Delayed sexual maturation in the female rat during chronic exposure to delta-9-tetrahydrocannabinol

delta-9-Tetrahydrocannabinol (THC), the major psychoactive component of marihuana, retarded sexual maturation in the pubertal female rat as indicated by a delayed appearance of estrus and ovulation. Twice daily intraperitoneal injections of 10 mg THC/kg body weight from 27 days of age until the first day of full vaginal cornification delayed the onset of estrus and the occurrence of the first ovulation by an average of 4.3 +/- 0.9 (S.E.M.) days in comparison with pair-fed, vehicle-treated animals (p less than 0.001). Ovulation during the first estrus occurred in 92% of the animals in each treatment group without a difference in the average number of ova ovulated. The delayed sexual maturation in animals treated with THC could not be attributed to reduced body weight gain since body weights in THC- and vehicle-treated groups were equivalent when vehicle-treated animals came into estrus. Delayed ovulation in THC-treated animals did not merely reflect the repeated blockade of ovulation from otherwise competent follicles in that the onset of vaginal cornification was delayed to a comparable extent. Rather, the data suggest retarded development of ovarian follicles, possibly as a result of pituitary suppression. It is noteworthy that, although delayed, both vaginal cornification and ovulation occurred in spite of continued THC treatment, suggesting the development of drug tolerance.     

Blockade of first ovulation in pubertal rats by delta-9-tetrahydrocannabinol: requirement for advanced treatment due to early initiation of the critical period

Successful blockade of ovulation in pubertal rats by delta-9-tetrahydrocannabinol (THC) required earlier treatment during proestrus than was required in adults under the same conditions. Only 1 of 8 adult rats ovulated after treatment with THC (10 mg/kg body weight, i.p.) at 1400 h proestrus, whereas 77% of pubertal rats released full sets of ova following similar treatment during proestrus of the first or second vaginal cycle. When treatment of pubertal rats was advanced to 1300 h, only 2 of 10 THC-treated rats exhibited full ovulation, an incidence significantly lower than the 80% ovulation rate observed in vehicle-treated animals (p less than 0.05). To determine whether the requirement for earlier THC treatment in pubertal rats was related specifically to THC or reflected possible age-associated differences in timing of the critical period, the ovulation-blocking efficacy of atropine sulfate (ATR) was tested in pubertal rats for comparison with that of THC. The serum concentrations of luteinizing hormone (LH) during the first proestrus (1200-1900 h) were determined in pubertal rats that remained untreated. The incidence of ovulation in rats treated with ATR (350 mg/kg, s.c.) at 1400 h proestrus was not significantly reduced from that in vehicle-treated rats; however, after ATR treatment at 1300 h, only 2 of 11 animals released full sets of ova whereas all vehicle-treated rats ovulated (p less than 0.025). The mean serum LH concentration in untreated pubertal rats was not significantly increased over baseline at 1300 h proestrus, but was markedly elevated by 1400 h (1009 +/- 375 ng/ml; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of acute and subchronic delta 9-tetrahydrocannabinol administration on the plasma catecholamine, beta-endorphin, and corticosterone levels and splenic natural killer cell activity in rats

The effect of acute (1 day) or subchronic (25 days) treatment with delta 9-tetrahydrocannabinol (THC), the major psychoactive constituent of marihuana, on plasma norepinephrine (NE), epinephrine (E), corticosterone, beta-endorphin (beta-end), and splenic natural killer (NK) cell activity of the rat was studied. Groups of animals received subcutaneously, either THC in corn oil + saline (3 mg THC/kg); oil + saline; or THC + naloxone (2 mg naloxone/kg and 3 mg THC/kg). Acute injection of THC with or without naloxone did not significantly change plasma levels of NE, E corticosterone, beta-end, or the NK cell activity. However, subchronic treatment with THC significantly reduced plasma levels of NE, E, corticosterone, and NK cell activity, compared to controls. The plasma beta-end levels were significantly elevated in the THC-treated animals. In the THC + naloxone group of animals, the plasma hormone levels (corticosterone and beta-end) were similar to control levels and the NK cell activity was significantly higher than in THC-treated animals. These results indicate that subchronic exposure to THC results in suppression of splenic NK cell activity. The interaction of THC with the endogenous opiate system appears to be a contributing factor leading to the NK cell suppression in rats. A direct suppressive action of THC or its metabolites on the NK cell is not ruled out by this study.     

