Immunohistochemical localization of tissue-type plasminogen activator in ovaries before and after induced and spontaneous ovulation in the rat

Cajander, Stefan; Hugin, M. P.; Kristensen, Peter; Hsueh, Aaron J. W.

doi:10.1007/bf00221627

Cited by 12 publications

(4 citation statements)

References 40 publications

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“…The pattern of ovarian tPA mRNA expression during the periovulatory period in spontaneously ovulating adult rats has not, to our knowledge, been previously described. We observed that tPA was expressed in thecal-interstitial cells and oocytes of developing and preovulatory follicles, similar to results obtained by ill situ hybridization analysis of ovaries from immature rats treated with exogenous gonadotropins (34 studies of adult cyclic rats (35), tPA message levels WCrC low in granulosa cells of preovulatory follicles prior to the LH surge, but were markedly increased following LH stimulation and peaked just prior to ovulation. The time interval between the peak of the proestrous LH surge and peak tPA message levels is also consistent with the interval required for hCG-induced tPA expression in immature rats (34).…”

Section: Discussionsupporting

confidence: 86%

Effects of Aging on Luteinizing Hormone Secretion, Ovulation, and Ovarian Tissue-Type Plasminogen Activator Expression

LaPolt

2001

Exp Biol Med (Maywood)

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This stUdy examined the effects of aging on LH surge magnitUde , OVUlation, and ovarian expression of tissue-type plasminogen activator (tPA), a protease Implicated in follicular rupture. While mean LH levels and ovulation rates were similar in middle-aged cyclic and young groups, there was a significant correlation between peak LH levels and ovulation rates In individual rats, such that females with lower LH surges ovulated fewer ova. In a separate experiment, proestrous LH levels were Characterized in young and middle-aged rats, followed by In situ hYbridization analysis of ovarian tPA mRNA. In young proestrous rats, tPA expression was observed In thecal-Interstitial ceils and oocytes, but not granulosa cells, prior to the LH surge. After the LH surge, there was a marked Increase in tPA mRNA levels In granUlosa cells of preovulatory, but not smaller follicles, peaking at 0200 hr estrus. By 0500 hr estrus, ovarian tPA expression declined, and ovulation had occurred. In contrast, LH-Induced follicular tPA mRNA levels were dramatically lower In middle-aged rats with attenuated LH surges, and persisting preovulatory follicles were common in ovaries of these females on estrus morning. These findings suggest that age-related declines in ovulatory function result In part from altered induction of ovarian tPA expression, likely due to decreased proestrous LH secretion.

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Section: Discussionsupporting

confidence: 86%

Effects of Aging on Luteinizing Hormone Secretion, Ovulation, and Ovarian Tissue-Type Plasminogen Activator Expression

LaPolt

2001

Exp Biol Med (Maywood)

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“…The biological activity of TGF‐β in the synapse may require activation by a matrix metalloprotease that is itself activated by proteolytic cleavage 10. The plasminogen activator/plasmin system has been implicated in biological processes involving tissue remodeling such as ovulation,11,12 metastasis,13,14 and neuronal plasticity 15,16. Plasminogen activators are expressed in many tissues including endocrine tissues 17.…”

Section: Introductionmentioning

confidence: 99%

Expression and Functional Characterization of the Serine Protease Inhibitor Neuroserpin in Endocrine Cells

Hill

Coates

Parmar

et al. 2002

Annals of the New York Academy of Sciences

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Serine proteases play essential roles in a wide variety of cellular processes in endocrine cells. There is a growing interest in the roles of serine protease inhibitors, or serpins, as key regulators of their activity. We have cloned two neuroserpin cDNAs from a rat pituitary cDNA library and confirmed tissue plasminogen activator as a potential target for this inhibitor. We show that neuroserpin transcripts are expressed by endocrine cells in the adrenal and pituitary glands and that immunoreactive neuroserpin is stored in densely cored secretory granules in these cells. Overexpression of neuroserpin in an anterior pituitary corticotroph cell line results in the extension of neurite-like processes, suggesting that neuroserpin may play a role in cell communication, cell adhesion, and/or cell migration.

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“…In the blood plasmin degrades fibrin, the major protein component of blood clots [1]. In addition to its role in fibrinolysis, the plasminogen activator\plasmin system has been implicated in biological processes involving tissue remodelling such as ovulation [2,3], metastasis [4,5] and neuronal plasticity [6,7]. Plasminogen activators are expressed in many tissues, including a number of endocrine tissues.…”

Section: Introductionmentioning

confidence: 99%

Neuroserpin is expressed in the pituitary and adrenal glands and induces the extension of neurite-like processes in AtT-20 cells

et al. 2000

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Two cDNAs encoding the serine protease inhibitor (serpin) neuroserpin were cloned from a rat pituitary cDNA library (rNS-1, 2922 bp; rNS-2, 1599 bp). In situ hybridization histochemistry showed neuroserpin transcripts in the intermediate, anterior and posterior lobes of the pituitary gland and medullary cells in the adrenal gland. Expression of rNS-1 mRNA was restricted to selected cells in the pituitary gland. Analysis of purified secretory-granule fractions from pituitary and adrenal tissues indicated that neuroserpin was found in dense-cored secretory granules. This result suggested that endocrine neuroserpin may regulate intragranular proteases or inhibit enzymes following regulated secretion. To investigate the function of neuroserpin in endocrine tissues we established stable anterior pituitary AtT-20 cell lines expressing neuroserpin. Cells with increased levels of neuroserpin responded by extending neurite-like processes. Extracellular proteolysis by serine protease plasminogen activators has been suggested to regulate neurite outgrowth. As neuroserpin inhibits tissue plasminogen activator (tPA) in vitro, we measured plasminogen-activator levels. Zymographic analysis indicated that AtT-20 cells synthesized and secreted a plasminogen activator identical in size to tPA. A higher-molecular-mass tPA-neuroserpin complex was also observed in AtT-20-cell conditioned culture medium. tPA levels were similar in parent AtT-20 cells and a stable cell line with increased levels of neuroserpin. There was no accumulation of a tPA-neuroserpin complex. Together these results identify endocrine cells as an important source of neuroserpin. Moreover they suggest that neuroserpin is released from dense-cored secretory granules to regulate cell-extracellular matrix interactions through a mechanism that may not directly involve tPA.

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Immunohistochemical localization of tissue-type plasminogen activator in ovaries before and after induced and spontaneous ovulation in the rat

Cited by 12 publications

References 40 publications

Effects of Aging on Luteinizing Hormone Secretion, Ovulation, and Ovarian Tissue-Type Plasminogen Activator Expression

Effects of Aging on Luteinizing Hormone Secretion, Ovulation, and Ovarian Tissue-Type Plasminogen Activator Expression

Expression and Functional Characterization of the Serine Protease Inhibitor Neuroserpin in Endocrine Cells

Neuroserpin is expressed in the pituitary and adrenal glands and induces the extension of neurite-like processes in AtT-20 cells

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