Inhibition of CYP21A2 enzyme activity caused by novel missense mutations identified in Brazilian and Scandinavian patients

BACKGROUND

Most patients with 21-hydroxylase deficiency carry CYP21A1P-derived mutations, but an increasing number of novel and rare mutations have been reported in disease-causing alleles.

OBJECTIVE

Functional effects of three novel (p.G56R, p.L107R, p.L142P) and one recurrent (p.R408C) CYP21A2 mutations were investigated. The degree of enzyme impairment caused by p.H62L alone or combined to p.P453S was also analyzed.

DESIGN

The study included 10 Brazilian and two Scandinavian patients. To determine the deleterious role of each mutant protein, in vitro assays were performed in transiently transfected COS-1 cells. For a correct genotype-phenotype correlation, the enzymatic activities were evaluated toward the two natural substrates, 17-hydroxyprogesterone and progesterone.

RESULTS

Low levels of residual activities obtained for p.G56R, p.L107R, p.L142P, and p.R408C mutants classified them as classical congenital adrenal hyperplasia mutations, whereas the p.H62L showed an activity within the range of nonclassical mutations. Apparent kinetic constants for p.H62L confirmed the nonclassical classification as the substrate binding capacity was within the same magnitude for mutant and normal enzymes. A synergistic effect was observed for the allele bearing the p.H62L+p.P453S combination because it caused a significant reduction in the enzymatic activity.

CONCLUSIONS

We describe the functional analysis of five rare missense mutations identified in Brazilian and Scandinavian patients. The p.G56R, p.L107R, and p.L142P are reported for the first time. Most probably these novel mutations are closer to null than the p.I172N, but for the p.G56R, that might not be the case, and the p.H62L is definitely a nonclassical mutation.

Molecular and biochemical screening for the diagnosis and management of medullary thyroid carcinoma in multiple endocrine neoplasia type 2A

Patients with Multiple Endocrine Neoplasia (MEN) type 2A are at risk for early medullary thyroid carcinoma (MTC). We performed different screening tests for MTC--a recently reported biochemical screening test using omeprazole-induced calcitonin (CT) stimulation and DNA analysis--in fifteen members of two non-consanguineous Brazilian families with MEN 2A. RET proto-oncogene analysis was carried out by direct DNA sequencing of PCR-amplified products for exons 10 and 11. Family 1 showed a germline mutation (C634Y) in three individuals; a sister and a brother with symptomatic MTC; the former also presented with pheochromocytoma and hyperparathyroidism, and her son was a nine-year-old boy of previously unknown status. Family 2 showed the C634R mutation only in the index case, who presented with cutaneous lichen amyloidosis in addition to MTC, pheochromocytoma and hyperparathyroidism. Neither her parents nor her four brothers showed this genetic abnormality, suggesting a de novo RET proto-oncogene mutation in this patient. The controls and patients presented normal basal gastrin levels and a significant increase after omeprazole. Basal CT levels were elevated in patients with MTC and undetectable in control and asymptomatic family members. No subject showed any increase in CT levels after omeprazole treatment. In conclusion, the two most frequent RET proto-oncogene mutations in MEN 2A are present in Brazilian families. In addition, the specificity of basal and omeprazole-stimulated calcitonin is rather limited, and the efficacy of the omeprazole test still needs to be systematically examined. Therefore, RET proto-oncogene analysis must be the first choice for a screening procedure to identify gene carriers in MEN 2A family members and to permit early prophylactic treatment of MTC.

H28+C insertion in the CYP21 gene: a novel frameshift mutation in a Brazilian patient with the classical form of 21-hydroxylase deficiency

In the classical form of 21-hydroxylase deficiency, CYP21- affected genes either carry mutations present in the CYP21P pseudogene (microconversions) or bear a chimeric gene that replaces the active gene as a result of large conversion or deletion mutational events. Previous genotyping of 41 Brazilian patients revealed 64% microconversion, whereas deletions and large gene conversions accounted for up to 21% of the molecular defect. The present paper describes a new mutation disclosed by sequencing an entire gene in which no pseudogene-originated mutation had been found. The patient with the classical form of 21-hydroxylase deficiency is the daughter of a consanguineous marriage, and she is homozygous for a novel frameshift H28+C within exon 1. The mutation causes a stop codon at amino acid 78. Both parents are heterozygous for the mutation as confirmed by allele-specific oligonucleotide PCR. The H28+C is not present in the published CYP21P sequences and is likely to result in an enzyme with no activity.

Chromosome segregation

The ability to visualise specific genes and proteins within bacterial cells is revolutionising knowledge of chromosome segregation. The essential elements appear to be the driving force behind DNA replication, which occurs at fixed cellular positions, the condensation of newly replicated DNA by a chromosome condensation machine located at the cell 1/4 and 3/4 positions, and molecular machines that act at midcell to allow chromosome separation after replication and movement of the sister chromosomes away from the division septum prior to cell division. This review attempts to provide a perspective on current views of the bacterial chromosome segregation mechanism and how it relates to other cellular processes.

