Interstitial Gland Research Articles

Epidermal growth factor and epidermal growth factor receptor in the ovary of the domestic cat (Felis catus).

Identification of epidermal growth factor (EGF) and its distribution in the ovary were examined with an immunohistochemical technique using a polyclonal rabbit antibody against mouse EGF. A combination of HPLC and enzymeimmunoassay was elaborated to quantify EGF in different compartments of the feline ovary. In addition, EGF receptors were localized in ovarian cryostat sections with a new ligand-histochemical technique using biotinylated EGF for labelling. Epidermal growth factor was present in theca interna cells, in specific aggregations of interstitial gland cells located next to tertiary follicles, in smaller, single cells of the ovarian cortex, and in the corpus luteum. The strongest EGF-positive reaction was found in vacuolized cells of the interstitium and in theca interna cells of large tertiary follicles rich in cytoplasm. The strictly cellular localization of the EGF-antibody reaction suggests the synthesis of EGF in these cells. Specific binding sites of EGF were present on granulosa cells of secondary and tertiary follicles and on interstitial gland cells. The EGF-binding capacity of granulosa cells of the cumulus oophorus was greater than that of the mural granulosa cells. Granulosa cells of atretic follicles showed a lower or no affinity for staining. In conclusion, we suggest that EGF plays an important role in ovarian folliculogenesis in cats.

Parvalbumin expression during developmental differentiation of the rat ovary

Parvalbumin (PV) is a high-affinity Ca 2+-binding protein which is expressed in a limited number of vertebrates tissues and restricted to a few distinct cell types. It has been shown by biochemical methods to be present in the adult rat ovary, but cellular localizations or developmental appearance have not been described until now. This study describes the presence of PV and its transcripts, analyzed by immunohistochemistry and in situ hybridization, respectively, during the postnatal development of the rat ovary: 13 developmental stages between day 1 and day 83 were examined. In ovaries 1–16 days old, neither PV mRNA nor PV was observed in any cell of the ovary. By contrast, starting from day 18 postpartum, both PV mRNA and PV were detected in low amounts, simultaneously with the onset of differentiation of secondary interstitial gland cells in the ovarian interfollicular stroma. PV and its transcripts were primarily detected in conspicuous patches of interstitial gland tissue and in the differentiated thecal cells around the large follicles, and PV appeared to be fully expressed 33 days after birth. The parallel time courses of PV mRNA and PV accumulation during developmental differentiation, and the appearance of a steroid-producing cellular phenotype as well as the strict cellular colocalization of these two features, strongly suggest involvement of PV in the steroid metabolism of these cells, as earlier proposed for the Leydig cells of the testis. According to this hypothesis, we also show that suppression of gonadotrophic hormone production by hypophysectomy of adult rats totally suppresses PV production in parallel with the disappearance of the morphological features typical of steroid-producing cells in the remaining interstitial tissue of the ovary.

Ovarian Carbonyl Reductase Delayed Onset of Persistent Estrus in the Offspring of Parathyroidectomized Mother Rats

We investigated the effects of maternal parathyroidectomy on day 5 of pregnancy on the ovarian carbonyl reductase (CR) in the offspring of rats. Changes in the ovarian CR of the offspring were examined at 4 and 8 months of age. In 8-month-old female offspring, the ovarian weight and the ovarian CR activity were significantly higher in rats from parathyroidectomized mothers than in rats from sham-operated mothers, and the offspring of the parathyroidectomized mothers showed the regular 4-day estrous cycles at 8 months of age, while the offspring of the sham-operated mothers were in the state of persistent estrus. Furthermore, intense immunostaining was found in the theca interna cells and the interstitial gland cells in the ovary of rats from the parathyroidectomized mothers, whereas in the ovary of the age-matched normal rats, immunostaining was faint. These results suggest that the maternal parathyroidectomy affect the activity and localization of CR in the ovary of female offspring.

Sex-dependent expression of a transcription factor, Ad4BP, regulating steroidogenic P-450 genes in the gonads during prenatal and postnatal rat development.

