Alkylphenol polyethoxylates and alkylphenols, such as 4-tert-octylphenol (OP), are environmental contaminants. Because these compounds are toxic to aquatic animals, we studied the effects of OP on splenocytes removed from male Fischer 344 rats or male Balb/c mice and culturedin vitro.Cell viability was assessed by trypan blue exclusion after 5 or 27 hr of culture. Culture with 0.08% ETOH (vehicle) or any dose of OP did not alter total cell number or the percentage of viable cells after 5 hr. Culture of cells with two different alkylphenol polyethoxylates for 5 hr resulted in the loss of all cells. The percentages of viable rat or mouse cells after 27 hr of culture were decreased significantly by 10−12mOP or greater concentrations. The actions of OP, dexamethasone (DEX), and 17β-estradiol on rat splenocytes were compared. Dexamethasone was more toxic than OP after 24 hr of culture; 17β-estradiol was not toxic. Dexamethasone and OP, but not 17β-estradiol, caused significant nuclear condensation after 3 hr of culture (acridine orange staining) or 4 hr of culture (propidium iodide staining). The toxicity of 10−6mOP, but not that of 10−6mDEX, was eliminated when mouse splenocytes were cultured in Ca2+-free medium. Significantly more mouse splenocytes containing free 3′-OH DNA ends were detected by activated cell sorter analyses when the cells had been incubated for 4 hr with 10−4or 10−6mOP or 10−6mDEX. The results of these studies demonstrate that OP is toxic to cultured rat and mouse splenocytes and suggest that this toxic effect is exerted, at least partially, through Ca2+-dependent apoptosis.

We investigated the influence of LHRH on the accumulation of FSH beta messenger RNA (mRNA) in anterior pituitary glands removed from hamster pups less than 36 h old and transplanted beneath the renal capsules of adult male hamsters (hosts). Three experiments were performed in which some hosts were injected sc with LHRH (1 microgram/injection) and others were injected with vehicle. Injections were begun in the afternoon of the day of transplantation (day 1) and were given at 0800 and 1700 h for 6 days and at 0800 h on the eighth day. An additional experiment was performed in which adult male hamsters not bearing allografts were injected with the same regimen of LHRH or vehicle. The hamsters were decapitated on the eighth day of the study, 2 h after the last injection. The allografts, adenohypophyses of the hosts, adenohypophyses of hamsters without allografts, and adenohypophyses of normal adult male rats were removed and frozen on dry ice immediately. Additionally, adenohypophyses were collected from hamster pups less than 36 h old and 8 and 15 days of age. Total RNAs from some pooled specimens were electrophoresed on a formaldehyde-agarose gel. After transfer to Nytran, the RNAs were hybridized sequentially to complementary DNAs for rat FSH beta and hamster beta-actin. The rat FSH beta complementary DNA probe hybridized to a single RNA (approximately 1.7 Kb) in rat adenohypophyses. It predominantly hybridized to RNA of approximately 1.7 Kb from hamster adenohypophyses. Sometimes it hybridized to RNAs ranging in size from 0.5 Kb to 1.7 kb. The hybridization signals for all samples obtained from dot blot analyses were quantitated and normalized to the signals for beta-actin. The hybridization signals obtained from adenohypophyses of hamsters of different ages increased from 36 h of age to adulthood. The hybridization signal obtained from adenohypophyses of hamsters less than 36 h old (the same age as the donor hamsters) was similar to the hybridization signal obtained from allografts in vehicle-treated hamsters. The relative levels of FSH beta mRNA in allografts of LHRH-treated hosts were: 1) greater than the relative levels in adenohypophyses of hamsters less than 36 h old (P less than 0.05) and in allografts in vehicle-treated hamsters (P less than 0.05), 2) greater than the relative levels in adenohypophyses of 8-day-old hamsters (P less than 0.05), and 3) not different compared to the relative levels in adenohypophyses of 15-day-old hamsters and adult male hamsters.(ABSTRACT TRUNCATED AT 400 WORDS)

