Immunolocalization of smooth muscle-like cells in the quail ovary.

We localized alpha-smooth muscle actin (alpha-SMA) in the quail ovary, using the peroxidase-anti-peroxidase technique. Special attention was paid to the influence of fixation on the immunoreactivity of the antigen. The immunostaining of alpha-SMA largely depended on the nature of the fixative. The antigen could most successfully be localized in ovaries fixed in Carnoy's fluid. We also localized alpha-SMA and desmin in semi-thin glycol methacrylate sections of the pre-ovulatory follicle, using the immunogold-silver staining method. The sections were pretreated with Lugol's iodine or sodium metaperiodate to enhance the immunoreactivity. alpha-SMA was demonstrated in the cells of the chordae, the tunica albuginea, and the theca externa of each follicle. These structures were inter-connected, forming an ovarian suspensory apparatus. The thecal cells of prelampbrush follicles also expressed alpha-SMA. In the wall of the pre-ovulatory follicle, desmin was found in the cells of the chordae and the tunica albuginea, and in a few cells of the theca externa. In the theca interna, desmin, and sometimes alpha-SMA, was observed in cells adjacent to the endothelium of sinusoids, which are probably pericytes. Our results support the hypothesis that in birds the ovarian follicles possess a thecal contractile system, that is presumably involved in the ovulatory process.     

Functional morphology of the theca interna of the vesicular follicle in human ovary]

A study of histological serial sections of human ovaries and histochemical reactions established that several cell types differentiate in the theca interna during the formation and development of tertiary follicles (2nd growth period). This leads, in turn, to triple-layering of the theca interna in follicles of the 2nd resting period. The inner thecal layer consists of fusiform cells from the basement membrane, which are apposed to the membrana granulosa and show a strong positive reaction to alkaline phosphatases. A tropic function for the follicular epithelium must be assigned to this layer. The middle layer consists of epitheloid thecal cells, which show a strong positive reaction to 3beta-ol-steroid hydrogenase. These represent the estrogen glands of the follicle. The outer layer of the theca interna, whose transition to the theca externa is indistinct, also has fusiform cells, which are available as reserve material for the differentiation of further epitheloid thecal cells to pre-ovulatory follicles in later periods of development.     

Histological and histochemical studies of post-ovulatory and pre-ovultory atretic follicles in Mustelus canis

The atresia of post-ovulatory and pre-ovulatory follicles of the viviparous smooth dogfish, Mustelus canis, is compared for approximately the first fourth of an 11 month gestation. A thick collagenous sheath and numerous tubules in the theca identify the large, folded stage A post-ovulatory follicle. In stage B the tubules have been filled by cells to form “islands.” In stage C the entire structure is greatly diminished, adjacent islands tend to fuse, the collagenous sheath is virtually gone and the granulosa is degenerating. Preovulatory follicles from large, yolky oocytes pass through four stages beginning with yolk phagocytosis by granulosa cells of the villi (stage I), which are long and granular in stage II; villi fuse, theca cells increase greatly, fill with granules (stage III), encroach on the granulosa and disperse it into small groups of cells which finally disappear (stage IV) leaving a mass of thecal cells. A special type of pre-ovulatory follicle from small non-yolky oocyte atresia exhibits prominent thecal tubules and an unusual arrangement of granulosa cells. This follicle appearrs to enlarge during the summer, becoming multilobed; few granules are present. The distribution of lipid in frozen sections, stained by Oil red O, is described for all types of follicles. Schultz and Lewis and Lobban tests for steroids were made on frozen sections with corresponding results. Positive green tests indicating the presence of steroids or possible steroidogenesis were limited to: (1) one post-ovulatory follicle, in the islands; (2) four stage III and seven late stage IV pre-ovulatory yolky atretic follicles; (3) two special atretic follicles. The special atretic follicle appears to be a unique feature of M. canis and it is suggested tentatively that it may be related to viviparity.     