We investigated the expression of Ad4BP (also known as SF-1), a transcription factor regulating steroidogenic P-450 genes, in the steroidogenic tissues such as adrenal glands, testes and ovaries through the prenatal and postnatal life of rats. Ad4BP was detected in the primordial adrenal glands and gonads of the 13.5 day postcoitum (d.p.c.) fetus. After the appearance of Ad4BP, a steroidogenic P-450 (P-450(SCC)) was also detected in the adrenal glands and its amount increased gradually. In the fetal gonads of 14.5 d.p.c., a significant amount of Ad4BP was detected in the somatic cells of the testes, whereas only a trace amount was present in the ovaries. The sexually dimorphic expression of Ad4BP continued throughout the neonatal age. Drastic alterations occurred during the first to third week of postnatal age accompanied by functional and structural changes of the gonads. The expression of Ad4BP in the testes attained a maximal level one week after birth and decreased markedly thereafter. By contrast, increase of Ad4BP in the ovary was detected after the first postnatal week. Expression of P-450c17 showed a good correlation with the proliferation of Leydig cells in the testes and theca cells in the ovaries. Immunohistochemical studies revealed the presence of Ad4BP in Sertoli cells as well as Leydig cells up to the pubertal age. In the adult rat testis, however, staining of Sertoli cells decreased significantly. Ad4BP was detected in granulosa, theca, corpus luteum and interstitial gland cells in the ovary although the expression levels in granulosa cells varied among follicles. It is suggested that the Müllerian inhibitory substance gene may be a target of Ad4BP since this gene has a conserved Ad4-binding site within the promoter, which is recognized by Ad4BP expressed in the fetal testes.

Localization of diazepam-binding inhibitor and peripheral type benzodiazepine binding sites in the rat ovary

Diazepam-binding inhibitor (DBI) is the precursor of a family of peptides, including an octadecaneuropeptide (ODN), that share with DBI the ability to specifically displace benzodiazepines (BZD) from their receptors. An association of ODN with the peripheral type BZD receptors (PBR) has been reported in the brain and a few peripheral tissues. In order to investigate whether DBI and PBR are present in ovarian tissue, we have localized DBI by means of immunocytochemistry, in situ hybridization and autoradiography of PBR in the rat ovary. Immunocytochemical localization was achieved by means of rabbit antibodies developed against rat ODN. Immunostaining was located in the cytoplasm of the theca interna, corpus luteum and interstitial gland cells, but not in the granulosa cells. Hybridization signal obtained following in situ hybridization with a [35S]-labelled single-stranded RNA probe complementary to DBI mRNA was observed in all the steroid-secreting cells, including granulosa cells of developing and mature follicles. Autoradiographic localization of PBR obtained by incubating ovary sections with [3H] PK11195, a ligand selective for PBR, revealed the presence of specific labelling in all the steroid-secreting cells. These results, which demonstrate for the first time that the ovarian steroid-secreting cells contain both PBR and its endogenous ligand, suggest that the BZD receptor might be involved in the regulation of ovarian function.

Several types of granule indicating steroidgenesis in the interstitial gland cells of murine ovary

The site of steroidgenesis in the mammalian ovary has been attributed to granulosa cells in follicles and internal thecal cells in the periphery of follicles. However, physiologically distinct estrogen or androgen has been detected in fetal ovary and sexually immature ovary, as well as post menopausal woman's ovary. More than a few reports have described the interstitial cells as another site of steroidgenesis. Electronmicrographs of interstitial cells so far published indicate only lipid droplets as the source of steroid hormones. Utilizing the super-wide grid method, we were able to observe the whole cross section of murine ovary at low and high magnifications by use of an electron microscope. Numerous osmiophilic granules were distributed in interstitial tissue. These granules were subdivided into at least four types based on their size and density. Only one type was localized in a given interstitial cell. Therefore, different types of granule may contain different substances and not all granules are a variety of lipid droplet. The immunocytochemistry of susbtances in each type of granule remains to be investigated.

Immunocytochemical Localization of Aromatase in The Ovary of Superovulated Cattle, Pigs and Sheep

The localization of aromatase, an enzyme converting androgens to estrogen, in the ovaries of superovulated cattle, pigs and sheep was studied immunocytochemically in the preovulatory and postovulatory period using anti-human placental aromatase cytochrome P-450 antiserum. Immunostaining for aromatase was detected in the granulosa cells of preovulatory follicles of all species studied. Theca interna cells were stained in preovulatory follicles in the pig but not in cattle and sheep. Interstitial gland cells, cumulus cells and oocytes were unstained in all species. In cattle and pig the corpora lutea were unstained whereas they displayed staining in the sheep. Preantral and small antral follicles were unstained during both the preovulatory and postovulatory period in all species. It is concluded that granulosa cells of preovulatory follicles are the main residence for aromatase activity in superovulated cattle, pig and sheep, whereas the activity of theca interna and corpora lutea is species specific.