Delta-9-tetrahydrocannabinol inhibits antitumor immunity by a CB2 receptor-mediated, cytokine-dependent pathway

In this study, we show that Delta-9-tetrahydrocannabinol (THC), the major psychoactive component of marijuana, suppresses host immune reactivity against lung cancer. In two different weakly immunogenic murine lung cancer models, intermittent administration of THC (5 mg/kg, four times/wk i.p. for 4 wk) led to accelerated growth of tumor implants compared with treatment with diluent alone. In contrast to our findings in immunocompetent mice, THC did not affect tumor growth in tumor-bearing SCID mice. The immune inhibitory cytokines, IL-10 and TGF-beta, were augmented, while IFN-gamma was down-regulated at both the tumor site and in the spleens of THC-treated mice. Administration of either anti-IL-10- or anti-TGF-beta-neutralizing Abs prevented the THC-induced enhancement in tumor growth. Both APC and T cells from THC-treated mice showed limited capacities to generate alloreactivity. Furthermore, lymphocytes from THC-treated mice transferred the effect to normal mice, resulting in accelerated tumor growth similar to that seen in the THC-treated mice. THC decreased tumor immunogenicity, as indicated by the limited capacity for tumor-immunized, THC-treated mice to withstand tumor rechallenge. In vivo administration of a specific antagonist of the CB2 cannabinoid receptor also blocked the effects of THC. Our findings suggest the THC promotes tumor growth by inhibiting antitumor immunity by a CB2 receptor-mediated, cytokine-dependent pathway.     

delta 9-Tetrahydrocannabinol antagonism of the anterior pituitary response to estradiol in immature female rats.

The potential estrogenicity or antiestrogenicity of delta 9-tetrahydrocannabinol (THC), the chief psychoactive constituent of marijuana, was evaluated in immature female rats treated for 3 days with estradiol (E2; 1 microgram/kg), THC (10 mg/kg body weight), or E2 + THC. Estradiol treatment significantly increased anterior pituitary, uterine, and oviduct weights. When THC was administered with E2, it prevented the E2-induced increase in pituitary weight, but had no effect on either the uterine or oviduct weight response to E2. In the E2 treatment group, basal prolactin levels were increased and a prolactin surge occurred on the afternoon of the 26th day of age. However, E2-stimulated basal and surge levels of prolactin were significantly attenuated by concomitant THC treatment. Moreover, pituitary prolactin concentrations, which were elevated in E2-treated rats, did not differ from control values in E2 + THC-treated animals. The E2-induced decrease in dopamine turnover rates in the medial basal hypothalamus and increase in the number of anterior pituitary dopamine D2-binding sites (Bmax) were not affected by concomitant THC treatment. Thus, THC antagonizes E2 action on the anterior pituitary via yet to be elucidated mechanism(s).     

Tetrahydrocannabinol suppresses immune function and enhances HIV replication in the huPBL-SCID mouse

Epidemiologic studies identify marijuana as a potential cofactor in the development and progression of HIV infection. To evaluate this interaction we employed a hybrid model in which human peripheral blood leukocytes (PBL) were implanted into severe combined immunodeficient mice (huPBL-SCID) and infected with an HIV reporter construct in the presence or absence of tetrahydrocannabinol (THC) exposure. Administration of THC alone, in the absence of HIV, decreased CD4 counts and the CD4:CD8 ratio. Co-administration of THC and HIV did not reduce CD4 counts further, but significantly increased the percentage of HIV-infected PBL when compared to saline-treated animals (17+/-4.6% vs. 7+/-1.4%). Quantitative PCR confirmed a 50-fold increase in systemic viral load in THC-treated animals. The CCR5 and CXCR4 chemokine receptors function as coreceptors essential for HIV infection. Administration of THC for 5 days increased the percentage of PBL expressing CCR5 and, to a lesser extent, CXCR4. This effect was lost after 10 days of THC administration, but the number of HIV-infected cells had significantly increased by that time suggesting a role for early upregulation of these coreceptors in the pathogenic effect of THC. Finally, the impact of treatment on the number of human interferon-gamma (IFN-gamma) producing cells was determined by ELISPOT. Both THC and HIV infection independently decreased the number of IFN-gamma producing cells and co-administration produced additive effects. These results suggest that exposure to THC in vivo can suppress immune function, increase HIV coreceptor expression, and act as a cofactor to significantly enhance HIV replication.     

