The selective estrogen receptor modulator, raloxifene: reproductive assessments in adult male rats.

Raloxifene HCl is a nonsteroidal, selective estrogen receptor modulator developed for postmenopausal osteoporosis. Reproductive toxicity of raloxifene was examined in adult male CD rats after the oral administration of doses of 0, 10, 30, or 100 mg/kg/d. In the first study, males (12/group) were treated for 2 weeks followed by 2 weeks without treatment. After dose administration on Day 13, 6 males/group were cohabited with untreated females (1:2) for up to 7 d. Males were killed on Day 14 or 28 (6/group each day). Sperm were collected from the right cauda epididymis and evaluated for relative concentration, motion characteristics, and breakage. The kinetics of spermatogenesis were examined by DNA flow cytometry. The left testis and epididymis were preserved for histopathologic evaluation. Females were examined for reproductive status on Gestation Day 13. In a second study, males (20/group) were treated for 7 weeks (4 weeks prior to cohabitation during a 2-week cohabitation period, and for 1 additional week). Treated males were cohabited with untreated females (1:1). On Gestation Day 20, untreated females were examined for reproductive status and fetuses were examined for viability, weight, gender, and morphology. At necropsy, male reproductive tissues were collected, weighed, and preserved for histopathologic evaluation. In both studies, male body weight gain and food consumption were depressed at all dose levels. There was no indication in either study that raloxifene caused important changes in sperm production, sperm quality, or male reproductive performance at doses as high as 100 mg/kg/d.

Short-term male reproductive toxicity study with sulfasalazine in the rat.

Sulfasalazine (2-hydroxy-5-[[4-[(2-pyridinylamino) sulfonyl] phenyl]azo]benzoic acid; SASP) was administered to rats in a short-term male reproductive toxicity study to further examine the utility of this grouping of techniques and to generate reference data with a substance that is known to cause reversible infertility in men. Adult male CD rats (10/group) were orally administered 0, 150, 300, or 600 mg SASP/kg body weight in divided doses for 14 d followed by a 2-week period without treatment. Males were killed on test day (TD) 15 or 29. At each time point, the reproductive system was evaluated by comparing testicular and epididymal weights, DNA ploidy distributions of testicular cell suspensions, testicular and epididymal histopathology, and epididymal sperm concentrations, motion, morphology, and breakage. Adding time as a factor in the protocol aids in distinguishing testicular from posttesticular effects. Changes in sperm quality after 2 weeks of test article administration (TD 15) predominantly reflect effects that occurred after the sperm entered the epididymis, while testicular effects predominated on TD 29. Beginning on TD 14, males to be killed on TD 29 were cohabited with untreated females (1:2). Females were killed at midgestation and examined for pregnancy status. Body weight gain was depressed in all SASP groups during the first 3 d of test article administration. Food consumption was depressed at the 300- and 600-mg/kg dose levels. No changes were seen in testicular weight, but epididymal weight was depressed at the 600-mg/kg dose level. DNA ploidy distributions determined by flow cytometry did not indicate that the kinetics of spermatogenesis were disturbed. However, alterations in sperm release, which have not previously been reported, were seen at all SASP dose levels. On TD 29, the percentage of progressively motile sperm was depressed and beat/cross frequency was increased at the 600-mg/kg dose level. No changes were observed in sperm morphology or breakage. Fertility was slightly depressed at the 600-mg/kg dose level. In this study, testicular histopathology provided the most sensitive endpoint for reproductive toxicity. The impairment of fertility immediately after treatment was stopped, when no changes were apparent in sperm release or sperm motion, suggested that decreased sperm concentrations and altered motility, while contributory, may not be the primary causes of SASP-mediated infertility.