The concentration of progesterone, 20 alpha-dihydroprogesterone, testosterone, oestrone and oestradiol-17 beta in serum, amniotic fluid and placental tissue of pregnant rabbits

The concentrations of progesterone (delta 4P), 20 alpha-dihydroprogesterone (20 alpha-DHP), testosterone (T), oestrone (E1) and oestradiol-17 beta (E2 beta) in peripheral blood serum (PBS), amniotic fluid (AF) and placental tissue of rabbits during gestation were determined by radioimmunoassay. The placenta of the 10-day pregnant rabbit was fragile and composed mainly of maternal tissue. By the 12th day of pregnancy it was separable into maternal and foetal placentae. The mean concentration of delta 4P in PBS rose from 200 pg/ml (day 1 pregnancy) to 17--21 ng/ml (days 10--15) and decreased gradually to 1 ng/ml a few hours before parturition. The 20 alpha-DHP in PBS also showed an increase from 1.5 ng/mg (day 1) to 12 ng/ml (day 6) but fluctuated thereafter. The concentration of 20 alpha-DHP in the PBS tended to be lower than that of delta 4 P during pregnancy until the regression of the corpus luteum. An interesting observation was an increase of T on days 6--8 of pregnancy, the time when implantation occurs. The concentrations of E1 and E2 beta in PBS remained very low throughout pregnancy. delta 4P and 20 alpha-DHP in AF ranged between 25 pg to 1 ng/ml and in no case during the course of pregnancy were the levels of T, E1 and E2 beta in AF higher than in PBS. Where the maternal placental delta 4P content remained between 1--2 ng/placenta, the foetal placenta delta 4P rose to a level of 15 ng/placenta by day 31 of pregnancy. A similar trend was recorded for 20 alpha-DHP content. It is concluded that although a parallelism between PBS and myometrial steroid concentration was observed, no relationship could be drawn between the concentrations of steroid in PBS and those of the placental tissue and AF.

The pituitary-ovarian complex in the aged anoestrous golden hamster

Plasma and pituitary hormones of young (3--5 months of age) dioestrous hamsters with normal cycles and aged (13--17 months of age) anoestrous hamsters were compared. The anoestrous hamsters exhibited lower plasma values of progesterone (P less than 0.001), oestradiol-17 beta (P less than 0.005) and prolactin (P less than 0.001) and higher levels of plasma gonadotrophins (P less than 0.001) than did the dioestrous animals. Pituitary concentrations of LH were higher (P less than 0.005) in anoestrous hamsters, but pituitary FSH and prolactin values did not differ. In another series of experiments three groups of hamsters (3--5- and 13--17-month-old with normal cycles and 13--17-month-old in anoestrus) were ovariectomized. Blood samples were taken by cardiac puncture every 3--4 weeks after receiving s.c. injections of oestradiol-17 beta (1 or 10 micrograms/100 g body wt) for 2 or 9 consecutive days. The markedly lower levels of gonadotrophins in aged anoestrous hamsters indicated that the hypothalamic-hypophysial complex was incapable of responding to the same degree as it did in young and aged cyclic animals. Prolactin values were similarly depressed in all 3 groups. Oestradiol-17 beta treatment caused reduced gonadotrophin and increasing prolactin concentrations in all 3 groups. These results indicate that the ovaries of the senescent anoestrous hamster produce less steroids and suggest that age-related changes in the hypothalamic-hypophysial complex are largely responsible for the cessation of regular oestrous cycles.

Effects of 17 beta-hydroxy-7 alpha-methylandrost-5-en-3-one on early pregnancy in the rat

A single sc injection of 1 mg 17-beta-hydroxy-7 alpha-methylandrost-5-en-3-one (RMI-12,936) given a few hours after mating interrupted pregnancy in all the treated rats. Circulating progesterone (delta 4P) levels were higher in RMI-12,936 treated females than in controls on the corresponding days during the course of termination of pregnancy. Higher levels of delta 4P were recorded on day-4 (P less than 0.01) and day-6 (P less than 0.05) of pregnancy. In addition to the changes in serum delta 4P, an acceleration of egg transport was encountered. The eggs were prematurely expelled from the uterus within 48 h of the treatment. Although the oestrous cycle of the RMI-12,935 treated females was disturbed, they were found sexually receptive. Successful matings resulting in normal gestation and morphologically normal foetuses were recorded 20-26 days after RMI-12,936 induced pregnancy termination. These results suggest that in addition to its mid-pregnancy terminating effect, RMI-12,936 is capable of interrupting early pregnancy when given soon after mating in the rat. The safety and efficacy of this compound as a post-coital contraceptive deserves further investigation.

Gossypol: its toxicological and endocrinological effects in male rabbits

The effects of different doses of orally administered polyphenolic compound 'Gossypol' on semen quality, circulating testosterone (T) and fertility of Dutch-belted male rabbits were studied. Bucks fed daily with 80, 40, 20 mg/kg day gossypol died within 8-17, 23-35 or 35-84 days, respectively, after initiation of treatment. Following gossypol treatment at 80, 40 or 20 mg/kg/day, animals lost appetite and body weight, developed hind limb paralysis, breathing difficulties and collapsed while sitting in their cages. At autopsy, the liver and lungs were found congested while the stomach and intestines contained gases. On the other hand, rabbits fed daily with 10 mg/kg/day gossypol exhibited a survival time ranging from 77 to 250 days. Despite the severe side effects resulting in eventual deaths, weekly semen samples from all treated animals did not show any apparent change in sperm motility, morphology or population. Likewise, gossypol-treated males mated to estrous does exhibited a fertility comparable to vehicle-treated controls. Gossypol fed at a dose of 10 mg/kg/day for up to 35 weeks failed to induce sterility. Male rabbits, fed with either 20 or 10 mg/kg/day gossypol, that survived for longer periods of time had substantially reduced T levels by 12-20 weeks depending upon the dose but were fertile at all times. When the in vitro release of T from the rat testes mince in the presence of hCG and gossypol was evaluated, an inhibiton of T release was recorded. It is concluded that although gossypol has been shown to be an effective antifertility agent in several mammalian species, it failed to exhibit such an effect in Dutch-belted rabbits, although serum T levels were reduced. In addition, gossypol exhibited a wide spectrum of toxicity. The in vitro study demonstrated that high concentration of gossypol can directly inhibit the T synthesis in the testis.