Localization of relaxin in the pig follicle during preovulatory development

The avidin-biotin immunoperoxidase method and antisera to purified porcine relaxin were used to localize relaxin in sections of follicles from pregnant mare's serum gonadotropin (PMSG)/human chorionic gonadotropin (hCG)-primed pigs during preovulatory development. Prepubertal pigs were treated i.m. with PMSG (750 IU) and 72 h later with hCG (500 IU) to induce follicular development and ovulation. Follicles were collected from untreated gilts or from gilts 24, 48, 60, 72, 84, 96, or 108 h after PMSG treatment. Light immunostaining in the theca interna was observed early in follicular development, at 48 and 60 h post-PMSG. At 72 h post-PMSG, relaxin immunostaining in the theca interna of the preovulatory follicle was more intense. After hCG treatment, the intense thecal immunostaining persisted and was apparent 84 and 96 h after PMSG. At about 6 h prior to expected ovulation (108 h post-PMSG), there was thinning of the follicle wall and a reduction in relaxin immunostaining in the theca interna. Immunoactive relaxin was not detected in follicles from untreated gilts, follicles 24 h post-PMSG, small healthy or atretic follicles, or in granulosa cells, theca externa or ovarian stroma, at any of the time points studied. These studies support the hypothesis that the theca interna is the primary source of follicular relaxin and provide further evidence for a paracrine role for relaxin in the ovulatory process.     

Ultrastructural observations of previtellogenic ovarian follicles of dove

Dove ovarian follicle is a complex structure composed of oocyte surrounded by a somatic compartment consisting of theca externa, theca interna and granulosa. The structure of ovarian follicle (1 and 2 mm) of dove was studied by electron microscopy. The granulosa was pseudostratified in the 1-mm-diameter follicles and stratified with two or three irregular rows of cells in the 2-mm-diameter follicles. In the larger follicle indentations between oocyte and granulosa cells become more numerous and the microvilli of granulosa cell elongated to form a zona radiata with similarly elongated oocyte microvilli. Lining bodies were present at the tips of granulosa microvilli and in the cortical region of the oocyte. In the oocyte cortex were observed coated pits, coated vesicles, dense tubules, multivesicular bodies and primordial yolk spheres. Primordial yolk spheres may contain lining bodies and were observed fused with dense tubules and multivesicular bodies or associated with smooth cisternae.     

消炎痛对大鼠成熟滤泡破裂的影响——形态学观察

本工作的目的是,观察前列腺素合成的抑制物——消炎痛对大鼠排卵的抑制作用,并从形态学的角度对已排卵的以及排卵受阻的滤泡壁成份进行比较,藉此,探讨卵巢自身的前列腺素在滤泡破裂机制中的作用。25—27天龄Wistar大鼠用PMSG与HCG诱导成熟,其中部分动物作为对照,排卵率为100%;另一部分动物皮下注射消炎痛3.0mg/只,94%的动物被抑制排卵。处于动情前期的自然成熟鼠,注射消炎痛5mg/只或7.5 mg/只,排卵抑制率达100%,而对照鼠均排卵。从诱导成熟及自然成熟的大鼠卵巢组织切片所见,对照鼠已排卵滤泡的裂口处的白膜与膜层的结缔组织纤维断裂;被消炎痛抑制排卵的动物,卵母细胞因不能突破膜层或白膜而受阻。于电镜下见到,对照动物滤泡裂口附近泡壁的白膜细胞及外膜细胞出现退化、解体;与此同时,存在于这两种组织巾的胶元蛋白纤维也呈溶解现象。实验组排卵被阻的滤泡,白膜下与外膜细胞中间仍存在大量胶元蛋白纤维,因而使白膜与外膜层成为阻挡卵母细胞排出的屏障。另外,内膜与颗粒细胞的高尔基体发达,粗糙的内质网趋向光滑,说明这两类细胞分泌功能旺盛。关于前列腺素对胶元蛋白纤维降解的可能作用以及动物经消炎痛处理后仍产生类固醇激素的可能性均进行了讨论。     

Electron microscopy of cytodifferentiation and its subcellular steroidogenic sites in the theca cell of the human ovary