三聚氰胺等物质给予幼年恒河猴的毒性试验

目的观察三聚氰胺及其同系物给予动物后,导致肾脏损伤、形成结石的过程,及肾脏损伤的恢复过程。方法选择6月龄恒河猴6只,雌雄各半,随机分为3组,2只/组,分别为T1（140 mg/kg三聚氰胺和14 mg/kg三聚氰酸）,T2（140 mg/kg三聚氰胺和50mg/kg腺嘌呤）和T3组（140mg/kg三聚氰胺）。连续70 d口服受试物,观察动物的一般状态,分别于不同时间点进行血液学、血生化、尿常规和肾脏B超的检测;并连续观察18个月,观察动物的生长发育情况。结果 1.各剂量组动物在给予受试物8周后所有动物肾脏中均出现多个结石;停止给予受试物后,所有动物结石数量和大小均呈下降趋势,至停止给予受试物16个月后,全部动物肾脏均未检测出结石。2.各剂量组,血清中β2微球蛋白（β2-MG）和尿酸（UA）等指标随着给药时间的延长而有所增高,但在正常范围内。在动物的恢复期,此两项指标的数值明显下降。结论 1.单纯三聚氰胺（相当于人体使用量48 mg/kg.w.d）不能造成恒河猴肾脏功能的明显损害,可形成肾结石。2.在三聚氰酸或腺嘌呤存在的情况下,三聚氰胺可以造成恒河猴肾功能指标β2-MG和UA在正常范围内升高,并可在肾脏形成结石;。3.经过16个月的恢复所有动物结石无法检出,其中三聚氰胺组动物恢复最快。     

甲、乙型肝炎联合疫苗接种恒河猴的初步观察

为了探索联合接种甲乙肝疫苗、实验性甲乙肝联合疫苗免疫恒河猴的安全性及免疫原性。实验中挑选了甲肝抗体阴性,乙肝两对半阴性,肝功能指标正常的健康恒河猴24只,随机分为10组。混合或分别接种,进行不同毒株的甲肝灭活疫苗与不同厂家的乙肝疫苗的配对效果比较。并接种了实验性甲乙肝联合疫苗;史克甲乙肝联合疫苗试验组。设甲肝单价灭活疫苗L8株、深圳乙肝单价疫苗作为对照。免疫方案0、4、24w。每只恒河猴接种lml。接种3d内,每天观察动物有无不良反应。接种1针和2针后4w内,每2w采集空腹静脉血,以后每4w采血1次检测抗HAV、抗HBs、ALT、AST直至40w。接种疫苗后4、8、24、28w穿刺肝组织做病理学检查。结果显示接种疫苗后3d内,所有恒河猴均无不良反应。ALT、AST无异常升高。4、8、24、28w肝组织无特殊病理改变。注射2针后4w,除3组外,其余各组抗HAV及抗HBs均阳转。3组抗HAV阳转时间迟至12w。全程免疫后12w(即40w),抗HAVGMT为258.75～37489.50mIU/ml;抗HBsGMT为8263.68～60008.064mIU/ml。甲乙肝疫苗联合免疫及实验性的甲乙肝联合疫苗接种恒河猴安全性及免疫原性均良好。     

Cannabinoids reduce fertility of sea urchin sperm

Cannabinoids are potent pharmacological substances derived from marihuana. The effects of delta 9-tetrahydrocannabinol (THC), cannabinol (CBN), and cannabidiol (CBD) on fertilization in the sea urchin Strongylocentrotus purpuratus were investigated. Insemination of THC-treated eggs (5-400 microM) with excess sperm did not result in polyspermic fertilization. At minimal sperm densities, THC (0.1-10 microM) inhibited fertilization in a dose-dependent manner. Pretreatment of eggs with THC did not reduce their receptivity to sperm. Pretreatment of sperm with THC reduced their fertilizing capacity. The concentration of THC required to reduce sperm fertility by 50% was 1.1 +/- 1.1 microM. The fertilizing capacity of THC-treated sperm depended on concentration of sperm and duration of pretreatment. The fertility of sperm at minimal densities was reduced by 50% at 129.3 +/- 43 s treatment with 10 microM THC. The adverse effect of THC on sperm fertility was reversible. CBN and CBD at comparable concentrations (0.1-10 microM) inhibited fertilization in a manner similar to THC. First division was not delayed in zygotes that were fertilized with sperm pretreated with 10 microM THC. These studies show that cannabinoids directly affect the process of fertilization in sea urchins by reducing the fertilizing capacity of sperm.     