Effects of Colprone on in vitro release of androgens from the reproductive organs of the male rat

Effects of medrogestone (6,17 alpha-dimethyl-4-,6-pregnadiene-3, 20-dione; Colprone) on the release of testosterone (T) and 5 alpha-dehydrotestosterone (5 alpha-DHT) in the reproductive organs of the male rat were tested in vitro. The minced testes released twice as much T into the medium when incubated in the presence of 50 mIU/ml of hCG. The release of T was inhibited significantly when 10 or 50 micrometers Colprone was added to the incubation medium. More 5 alpha-DHT was released into the medium from the testes mince in the presence of hCG, while the addition of 10 or 50 micrometers of Colprone inhibited 5 alpha-DHT release as compared to hCG controls. On the other hand, hCG failed to stimulate the release of T and 5 alpha-DHT from the minced caput and cauda epididymis and ventral prostate. The addition of Colprone (10--50 micrometers/ml) to the medium containing caput epididymis or ventral prostate resulted in a significant inhibition of T and 5 alpha-DHT. However, no significant change in the rate of T or 5 alpha-DHT release was recorded in medium containing cauda epididymis. In spite of its anti-androgenic effects reported by several investigators, Colprone in the present study has shown differential effects on T and 5 alpha-DHT release from different reproductive tissues of the male rat.

Effects of prostaglandin-F2 alpha and a plant protein "Trichosanthin", on 10-day pregnant rabbits

The effect of Trichosanthin (TCS), a protein obtained from the roots of Trichosanthis kirilowii, alone or in combination with prostaglandin-F2 alpha (PGF2 alpha; Tromethamine salt) on the termination of pregnancy in rabbits was investigated. Intraperitoneal injection of 1 or 2 mg TCS/10-day pregnant rabbits neither altered the serum progesterone (delta 4P) level nor interrupted pregnancy. Doses of 0.5 or 0.25 mg PGF2 alpha incorporated in a Silastic-PVP tube and inserted intravaginally, terminated pregnancy within 72 h of treatment in 75 and 16% of the treated does, respectively. By contrast, does treated on day-10 of pregnancy with a combination of a non-effective dose of TCS (1 mg) and a sub-effective dose of PGF2 alpha (0.25 mg) terminated pregnancy in all the treated animals as no live embryos were found within 3 days of treatment. Pregnancy interruption was associated with a significant reduction of serum delta 4P and delta 4P/20 alpha-dihydroprogesterone (20 alpha-DHP) ratio. The present study indicates that TCS and PGF2 alpha act synergistically, rendering the termination of 10-day pregnancy possible in the rabbit. It was also noted that pregnancy cannot be maintained when the serum delta 4 P level drops below 4 ng/ml and delta 4P/20 alpha-DHP falls lower than 0.6 in the 10-day pregnant rabbit.

Temporal relationship between progestin and luteinizing hormone concentrations in pseudopregnant rats treated with prostaglandin-F2 alpha

The temporal changes in progesterone (delta 4P), 20 alpha-dihydroprogesterone (20 alpha-DHP) and luteinizing hormone (LH) concentrations in pseudopregnant (PSP) rats after treatment with a single subcutaneous Silastic-PVP tube containing 600 micrograms PGF2 alpha were correlated. Progesterone levels fell and LH levels rose significantly 2h after initiation of treatment, while 20 alpha-DHP levels were found to increase significantly 12h after treatment. Since the changes in delta 4P and LH concentrations occurred concurrently, it seems that the increase in LH levels could have been due to a direct effect of PGF2 alpha on the ovary causing a reduction in delta 4P and thus a negative feedback effect on LH release. Alternatively, PGF2 alpha might exert a direct effect on LH secretion at the hypothalamic-pituitary level.

Effects of prostaglandin F2 alpha and an antiprogestational steroid, RMI 12,936, on rat pregnancy

