglandin-induced luteal regression.

Controlled induction of ovulation in the marmoset monkey was attempted with a single injection of human chorionic gonadotropin (hCG; 50 IU) given on day 7 after prostaglandin-induced luteal regression. Animals given hCG (n = 12) ovulated within a 2-day period (days 9 and 10 after prostaglandin) compared with a 4-day period (days 9 to 12) in the control group (n = 12). The mean interval to ovulation was similar in both groups. There was no difference in the timing of the preovulatory estradiol (E2) peak between groups, although E2 levels on the day of hCG injection were lower than in controls on the day of the onset of the luteinizing hormone surge. All animals given hCG ovulated and 11 of 12 became pregnant. Ten of 11 embryos recovered surgically from six of these animals were normal blastocysts; 5 of the remaining 6 animals carried pregnancies to term. The results are of practical importance for experiments involving follicular and oocyte maturation and the collection and transfer of embryos.

Animals↗

PubMed1987

Successful transfer of the embryos of Przewalski's horses (Equus przewalskii) and Grant's zebra (E. burchelli) to domestic mares (E. caballus).

Blastocysts were collected non-surgically from 2 Przewalski's horse and 2 Grant's zebra mares and transferred extra-specifically to domestic horse and donkey recipients. Nine Przewalski's horse embryos were transferred surgically, and 2 non-surgically, to domestic Welsh-type pony mares. After surgical transfer, 7 (77.8%) pregnancies were established and 4 foals were born. Twelve Grant's zebra embryos were transferred surgically to 5 pony and 7 domestic donkey recipients respectively and 1 non-surgically to a donkey; 3 (60%) zebra-in-horse pregnancies were established and 2 went to term. Only 2 (28.6%) zebra-in-donkey pregnancies were established but neither went to term, although one zebra foal was aborted alive at Day 292 but failed to survive. No pregnancies resulted from the non-surgical transfers. Measurement of chorionic gonadotrophin concentrations and parental-specific lymphocytotoxic antibodies in the serum of the recipient animals indicated a pronounced maternal immunological response to the extra-specific embryo, but this could not be correlated with success or failure of pregnancy. The results indicate that extra-specific embryo transfer may be a useful aid to breeding exotic equids in captivity.

Animals↗

PubMed1987

Modulation of plasminogen activation by glucocorticoid hormones in the rat granulosa cell.

Granulosa cells from immature rats primed with diethylstilbestrol (DES) showed a fivefold rise in the activity of secreted plasminogen activator (PA) in response to human FSH. The dose giving 50% of the maximum response (ED50) was 10 ng/ml. Glucocorticoid hormones significantly suppressed PA activity in both control cells and cells stimulated with FSH (ED50 = 50 nmol dexamethasone/l; 1 mumol corticosterone/l). Cortexolone (2.5 mumol/l) significantly ameliorated this suppression, indicating that the response to glucocorticoids is receptor-mediated. These data, together with the time delay required for glucocorticoids to take effect (5 h), suggest that glucocorticoids induce the production of a specific PA inhibitor in granulosa cells.

Animals↗

PubMed1986

Androgen modulation of follicle-stimulating hormone-induced granulosa cell steroidogenesis in the primate ovary.

The role of androgen in regulating FSH-induced steroidogenesis in primates was investigated in granulosa cell cultures from reproductively suppressed (acyclic) marmoset monkeys. Progesterone accumulation and induction of aromatase activity were measured during a 48-h culture of granulosa cells (isolated from 0.5-1.0 mm diameter follicles) in medium 199 containing human (h) FSH and/or various sex steroids. Steroidogenesis in control cultures was minimal, but the presence of hFSH (0.3-100 ng/ml) caused dose-dependent stimulation. Maximal responses (mean +/- SE) were observed with 30 ng/ml of hFSH (aromatase, 1.0 +/- 0.2 pmol estradiol/10(3) cells X 3 h; progesterone, 4.5 +/- 0.8 pmol/10(3) cells X 48 h) and were 100 times basal values. The presence of testosterone (10(-6)M) during the 48-h culture enhanced the responses to hFSH two- to six-fold over the range 0.3-3.0 ng hFSH/ml. In the presence of a submaximal stimulatory dose of hFSH (3 ng/ml), the effects of testosterone on granulosa cell steroidogenesis were dose-related. Maximum responses were obtained with doses of testosterone between 10(-8) and 10(-7)M. Similar dose-dependent effects were found with 5 alpha-dihydrotestosterone (a non-aromatizable androgen), but not with estradiol, suggesting specific androgen synergism with FSH. Maximal aromatase activity induced after in vitro treatment with hFSH approached that in granulosa cells freshly isolated from a preovulatory follicle of a cyclic animal. These results demonstrate steroid modulation in vitro of FSH-responsive function, similar to that observed in rodent granulosa cells. Therefore, androgen may play a local role in the regulation of FSH-stimulated granulosa cell function during follicular development in primates.