Interactions of aging and annual rhythms on the recovery of cryopreserved murine splenic lymphocytes

The physiological status of donor organisms is an often overlooked factor in cryopreservation experiments. Murine splenic lymphocytes exhibit systematic changes in function which are endogenous and influence recoveries of viable and functional frozen-thawed cells over the life span of mice. One of these changes is the decline in the performance of unfrozen cells as organisms age. Superimposed on the age-related decline in lymphocyte functions are circannual rhythms in T- and B-cell mitogenesis, and the properties of these rhythms also change with age. Splenocytes from young, 15-month-old and 23- to 27-month-old C57BL/6 mice were cryopreserved and tested for recovery of mitogenic responses to activation by the T-cell mitogens, phytohemagglutinin and concanavalin A, and the B-cell mitogen, lipopolysaccharide. Tritiated thymidine incorporation by activated, dividing cells was determined after 72 hr of in vitro culture. Seasonal patterns in recovery of viable and functional cryopreserved cells from young mice resembled those of their unfrozen controls (6). By 15 months of age, the responses after freeze-thaw stress decreased to the levels observed for cells obtained from senescent mice, and seasonal patterns were no longer observed. In these middle-aged mice, intracellular changes in lymphocytes that are equivalent to those in senescent animals resulted in irreparable structural-functional injury during cryopreservation.     

Effect of tetrahydrocurcumin on insulin receptor status in type 2 diabetic rats: studies on insulin binding to erythrocytes

Curcumin is the most active component of turmeric. It is believed that curcumin is a potent antioxidant and anti-inflammatory agent. Tetrahydrocurcumin (THC) is one of the major metabolites of curcumin, and exhibits many of the same physiological and pharmacological activities as curcumin and, in some systems, may exert greater antioxidant activity than curcumin. Using circulating erythrocytes as the cellular mode, the insulin-binding effect of THC and curcumin was investigated. Streptozotocin (STZ)-nicotinamide-induced male Wistar rats were used as the experimental models. THC (80 mg/kg body weight) was administered orally for 45 days. The effect of THC on blood glucose, plasma insulin and insulin binding to its receptor on the cell membrane of erythrocytes were studied. Mean specific binding of insulin was significantly lowered in diabetic rats with a decrease in plasma insulin. This was due to a significant decrease in mean insulin receptors. Erythrocytes from diabetic rats showed a decreased ability for insulin-receptor binding when compared with THC-treated diabetic rats. Scatchard analysis demonstrated that the decrease in insulin binding was accounted for by a decrease in insulin receptor sites per cell, with erythrocytes of diabetic rats having less insulin receptor sites per cell than THC-treated rats. High affinity (K d1), low affinity (K d2) and kinetic analyses revealed an increase in the average receptor affinity of erythrocytes from THC-treated rats compared with those of diabetic rats. These results suggest that acute alteration of the insulin receptor on the membranes of erythrocytes occurred in diabetic rats. Treatment with THC significantly improved specific insulin binding to the receptors, with receptor numbers and affinity binding reaching near-normal levels. Our study suggests the mechanism by which THC increases the number of total cellular insulin binding sites resulting in a significant increase in plasma insulin. The effect of THC is more prominent than that of curcumin.     