The abortifacient efficacy of RMI 12,936 (17 beta-hydroxy-7 alpha-methyl androst-5-en-3-one), a synthetic steroid, alone or in combination with prostaglandin-f2 alpha (PGF2 alpha), was studied in the rat. Administration on day-8 of pregnancy (PD-8) of 0.25 mg RMI 12,936/rat neither altered the progesterone (delta 4P) levels, the relative ovarian weight (ROW) nor terminated pregnancy. Doses of 2.0, 1.0 or 0.5 mg RMI 12,936/rat, when given on PD-8, terminated pregnancy in 100% of the animals. Highly significant increases in ROW and serum alpha 4P level were recorded on PD-14. However, delta 4P/20 alpha-dihydroprogesterone ratio remained unaltered. These results suggest that RMI 12,936 increased luteal activity which contributed to the enhanced serum delta 4P levels and ROW. Bilateral insertion of Silastic-PVP tubes containing 75 micrograms PGF2 alpha/tube into each uterine horn on PD-10 did not disturb pregnancy, whereas similar tubes given on PD-10 to rats treated with 1.0 mg RMI 12,936 on PD-8 expelled the embryos and placental tissue on PD-11. This phenomenon was attributed to a decreased serum delta 4P caused by PGF2 alpha, allowing the expulsion of uterine contents. A time lapse of 17--35 days was needed for the rats to regain fertility in terms of normal gestation period and offsprings. Although expulsion of conceptus was facilitated by PGF2 alpha in the RMI 12,936 treated rats, PGF2 alpha treatment did not alter the time lapse between RMI 12,936 treatment and subsequent conception. It is concluded that RMI 12,936 is feto-toxic; it possesses high contraceptive activity and its abortifacient efficacy can be improved by PGF2 alpha.

Further studies on the trichosanthin-induced termination of pregnancy

Trichosanthin (TCS), a protein from the root extract of Trichosanthis kirilowii, terminated pregnancy when injected once in 15-day pregnant rabbits (2 mg/doe) but failed to interrupt pregnancy in 12-day pregnant rabbits even at higher doses. In vitro release of progesterone (delta 4P) from the maternal or fetal placental tissue into the incubation medium was not affected by TCS. When the distribution of 125I-TCS was traced in 12-day pregnant mice, persistently higher concentration of 125I-radioactivity was detected in the kidney. By contrast, in other organs, including the reproductive organs, blood serum and amniotic fluid 125I-radioactivity declined between 12-48 h after treatment. The low 125I-radioactivity in both the reproductive organs and amniotic fluid suggests a possible barrier between the embryo and maternal blood. It is suggested that TCS might be acting directly on the placental unit, causing fetal death and dislodging of the placenta. Administration of TCS to PD-19 mice or PD-28 rabbits resulted in premature delivery. This effect of TCS in pregnant mice was comparable to the administration of PGF2 alpha.

Effects of 17 beta-hydroxy-7 alpha-methylandrost-5-en-3-one (RMI 12,936) on pregnant rabbits

A single subcutaneous injection of RMI 12,936 interrupted 8- and 15-day pregnancy in the rabbit. A dose dependent loss of embryos was observed. Higher doses of RMI 12,936 were needed to terminate pregnancy in 8-day pregnant (74% efficacy with 10 mg/kg) than in 15-day pregnant rabbits (100% efficacy with 8 mg/kg). Termination of pregnancy by RMI 12,936 was accompanied by a significant increase of progesterone (delta 4 p) in rabbits receiving 10 mg/kg RMI 12,936 on day 8 of pregnancy. On the other hand, treatment with 8 mg/kg RMI 12,936 on day 15 of pregnancy did not alter the delta 4 p levels, but induced a significant decrease in 20 alpha-dihydroprogesterone. In these two treatment groups, a consistent and highly significant increase of serum testosterone (T) was observed. The increase of T value possibly was due to a decrease in aromatizing ability of the follicles after RMI 12, 936 treatment and might have contributed towards the interruption of pregnancy. The failure of RMI 12,936-treated rabbits to ovulate even after hCG administration suggests that his compound might have lowered the sensitivity of the mature follicles to LH stimulation.

Termination of pregnancy in rabbit and mouse by Trichosanthin

The effects of a single intraperitoneal injection of Trichosanthin in 6-, 10-, 17- or 22-day pregnant rabbit (2 mg/rabbit) or in 11-day pregnant mouse (50 micrograms/mouse) were studied. Trichosanthin induced abortion in 100% of the 17- or 22-day pregnant rabbits within 48-72 hours and decreased circulating progesterone (delta 4P)concentrations with 24 hrs. On the other hand, the same dose failed to terminate pregnancy in 6- or 10-day pregnant rabbits and caused no significant changes in circulating delta 4P levels. Exogenous delta 4P or prolactin + human chorionic gonadotropin given twice daily failed to reverse the Trichosanthin-induced termination of pregnancy. However, this resulted in a delay of fetal expulsion. It is concluded that Trichosanthin-induced termination of pregnancy is not solely a result of luteolysis but is likely to be due to its toxic effects on placenta, embryo or both. A dose of 50 microgram Trichosanthin given to 11-day pregnant mice resulted in a termination of pregnancy within 96 hours and also a significant decrease in delta 4P levels in 24 hrs. The ratio of delta 4P to 20 alpha-dihydroprogesterone was also decreased steadily after Trichosanthin administration.

Temporary sterility induced by intrascrotal deposition of silastic-polyvinylpyrrolidone-prostaglandin F2alpha tubes in the rabbit: effect on fetal survival after regain of fertility

In male rabbits of proven fertility, the intrascrotal deposition of two Silastic-polyvinylpyrrolidone tubes containing 3 mg of prostaglandin F2alpha (PGF2alpha)/tube induced within 2 to 4 weeks temporary sterility which lasted for 10 to 14 weeks. Associated with induced sterility were reduction in testicular weight, increase in abnormal spermatozoa (8% to 78% versus 0 to 3.7%), and reduction in sperm motility along the reproductive tract and in the semen for a period of 6 to 7 weeks. During the period of temporary sterility the weight of the epididymis, the sexual drive, and semen volume remained unaltered. Normal fertility was associated with an increase in testicular weight, reduction in the proportion of abnormal sperm, and improved sperm motility. In addition to an altered spermatogenesis, the integrity of mature spermatozoa seemed to be severely affected after PGF2alpha treatment. The reduced number of viable young sired by males that recovered from temporary sterility (pregnancy wastage 35%) as compared with sham-treated controls (pregnancy wastage 3%) suggests that a small percentage of spermatozoa might still be defective at the time of testing. A longer waiting period might be needed to ensure a completely normal reproductive process.