Summary The cytodifferentiation and subcellular steroidogenic sites in the theca cell of the human ovary during the follicular phase were investigated using the electron microscopic cytochemistry. Only fibroblast-like cells were seen around or near the primordial follicle. In the theca interna of the secondary and Graafian follicle however there were three different cell types: fibroblast-like cells, theca gland cells (steroid-secreting cells) and transitional cells (partially or incompletely differentiated theca cells). On the other hand the theca externa of these follicles consisted mainly of fibroblast-like cells. The hallmarks of the cytodifferentiation of the theca cells were: 1) the appearance of lipid droplets, 2) a structural change of the mitochondrial cristae from lamellar to tubular form and 3) the appearance and development of smooth endoplasmic reticulum. Reaction products of 3-hydroxysteroid ferricyanide reductase, indicating 3-hydroxysteroid dehydrogenase activity, were localized on tubular or lamellar cristae and inner membrane of the mitochondria, and on the membranes of smooth endoplasmic reticulum in the transitional cell as well as in the theca gland cell of the secondary and Graafian follicle. From these data, it is suggested that the transitional cell has a steroid-secreting activity and also plays an important role in follicular development in human reproduction.Supported by a grant from the Japanese Educational Ministry     

Mast cell histamine and ovarian follicular growth in the lizard Anolis carolinensis.

The hypothesis is proposed that histamine released from mast cells in the theca of ovarian follicles increases thecal hyperemia and vessel permeability, and thus plays a role in follicular growth in Anolis carolinensis. Mast cells are present in the stroma and theca, and the number of thecal mast cells increases as follicles grow. The levels of histamine in follicular walls varies with follicular size. Histamine causes vasodilatation of thecal vessels. Antihistamine blocks the effects of histamine and, when given alone, stimulates vasoconstriction. Antihistamine also blocks estradiol-induced growth of large follicles. These findings are consistent with the above hypothesis.     

Apelin and APJ receptor expression in granulosa and theca cells during different stages of follicular development in the bovine ovary: Involvement of apoptosis and hormonal regulation

In the mammalian ovary, the microvasculature in the thecal layer of follicles is associated with follicular development. Apelin and its receptor, APJ, are expressed in the tissues and organs which include the vasculature. The aims of the present study were to examine the mRNA expression of apelin and the APJ receptor in granulosa cells and theca tissue of bovine follicles and the effects of steroid hormone and gonadotrophins on the expression of these genes in cultured granulosa cells and theca cells. The expression of apelin mRNA was not found in the granulosa cells of bovine follicles. The expression of the APJ gene was increased in granulosa cells of estrogen-inactive dominant follicles. The expression of apelin mRNA increased in theca tissues of estrogen-inactive dominant follicles. APJ expression in theca tissues increased with follicle growth. Progesterone stimulated the expression of APJ mRNA in the cultured granulosa cells. FSH stimulated the expression of APJ mRNA in the cultured granulosa cells. LH induced the expression of apelin and APJ receptor mRNAs in cultured theca cells. Taken together, our data indicate that the APJ receptor in granulosa cells and both apelin and the APJ receptor in theca tissues are expressed in bovine ovary, that APJ in granulosa cells may be involved in the appearance of the cell apoptosis, and that LH stimulates the expression of apelin and APJ genes in theca cells.     

Kinetic aspects of follicle development in the rat

The eighth and ninth generations of follicle growth in rats represent a turning point in development. This stage is characterized by establishing a complete regulatory control based on feedback in follicle development. The feedback between follicles and gonadotropin secretion regulates a number of follicles maturing for ovulation. Gonadotropins seem to play a permissive, and not a directive part in regulation of follicle development in the eighth and ninth generations. By this stage of development, possibilities for theca and granule cells become sharply limited. Whereas expression of many maturation features may be hastened or hindered by changes in hormonal status, the result of development cannot be changed. Although only last generations of theca and granule cells exhibit mature functional features, their precursors seem to become committed to a single direction of development at early stages of follicle development. Neither the stage when precursor cells become irreversibly committed to differentiation into granule or theca cells, neither regulatory factors which determine this process have been identified yet. We suppose that precursor cells become committed to thecal tissue compartment when the follicle is at a primordial stage of development. Precursors of all the follicle components may already be assembled into one unit by the beginning of follicle growth. Accumulation of sufficient number of precursor cells around the primordial follicle may serve as a signal for follicle growth initiation. We think that the understanding of follicle postnatal growth and development should be based on understanding of origins, destiny, and possibilities of cells which form ovary and its compartments. First generations of follicle growth seem to be most promising for future research.     