Androgens↗

PubMed1985

Cloprostenol-induced luteolysis in the marmoset monkey (Callithrix jacchus).

A single intramuscular injection of 0.5 micrograms cloprostenol was not luteolytic on Day 6 or 7 of the ovarian cycle (N = 3), but was luteolytic in some animals (3/5) on Day 8 and 9 and luteolytic in all 23 animals treated between Days 10 and 17 of the ovarian cycle, and in 7 animals treated between Days 19 and 43 of pregnancy. Luteal function was monitored by measurement of progesterone in peripheral blood using a simple and rapid non-extraction assay. There was a dramatic fall in peripheral blood progesterone to less than 10 ng/ml within 24 h of cloprostenol injection; progesterone remained at this low level until the day after post-treatment ovulation. The interval from cloprostenol injection to ovulation in animals treated between Days 8 and 17 was 10.7 +/- 0.3 days. A similar interval was found in pregnant animals. Embryos recovered from the uterus after cloprostenol treatment were morphologically normal (23/24).

Animals↗

PubMed1984

Reproductive status of adult daughters in family groups of common marmosets (Callithrix jacchus jacchus).

Urine samples were collected from 6 pubertal female common marmosets at approximately 3-day intervals over a period of 3-7 months. All 6 females were the eldest daughters in their family groups. 3 of these females were subsequently removed from their families and sampled in isolation for another 2-3 months. Levels of urinary pregnanediol-3 alpha-glucuronide were measured by radioimmunoassay in order to establish whether these females showed ovarian cyclicity. No cyclical fluctuations in the levels of pregnanediol were observed in the females housed with their families even though the females were of a reproductively mature age. Cyclicity was quickly established (within 18-22 days) when the females were removed from the family. These results are discussed in the light of similar recent investigations on callitrichid reproduction and the behavioural implications are considered.

Animals↗

PubMed1984

Pattern of excretion of urinary steroid metabolites during the ovarian cycle and pregnancy in the marmoset monkey.

Non-invasive methods for monitoring reproductive status based on the measurement of urinary steroid conjugates were examined. Levels of urinary oestrone-3-glucuronide, oestrone-3-sulphate, oestradiol glucuronide, oestradiol sulphate and pregnanediol-3 alpha-glucuronide were determined during the ovarian cycle and pregnancy. Sequential hydrolysis showed oestradiol conjugates to be more abundant than oestrone conjugates. The levels of sulphates and glucuronides were similar in the follicular phase whereas sulphates predominated during the luteal phase and pregnancy. Although levels of oestrone-3-sulphate were two- to fourfold lower than those of oestradiol sulphate, measured after hydrolysis, the profiles throughout the cycle and pregnancy were similar. Levels of oestrone-3-sulphate, measured by direct assay, were below 1 mumol/mmol creatinine during the follicular phase, rising 3-4 days after ovulation to reach maximum values (2-8 mumol/mmol creatinine) in the mid-luteal phase. There was no consistent increase before ovulation. Levels during pregnancy rose gradually until days 70-90, after which there was no further increase (gestation length = 144 days). The pattern of pregnanediol-3 alpha-glucuronide was similar to that of oestrone-3-sulphate during the ovarian cycle but levels did not increase during pregnancy. The patterns of excretion of oestrogen and progesterone metabolites were similar to the pattern of the circulating hormones during the ovarian cycle. Circulating and urinary hormone patterns were similar for oestrogens throughout pregnancy but pregnanediol-3 alpha-glucuronide did not reflect progesterone secretion beyond day 70 of gestation.