Activation by human chorionic gonadotropin of ovarian carbonyl reductase in mature rats exposed in vivo to estrogens

We investigated the effects of exogenous estrogens and human chorionic gonadotropin (hCG) on the activity, content, and immunohistochemical localization of ovarian carbonyl reductase (CR) in mature cycling rats. Estrogens, estradiol, hexestrol (HEX) and diethylstilbestrol (DES) were given s.c. to rats daily for 3 days from the first day of diestrus, and hCG was given s.c. at 3:00 p.m. on the day of expected proestrus. The ovaries were isolated on the day of expected estrus. Ovarian CR activity was measured by using two substrates that reflect the activity of the enzyme in rats, and the enzyme content was determined by western blot analysis. Ovarian CR activity and content were decreased by estrogens as well as by inhibition of ovulation; hCG restored both the activity and the content decreased by estrogens to levels produced by nGC alone. Nevertheless, the number of ova in the oviduct when ovulation was decreased or blocked by estrogens was not restored completely by hCG treatment. Faint immunostaining in the interstitial gland cells of HEX-treated rat ovaries was observed. These results suggest that (i) although hCG activates ovarian CR in estrogen-treated rats, this increase in both enzyme activity and content may not be an obligatory event in the ovulatory process, and (ii) exogenous estrogens may predominantly influence the ovarian CR in the interstitial gland cells in mature rats by inhibiting luteinizing hormone release from the pituitary.

Association of immunolocalization of matrix metalloproteinase 1 with ovulation in hCG-treated rabbit ovary.

Matrix metalloproteinase 1, MMP-1, which was previously called interstitial collagenase, is necessary for extracellular matrix reconstruction. The immunolocalization of the latent form of MMP-1 (proMMP-1) was examined in the ovulatory process in hCG-treated (100 iu per animal) rabbit ovaries. Immunoreactive products of proMMP-1 were identified by the avidin-biotin peroxidase complex formation using an anti-rabbit proMMP-1 polyclonal antibody. ProMMP-1 was distributed in the cytoplasm of theca interna cells, theca externa cells, interstitial glands and germinal epithelium throughout ovulation. However, at 9 or 10 h after hCG treatment, this enzyme was identified in several capillary lumina around the apex of preovulatory follicles. In addition, the staining density of immunoreactive products apparently increased in granulosa cells and theca interna cells around the orifice of the ruptured follicle 10 h after the stimulation. These results indicate that the spatiotemporal appearance of proMMP-1 in ovulation may be closely associated with the initiation of rupture of the follicle.

Ontogenesis of 3 beta-hydroxysteroid dehydrogenase delta 5-delta 4 isomerase in the rat ovary as studied by immunocytochemistry and in situ hybridization.

The enzyme complex 3 beta-hydroxy-5-ene-steroid dehydrogenase and steroid 5-4-ene isomerase (3 beta-HSD) is involved in the biosynthesis of all classes of active steroids, namely glucocorticoids, mineralocorticoids, and sex steroids. To obtain more information about the age-specific expression and localization of 3 beta-HSD during development in the rat ovary, two complementary cytochemical techniques were used, immunocytochemical localization with antibodies against purified human placental 3 beta-HSD, and 3 beta-HSD mRNA localization achieved by in situ hybridization with a [35S]-labeled cDNA encoding 3 beta-HSD. In the fetal ovary, no significant immunolabeling or hybridization signal could be observed. The first expression of the enzyme was observed 6 days after birth, immunolabeling as well as autoradiographic reaction being found in a few interstitial gland cells. At the 10th day of postnatal life, the theca interna cells of growing follicles appeared to be labeled with both techniques. The granulosa cells of growing follicles also exhibited hybridization signal, whereas no immunostaining could be detected in these cells at any of the time intervals studied. At puberty, 3 beta-HSD was localized in theca interna and granulosa cells of the growing and mature follicles as well as in the interstitial gland and corpus luteum cells. Similar results were obtained in 40-day-old and adult animals. The present data indicate a progressive expression of 3 beta-HSD in different morphological structures during ovarian development in the rat.

Microvasculature of growing and atretic follicles in the rabbit ovary: a SEM study of corrosion casts.