Age dependent changes in the sperm population and fertility in the male rat

The entire reproductive tract was devoid of spermatozoa during the first 42 days of life. The first appearance of spermatozoa was detected in the caput epididymidis of 45-day old rats and in the cauda epididymidis of 52-day or older rats. The number of spermatozoa in the reproductive tract increased with age. The sperm population reached its maximum in the caput epididymidis by day-72 and in the caud epididymidis by day-100. These high levels were maintained beyond 450 days of age. Fifty-two day old male rats failed to impregnate the female. Although male rats of 62-500 days were able to sire litters, the peak reproductive period was found to be between days 100-270, during which the number of young per litter ranged between 11-16. Towards advanced age the litter size dropped to 8. The lower fertility in the males of advanced age might be due to a lower proportion of fertile spermatozoa, a change in the physiology of epididymis or an altered sperm transport in the reproductive tract.

Variations in serum androgens, estrogens, progestins, gonadotropins and prolactin levels in male rats from prepubertal to advanced age

The concentrations of blood serum steroids from 12 to 450 days old male rats were determined by radioimmunoassay. Testosterone (T) was low (270 pg to less than 1 ng/ml) until day 42; adult levels (3--4 ng/ml) were attained by day 62 and declined tradually with advanced age. 5 alpha-dihydrotestosterone (5 alpha-DHT) did not change markedly (90--160 pg/ml) from prepubertal to advanced age. Except for a small peak on day 22, androstenedione (delta 4 A) levels ranged between 400-500 pg/ml in the adult but declined in older males. Progesterone (delta 4 P) rose steadily to a mean of 5.46 ng/ml at 52 days of age and dropped thereafter. High levels of estrone (268 +/- 38 pg/ml) and estradiol-17 beta (2.76 +/- 0.28 ng/ml) in 12 days old males are in contrast to the low estrogens (20-35 pg/ml) in adult animals. Both T/5 alpha-DHT and total T/estrogen ratios were low before puberty, increased in adults and decreased towards old age. The interplay between gonadotropin and prolactin, which exhibited reciprocal changes in the regulation of steroid production by the gonads with age, are discussed.

Inhibition of ovulation and fertilization by indomethacin and effect of prostaglandin-F2 alpha on early pregnancy in the rabbit

Ovulation induced by HCG in rabbits was blocked by a single subcutaneous injection of 6 mg/kg indomethacin given 6 h after the insemination and HCG treatment. In addition, a time-dependent inhibition in the fertilization rate after indomethacin treatment was also recorded. This suggests that indomethacin, when given at a critical time and at an appropriate dose level, not only blocks ovulation but also interferes with fertilization. Treatment with graded amounts of prostaglandin-F2 alpha incorporated in a Silastic-polyvinylpyrrolidone-gel (PVP) had marginal to no effect after intravaginal placement on 4- or 6-day pregnancy. However, 5 mg PGF 2 alpha/ Silastic-PVP tube when placed intravaginally on Day-7 of pregnancy resulted in termination of pregnancy in 66% of the treated does. This implies that young corpora lutea are resistant of PGF2 alpha treatment and that pregnancy at the time of ovo-implantation can be terminated by PGF2 alpha incorporated in a Silastic-PVP tube.

Termination of pregnancy in the rat by RMI 12,936

Administration of a steroid RMI 12,936 (2 MG) ON DAY 8 OF PREGNANCY RESULted in an interruption of gestation within 5 days. No significant changes in progesterone (delta 4P), 20 alpha-dihydroprogesterone (20 alpha-DHP) and pregnenolone (delta 5P) were recorded during the course of termination of pregnancy by RMI 12,936. However, a significant rise in serum delta 4P and hypertropic corpora lutea were evident on day 13 of pregnancy when all treated females showed dead conceptus. The placental tissue was still present at the time of pregnancy termination. On the other hand, serum LH levels was significantly suppressed 24 hr after the treatment and maintained at a very low level. The reduction of LH might be due to a lowered hypophyseal sensitivity towards LH-RH. The occurrence of in utero dead fetus without interference of delta 4P production suggests that in the rat RMI 12,936-induced termination of pregnancy is due to its embryotoxic rather than luteolytic effect. Although the treated females did not return to normal estrous cycles for a period of 2 weeks after pregnancy termination, they were sexually receptive. Successful mating resulted in normal pregnancy which occurred 30-35 days after RMI 12,936 treatment.

