Ovariectomy and age alter gonadotropin hormone releasing hormone-noradrenergic interactions

The noradrenergic (NA) system influences gonadotropin hormone releasing hormone (GnRH) neurons resulting in the luteinizing hormone surge. Direct neuroanatomical interactions between preoptic area (POA) GnRH neuronal elements and NA [i.e., dopamine-beta-hydroxylase (DBH)] terminals; effects of short-term ovariectomy (S-OVX) on these interactions; and the stability of these interactions with age were studied in young (5-month-old) proestrous, 5-month-old S-OVX (6d), old (24-month-old) constant diestrous, and 24-month-old long-term (L)-OVX mice. Proestrous females demonstrated direct interactions between NA terminals and GnRH neuronal elements. The percentage of GnRH dendritic profiles contacted by DBH terminals at proestrous (6.96 +/- 1.07%) did not differ versus young S-OVX females (4.55 +/- 0.91%). No GnRH-NA interactions were observed in old mice. S-OVX resulted in a decrease in DBH terminals but an increase in dendrite and nonmyelinated axon number versus young proestrous females (p < or = 0.05 ANOVA). Findings show direct GnRH-DBH interactions, confirm S-OVX effects on neural ultrastructure, and demonstrate some S-OVX changes resembling those in older mice. L-OVX failed to prevent aging changes. Diminished capacity to produce normal estrous cycles in aging females could result in part from absence of direct GnRH-DBH interactions.

Age-related alterations in the expression of prohormone convertase messenger ribonucleic acid (mRNA) levels in hypothalamic proopiomelanocortin mRNA neurons in the female C57BL/6J mouse

POMC processing is mediated by the prohormone convertases (PC1 and PC2). The cleavage of beta-endorphin-(1-31) is mediated by PC2. PC2 can also further cleave beta-endorphin-(1-31) to beta-endorphin-(1-27). We previously reported a significant increase in the proportion of beta-endorphin-(1-27) and -(1-27) forms in the arcuate nucleus (ARC) of the hypothalamus in middle-aged females with irregular estrous cycles (5-7 days) compared to young female C57BL/6J mice with regular cycles (4-5 days). Changes in processing enzymes may be a mechanism underlying this change. We compared ARC messenger RNA (mRNA) levels of PC1, PC2, and furin by Northern blot and in situ hybridization analyses in young, middle-aged, and old mice. Antisense complementary RNA probes to mouse PC1, PC2, and furin were radiolabeled and used in single label studies, alone or in combination with a mouse POMC digoxigenin-labeled complementary RNA probe for double label studies. For Northern blot analysis, young (4- to 5-month-old) normally cycling (4-5 days) mice at diestrus were compared to middle-aged (12- to 13-month-old) irregularly cycling (5-7 days) mice at diestrus. By Northern blot analysis, a significant increase (P < 0.05) in ARC PC2 mRNA levels was detected in middle-aged compared to young mice, but ARC PC1 and furin mRNA levels were unaltered. Single label in situ hybridization analysis confirmed these findings in the general neuron population. We also observed a significant reduction in ARC furin mRNA levels in old mice compared to either young or middle-aged mice. Double labeling in situ hybridization histochemistry demonstrated that PC2 mRNA levels were significantly increased (at least 2-fold) in POMC mRNA-containing neurons of middle-aged compared to young mice. Selective changes in PC2 mRNA levels in ARC POMC neurons are correlated with changes in beta-endorphin-(1-31) processing to beta-endorphin-(1-27)/(1-26) in middle-aged animals. Our data suggest that the natural age-related shift in beta-endorphin peptide processing is mediated by PC2.

Selective expression of major histocompatibility complex (MHC) antigens and modulation of T-cell differentiation in chickens with increased MHC-chromosome dosages