Utilization of a short-term male reproductive toxicity study design to examine effects of alpha-chlorohydrin (3-chloro-1,2-propanediol).

alpha-Chlorohydrin (ACH) was administered to rats in a short-term male reproductive toxicity study to examine the usefulness of the method and to provide reference data with a substance that is known to elicit adverse effects on both sperm production and sperm quality within or following a 2-week treatment period. Adult male CD rats (10 per group) were administered ACH orally by gavage at doses of 0, 1, 5, or 25 mg/kg/day for 14 days. Males were killed on Test Day (TD) 15 or 29. A 2-week period without treatment was included to distinguish between testicular and posttesticular effects. At each time point, the reproductive system was evaluated by comparing testes weight, DNA ploidy distributions of testicular cell suspensions, testicular and epididymal histopathology, and epididymal sperm concentration, motility, morphology, and breakage. Beginning on TD 14, males to be killed on TD 29 were cohabited with untreated females (1:2). Females were killed on Gestation Day 13 and examined for pregnancy status. During the treatment period, minor depressions in body weight and relative food consumption occurred in rats administered 25 mg/kg ACH. Testicular and epididymal lesions also occurred at this dose level. DNA ploidy distributions determined by flow cytometry were predictive of testicular damage, with effects more pronounced on TD 29 than on TD 15. The preparation methods used selected for the most motile and vigorous population of epididymal sperm. Sperm motion was altered at the 5- and 25-mg/kg dose levels on TD 15. The percentage of motile sperm and the percentage of progressively motile sperm were markedly depressed at both the 5- and 25-mg/kg dose levels where antifertility effects occurred. Sperm velocities and amplitude of lateral head displacement were depressed at the 25-mg/kg dose level on both TD 15 and 29. Additionally, decreased epididymal sperm concentrations and increased breakage were recorded at this dose level. The findings in this study are consistent with the scientific literature for ACH and demonstrate posttesticular effects on epididymal sperm and delayed expression of testicular lesions. They also support the use of this methodology for an initial assessment of male reproductive effects.

The effect of exogenous intrauterine progesterone on the amount and prostaglandin F2alpha content of menstrual blood in dysmenorrheic women.

Women with complaints of moderate or severe dysmenorrhea received intrauterine progesterone contraceptive system (16 patients) or placebo systems releasing no hormone (8 patients). Tampons were collected during the period prior to insertion and from 11 and 6 women, respectively, in the two groups at the second and fourth postinsertion periods. Prostaglandins in menstrual blood were extracted, and the amount and concentration of PGF2alpha analyzed for each patient. The menstrual blood loss (MBL) was determined by the method of Hallberg and Nilsson. The total PGF2alpha content was significantly lower in the group using progesterone systems than in the placebo group at collections 2 and 4 and was well below the preinsertion level; in placebo users the content tended to be slightly higher than it had been before insertion. The MBL increased approximately 60% above preinsertion levels in five of the six women using placebo units and decreased approximately 40% in 10 of 11 women with progesterone systems. Of the eight women in the progesterone group who had reported severe dysmenorrhea prior to insertion, seven reported an improvement; three of six in the placebo group reported a lower degree of improvement. These findings suggest that the decreased biosynthesis of PGF2alpha is a concomitant of intrauterine progesterone administration and may be a basis for the ability of the Progestasert system to diminish menstrual pain.

Cerebellar histogenesis in the lurcher (Lc) mutant mouse.

The postnatal development of the cerebellar cortex of normal and lurcher (Lc) mutant mice was studied by neurohistological and autoradiographic techniques at ages ranging from 2 days through 18 days after birth. Lurcher shows severe defects in the granule cells and Purkinje cells soon after birth. A decrease in the generative layers of the external granular layer is seen as early as two days in the lobulus simplex and by six days of age in the uvula. Granule cell death is common before and during granule cell migration, from 2 to 18 days of age. Loss of granule cells is reflected in reduced growth of the molecular and granular layers. Purkinje cell abnormalities appear at three to four days after birth in the form of crowding failure of nuclear growth, and condensed or lessened cytoplasm; Purkinje cell death is apparent at four to six days of age depending on the region of the cerebellum.