Termination of pseudopregnancy in rats by silastic-PVP-PGF2 alpha tube

The efficacy of a one-end or both-end open Silastic-polyvinyl-pyrrolidone (Silastic-PVP) tube containing 600 microgram prostaglandin-F2 alpha (PGF2 alpha) and placed subcutaneously on day-6 of pseudopregnancy (PSP) in the induction of premature termination of PSP was compared. A both-end open Silastic-PVP-PGF2 alpha tube was more efficacious in inducing an early termination of PSP with a mean duration of 7.8 days. By contrast, PSP females receiving a one-end open Silastic-PVP-PGF2 alpha tube showed a mean duration of PSP of 9.9 days. The shortened duration of PSP in both these treatment groups was significantly different from the control value of 13.1 days. The significant drop in progesterone (delta 4P) but rise in 20 alpha-dihydroprogesterone (20 alpha-DHP) occurred 24 hr after treatment in PSP rats treated with both-end open Silastic-PVP-PGF2 alpha tube, whereas similar changes in delta 4P and 20 alpha-DHP took place 48-72 hr after the deposition of a one-end open Silastic-PVP PGF2 alpha tube. It is concluded than an initial larger amount of circulating PGF2 alpha is needed to induce an early premature termination of PSP. The exposure of corpus luteum to a more sustained but lower level of PGF2 alpha leads to a slower response.

RMI 12,936 and pseudopregnancy in rats

RMI 12,936, when injected subcutaneously at a dose of 2 mg, either on Day 6 of psuedopregnancy (PSP-6) or on PSP-6,7 and 8, shortened the duration of PSP from 12.3 +/- 0.3 (control) to 8.3 +/- 0.1 or 8.7 +/- 0.2 days, respectively. During PSP, plasma progesterone (delta 4P) levels in the peripheral plasma showed a trend of decrease by PSP-9 (52.0 +/- 4.6 on PSP-8 to 42.3 +/- 3.1 ng/ml on PSP-9). Administration of RMI 12,936 on PSP-6 resulted in a significant decrease in delta 4P and pregnenolone (delta 5P) within 24 hr after treatment but caused no apparent changes in 20 alpha-dihydroprogesterone (20 alpha-DHP) levels. However, a significant decrease of delta 4P/20 alpha DHP ratio was encountered 24 hr after RMI 12,936 treatment. The persistent occurrence of proestrous smear after PSP termination, but absence of estrous vaginal cytology, might be attributed to the slight estrogenicity of RMI 12,936. After the premature termination of pseudopregnancy induced by RMI 12,936, the female rats were sexually receptive for at least 3 weeks but failed to conceive, suggesting that this compound has a prolonged contraceptive effect.

Effects of cadmium chloride on testicular steroidogenesis and fertility of male rats

Effects of a single subcutaneous injection of 1 or 5 mg/rat of cadmium chloride (CdCl2) on circulating steroids and fertility were studied over a period of 120 days in fertile male rats. Androgens and fertility returned to normal 120 days after 1 mg CdCl2 but males treated with 5 mg showed none to poor restoration of some of these parameters. The in vitro release of testosterone (T), 5 alpha-dihydrotestosterone (5 alpha-DHT) and androstenedione (delta 4A) by the decapsulated tests from CdCl2 treated males was significantly reduced whereas progesterone (delta 4P) was accumulated in significantly higher amounts into the incubation medium. When testes from CdCl2 treated males were incubated in vitro with hCG, a dose and time dependent stimulation of steroidogenesis was evident. Since the testes regained the steroidogenic capacity but the males remained sterile 120 days after 5 mg CdCl2 treatment, it appeared that CdCl2 induced a permanent damage to the germinal components of the testes.

Effects of RMI 12,936 on some reproductive processes in the female golden hamster

A single subcutaneous injection of 2 mg RMI 12,936 (17 beta-hydroxy-7 alpha-methylandrost-5-en-3-one) given a day after estrus disrupted estrous cycle for over 30 days and inhibited ovulation in 100 percent of treated Golden hamsters. Administration of RMI 12,936 (2 mg) on Day 6 of pregnancy caused termination of pregnancy within 4 days of treatment. In association with the termination of pregnancy was a significant reduction in the concentrations of progesterone and estradiol-17 beta together with an elevated testosterone level. After termination of pregnancy by RMI 12,936, the hamsters remained sexually receptive for 4 weeks but failed to conceive. It is concluded that RMI 12,936 causes termination of pregnancy due to an induction of functional luteolysis.

Induction of mid-term abortion by trichosanthin in laboratory animals

Trichosanthin, a protein purified from the extract of the root tuber of Trichosanthis Kirilowii, Maxim, given once only induced midterm abortion in the mice and rabbits. The effective I.P. dose for the induction of abortion in 10- or 11-day pregnant mouse was 50 micrograms. In the rabbit a dose and state of pregnancy-dependent response to Trichosanthin-induced abortion was encountered. A dose as low as 0.5 mg Trichosanthin in 22-day pregnant rabbit was adequate but 2.0 mg was needed in 17-day pregnant rabbit. Attempts to terminate pregnancy in the rat and hamster using Trichosanthin was not successful even with higher doses. When compared with prostaglandin-F2 alpha, an established abortifacient, Trichosanthin appeared to be more effective and associated with less side effects in the induction of abortion in the rabbit. Trichosanthin was ineffective to terminate early pregnancy in the 4 species studied.