Ultrastructural observations of previtellogenic ovarian follicles of the caecilians Ichthyophis tricolor and Gegeneophis ramaswamii

The ultrastructural organization of the previtellogenic follicles of the caecilians Ichthyophis tricolor and Gegeneophis ramaswamii, of the Western Ghats of India, were observed. Both species follow a similar seasonal reproductive pattern. The ovaries contain primordial follicles throughout the year with previtellogenic, vitellogenic, or postvitellogenic follicles, depending upon the reproductive status. The just-recruited primordial follicle includes an oocyte surrounded by a single layer of follicle and thecal cells. The differentiation of the theca into externa and interna layers, the follicle cells into dark and light variants, and the appearance of primordial yolk platelets and mitochondrial clouds in the ooplasm mark the transition of the primordial follicle into a previtellogenic follicle. During further development of the previtellogenic follicle the following changes occur: i) the theca loses distinction as externa and interna; ii) all the follicle cells become the dark variant and increase in the complexity of ultrastructural organization; iii) the nucleus of the oocyte transforms into the germinal vesicle and there is amplification of the nucleoli; iv) the primordial yolk platelets of the cortical cytoplasm of the oocyte increase in abundance; v) the mitochondrial clouds fragment and the mitochondria move away from the clouds, leaving behind the cementing matrix, which contains membrane-bound vesicles of various sizes, either empty or filled with a lipid material; vi) the perivitelline space appears first as troughs at the junctional points between the follicle cells and oocyte, which subsequently spread all around to become continuous; vii) macrovilli and microvilli develop from the follicle cells and oocyte, respectively; and viii) the precursor material of the vitelline envelop arrives at the perivitelline space. The sequential changes in the previtellogenic follicles of two species of caecilians are described.     

Effects of Gonadotropins on Motility of Human Ovary

THE occurrence of smooth muscle cells in the ovaries of many mammalian species suggests their possible function in the rupture of the ripe follicle by their contractions¹. In the rabbit, pig and sheep ovarian follicles, true smooth muscle cells are present in either or both the theca interna and externa. In women, follicles are surrounded by a network of reticular fibres and cells which resemble smooth muscle cells without fibrils². In a recent report, the ovaries of the cat have not only demonstrated spontaneous contractions in vitro but have also responded to adrenergic stimulation³. On the basis of these findings and in view of the fact that the stromal region of the ovaries of many species, including man, has adrenergic innervation, it has been proposed that contractions of the fibromuscular tissue may play a role in rupture of the follicle and extrusion of the ova³. In this report we describe changes in human intraovarian pressure which seem to result from contraction of the surrounding fibromuscular tissue. In some women marked changes in intraovarian pressure were observed after administration of human menopausal gonadotrophin and chorionic gonadotrophin. The study was carried out in six women of reproductive age who had to undergo abdominal surgery for correction of tubal occlusion (four patients) or tubal ligation. The two patients undergoing tubal ligation were on contraceptive pills for 3–5 years before the operation.     

Effects of methoxychlor on IGF-I signaling pathway in rat ovary

Follicular development and other ovarian functions are regulated by growth factors that can be affected by exogenous agents. Methoxychlor (MXC) is an organochloride pesticide that causes female infertility. We investigated how MXC affects the distribution of developing ovarian follicles in adult rats after treatment between embryonic day (E) 18 and postnatal day (PND) 7. We also measured insulin-like growth factor-I (IGF-I) and its receptor, IGF-IR, expressions in ovarian follicles and investigated whether MXC changed the levels of IGF-I and IGF-IR in the ovary. Using immunohistochemical (IHC) staining, we detected IGF-I expression in oocytes and granulosa cells of the follicles, luteal cells, interstitial cells, theca externa and theca interna, and the smooth muscle of ovarian vessels. IGF-IR was co-localized with IGF-I in the ovary except for the theca externa. IGF-I expression was decreased in granulosa cells of preantral and antral follicles after treatment with MXC compared to granulosa cells of preantral and antral follicles of the control group. We also observed that oocytes of secondary follicles and granulosa cells of secondary and preantral follicles of the MXC treated groups showed increased IGF-IR expression compared to oocytes of secondary follicles and granulosa cells of secondary and preantral follicles of the control group. We also detected more secondary and preantral follicles, and fewer primordial and antral follicles after MXC administration compared to controls. Therefore, the IGF signaling pathway may participate in MXC induced ovary dysfunction and female infertility.     