Increased dosage of genes belonging to the immunoglobulin superfamily may be responsible for some of the less noticeable but targeted phenotypic disturbances seen in trisomy conditions of humans and animals. We used an avian aneuploidy model to study the specific effects of extra major histocompatibility complex (MHC)-microchromosome dosage on the progression of thymocyte differentiation through a broad period of embryonic and neonatal development. The particular goal in the present investigation was to determine whether a reduction in the number of thymocytes, previously observed in the developing thymus of MHC aneuploids, is accompanied by particular alterations in thymocyte differentiation. We hypothesized that the subpopulation structure and/or developmental pattern for thymocyte differentiation are characteristically perturbed (delayed or modified) by increased MHC-chromosome dosage in cells. The regulation of MHC surface antigen expression in aneuploid thymocytes was also studied to detect dosage-dependent expression for one and possibly more sub-regions (class I, II, IV) of the avian MHC. Surface densities of MHC class I antigens on thymocytes were increased significantly at all ages studied, for example by 15% and 45% in trisomics and tetrasomics, respectively at 22 days post-hatching. The surface density of CT1 antigen, a thymocyte-specific marker, was also increased in a dosage-dependent manner, but only in juveniles. Increases in the proportion of alpha beta 1, TCR+ and CD3+ thymocytes were observed in juveniles, with no alterations in other TCR-expressing thymocytes. No major alterations in CD4 and CD8 thymocyte populations were observed. These results demonstrate a targeted effect of extra MHC-chromosome dosage towards enhanced class I and CT1, and not class II or IV, expression. The increased MHC-microchromosome dosage appears to influence primarily immature thymocytes expressing alpha beta 1 TCR and CD3.

Effects of age and long-term ovariectomy on the estrogen-receptor containing subpopulations of beta-endorphin-immunoreactive neurons in the arcuate nucleus of female C57BL/6J mice

We have reported a decrease in the number of arcuate nucleus (ARC)-immunoreactive beta-endorphin neurons in old (24 months) female C57BL/6J mice versus young (5 months) mice. Here, we have tested by immunocytochemistry whether age-related changes in beta-endorphin neuron numbers are selective for beta-endorphin neurons which do or do not contain estrogen receptors (E2R). We also compared beta-endorphin neuron number in mice with short- (S) and long-duration (L) ovariectomy (OVX), since the latter may protect against neuroendocrine aging. Mice were studied at 5 (young), 12 (middle-aged), or 23-24 months (old). When the mean number of neurons per tissue section (15 sections per animal) was examined, there were no significant differences between young and middle-aged S-OVX females for either beta-endorphin, E2R, or beta-endorphin/E2R neuron number. However, there were significant decreases in beta-endorphin-containing neurons in the oldest age group versus young females (young S-OVX: 74.4 +/- 11 (+/- SD) immunopositive neurons per tissue section, n = 10 mice; young L-OVX: 61.6 +/- 6.9, n = 6; old S-OVX: 45.7 +/- 9.9, n = 7; and old L-OVX: 37.5 +/- 7.3, n = 7). There were also decreases in beta-endorphin neurons which contained E2R in the oldest animals (young S-OVX: 16.6 +/- 6.4; young L-OVX: 13.7 +/- 1.3; old S-OVX: 9.2 +/- 1.8; L-OVX: 6.0 +/- 1.5) (p < 0.05 ANOVA). Both age (p < or = 0.001, two-way ANOVA) and ovarian status (p < or = 0.05) independently affected neuron number for both the beta-endorphin and beta-endorphin/E2R populations versus young mice. We tested whether the observed age and/or ovarian-related decreases were proportionally greater in the subpopulation of beta-endorphin neurons which contained E2R compared to the total beta-endorphin neuron population. In the oldest age group, there was no significant difference in the decrease with age in the population of beta-endorphin neurons which contained E2R and the total beta-endorphin population (p = 0.208). When we examined the E2R neuron population as compared to the beta-endorphin neuron populations, age-related decreases in the beta-endorphin neuronal population tended to be greater than the decreases seen in the E2R neuron population (p = 0.054 repeated measures ANOVA). The tyrosine hydroxylase (TH) neuron population was studied to test whether there were changes in another ARC neuron population.(ABSTRACT TRUNCATED AT 400 WORDS)