Endocrinological and physiological features after steroid treatment of male rats

The effects of medroxyprogesterone acetate (Provera), testosterone propionate (TP), ethinyl estradiol (EE), and ethynodiol diacetate (ED) treatments on sperm population in different segments of the male rat reproductive tract, reproductive organ weights, circulating androgens and fertility were studied. Ten microgram TP given for five days reduced the sperm population and organ weights. A marked reduction in the number of sperm and reproductive organ weights was observed in males orally treated with estrogens. Only long-term (20 days) treatment with Provera (1 mg/day) significantly reduced sperm population and reproductive organ weights. Combination of TP and Provera resulted in a more pronounced reduction in sperm counts and organ weights. Among steroids studied, estrogen was the only compound which suppressed fertility and circulating steroid levels.

Prostaglandin F2alpha induced termination of pregnancy and its reversal by prolactin or progesterone in rats

Intrauterine insertion of a Silastic-PVP tube containing 400 microgram PGF2alpha terminated midterm pregnancy in 100 per cent of the animals. Progesterone (2 mg/day) or prolactin (PRL) reversed the abortifacient effect of PGF2alpha. A dose- and duration-related effect of the PRL on PGF2alpha induced termination of pregnancy was evident. The results suggest that PGF2alpha and PRL are antagonistic to each other and multiple doses of PRL are needed to neutralize the luteolytic action of PGF2alpha.

Effects of prostaglandin-F2alpha on some reproductive parameters of fertile male rats

Silastic-PVP-PGF2alpha tubes significantly reduced the sperm population in the epididymis and vas-deferens of male rats 14 days after their insertion into the scrotal sacs. A reduction in testis and epididymal weights was also evident. The reduction of sperm population was accompanied by a normal sexual drive and circulating testosterone level and partial sterility. The reduction in sperm population and induction of partial sterility was detected at least 7 days after the total release of prostaglandin F2alpha from the Silastic-PVP tubes. The results suggest that the changes in the reproductive parameters might be a consequence of endocrinological and functional disturbances induced by PGF2alpha and that PGs can be used to induce temporary sterility in the male.

Postovulatory levels of progestogens, oestrogens, luteinizing hormone and follicle-stimulating hormone in the plasma of aged golden hamsters exhibiting a delay in fertilization

* Department of Anatomy, University of Texas Medical Branch, Galveston, Texas 77550, U.S.A. and †The Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545, U.S.A.

(Received 5 December 1977)

Fertilization is delayed approximately 2–5 h in the majority of ova recovered from aged hamsters (14–17 months old), compared with younger (3–5 months old) animals (Parkening & Soderwall, 1975). This delay may explain the relatively large percentage (40%) of ova which is incapable of developing to the implantation stage in this species (Parkening & Soderwall, 1975). Blaha & Leavitt (1974) have shown that there is a wider variation in the peripheral plasma concentration of progesterone at the time of fertilization in aged than in younger hamsters. A hormonal imbalance in the senescent female hamster may disturb normal gamete interactions, thus causing the delay in fertilization. In order to determine the significance of hormonal levels with respect to fertilization, the concentrations of progestogens,

Circulating plasma levels of pregnenolone, progesterone, estrogen, luteinizing hormone, and follicle stimulating hormone in young and aged C57BL/6 mice during various stages of pregnancy

Young (3-5 mo of age) and senescent (12-15 mo of age) multiparous C57BL/6 mice were mated with young males (3-6 mo of age) and the numbers of preimplantation embryos and implantation sites determined on days 1 (day of plug), 4, 9, and 16 of pregnancy. The numbers of viable embryos were significantly lower (p less than 0.02 to p less than 0.001) in senescent females compared with young females on all days except day 1 of pregnancy. Plasma samples tested by radioimmunoassay indicated circulating estradiol-17B was significantly lower (P less than 0.05) on day 1 and higher (p less than 0.05) on day 4 in older females, whereas FSH was higher on days 4, 9, and 16 (p less than 0.02 to p less than 0.001) in senescent females when compared with samples from young females. Levels of pregnenolone, progesterone, estrone, and LH were not significantly different at any stage of pregnancy in the two age groups. From the hormonal data it did not appear that degenerating corpora lutea were responsible for the declining litter size in this strain of aged mouse.

Periovulatory steroid concentrations in HCG-treated rabbits

The level of pregnenolone increased within 1 h and remained high for 4 h after an intravenous injection of HCG in conscious rabbits. Peaks for progesterone, estrogens and dehydroepiandrosterone were recorded at 2 h, and that of 20alpha-dihydroprogesterone 6 h after HCG injection. At the time of ovulation the serum concentrations of all steroids had returned to their basal levels. It seems that HCG maintained a high production of pregnenolone and promoted the synthesis of different steroids.

Effects of hCG on serum levels of testosterone, dihydrotestosterone and androstenedione in male mice

The concentrations of testosterone (T), 5alpha-dihydrotestosterone (5alpha-DHT) and delta4-androstenedione (delta4 A) in the circulating blood were increased by a single subcutaneous injection of 10 IU of hCG in the mouse. The response of androgen synthesis to hCG stimulation was rapid and persisted over a period of 96 h. The increased supply of T to the peripheral organ(s) under the stimulation of hCG might contribute to an increase in circulating 5alpha-DHT. However, the changes in T/5alpha-DHT ratio implies that the stimulation of T and 5alpha-DHT production by hCG were not of the same degree.