Rabbit ovarian microvasculature, with particular regard to developing and atretic follicles, was studied by scanning electron microscopy (SEM) of vascular corrosion casts. The microvascular network of the follicles was arranged in typical round plexuses of varying shape and size. Four different morphological types of vascular plexuses supplied the follicles: Type 1 (100-250 microns in diameter) consisted of a simple net of thin capillaries that delimited a small empty central cavity. Type 2 (diameter > 250 microns) consisted of a multilayered capillary wall delimiting a large empty central cavity. This wall presented an inner layer made of uniformly distributed dilated and tortuous capillaries with numerous angiogenetic sprouts. Type 3 (diameter of 100-300 microns) lacked the central cavity and comprised randomly arranged thin capillaries. Type 4 (diameter > 250 microns) consisted of a multilayered capillary wall delimiting a central cavity. Its inner layer was made of capillaries not homogeneous in size and course (thin in some areas, sinusoidal in others, sometimes highly dilated). In addition, the wall showed large interruptions (avascular areas) and focal invasion of the central cavity by newly formed vessels. Types 1 and 2 showed the gradual transformation of thin capillaries into sinusoids as has been demonstrated in evolutive follicles. Types 3 and 4, described here for the first time, probably represent the vascular supply to atretic follicles. In particular, Type 3 supplied follicles undergoing obliterating atretic degeneration, whereas Type 4 supplied atretic follicles with hypertrophy of the theca layer. In fact, follicular atresia is a pleiomorphic phenomenon which ends in a regression of the follicles (obliterant atresia), but which may induce a temporary follicular hyperactivation (luteinizing atresia). These changes in the microvasculature prelude the formation of the so called "interstitial gland of the ovary". Furthermore, these data prove that: 1) both thecal capillary vasodilatation and angiogenetic processes basically support the gradual increase of ovarian blood flow during follicle growth; 2) microvascular changes of atretic follicles are possibly related to a type of inflammatory reaction since they seem to be a consequential rather than primary cause of atresia.

Localized increases in ovarian vascular permeability and leucocyte accumulation after induced ovulation in rabbits.

Colloidal carbon was injected i.v. in mature virgin rabbits at different times after induction of ovulation by human chorionic gonadotrophin (hCG, 100 iu) or mating. Before induction of ovulation, slight carbon leakage was observed in the inner vascular ring of the theca interna of antral follicles, but blood vessels in the other ovarian compartments were unstained. Between 4 and 10.5 h after hCG-treatment or mating, vascular leakage was most marked in the blood vessels of the interstitial gland and in the theca interna of antral follicles. Just before ovulation, carbon particles were observed between granulosa cells and some carbon was seeping into the follicular fluid of preruptured follicles. Vascular leakage was also observed over the follicle dome before rupture as well as at the dorsomedial junction between the mesovarium and the ovary. The blood vessels stained with carbon were 7-70 microns diameter, representing capillaries and postcapillary venules. About 6 h after hCG injection, an increased number of polymorphonuclear leucocytes migrated from the vessels of these ovarian compartments into the surrounding interstitial tissue. The number of leucocytes seen in the follicular wall and ovarian medulla increased markedly towards ovulation. During early corpus luteum formation, the number of leucocytes decreased markedly. The localized vascular changes seen after mating and hCG stimulation were similar to an inflammatory reaction and could form the basis for the formation of peritoneal exudate after ovulation in rabbits and periovulatory ascitic accumulation seen in the peritoneal cavity of women during the menstrual cycle.

Age‐related changes in ovarian morphology of the South American tamarin Saguinus fuscicollis (Callitrichidae)

The aim of this histological study was to investigate the postnatal ontogeny of the ovaries in Saguinus fuscicollis to provide a detailed knowledge of the ovarian morphology for further endocrinological studies. Gonads from 43 animals between one day and 18 years of age were investigated. Based on the available material the ovarian development is characterized by seven distinct stages. 1. Neonatal stage: Folliculogenesis is still in progress. The ovarian medulla is filled with an intraovarian rete system, which forms open connections between the rete tubules and the cords containing oocytes. 2. Infantile stage: One month after birth the ovarian cortex is mainly composed of primordial follicles and a few primary follicles at the corticomedullary border, which are separated from each other by connective tissue. At two months, folliculogenesis is nearly completed. The first secondary follicles are present. 3. Juvenile stage: In six‐month‐old females weighing 184±9.5 g, folliculogenesis has reached the stage of secondary follicles with up to six layers of granulosa cells. In females of the same age weighing 251.5±37 g, antral follicles attain a maximum diameter of 925 μmm. 4. Pubertal stage: At the age of 8–10 months, corpora lutea accessoria (CLA) begin to form from atretic antral follicles. 5. Adult stage: The ovaries of all females older than 1.2 years are filled with large patches of interstitial gland tissue (IGT). In breeding females up to 58.4%of the antral follicles are intact. In non‐breeding daughters living in the family group only 1.8%are intact, the rest are in various stages of atresia and form CLA. 6. Climacterial stage: With increasing age (8–13 years), the number of intact follicles decreases dramatically and IGT fills nearly the whole ovary. 7. Senile stage: In females older than 14 years, nearly all remaining follicles show signs of atresia.