Neurotoxicity of Glucocorticoids in the Primate Brain

Severe and prolonged physical and psychological stress is known to cause brain damage; long-term torture victims in prison bare later developed psychiatric disorders and cerebral cortical atrophy observed in CT scans (Jensen, Genefke, Hyldebrandt, Pedersen, Petersen, and Weile. 1982). In nonhuman primates, we observed degeneration and depletion of the hippocampal neurons in African green monkeys that had been severely abused by cagemates and died with complications of multiple gastric ulcers and adrenal cortical hyperplasia (Uno, Tarara, Else, Suleman and Sapolsky, 1989). In our previous studies the administration of dexamethasone (DEX) (5 mg/kg) to pregnant rhesus monkeys at 132 to 133 days of gestation induced degeneration and depletion of the hippocampal pyramidal and dentate granular neurons in the brains of 135-gestation-day fetuses, and these changes were retained in the brains of fetuses at near term, 165 days of gestation (Uno, Lohmiller, Thieme, Kemnitz, Engle, Roecker, and Farrell, 1990). We also found that implantation of a cortisol pellet in the vicinity of the hippocampus in adult vervet monkeys induced degeneration of the CA3 pyramidal neurons and their dendritic branches (Sapolsky, Uno, Rebert, and Finch, 1990). Thus, hippocampal pyramidal neurons containing a high concentration of glucocorticoid receptors appear to be highly vulnerable to either hypercortisolemia caused by severe stress or to exposure to exogenous glucocorticoids. To study the long-term postnatal sequelae of prenatal brain damage, eight rhesus monkeys were treated with either DEX (5 mg/kg), 5 animals, or vehicle, 3 animals, at 132 to 133 days of gestation. After natural birth, all animals lived with their mothers for 1 year. At 9 months of age, we found that DEX-treated animals had significantly high plasma cortisol at both base and post stress (isolation) levels compared to age-matched vehicle-treated animals. Magnetic resonance images (MRI) of the brain at 20 months of age showed an approximately 30% reduction in size and segmental volumes of the hippocampus in DEX-treated compared to vehicle-treated animals. Measurements of whole brain volume by MRI showed no significant differences between DEX and vehicle groups. Prenatal administration of a potent glucocorticoid (DEX) induced an irreversible deficiency of the hippocampal neurons and high plasma cortisol at the circadian baseline and post-stress levels in juvenile rhesus monkeys. These results suggest that the hippocampus mediates negative feedback of cortisol release; a lack or deficiency of the hippocampal neurons attenuates this feedback resulting in hypercortisolemia. The hippocampal deficiency in rhesus monkeys induced by prenatal administration of DEX appears to be a good model for neuroendocrinological dysfunctions and hippocampal development in human juveniles whose mothers were exposed to severe stress or received a high dose of glucocorticosteroids during pregnancy.     

Sex-Dependent Psychoneuroendocrine Effects of THC and MDMA in an Animal Model of Adolescent Drug Consumption

Ecstasy is a drug that is usually consumed by young people at the weekends and frequently, in combination with cannabis. In the present study we have investigated the long-term effects of administering increasing doses of delta-9-tetrahydrocannabinol [THC; 2.5, 5, 10 mg/kg; i.p.] from postnatal day (pnd) 28 to 45, alone and/or in conjunction with 3,4-methylenedioxymethamphetamine [MDMA; two daily doses of 10 mg/kg every 5 days; s.c.] from pnd 30 to 45, in both male and female Wistar rats. When tested one day after the end of the pharmacological treatment (pnd 46), MDMA administration induced a reduction in directed exploration in the holeboard test and an increase in open-arm exploration in an elevated plus maze. In the long-term, cognitive functions in the novel object test were seen to be disrupted by THC administration to female but not male rats. In the prepulse inhibition test, MDMA-treated animals showed a decrease in prepulse inhibition at the most intense prepulse studied (80 dB), whereas in combination with THC it induced a similar decrease at 75 dB. THC decreased hippocampal Arc expression in both sexes, while in the frontal cortex this reduction was only evident in females. MDMA induced a reduction in ERK1/2 immunoreactivity in the frontal cortex of male but not female animals, and THC decreased prepro-orexin mRNA levels in the hypothalamus of males, although this effect was prevented when the animals also received MDMA. The results presented indicate that adolescent exposure to THC and/or MDMA induces long-term, sex-dependent psychophysiological alterations and they reveal functional interactions between the two drugs.     