Hypothalamic processing of beta-endorphin in female C57BL/6J mice is altered at middle age

beta-Endorphin (beta-endo) (1-31) is the active opioid peptide product of pro-opiomelanocortin processing. Further post-translational modifications of beta-endo(1-31) yield beta-endo(1-27), (1-26) and their acetylated forms which are considered to be opiate receptor antagonists. Mechanistically, alteration in opiatergic properties is likely to result in the loss of a number of physiological functions including reproductive capacity. The purpose of this study was to determine whether there are changes in the way beta-endo neurones process the peptide with age in female C57BL/6J mice. Pooled extracts of arcuate nucleus (ARC) and preoptic area (POA) of 3- to 4-month-old normally cycling (4-5 days at dioestrus), 12- to 13-month-old irregularly cycling (5-7 days at dioestrus), 23- to 24-month-old acyclic (in persistent dioestrus) animals were subjected to reversed-phase HPLC (n = 4 experiments). Column fractions were assayed for beta-endo-like-immunoreactivity by sequence-specific RIAs. The opiate receptor active as well as opiate receptor antagonist forms of beta-endo were present in both ARC and POA at all three age groups although their ratios varied. beta-Endo(1-31), the active opiate, was the predominant form in young animals. At middle age there was a threefold (P < 0.05, ANOVA) increase in the antagonist forms of beta-endo and this was associated with a significant (P < 0.05, ANOVA) increase in the ratio of antagonist to active forms. This was accompanied by a trend toward an increase in acetylated forms of beta-endo in middle-aged mice. HPLC profiles from hypothalami of old animals more closely resembled those of young females. The increase in the antagonist forms of beta-endo at middle age may contribute to a decline of opiatergic influences in the female C57BL/6J mouse and suggest a mechanism whereby alterations in opiate influence over gonadotrophin control may occur.

Prevalence of spondyloarthropathies in Alaskan Eskimos

OBJECTIVE

To estimate the prevalence of spondyloarthropathies (SpA) in 2 Alaskan Eskimo populations, using improved methodology for case ascertainment and new, more inclusive classification criteria.

METHODS

Through existing rheumatic disease registries, health care providers and the Alaska Area Native Health Service (AANHS) computerized patient information system, we identified all native residents of the 2 study regions with a diagnosis of any inflammatory arthritis or problems characteristic of SpA, such as iritis or persistent back pain. Individuals with such diagnoses or problems were evaluated in clinic, according to a standardized protocol (interview, examination), and by medical record review, pelvic radiography and laboratory tests. Each case was evaluated according to standard diagnostic criteria for the individual disease entities and by the Amor and European Spondylarthropathy Study Group (ESSG) preliminary classification criteria for SpA.

RESULTS

We identified 104 cases of SpA in the combined Eskimo populations, an overall prevalence of 2.5% in adults aged 20 and over. Both undifferentiated (USpA) and reactive SpA were more common than ankylosing spondylitis (AS).

CONCLUSION

Using the new criteria and a more effective approach to case ascertainment we found the prevalence of SpA to be about twice that found in our earlier studies of adult Eskimo populations. The prevalence of SpA was very similar in men and women. Despite the known high prevalence (25-40%) of HLA-B27 in the study populations we did not find the prevalence of any form of SpA to be as strikingly high as that of AS (6-10%) for the Canadian Haida.

Syngeneic lysis of reticuloendotheliosis virus-transformed cell lines transfected with Marek's disease virus genes by virus-specific cytotoxic T cells

Cell-mediated immune responses against Marek's disease virus (MDV) antigens were examined using reticuloendotheliosis virus (REV)-transformed cell lines of two haplotypes (B19B19 and B13B13). These cell lines were stably transfected with cloned fragments of MDV DNA resulting in the expression of the MDV-specific phosphoprotein pp38. Effector cells were obtained from P2a (B19B19) and S13 (B13B13) chickens at 7 days post inoculation with REV, oncogenic or attenuated serotype 1 MDV (JM-16/O and JM-16/A, respectively), serotype 2 MDV (SB-1), or herpesvirus of turkeys (HVT). Transfection of MDV genes did not influence the expression of Class I major histocompatibility complex antigens. The optimal effector to target cell ratio was determined to be 100:1. REV-sensitized effector cells lysed REV cell lines and REV cell lines transfected with MDV DNA in a syngeneic fashion. Effector cells from chickens inoculated with JM-16/O, JM-16/A, SB-1 or HVT lysed only the syngeneic, transfected cell lines, but not the parent REV cell lines. The percentage specific release caused by the MDV-sensitized effector cells was low, but statistically significant.