Determination of seven unconjugated steroids in the blood and seminal plasma of the fertile male rabbit

Seven unconjugated steroids were measured in the blood and seminal plasmas of fertile male rabbits by radioimmunoassay. The blood plasma testosterone concentration was 4--5 times that of the seminal plasma. Dehydroepiandrosterone, estrone and 17beta-estradiol were found in measurable amounts in the blood plasma; however, these steroid levels were slightly lower in seminal plasma. Androstenedione and 5alpha-dihydrotestosterone were present in equal quantities in both the seminal and blood plasmas. By contrast, seminal plasma pregnenolone level was about twice that of the blood plasma. The determination of seminal plasma steroids may lend itself as a complementary assessment to blood steroid determinations for the evaluation of the normal function of various reproductive organs.

The inhibition of the conversion of testosterone into 5alpha-dihydrotestosterone in the reproductive organs of the male rat

The inhibition of testosterone 5alpha-reductase activity by 3-oxo-4-androstene-17beta-carboxylic acid in the male reproductive organs of the rat was demonstrated in vitro. The medium for incubation of caput epididymis showed the highest concentration of 5alpha-dihydrotestosterone (5alpha-DHT) whereas the highest concentration of testosterone (T) was recorded in medium for incubation of decapsulated testis after two hours of incubation. The 3-oxo-4-androstene-17beta-carboxylic acid (1.58 X 10(-5)M) inhibited the conversion of T to 5alpha-DHT in all the organs tested (testis, caput and cauda epididymis and ventral prostate) under identical incubation conditions.

Temporal changes in circulating steroids during prostaglandin F2alpha induced abortion in the rat and rabbit

The serum levels of progesterone (delta4P), 20alpha-dihydroxyprogesterone (20alpha-DHP), pregnenolone (delta5P) and estrogens at different time intervals during Silastic-PVP-PGF2alpha tube induced midterm abortion were measured by radioimmunoassay in the rat and rabbit. The concentrations of delta4P and delta5P were significantly reduced but that of 20alpha-DHP was increased significantly as early as 20 hours after PGF2alpha treatment. Estrogen levels showed slight reduction in the rat but remained unchanged in the rabbit. The ratio of delta4P/20alpha-DHP recorded were 2.15 and 16.86 (pretreatment) and dropped to 0.08 and 0.37 (60 hours after insertion of Silastic-PVP-PGF2alpha tube) in the rat and rabbit, respectively. These findings suggest that the suppression of circulating delta4P by PGF2alpha might be the result of a reduced precursor (delta5P) pool size as well as changes in the enzymic systems responsible for the formation and conversion of delta4P. It is still to be determined if changes in estrogen levels in the rat have any bearing on abortion induced by PGF2alpha.

Relationship between oestrogen, prostaglandin F2alpha and histamine in delayed implantation in the mouse

Treatment of pregnant mice ovariectomized on day 3 (23.00-2330 h) with progesterone (1 mg/day/mouse, from day 4 through 11 post coitum (p.c.)) and oestrogen (single injection of 0.05 mug on day 8 p.c.) induced implantation in all the animals. Implantation was inhibited in animals following three subcutaneous injections of indomethacin given on the morning and afternoon of day 8 and the morning of day 9 p.c. A single injection of histamine on day 8 p.c. partially compensated the effect of indomethacin. A complete reversal of the antifertility effect of indomethacin was achieved following intraperitoneal administration of histamine (2 mug at noon of day 8 p.c.) and PGF2alpha (20 mug on the morning and afternoon of day 8 p.c.). This study suggests that in the mouse uterus indomethacin impairs the physiological changes which are required for the decidual cell formation and implantation. It is likely that an injection of oestradiol in the progesterone treated ovariectomized mice triggers the release of PGF2alpha and histamine and that these compounds are involved in the chain of events leading to implantation of blastocysts.

Effects of indomethacin and prostaglandin F2alpha on parturition in the hamster

In the hamster administration of indomethacin twice a day on days 14 to 16 of pregnancy delayed the onset of parturition; a delay of 5 and 8 hours was observed following treatments of 300 or 600 mug/injection of indomethacin, respectively. Injection of PGF2alpha to the indomethacin treated hamsters on day 15 of pregnancy, on the other hand, advanced the onset of parturition. Treatments of indomethacin and/or PGF2alpha did not affect the duration of parturition.

Induction of temporary sterility in female hamsters by an intraperitoneal silastic-PVP-PGF2alpha tube

In the female hamster, temporary sterility for a period of 10 or 15 days was induced by an intraperitoneal Silastic-PVP-tube containing 3.5 or 1.0 mg of PGF2alpha, respectively. All Silastic-PVP-PGF2alpha tube hearing animals regained fertility and delivered normal litters at various times after the placement of the tube. The release rate of 3-H-PGF2alpha from the Silastic-PVP tube was described and their potential use as a drug delivery system discussed.

Effect of indomethacin on blood plasma levels of LH and testosterone in male rats

Treatment of adult male rats with indomethacin, an inhibitor of prostaglandin (PG) synthesis, caused a significant decrease in LH and testosterone levels in the blood plasma and in the weight of the seminal vesicles, but the weight of the testes and ventral prostate, the levels of FSH in the plasma and fertility were not affected. The concentration of PGF in the blood plasma of the treated animals was reduced, even though measurable amounts of PGs were present in every group. The results of this study, together with the known effects of PG administration on LH release, suggest that the reduction of plasma LH levels in rats injected with indomethacin was due to decreased PG synthesis. It appears that PGs are normally involved in the regulation of LH release.