Effects of intrinsic and extrinsic factors on the haemocyte profile of the prawn, Macrobrachium rosenbergii

The giant freshwater prawn Macrobrachium rosenbergii was investigated for its total haemocyte count (THC) based on season, sex, size and feeding rate. The THC, when the prawns were subjected to injections of foreign materials was also investigated. The prawns displayed the highest and lowest THC in autumn and winter respectively, with no significant difference between male and female, or among animals with a body weight range of 7-115 g. The prawns displayed the lowest THC at D3 stage, and the highest in C stage. The prawns displayed the lowest THC when they were fed at 0.1% feeding rate among feeding rates of 0.1%, 0.5%, 1.0% and 1.5% body weight x day(-1). Prawns injected with carbon powder and Enterococcus showed increased THC during the first 6 h. Prawns injected with saline and carbon powder had the lowest THC after 30 h, and recovered to the normal value after 54 h. Prawns injected with Enterococcus showed the lowest THC after 42 h, and showed delayed recovery.     

Antiretroviral therapy during primary immunodeficiency virus infection can induce persistent suppression of virus load and protection from heterologous challenge in rhesus macaques

A limited period of chemotherapy during primary immunodeficiency virus infection might provide a long-term clinical benefit even if treatment is initiated at a time point when virus is already detectable in plasma. To evaluate this strategy, we infected rhesus macaques with the pathogenic simian/human immunodeficiency virus RT-SHIV and treated them with the antiretroviral drug (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA) for 8 weeks starting 7 or 14 days postinfection. PMPA treatment suppressed viral replication efficiently in all of the monkeys. After chemotherapy ended, virus replication rebounded and viral RNA in plasma reached levels comparable to that of the controls in four of the six monkeys. However, in the other two animals, virus loads peaked only moderately after withdrawal of the drug and then declined to low or even undetectable levels. These low levels of viremia remained stable for at least 31 weeks after cessation of therapy. At this time point, these two monkeys were challenged with SIV(8980) to evaluate whether the host responses which were able to keep RT-SHIV replication under control were also sufficient to protect against infection with a highly pathogenic heterologous virus. Both monkeys proved to be protected against the heterologous virus. In one of the two animals, low levels of SIV(8980) replication were detected. Thus, by chemotherapy during the acute phase of pathogenic virus replication, we could achieve not only persistent virus load suppression in two out of six monkeys but also protection from subsequent heterologous challenge. By this chemotherapeutic attenuation, the replication kinetics of attenuated viruses could be mimicked and a vaccination effect similar to that induced by live attenuated simian immunodeficiency virus vaccines was achieved.     

Gonadotropin-independent proliferation of the pale type A spermatogonia in the adult rhesus monkey (Macaca mulatta)

The goal of the present study was to examine the relative roles of testosterone (T) and FSH in the proliferation and differentiation of pale type A (Ap) spermatogonia in the rhesus monkey (Macaca mulatta). Twenty adult male monkeys were treated with daily injections of a GnRH-receptor antagonist, acyline, to suppress endogenous gonadotropin secretion during an experiment comprising three phases. Phase 1 established a chronic hypogonadotropic state marked by a profound decrease in testicular size. During phase 2, half the monkeys were implanted with T-filled capsules, and the other half received control implants. Treatment with T produced circulating T levels of approximately 15 ng/ml and normal testicular T content. At the end of phase 2, monkeys were fitted with indwelling i.v. catheters and housed in remote sampling cages for the final phase. During phase 3, five monkeys from the T- and non-T-treated groups were stimulated with recombinant human FSH. The remaining five monkeys from each group received an infusion of vehicle. On the last day of FSH or vehicle infusion, monkeys were bilaterally castrated after receiving an i.v. bolus of bromodeoxyuridine (BrdU). The BrdU labeling of Ap spermatogonia was robust in the hypogonadotropic group and was uninfluenced by treatment with T and FSH, either alone or in combination. In contrast, both T and FSH stimulated spermatogonial differentiation, and this effect was amplified by combined treatment. We conclude that marked Ap spermatogonial proliferation occurs constitutively and in a gonadotropin-independent manner and that differentiation of Ap into B spermatogonia is absolutely gonadotropin dependent and may be driven by either T or FSH.     