Animals↗

PubMed1984

Ovulation in the marmoset monkey: endocrinology, prediction and detection.

Circulating progesterone, oestrogens and LH were measured in female marmosets (Callithrix jacchus) over the periovulatory period. Progesterone concentrations increased in all animals within 1 day of the estimated day of ovulation, confirming the usefulness of this hormone for retrospective detection of ovulation. Oestradiol-17 beta and LH both showed a preovulatory rise, but due to the large quantity of plasma required (oestradiol: 0.2 ml) and the length of time taken for the assay (LH: 2-3 days), measurement of these hormones is not practical for the prediction of ovulation. There were no preovulatory changes in unconjugated oestrone, but a rise in total (i.e. conjugated plus unconjugated) oestrone was used to time the collection of recently ovulated oocytes. Levels of oestrone-3-sulphate showed an increase at least 1 day before the expected day of ovulation in four out of five animals. This preovulatory rise can be measured easily by a rapid direct assay, thereby providing a practical method for predicting ovulation in this species.

Animals↗

PubMed1983

Levels of circulating and urinary oestrogens during pregnancy in the marmoset monkey (Callithrix jacchus).

The levels of immunoreactive oestrone, oestradiol-17 beta and oestriol in plasma and urine were measured during early, mid- and late pregnancy in the marmoset monkey. In plasma, unconjugated oestrone remained less than 2% of total (conjugated plus unconjugated) oestrone throughout gestation, whereas unconjugated oestradiol-17 beta increased from 3% of the total value in early and mid-pregnancy to 35% in late pregnancy. The reversal in the unconjugated oestrone: oestradiol-17 beta concentration ratio from early (12:1) to late (0 . 15:1) pregnancy occurred despite the continuing predominance of oestrone in terms of total hormone. Total oestriol was measurable but in relatively low concentrations. Oestradiol conjugate was the predominant urinary oestrogen metabolite measured at each stage of pregnancy. The pattern of urinary oestrone and oestradiol-17 beta reflected plasma levels of total hormone, rather than unconjugated hormone, showing no further increase after mid-pregnancy. In contrast, oestriol increased throughout pregnancy and to a proportionately greater extent than oestrone or oestradiol-17 beta, but at lower absolute levels. High-pressure liquid chromatography of urine extract indicated the presence of considerable amounts of oestrogen immunoreactivity not accounted for by oestrone, oestradiol-17 beta and oestriol and with a retention time similar to that of 16 alpha-hydroxyoestrone. Gas chromatography and mass spectroscopy provided further evidence to suggest that 16 alpha-hydroxyoestrone is an abundant urinary oestrogen metabolite during pregnancy in the marmoset monkey.

Animals↗

PubMed1983

Blood concentrations of gonadotrophins, prolactin and gonadal steroids in males and in non-pregnant and pregnant female African elephants (Loxodonta africana).

No seasonal variation in any of the hormones measured was apparent in males or females. Testosterone levels in males increased around puberty (10-11 years) and remained significantly higher in adult than prepubertal males. This was not accompanied by any significant change in levels of LH, FSH or prolactin. In non-pregnant females there was no apparent difference in levels of LH, FSH or prolactin with age. There was a significant increase in progesterone around puberty (12 years) but there was considerable overlap in values between prepubertal and adult females. During pregnancy, progesterone levels were significantly higher than in non-pregnant females with maximum levels occurring at mid-pregnancy (9-12 months). However, there was considerable overlap in values between non-pregnancy and pregnancy. Concentrations of LH and FSH decreased significantly during mid-pregnancy while prolactin levels increased dramatically during pregnancy; after 7 months of gestation until term levels were always at least 8 ng/ml greater than in any non-pregnant female. It is suggested that this consistent increase in plasma/serum levels of prolactin can be used to diagnose pregnancy in the elephant.