Loss of fusion and the development of A or V patterns

To test the hypothesis that loss of fusion predisposes the ocular motor system to the development of A or V patterns, we reviewed the pre- and postoperative courses of patients with intermittent exotropia overcorrected with horizontal muscle surgery. Of 332 patients who had surgery, 21 experienced at least 1 month of consecutive esotropia. An equal number of age-matched patients who maintained fusion postoperatively served as controls. No patient in either group had a preoperative A or V pattern. At the first return visit, at least 4 weeks postoperatively, 4 (19%) of the 21 patients with consecutive esotropia showed an A or V pattern, whereas none of the 21 control patients did so. At the end of follow up (mean of 27 months for patients with consecutive esotropia and 29 months for controls), 9 (43%) of the 21 patients with consecutive esotropia showed an A or V pattern versus 1 (5%) of the 21 controls. These findings strongly suggest that loss of fusion is instrumental in the development of A or V patterns, consistent with "sensory torsion" theory of A and V pattern development.

Two Mhc class I and two Mhc class II genes map to the chicken Rfp-Y system outside the B complex

Gene sequences highly similar to major histocompatibility complex (Mhc) class I and class II genes were recently recognized as mapping to a site in the genome of the chicken separate from the Mhc class I, class II, and B-G genes of the major histocompatibility (B) complex. The present study was undertaken to see whether this complex of Mhc-like genes designated as restriction fragment pattern Y (Rfp-Y) might reside in one of three clusters of cosmid clones contained within the molecular map of chicken Mhc genes, since only two of the three clusters can be assigned to the B system. To determine whether the third cluster (cluster II/IV) might contain Rfp-Y, a subclone (18.1) from within cluster II/IV near a polymorphic lectin gene was used to analyze the DNA of families in which Rfp-Y haplotypes are known to be segregating. The restriction fragment polymorphisms revealed by the 18.1 probe were found to segregate in parallel with the restriction fragment polymorphisms defining the Rfp-Y haplotypes, thus establishing the location of Rfp-Y within cosmid cluster II/IV. Two of six Mhc class I genes and two of five Mhc class II genes map to cosmid cluster II/IV, so a substantial fraction of chicken Mhc genes, including at least one that may be expressed, are located in a chromosomal region separate from the B system. In further linkage analyses, Rfp-Y was found to assort independently from more than 400 markers in the present linkage map of the chicken genome.

Current trends in the primary care management of chronic congestive heart failure

Congestive heart failure affects over 2.3 million Americans; approximately 400,000 new cases are diagnosed yearly in this country. Congestive heart failure is a complex disorder with a poor long-term prognosis. The major causes of congestive heart failure are ischemia, infarction, and idiopathic cardiomyopathy. Patients often present with dyspnea and a low exercise tolerance. In congestive heart failure there may be an alteration in preload, afterload, and contractility of the heart. Many compensatory mechanisms occur to support the failing heart. Cardiac symptoms slowly develop and eventually systemic symptoms develop. The cornerstones of pharmacologic therapy are cardiac glycosides, diuretics, and angiotensin-converting enzyme inhibitors.

Ontogeny of arginine vasopressin-immunoreactive neurons in the hypothalamus of fetal and newborn sheep

Arginine vasopressin (AVP) is a peptide hormone which is found in neurons within the paraventricular (PVN) and the supraoptic (SON) nuclei of the hypothalamus. In fetal sheep, this neuropeptide is involved in maturational processes and adaptive responses to 'stress'. This study examined the effect of age on the total number and distribution of AVP-containing neurons in the PVN and SON of fetal sheep and newborn lambs by quantitative light-microscopic immunocytochemistry. Serial coronal sections of hypothalami from three groups of animals were studied: fetuses at 104-109 days of gestation (n = 6) comprising the early group, fetuses at 130-139 days of gestation (n = 5) comprising the late group and newborn lambs at 12-20 postnatal days (n = 5) comprising the neonatal group. This period of development was chosen since adaptive mechanisms to stress are operative at or near the time of birth. Hypothalamic dimensions were measured to determine if maturation had an effect on the size of the AVP-containing subregions of the hypothalamus during this period of development. Dimensions included: ventricle height, optic chiasm width, distances from the dorsal margin of the ventricle to the lateral and medial margins of the optic tract, and distance between the medial margins of the optic tracts. As expected, with increase in maturational age, overall dimensions of the AVP-containing subregions increased significantly (p < 0.05). When early- and late-gestation fetuses were compared to newborn lambs, there was a significant increase in the total number of immunoreactive neurons in both the PVN (p < 0.01, Anova) and SON (p < 0.001, Anova) with age. With advancing age, we also observed an increase in the density of AVP neurons in the middle subregion of the PVN and in the midrostral subregion of the SON. These data suggest that, during the late gestational and early postnatal period, de novo synthesis of AVP genes occurs in these hypothalamic nuclei. This study provides a baseline for further investigation to study the effects of stress on these neurons in the developing ovine fetus and newborn lamb.