Evidence for Follicle Wall Involvement in Ovulation and Progesterone Production by Frog (Rana pipiens) Follicles in vitro

Involvement of different cellular investments of the amphibian ovarian follicle wall in the ovulatory process, progesterone production, and oocyte maturation was investigated. Following microdissection, to selectively remove one or more layers (surface epithelium, theca, follicle cells) of the follicle wall, dissected and undirected ovarian follicles were treated with frog pituitary homogenate (FPH) or progesterone. Intact follicles ovulated in response to pituitary homogenate and this was associated with contractions of the follicle wall. Ovulation and follicular contractions were not observed following removal of the surface epithelium without removing the thecal layer. Oocyte maturation occured in response to FPH following removal of the surface epithelium alone or together with the theca, but not in the absence of the follicle cells. Intact follicles were most responsive to FPH with respect to progesterone production, and removal of all somatic cells from oocytes obliterated FPH stimulated progesterone production. Oocytes, regardless of wether any or all follicular wall layers were removed, matured but did not ovulate following exposure to progesterone. The results suggest that the surface epithelium, but not the theca, is required for FPH-induced extrusion (ovulation) of the oocyte from ovarian follicle wall. Additionally, the somatic tissue rather than the oocyte appears to be the cells producing progesterone following FPH treatment. The results indicate that separate cellular layers (individually and/or as a result of interactions) of the follicle wall carry out different functions during follicular differentiation and mediation of ovulation. Data provide functional evidence for a role of the surface epithelium in controlling the process of ovulation and follicular contraction.     

Ultrastructure of the theca interna of ovarian follicles in sheep

Summary The theca interna of non-atretic ovarian follicles from 2.0 mm in diameter up to the stage shortly following ovulation was studied by light and electron microscopy.In follicles <3.0mm in diameter, the theca interna consisted of about 8–12 layers of flattened cells, together with many capillaries and small bundles of collagen. Two main forms of cellular differentiation were seen. These were towards either fibroblast-like cells or presumed steroidogenic cells whose cytoplasm contained large amounts of predominantly smooth tubular endoplasmic reticulum, to which some ribosomes were attached. The majority of cells were of relatively undifferentiated or intermediate structure.In larger follicles up to the early stages of oestrus the theca interna cells became larger and less flattened, and cells rich in tubular endoplasmic reticulum became proportionately more numerous. By 18 h after the onset of oestrus the theca interna was oedematous, and many cells possessed pseudopodia. Many cells also contained numerous lipid droplets, but there were no signs of thecal cell degeneration or death. Shortly after ovulation the basal lamina of the membrana granulosa was incomplete, and it became more difficult to distinguish between theca and granulosa layers. Structural heterogeneity, with two major cell types and cells of intermediate structure, was present at all stages.It was concluded that: (1) the theca interna of 2.0–2.9 mm follicles contained many cells whose structure was compatible with a steroidogenic capacity; (2) changes in the differentiated thecal cells up to the early stages of oestrus were quantitative rather than qualitative, and suggestive of an increased steroidogenic capacity; (3) the accumulation of lipid in many cells of the theca interna by 18 h after the onset of oestrus probably reflected a reduction in steroidogenic activity; and (4) there was no evidence of any structural specialization to facilitate the transport of steroids from the theca interna to the membrana granulosa.     

The distribution of smooth muscle in the cat ovary with a note on its adrenergic innervation

Smooth muscle in the ovaries of estrus and anestrus cats was studied with the TP-Levanol Fast Cyanine 5 RN technique and adrenergic nerves were visualized with the Falck-Hillarp fluorescence procedure. Numerous bundles of smooth muscle fibers were observed in the mesovarium, and the hilar, medullary, and cortical regions of the estrus ovary. Also, theca externa of large vesicular follicles contained many smooth muscle fibers. Adrenergic nerves with varicosities were present in ovarian perifollicular tissue. Anestrus animals had a reduced number of cortical and perifollicular muscle fibers and the intensity and density of fluorescent nerves was reduced. It is suggested that contraction of ovarian smooth muscle facilitates ovulation. These contractions may be, at least partially, under local neural control.     

Localization of an activin/activin receptor system in the porcine ovary.