Animals↗

PubMed1983

Circulating oestrogen concentrations during pregnancy in the African elephant (Loxodonta africana).

Oestrone, oestradiol-17 beta and oestriol were measured in plasma samples from non-pregnant and pregnant African elephants shot in the wild. Enzymic hydrolysis of plasma showed that approximately 90 and 96% of the total (i.e. conjugated plus unconjugated) concentrations of oestrone and oestradiol-17 beta, respectively were represented by conjugated hormones. Unconjugated oestrogens remained low (less than 50 pg ml) in all samples, with no distinction between non-pregnant and pregnant animals. Levels of total oestrone during pregnancy varied between 160 and 594 pg/ml but were not significantly different from non-pregnant values. Total oestradiol-17 beta concentrations were significantly elevated during pregnancy (P less than 0 X 01) and, despite considerable individual variation (193-1428 pg/ml), were consistently higher than non-pregnant values after 6 months of gestation. The elevated levels of oestradiol-17 beta resulted in a reversal of the total oestradiol-17 beta: oestrone concentration ratio at about 6 months of pregnancy. Concentrations of total oestriol did not exceed 103 pg/ml. An indirect method of measurement indicated that oestradiol-17 beta sulphate was probably the most abundant circulating oestrogen during pregnancy in the African elephant.

Animals↗

PubMed1983

Relationship between ovarian and placental steroid production during early pregnancy in the marmoset monkey (Callithrix jacchus).

Concentrations of progesterone, 17 alpha-hydroxyprogesterone, oestrone and oestradiol-17 beta in peripheral and utero-ovarian vein blood were measured during the first 60 days of pregnancy. The same hormones were also measured in peripheral blood samples from non-fertile cycles. Peripheral levels of 17 alpha-hydroxyprogesterone, oestrone and oestradiol increased gradually during early pregnancy whereas concentrations of progesterone declined. The patterns of secretion of progesterone, 17 alpha-hydroxyprogesterone and oestrone, but not oestradiol, were significantly different in fertile and non-fertile cycles by 15 days after ovulation. Comparison of hormone values in peripheral and utero-ovarian vein samples from ovaries with and without corpora lutea (Days 7, 9, 13, 21, 40 and 60 of pregnancy) showed that: (a) progesterone was secreted by the corpus luteum until at least Day 40 by which time there was also placental secretion; (2) although 17 alpha-hydroxyprogesterone was secreted by the corpus luteum, the relative contribution of luteal and placental secretion after Day 21 was not clear; (3) oestrone secretion by the corpus luteum was no longer detectable by Day 40, but placental oestrone secretion appeared to be present by this time; (4) the corpus luteum did not secrete significant amounts of oestradiol at any stage of early pregnancy, although there was evidence for placental secretion by Day 40. These results suggest that progesterone secretion by the corpus luteum of early pregnancy continues beyond the time when oestrogen secretion has declined. The corpus luteum to placental shift in the marmoset appears to occur at a later stage of pregnancy than it does in the macaque monkey and probably also in man.

17-alpha-Hydroxyprogesterone↗

PubMed1983

Sex steroids and their relationship to binding proteins in the serum of the marmoset monkey (Callithrix jacchus).

A sex hormone binding globulin (SHBG) similar to human SHBG was identified in marmoset serum based on its gel electrophoretic mobility, isoelectric point and steroid binding properties. Levels of serum SHBG were measured in immature and mature males, immature females and females during the luteal phase and pregnancy; serum progesterone, 5 alpha-dihydrotestosterone (5 alpha-DHT), testosterone, oestradiol-17 beta and oestrone were also measured. Mean (+/- S.E.M.) concentrations of SHBG in immature males (336 +/- 19 nmol/l) were higher (P less than 0.01) than those in mature males (251 +/- 13 nmol/l), whereas values in the groups of females were similar (359 +/- 12, 395 +/- 17, 397 +/- 39 nmol/l in immature, non-pregnant and pregnant females respectively). There was an inverse relationship between SHBG and the levels of testosterone (r = -0.67) and 5 alpha-DHT (r = -0.86) in males, but the correlation was significant (P less than 0.05) only for 5 alpha-DHT. There was no correlation between levels of SHBG and oestrogens in males or between levels of SHBG and any of the steroids measured in females. Equilibrium dialysis was used to assess the percentage of steroid in serum in the unbound form. Mean percentage values for unbound testosterone and 5 alpha-DHT were lower in immature males than in mature males (P less than 0.01) and negatively correlated with levels of SHBG (r = -0.78, testosterone; r = -0.56, 5 alpha-DHT).