We investigated the reason for the high mortality we had observed in hypophysectomized-orchidectomized Golden Syrian hamsters that were anesthetized with intraperitoneal (i.p.) injections of chloral hydrate (CH). Intact male Golden Syrian hamsters were injected intraperitoneally with 0.1cc/100g BW of a 35% solution of CH, a 35% solution of sodium chloride, or double-distilled water. Equal numbers of hamsters in each group were injected on the right or left side of the abdomen. Within 10 days, 35% of the CH-injected hamsters were dead or had to be euthanized. Autopsy revealed severe peritonitis and adynamic ileus. CH-injected hamsters that survived gained weight at a rate similar to that of the controls. All surviving hamsters were killed 18 days after the injections. Among the surviving CH-injected hamsters, 84.6% had intra-abdominal adhesions, 61.5% had unilateral testicular atrophy, and 53.8% had a yellowish necrotic mass in the epididymal fat pad (EFP). All the lesions occurred on the side that was injected. The atrophied testes had been rendered cryptorchid due to involvement with intra-abdominal adhesions. In the water-treated controls, there were no abnormalities; whereas, in the saline controls, 75% had a mass in the EFP. Histology of the EFP mass was similar in hamsters injected with CH or hypertonic saline and suggested a diagnosis of fat necrosis. The results suggest that the mortality, the intra-abdominal adhesions, and the unilateral cryptorchidism were caused by a single i.p. injection of CH, but the fat necrosis in the EFP was probably caused by high concentrations of salt. The results further suggest that high concentrations of CH should not be injected intraperitoneally for anesthesia in chronic studies, particularly of the male reproductive system.

These experiments were undertaken to investigate the effects of systemically administered neuropeptide Y (NPY) on gonadotropin secretion in the intact male rat and to determine whether the effects observed might be mediated by a direct action of NPY alone on the anterior pituitary gland (APG). Subcutaneous administration of 10 μg of NPY caused a greater than 2-fold increase in serum luteinizing hormone (LH) concentration at 15 min after injection but was without effect on serum follicle-stimulating hormone (FSH) or thyrotropin-stimulatng hormone (TSH) levels. The addition of NPY (final concentrations of 10−8 to 10−11 M) or the structurally similar neuropeptide, rat pancreatic polypeptide, to culture medium containing hemi-APG did not alter the release of LH, FSH, or TSH. The results indicate that systemically administered NPY can elevate serum LH concentration in intact male rats. This effect does not appear to be due to NPY acting alone at the level of the APG.

Recent reports indicate that luteinizing hormone-releasing hormone (LHRH) releases prolactin (PRL) under some circumstances. We examined the chronic effects of LHRH, growth hormone-releasing hormone (GHRH), and corticotrophin-releasing hormone (CRH) on the release of PRL, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) by pituitary allografts in hypophysectomized, orchidectomized hamsters. Entire pituitary glands removed from 7-week-old-male Golden Syrian hamsters were placed under the renal capsule of hypophysectomized, orchidectomized 12-week-old hamsters. Beginning 6 days postgrafting, hamsters were injected subcutaneously twice daily with 1 microgram LHRH, 4 micrograms GHRH, or 4 micrograms CRH in 100 microliter of vehicle for 16 days. Six hosts from each of the four groups were decapitated on Day 17, 16 hr after the last injection. Prolactin, LH, and FSH were measured in serum collected from the trunk blood. Treatment with LHRH significantly elevated serum PRL levels above those measured in the other three groups, which were all similar to one another. Serum LH levels in hosts treated with vehicle were elevated above those measured in the other three groups. Serum FSH levels in hosts treated with LHRH were greater than FSH levels in any of the other three groups. These results indicate that chronic treatment with LHRH can stimulate PRL and FSH release by ectopic pituitary cells in the hamster.