Methylene blue but not indigo carmine is toxic to human luteal cells in vitro

Methylene blue (MB) is reported to be teratogenic when injected intra-amniotically. Indigo carmine (IC) appears to be a safe alternative. To determine if MB has potential detrimental effects on ovarian tissue, we compared the effect of MB and IC on human granulosa luteal cell (GC) function in vitro. Human oocyte-cumulus complexes were obtained during in vitro fertilization cycles and one to three were placed in an organ culture dish. After insemination with sperm, oocytes were removed the day after retrieval and the attached GC were washed daily for 3 more days by changing 2 mL of culture medium. All the dishes were treated with human chorionic gonadotropin (hCG) for the next 24 h and progesterone (P) production during this interval was taken as baseline. Test chemicals were added with hCG for the next 48 h with daily media changes. The P production during the last 24 h of chemical treatment was expressed as a percentage of the baseline. MB significantly reduced P production whereas IC did not appear to have any effect. Moreover, under inverted microscopy more than 90% of the GC cells contained several small bluish intracellular granules when exposed to 0.01% MB but not 0.01% IC. These results indicate that MB may be taken up and processed by GC cells and inhibits P production. This finding adds to previous reports on the use of in vitro GC assay to identify potential reproductive toxicants. The clinical significance of this preliminary study needs further investigation.

Gonadotropin hormone-releasing hormone induced luteinizing hormone responses in young and old female C57BL/6J mice

The estrogen-induced luteinizing hormone (LH) surge is markedly attenuated in old (24 months) female mice compared with young (6 months) females. To test whether or not this attenuated LH response is due to a diminished capacity of the pituitary to respond to hypothalamic gonadotropin hormone-releasing hormone (GnRH), the pituitary response to exogenous GnRH was measured in young (5-6 months), normally cycling (n = 6) and old (24 months), acyclic constant diestrus (n = 6) C57BL/6J female mice. Mice were ovariectomized and estrogen-treated for 7 days. After intrajugular catheterization on Day 6, serial blood samples were taken at 15-min intervals for 165 min on Day 7. Serum LH was measured in samples obtained before and after infusion of either saline or GnRH (5 micrograms/5 microliters saline/kg body wt) and 15 micrograms/15 microliters saline/kg body wt 1 hr apart). Saline-treated animals demonstrated no LH response in either young (0.09 +/- 0.02 ng/ml baseline) or old (0.11 +/- 0.01 ng/ml baseline) females. However, a significant release of LH was obtained in response to each challenge of GnRH in both young (0.3 +/- 0.04 ng/ml first challenge, 0.69 +/- 0.1 ng/ml second challenge) and old (0.78 +/- 0.1 ng/ml first challenge, 1.76 +/- 0.2 ng/ml second challenge) mice. The LH response in the aged group was significantly greater (P < 0.05, analysis of variance) than in the young group. These results show that pituitaries of old female mice were at least as capable of responding to exogenous stimulation by GnRH as those of young. We conclude that alteration in the capacity of the pituitary to respond to GnRH is not likely to be a factor contributing to altered LH secretion with age in C57BL/6J mice.

Serial transvaginal ultrasound scans and beta-human chorionic gonadotropin levels in early singleton and multiple pregnancies

OBJECTIVE

To determine if serum beta-hCG levels are higher in multiple gestation than in singleton pregnancy at the time of intrauterine sac visualization and the first appearance of fetal heart activity as documented by serial transvaginal ultrasound (US).

DESIGN

Prospective analysis of serial transvaginal US findings in 19 pregnancies correlated with serum hCG levels during early gestation.

SETTING

Reproductive endocrinology division of the University of Arkansas for Medical Sciences, Little Rock, Arkansas.

PATIENTS

Nineteen infertility patients were studied after conceiving. Thirteen underwent IVF or GIFT, 4 received hMG therapy, 1 was treated with clomiphene citrate, and 1 pregnancy followed spontaneous ovulation.