The aim of this study was to locate a possible activin/activin receptor system within porcine ovaries containing functional corpora lutea. In situ hybridization was used to assess the gene expression of beta(A)- and beta(B)-activin subunits, and immunohistochemical studies were done to detect activin-A protein and activin receptor type II. mRNA expression of the beta(A)- and beta(B)-activin subunits was found in the granulosa from the unilaminar follicle stage onward, in the developing thecal layer of multilaminar and small antral follicles, in the theca interna of mid-sized antral follicles, in corpora lutea, and in the ovarian surface epithelium. Immunoreactive activin A protein could be detected at the same ovarian sites, but in thecal tissue of small antral follicles only. This protein was also demonstrated at the peripheral zone of oocytes from multilaminar and antral follicles. A positive immunoreaction for activin receptor was found in granulosa cells from multilaminar and older follicles and in oocytes from the earliest stages of follicular development onward. In late multilaminar follicles and in antral follicles, the oolemma was stained. Except for small antral follicles, a positive activin receptor immunoreaction was absent in the follicular theca. Activin receptor immunoreaction was furthermore present in corpora lutea and in the ovarian surface epithelium. It is concluded that, within porcine ovaries containing functional corpora lutea, an activin/activin receptor system is present in all intact follicles, the corpora lutea and the surface epithelium. Within follicles, granulosa and theca cells are the main sites of activin synthesis, while oocytes and granulosa cells are the main activin binding sites.     

Ultrastructural changes in the theca interna during follicular atresia in sheep

Sixteen antral follicles, 1.8--4.2 mm in diameter, at various stages of atresia, were studied by electron microscopy. Deletion of theca interna cells by condensation followed by fragmentation (apoptosis), with subsequent engulfment of the fragments by remaining thecal cells, was present at all stages, but was most marked during secondary and tertiary atresia. In primary and secondary atresia, the relative numbers of thecal cells whose cytoplasm was rich in tubular endoplasmic reticulum were higher than in non-atretic follicles of comparable size. During tertiary atresia the number of cell layers in the theca interna was reduced, and cells rich in tubular endoplasmic reticulum became proportionately less numerous. Degenerating cellular material was present within the lumina of thecal capillaries at all stages of atresia. Such material was rarely seen in primary atresia, and increased in incidence progressively in later stages. It was concluded that during atresia a large number of theca interna cells are deleted by apoptosis, and many thecal capillaries become blocked with cellular debris.     

Production of tissue inhibitors of metalloproteinases (TIMPs) by pig ovarian cells in vivo and the effect of TIMP-1 on steroidogenesis in vitro

Precisely which ovarian cells produce tissue inhibitors of metalloproteinases (TIMPs) is unclear. Although granulosa cells are reported to produce TIMPs, thecal TIMP production has not been investigated nor has the influence of TIMPs on theca cells. Furthermore, although periovulatory follicles have been examined, little is known about smaller ovarian follicles. Follicles >/= 2 mm in diameter were collected from Large White hybrid gilts on the day before predicted oestrus (n = 3) or after hCG treatment (n = 3) and divided into 1 mm size classes. Small (2 to < 5 mm) follicles were kept intact, whereas follicles >/= 5 mm were separated into follicular fluid, granulosa and theca cell compartments. After homogenization, TIMP-1, -2 and -3 were detected by reverse zymography. Theca cells (50 x 10(3) per well) were cultured with TIMP-1 (10, 100 or 200 ng ml(-1) with or without long-R3 insulin-like growth factor I (IGF-I)) in a serum-free system to investigate the effect on steroidogenesis and the number of cells. Both large and small pig follicles produced TIMPs and TIMP-1, -2 and -3 were detected in follicular fluid, granulosa and theca cell samples. There was a phase x tissue type interaction for the presence of both TIMP-1 and -2 (P < 0.03, P < 0.05, respectively), and TIMPs were detected in more granulosa and theca cell samples after hCG than during the follicular phase. The concentrations were influenced by the type of tissue (TIMP-1, P < 0.005; TIMP-2, P < 0.005, TIMP-3, P > 0.05), and the highest concentrations occurred in the theca tissue. There were tissue type x follicle size interactions for the presence of both TIMP-1 and -2 (P < 0.001). In vitro, TIMP-1 increased thecal steroidogenesis after 144 h (oestradiol, P < 0.05, progesterone, P < 0.001) but reduced the number of viable cells (P < 0.001). In conclusion, TIMP-1, -2 and -3 were present in large and small pig follicles and were produced by both granulosa and theca cells, although concentrations differed with the type of tissue. Production was regulated by factors including follicle size and phase of the oestrous cycle. In addition to controlling tissue remodelling, TIMP-1 may also regulate steroidogenesis.