Androgens↗

PubMed1981

Pregnancy monitoring in diverse primate species by estrogen and bioactive luteinizing hormone determinations in small volumes of urine.

Immunoreactive estrogen and luteinizing hormone/chorionic gonadotropin (LH/CG) bioactivity have been measured throughout pregnancy in diverse primate species with a sample methodological approach utilizing small volumes of urine collected randomly. Total immunoreactive estrogen levels and the relative abundance of component estrogens (estrone, estradiol and estriol) at various stages of gestation were compared in the human, orangutan, pygmy chimpanzee, Douc langur and capuchin. Measurement of urinary LH/CG bioactivity enables an earlier detection of pregnancy when compared to the nonhuman primate pregnancy test. The methods described provide a practical and non-stressful way to detect and monitor pregnancy in widely divergent primate species.

Animals↗

PubMed1981

Comparison of urinary oestrogen excretion in South American primates.

Changes in the excretion of immunoreactive oestrogens and biologically active LH were assessed from measurements on small samples of urine collected from a capuchin, a tamarin, a spider monkey and a squirrel monkey. The hormone profiles were used to time matings of the capuchin and spider monkey; conception and pregnancy ensued. Detailed analysis of one urine sample from each female by using partition chromatography and reverse-phase high-pressure liquid chromatography showed that oestrone was more abundant than oestradiol-17 beta and oestriol combined, but the relative contribution of individual oestrogens to the total oestrogen complement differed. In the sample from the capuchin, an immunoreactive oestrogen slightly less polar than oestradiol appeared to be the most abundant urinary oestrogen.

Animals↗

PubMed1980

Regulation of oestrogen-induced LH release in male and female marmoset monkeys (Callithrix jacchus).

The positive-feedback action of oestradiol-17 beta on LH release was studied in gonadectomized male and female and intact male marmoset monkeys. Positive feedback was observed in normal intact males in response to a single subcutaneous injection of 35 micrograms oestradiol benzoate. The sustained elevation in oestradiol-17 beta levels achieved by the injections resulted in a marked suppression of circulating testosterone concentrations. Subcutaneous injections (0.5 mg/injection) of testosterone or dihydrotestosterone to gonadectomized males and females immediately following and 8 h after oestradiol benzoate failed to inhibit positive feedback. Similar treatment with progesterone (1.0 mg/injection) tended to standardize both positive and negative components of the feedback response. In contrast, progesterone implants (achieving progesterone concentrations similar to those obtained with the injections), maintained during and for 8 days before the oestradiol benzoate treatment, effectively inhibited positive feedback. LH responses to the various treatments were similar in gonadectomized males and females. These data suggest a relative unimportance of testicular secretions in suppressing oestrogen-induced LH release in the adult marmoset and indicate similarities between the control of positive feedback in male and female primates.

Animals↗

PubMed1980

Monitoring the female reproductive cycle of great apes and other primate species by determination of oestrogen and LH in small volumes of urine.

A practical approach for monitoring the reproductive cycle of primates is described. Ovulation, implantation, gestation and post-partum amenorrhoea were identified from measurements of total immunoreactive oestrogen and LH bioactivity in incomplete daily urine samples collected from various species, including a gorilla, a chimpanzee and an orang-utan. Oestrogen values were determined by radioimmunoassay of hydrolysed urine using a non-specific oestriol antiserum and LH was assessed by measuring testosterone output from dispersed rat Leydig cells. Both hormone measurements were indexed by urinary creatinine levels to help adjust for differences in urine concentration and volume.

Animals↗