Expression and distribution of carbohydrate sequences in chick germ cells: a comparative study with lectins and the NC-1/HNK-1 monoclonal antibody.

The expression of end-chain sugar residues and of oligosaccharidic sequences has been investigated in chick germ cells at critical stages during the migration, proliferation and sexual differentiation of these cells. Fluorescent lectins and indirect immunofluorescence studies using the NC-1/HNK-1 monoclonal antibody indicate a remarkable control of glycosylation during germ cell embryonal life. Besides a retained expression of glucose/mannose residues, it was found that alpha- and beta-galactose residues, N-acetyllactosamine and N-N' diacetylchitobiose sequences as well as the sulfated trisaccharidic NC-1 epitope were detectable in a stage-specific pattern. Present at a very high density in the cytoplasm and on the surface of the early germ cells at premigrative and migratory stages, the staining for these carbohydrate sequences gradually disappeared when the germ cells settled and proliferated in the developing gonadal primordia. The disaccharide Gal beta 1----3 Gal NAc was exclusively detected in migrating PGCs. In sexualized gonads, acetyllactosamine and/or diacetylchitobiose were similarly reexpressed in both oogonia and spermatogonia. Spermatogonia displayed beta-galactose residues and a high immunoreactivity with the NC1 Mab, indicating modulations in PGC glycosylations related to the acquisition of sexual phenotypes. In addition NC-1 was found to be expressed in the somatic component of the undifferentiated gonad and in the testis interstitial gland.

Vasoactive intestinal polypeptide in the PMSG-primed immature rat ovary and its effect on ovulation in the isolated rat ovary perfused in vitro

The immature rat ovary contains VIP immunoreactive nerve fibres sparsely distributed around blood vessels, in the interstitial gland and around follicles. The VIP concentration, measured radioimmunologically, decreased significantly after PMSG treatment (10 i.u.), probably due to ovarian enlargement and oedema, while the total VIP content (total of 0.12 pmol in both ovaries) did not change after PMSG priming. The ovulatory effect of VIP was studied using in-vitro perfused ovaries from immature 28-day-old rats primed with 10 i.u. PMSG. In all ovaries perfused, VIP (10(-7) M) induced ovulations with a rate of 2.33 +/- 0.56. The ovulation rate was significantly lower than that of ovaries stimulated by LH (0.1 microgram/ml) (5.20 +/- 0.86 ovulations per ovary). No synergistic effect on the ovulation rate was seen when LH and VIP were administered together (5.20 +/- 0.49 ovulations per ovary). The results suggest that the neuropeptide VIP may represent one of the local factors involved in the ovulation process.

Changes and Localization of Ovarian Carbonyl Reductase during Pseudopregnancy and Pregnancy in Rats

The present study investigates changes in the activity and enzyme content of ovarian carbonyl reductase (CR), which catalyzes the reduction of 9-keto and 15-ketoprostaglandins in rats during pseudopregnancy and pregnancy. The activity of ovarian CR decreased from the onset of pseudopregnancy and pregnancy, reaching 20-30% of the Day 1 value by Day 12 of pseudopregnancy and 50-60% of the Day 1 value by Day 14 of pregnancy. In the case of pregnant rats, the enzyme activity maintained a minimal level between Day 14 of pregnancy and Day 22 of parturition. An acute increase of the enzyme activity was found on the morning after parturition. The CR content in the ovary maintained a constant level from Day 1 to Day 12 of pseudopregnancy and to Day 18 of pregnancy. In pregnant rats, there was a gradual decrease after 18 days and then a surge during parturition. CR was primarily localized in interstitial gland cells and in theca interna cells but was not found in corpora lutea cells in the ovary during the estrous cycle. Additional immunostaining was also observed in corpora lutea cells during pseudopregnancy and pregnancy. The changes in ovarian CR activity, i.e. the rapid decrease with progressing pseudopregnancy and pregnancy, correlated with the increase in progesterone and the decrease in LH. These results indicate that rat ovarian CR may be regulated via the hypothalamo-pituitary-ovarian axis and may also be involved in luteal function.