Effect of inhibition of estrogen synthesis during the luteal phase on function of the corpus luteum in rhesus monkeys

It has been hypothesized that estrogen synthesized by the corpus luteum initiates luteal regression during the nonfertile menstrual cycle in primates. To study the role of endogenous estrogens in functional regression of the monkey corpus luteum, we administered the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD) to rhesus monkeys during the luteal phase of the menstrual cycle. Twice-daily oral administration of ATD suppressed systemic and intraluteal estrogen levels by 80-90%. The midluteal phase rise in estradiol concentrations that occurs in rhesus monkeys was completely abolished by ATD treatment. Despite suppression of estrogen synthesis during the luteal phase, mean menstrual cycle length and length of the luteal phase were not different than in control monkeys treated with vehicle only. Progesterone levels were lower in the ATD-treated group on the second and third day of treatment, but did not differ from control levels during the remainder of the cycle. These data suggest that elevated estrogen synthesis during the luteal phase of the menstrual cycle is not a prerequisite for spontaneous luteolysis in rhesus monkeys.     

Inhibition of cerebroside synthesis in the brains of mice treated with L-cycloserine

Subcutaneous injection of L-cycloserine resulted in a 28% reduction in cerebroside levels in mouse brain but had no effect on the levels of gangliosides. In contrast, intraperitoneal injection results in a reduction of ganglioside as well as cerebroside + sulfatide levels. The route of injection influenced the degree of 3-ketodihydrosphingosine synthase inhibition. Intraperitoneal injection caused a rapid decrease in synthase activity followed by recovery over 48 hr, whereas subcutaneous injection resulted in no inhibition over this time; only after daily injection for a week was synthase activity reduced 35%. One week following cessation of L-cycloserine administration, enzyme activity had recovered, whereas the cerebroside level continued to fall. All lipids and enzymes showed normal levels 3 weeks post-cycloserine administration. L-[3H]serine incorporation into glycolipids showed that cerebroside synthesis was most affected, whereas sulfatide synthesis was less affected. One week after cessation of cycloserine treatment, cerebroside synthesis was still severely inhibited, whereas sulfatide levels were near normal. Two weeks after cessation of L-cycloserine administration, synthesis of these glycolipids was similar to that of controls.     

Effects of fetectomy on plasma estrogens and progesterone in monkeys (Macaca mulatta)

Effects of fetectomy on peripheral plasma levels of estrogens and progesterone were studied at 10 weeks (3 monkeys) and 16 weeks gestation (4 monkeys). Fetectomy was followed by a decrease in maternal peripheral plasma estradiol 17-β (E₂) at a time when E₂ levels remained elevated in intact pregnant monkeys. Estrone (E₁) levels, initially low at fetectomy (10 weeks), were maintained at similar low levels in contrast to elevated concentrations observed in normal animals during the final 30 days of pregnancy. In the absence of the fetus, progesterone (P) levels were similar to those of the normal pregnancies. After removal or delivery of the placenta, P levels decreased rapidly. Maternal hypophysectomy in one animal (10 weeks) produced a transient decrease in E₂ followed by recovery to control levels by 16 weeks. Subsequent fetectomy (16 weeks) was followed by a precipitous decline in maternal E₂ levels. In conclusion, results indicate: a fetal origin, possibly from adrenal precursors, for the major contribution of E₂ during the last 3 months and E₁ during the last month of gestation; and placental production of most of the P found in peripheral plasma of pregnant rhesus monkeys.     

Safe and efficient methods of autologous hematopoietic stem cell transplantation for biomedical research in cynomolgus monkeys

We have established safe and efficient methods for autologous hematopoietic stem cell (HSC) transplantation in cynomolgus monkeys (Macaca fascicularis) that include regimens of supportive care to ensure survival during hematopoietic reconstitution following otherwise lethal total body irradiation. Eleven young adult cynomolgus monkeys were studied. Bone marrow was aspirated from the ilium and/or tuber ischiae after administration of recombinant human stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF). Using the immunomagnetic selection method, CD34+ cells were then isolated (90 to 95% pure) as a fraction containing HSCs. Just prior to transplantation, the animals received myeloablative total body irradiation-500 to 550 cGy daily for two days. The monkeys re-infused with CD34+ cells developed moderate to severe myelosuppression, with some animals requiring intravenous hyperalimentation, antibiotic administration, and blood transfusion. Hematopoiesis was restored in all animals after transplantation. It took 12 days, on average, until the peripheral white blood cell count reached more than 1,000 cells/microl. Up to two years after transplantation, signs of radiation-induced pneumonitis or other radiation-related disorders were not evident at the aforementioned dose of irradiation. This transplantation model will be useful for testing new approaches using HSCs for therapy of many diseases and will offer unique insights into the biology of these cells.