INTERVENTIONS

Transvaginal US and hCG levels were obtained every Monday, Wednesday, and Friday from 20 to 22 days after ovulation until the appearance of fetal heart activity.

RESULTS

Initial sac visualization occurred at lower serum hCG levels in singleton versus multiple pregnancies (2,180 +/- 1,170 versus 7,028 +/- 4,280 mIU/mL, mean +/- SD). Sacs were always seen when the serum hCG level (mIU/mL) was > or = 1,161 in singleton, 1,556 in twin, 3,372 in triplet, and 9,399 in quadruplet pregnancies.

CONCLUSION

Failure to observe an intrauterine sac by transvaginal US in the presence of serum hCG levels in the 1,000 to 2,000 mIU/mL range is not pathognomonic for an ectopic gestation. Clinical symptomatology, risk of multiple pregnancies, and gestational age must also be considered.

A polymorphic system related to but genetically independent of the chicken major histocompatibility complex

Analyses of the major histocompatibility complex (Mhc) in chickens have shown inconsistencies between serologically defined haplotypes and haplotypes defined by the restriction fragment patterns of Mhc class I and class II genes in Southern hybridizations. Often more than one pattern of restriction fragments for Mhc class I and/or class II genes has been found among DNA samples collected from birds homozygous for a single serologically defined B haplotype. Such findings have been interpreted as evidence for variability within the Mhc haplotypes of chickens not detected previously with serological methods. In this study of a fully pedigreed family over three generations, the heterogeneity observed in restriction fragment patterns was found to be the result of the presence of a second, independently segregating polymorphic Mhc-like locus, designated Rfp-Y. Three alleles (haplotypes) are identified in this new system.

Modulation of hypothalamic mu-opioid receptor density by estrogen: a quantitative autoradiographic study of the female C57BL/6J mouse

The labelling of hypothalamic binding sites by [125I]-FK, a specific mu-opioid receptor ligand, was studied in female C57BL/6J mice to test whether removal of ovarian steroids affected the density of distribution of receptor binding. Labelling densities in the forebrain of normally cycling (intact) females (N = 12), were compared to those in mice that had been ovariectomized (OVX) for 6 weeks (n = 8) and in mice that had been OVX and implanted with an estradiol (E2) capsule (OVX+E2) for 6 weeks (n = 11). Frozen sections from the rostral forebrain were incubated with 1 nM [125I]-FK and processed for light microscopic autoradiography. The diagonal band of Broca (DBB), organum vasculosum lamina terminalis (OVLT), preoptic area (POA), septum, parietal cortex, and striatum were analyzed using computerized image analysis. The distribution of labelling was similar in all three experimental groups in all the regions; however, labelling was significantly reduced in the ventrolateral POA of OVX animals compared to intact females. Labelling densities in the OVX animals replaced with the gonadal steroid estradiol were not significantly different from those in normally cycling mice. This study demonstrates a region-specific loss of mu-opiate receptor labelling following long-term deprivation of gonadal steroids, and supports the hypothesis that estrogen directly or indirectly influences the density of mu-opioid receptors in the rostral forebrain of female mice.

Beta IV is the major beta-tubulin isotype in bovine cilia

Four different isotypes of beta-tubulin are known to be expressed in mammalian brain. Monoclonal antibodies against beta II, beta III, and beta IV were used to characterize the beta-tubulin isotypes in two ciliated bovine tissues: non-motile sensory cilia of retinal rod cells and motile cilia of tracheal epithelium. Retinal rod outer segment (ROS) connecting cilia and cytoskeletons were purified by density gradient centrifugation. This preparation contained more than 20 major protein components, as shown by dodecyl sulfate polyacrylamide gel electrophoresis. Electroblots were used to quantitate the relative amounts of beta II, beta III, and beta IV. The connecting cilium and cytoskeleton of the rod outer segment has less type III beta-tubulin than brain and more type IV. The ratio of beta IV to beta II in the ROS is nearly a factor of 8 larger than in brain. Electron microscopic immunocytochemistry showed extensive labeling of cilia by anti-type IV in thin sections of retinas and trachea, and also in purified ROS cilia and cytoskeletons. Labeling of cilia by anti-beta II was also observed, although in the purified ROS cilia and cytoskeleton, the anti-beta II labeling was primarily on amorphous non-ciliary material. The results suggest that both motile and non-motile cilia are enriched in the type IV beta-tubulin subunit.