We studied whether an increase in the basal LH release rate and/or the anterior pituitary gland (APG) LH response to LHRH is involved in maintaining normal or near-normal serum LH levels in monosodium L-glutamate (MSG)-treated rats which have small APGs for their body weight. Female rats were injected with MSG (4 mg/g BW) or saline on days 1, 3, 5, 7, and 9 after birth (day of birth = 0). At 8-9 weeks of age, saline-treated and MSG-treated rats were ovariectomized, and 7 days later, they were decapitated. Trunk blood was collected from 18 controls and 19 MSG-treated rats, and serum LH concentrations were measured by RIA. APGs were bisected and each hemi-APG was placed in culture medium for a 30-min preincubation period, followed by two 30-min incubation periods during which water or 10 or 30 ng LHRH were added to the medium. Despite the fact that the APGs of the MSG-treated rats were half the size of those of the saline-treated rats, the serum LH levels in the 2 groups were not different. Basal LH release rates (the response to water) and LHRH-induced LH release per mg APG were increased in MSG-treated rats. Calculation of the basal LH release rates and LHRH-induced LH release on the basis of the entire weights of the APGs showed no differences between the MSG-treated rats and the controls. In 6 additional control and 6 additional MSG-treated rats, the APG LH concentration was measured and was not different between the 2 groups. The results suggest that increases in both the basal LH release rate per mg APG and the amount of LH released per mg APG in response to LHRH are of importance in the maintenance of normal or near-normal serum LH concentrations in MSG-treated rats with small APGs.

We have studied gonadotrophin secretion and immunocytochemically stained gonadotrophs and mammotrophs in 35-day-old female rats which had been treated with monosodium glutamate (MSG) as neonates. We also compared our morphometric data in the saline-treated controls with those we have previously obtained in normal adult female rats. The size of the anterior pituitary glands was reduced but the serum levels, the pituitary gland concentrations and contents, and the in-vitro basal release rates of LH and FSH were not significantly altered by MSG treatment. The size of the LH and FSH cells was reduced by MSG administration, but the volume and numerical densities of LH and FSH cells, and the percentage of LH and FSH cells in the pars distalis were not affected. The results suggest that in spite of the smaller size of LH and FSH cells and of the anterior pituitary glands in the MSG-treated rats, the cells contain normal amounts of hormone and the basal LH and FSH secretion rates of the glands are not significantly depressed, contributing to the maintenance of normal serum gonadotrophin concentrations. The volume density of prolactin cells was not increased by MSG treatment. The volume density of gonadotrophs and the percentage of cells which are gonadotrophs in anterior pituitary glands of prepubertal female rats were greater than those in adult female rats, but the reverse was true for the volume density of prolactin cells, suggesting a reciprocal relationship between the relative numbers of gonadotrophs and mammotrophs in prepubertal and adult female rats.

We analysed cell types in the pars distalis of normal young adult male and female rats with respect to their percentages and the relative volumes they occupy. In male rats the percentages of the cell types were: prolactin 49.80, GH 22.67, LH 5.04, FSH 4.22, ACTH 2.93 and TSH 2.09. The volume densities were: prolactin 20.48, GH 20.95, LH 7.34, FSH 6.73, ACTH 3.75 and TSH 3.19. In female rats the percentages of the cell types were: prolactin 52.40, GH 20.30, LH 5.89, FSH 4.06, ACTH 2.53, TSH 2.40 and the volume densities were: prolactin 28.09, GH 20.86, LH 8.11, FSH 5.46, ACTH 3.49 and TSH 2.91. The percentages of pars distalis cells which did not stain with the antisera to the six classical hormones were 17.47 in male and 16.48 in female rats. The results suggest that (1) in both sexes the number (N) of prolactin cells greater than N of GH cells greater than N of gonadotrophs greater than N of TSH or ACTH cells, (2) the percentage of each cell type was similar in both sexes, (3) the volume density (Vv) of prolactin cells was greater than the Vv of GH cells in female but not in male rats and in both sexes the Vv of GH cells greater than the Vv of gonadotrophs greater than the Vv of TSH or ACTH cells, (4) in both sexes the volume (V) of prolactin cells less than the V of GH cells less than the V of gonadotrophs, the V of TSH cells or the V of ACTH cells, (5) the V of prolactin cells was greater in female than in male rats and (6) approximately 17% of the cells in the pars distalis of both sexes did not contain 'immunoreactive' prolactin, GH, LH, FSH, TSH or ACTH.