Immunocytochemical and biochemical studies on the localization and changes of 17 ?-hydroxylase/C17?C20 lyase activity in immature rat ovary treated with PMSG and hCG

The localization of cytochrome P-450 of 17 alpha-hydroxylase/C17-C20 lyase (P-450(17 alpha, lyase] and the changes of the enzyme activity were studied immunocytochemically and biochemically in the ovaries of immature rats treated with PMSG (pregnant mare serum gonadotropin) and hCG (human chorionic gonadotropin). Immunocytochemically, P-450(17 alpha, lyase) was localized in both the theca interna cells and interstitial gland cells of the ovaries of immature rats treated with PMSG for 48 h. After hCG administration, the immunoreactive cells rapidly decreased in number in the PMSG-pretreated rat ovary. Namely, 6 h after the hCG injection, positive staining for P-450(17 alpha, lyase) was recognized only in a few theca interna cells, while 12 h after the injection to immunostained cells were detected in the ovary. Forty-eight hours after the hGC treatment (96 h after the PMSG injection), most of the theca interna cells and the interstitial gland cells became immunopositive for P-450(17 alpha, lyase) again. The 17 alpha-hydroxylating activity of P-450(17 alpha, lyase) was 0.5, 0.22 and 0.03 nmol/min/mg protein in the ovarian microsomes of PMSG-treated, PMSG + hCG(3 h)-treated and PMSG + hCG(6 h)-treated rats, respectively. Changes of the hydroxylase activities in all the experimental groups are almost parallel to those of P-450 contents in the microsomes.(ABSTRACT TRUNCATED AT 250 WORDS)

The noradrenergic innervation of the ovary in old rats

The influence of ageing on the noradrenergic innervation of the ovary was studied in female Wistar rats using high pressure liquid chromatography (HPLC) with electrochemical detection and catecholamine histofluorescence techniques. Old age was accompanied by a significant decrease in ovarian noradrenaline levels. In young animals (3-month-old) noradrenergic nerve fibres were distributed primarily to blood vessels and in lesser amounts to the interstitial glands. In aged animals (24-month-old) perivascular noradrenergic fibres were reduced by more than 40%; interstitial gland nerve fibres were reduced by approximately 20%. The possibility that impaired noradrenergic ovarian innervation occurring in old age may be in some way related with age-dependent failure in reproductive activity is discussed.

Changes in Rat Ovarian Carbonyl Reductase Activity and Content during the Estrous Cycle, and Localization1

Carbonyl reductase activity and content in the rat ovary were measured at various stages of the estrous cycle, and the enzyme protein in the ovary was localized by immunohistochemistry. The enzyme activity increased after the preovulatory surge of luteinizing hormone (LH) on proestrus, and the enzyme content began to increase prior to the LH surge. Although the enzyme content reached the highest level at 2000 h and remained at a plateau for 8 h, the enzyme activity increased linearly until it reached the highest level at 0800 h on the morning of estrus. At their maximum, enzyme activity and content were approximately 1.5-fold and 2-fold greater, respectively, then basal diestrus values. The enzyme protein amounted to 1-4% of the ovarian cytosolic protein. An immunohistochemical study revealed that the enzyme was primarily localized in interstitial gland cells and theca interna cells of secondary and Graafian follicles as well as atretic follicles.

Immunohistochemical Localization and Physiological Regulation of Carbonyl Reductase in Immature Rat Ovary

The present study was performed to clarify the role of the ovarian carbonyl reductase (OCR) in ovarian function in immature rats. The OCR activities towards three specific substrates, 13,14-dihydro-PGF2α, 4-benzoylpyridine and menadione, were photometrically and radiochemically determined in the 9,000 × g supernatants of ovaries, and OCR content was measured by Western-blot-peroxidase anti-peroxidase (PAP) analysis. Immunohistochemical locafization of the enzyme in the ovary was performed by the avidin-biotin-complex (ABC) method for paraffin sections. Positive immunoreactivity with OCR antibody was observed for the theca cells and interstitial gland cells at 72 hr after pregnant mare serum gonadotropin (PMSG) treatment when ovulation was confirmed, and the granulosa cells were consistently negatively stained. The OCR activity was significantly increased by PMSG, human chorionic gonadotropin (hCG) and PMSG-hCG treatments, but estradiol and tamoxifen overcame the effect of PMSG on the enzyme activity. Moreover, estradiol enhanced the effect of hCG, but tamoxifen did not. Changes in the OCR activity well-correlated with those in the OCR content. These findings indicate that the OCR is regulated by gonadotropin and estrogen and that metabolites formed by the enzyme could be closely involved in ovarian cell function.