Aging changes in the beta-endorphin neuronal system in the preoptic area of the C57BL/6J mouse: ultrastructural analysis

In hypothalami of aging rodents, beta-endorphin (beta-EP) neuron number and content are reduced. The objectives of this study were: first, to analyze ultrastructurally the population of neuronal elements in a selected region of the preoptic area (POA) in young and old mice; second, to study the beta-EP neuronal system in the same region to determine whether or not this population remains stable with age. Vibratome sections from the most caudal POA through the diagonal band of Broca were examined by light microscopy and immunocytochemistry in mature, cycling (5-6 months old) and old, acyclic, disease-free (24-26 months old) mice. A subset of beta-EP-like perikarya and associated structures was observed in the periventricular POA. When this subregion was examined at the ultrastructural level, there was a significant decrease in the number of recipient dendrites [3.78 +/- 0.04 SEM/micron 2 young vs. 0.82 +/- 0.03/micron 2 old; p < 0.007, analysis of variance (ANOVA)], but a significant increase in the number of nonmyelinated axons (20.0 +/- 2.6/micron 2 young vs. 26.8 +/- 0.7/micron 2 old; p < 0.05). Immunolabeled terminals that contained a synapse comprised 2.56 +/- 0.08% of all terminals with synapses in young mice but only 0.34 +/- 0.04% in old ones when corrected for surface area examined (p < 0.03). A significant age-related loss was also observed in the nonmyelinated beta-EP-labeled axon population (1.50 +/- 0.10% young vs. 0.40 +/- 0.01% old; p < 0.009, ANOVA). We conclude that there are critical changes in the microenvironment of the POA in old, noncycling female mice that are likely to affect neuron function.

Evidence for the presence of the estrogen receptor in the ovary of the baboon (Papio anubis)

Although intraovarian estrogen has been firmly established as an important factor in the regulation of ovarian follicular development and function in the rat, an autocrine-paracrine role for estrogen in the primate ovary is not yet established. Immunocytochemical identification of an estrogen receptor in the monkey follicle was negative, but it was positive for the granulosa cells of antral follicles of the human ovary. In the present study baboon ovaries obtained during the follicular phase were examined for the presence of estrogen receptor by immunocytochemical analysis of frozen sections and Northern blot analysis of RNA extracts of the ovaries. Immunocytochemistry identified the estrogen receptor in the granulosa cells of healthy appearing and atretic or cystic-like antral follicles and in occasional, but rare, thecal cells. The ovaries contained a prominent mRNA species for the estrogen receptor, approximately 7 kilobases in size, which was present in relatively low abundance compared to that in the nonpregnant baboon uterus, but in a similar abundance to the estrogen receptor mRNA content of the pregnant endometrium. These studies are the first to report the presence of estrogen receptor mRNA in the ovary of a primate. These results in conjunction with the immunocytochemical studies firmly establish the presence of the estrogen receptor in the primate ovary and suggest an autocrine-paracrine role for intraovarian estrogen in primate ovarian physiology.

The effect of benzo(a)pyrene on murine ovarian and corpora lutea volumes

OBJECTIVE

Women who smoke have impaired fertility and experience menopause at an earlier age. This experiment determined the effect of benzo(a)pyrene, a polycyclic aromatic hydrocarbon contained in cigarette smoke, on murine ovarian volume, total corpora lutea volume, individual corpora lutea volumes, and corpora lutea numbers.

STUDY DESIGN

C57BL/6N mice were treated with intraperitoneal injections of 0 to 500 mg/kg benzo(a)pyrene in corn oil. The 20 mice at each dose were divided into four groups of five each and were killed at 1, 2, 3, or 4 weeks after treatment. Ovaries were serially sectioned and analyzed morphometrically.

RESULTS

Benzo(a)pyrene produced a dose- and time-dependent decrease in ovarian volume, total corpora lutea volume, and number of corpora lutea per ovary. This effect was transitory at low doses with complete recovery of corpora lutea by 4 weeks. Compensatory hypertrophy of the individual corpora lutea occurred during the recovery phase. Ovarian function did not return in animals treated with the two highest doses.

CONCLUSION

Benzo(a)pyrene is a murine ovarian toxicant that inhibits corpus luteum formation in a dose- and time-dependent fashion.