Growth hormone and prolactin affect oxytocin, vasopressin, progesterone and cyclic nucleotide secretion by bovine granulosa cells in vitro.

The effects of growth hormone (GH) and prolactin (PRL) (1, 10, 100, 1000 or 10,000 ng/ml medium) on oxytocin, vasopressin, progesterone, cAMP and cGMP release by cultured bovine granulosa cells were studied. It was found that GH significantly stimulated oxytocin, vasopressin and cAMP but suppressed progesterone secretion. PRL tended to have the same pattern of action on nonapeptide, cAMP and steroid release, but its effect was not as great, with only a high supraphysiological dose (10,000 ng/ml) producing a statistically significant effect.

Direct action of LH RH and its antagonist on isolated bovine granulosa cells steroidogenesis.

Progesterone, 4-androstene-3,17-dione, testosterone and estradiol-17 beta secretion by bovine granulosa cells culture without or in the presence of 10, 100 or 10.000 ng/ml LH RH or of its antagonist (D Phe2, D Phe6) LH RH were analyzed. It was observed that both LH RH and its antagonist significantly activated progesterone and estradiol output.

The role of cAMP- and Ca(2+)-dependent intracellular mechanisms in the control of oxytocin and vasopressin secretion by bovine ovarian granulosa cells in vitro.

The secretion of oxytocin and arginine-vasopressin was demonstrated in bovine granulosa cell culture. It was found that dbcAMP or 3-isobutyl-1-methyl-xanthine (an inhibitor of intracellular cAMP metabolization) additions increased both oxytocin and vasopressin release. The Ca2+ ionophore A23187 also stimulated, while the Ca2+ channel blocker verapamil inhibited the secretion of both nonapeptide hormones.

Cooperation between LH-RH and LH in the direct action on the ovary: LH-RH stimulation of LH/hCG receptors, basal and LH-induced cAMP and cGMP release by porcine granulosa cells in vitro.

LH-RH effects on LH/hCG receptors content, on basal and LH-stimulated cAMP and cGMP release by cultured porcine granulosa cells, were investigated by radioreceptor analysis and radioimmunoassay. It was found that LH-RH additions (10, 100, 1000 or 10,000 ng/ml medium) increased the number of LH/hCG binding sites in granulosa cells. LH or hCG (0.

Effects of prolactin on estrogen, cAMP and oxytocin secretion by porcine granulosa cells in vitro.

Granulosa cells were isolated from ovaries (without pre-ovulatory follicles or corpora lutea) of cycling gilts slaughtered at 8 months of age. They were cultured in the presence or absence of exogenous porcine prolactin (1, 10, 1,000, 10,000, or 100,000 pmol/ml medium). The secretion of estrogen, cAMP and oxytocin into the incubation medium was analysed by radioimmunoassay.

Release of a prolactin-like substance by bovine granulosa cells in vitro: effects of ovarian steroids.

The time-dependent accumulation of prolactin (PRL) immunoreactivity in serum-free and in serum-supplemented cultures of bovine granulosa cells was observed. Blockade of endogenous progesterone by specific antiserum had no significant influence on PRL immunoreactivity, but progesterone addition (10-10,000 ng/ml) lead to a dose-dependent decrease. Antisera against testosterone and against estradiol-17 beta were inhibitors, and additions of these hormones (100-10,000 ng/ml) stimulated the release of PRL immunoreactivity.

Steroid hormones regulate cAMP and cGMP production by porcine granulosa cells in vitro.

The influence of steroid hormones on the output of the cyclic nucleotides adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) by porcine granulosa cells was investigated. Both progesterone (100, 1000, 10,000 and 100,000 pg/ml medium) and estradiol (100, 1000, 10,000 and 100,000 pg/ml medium) activated cAMP and cGMP production. Testosterone (100 or 1000 pg/ml medium) also stimulated cAMP output.

The action of LH-releasing hormone and five analogues on oestradiol, oxytocin and vasopressin secretion by bovine granulosa cells in culture.

The release of oxytocin, arginine-8-vasopressin and oestradiol-17 beta by bovine granulosa cells in culture was analysed either with or without LH-releasing hormone (LHRH), its agonists (cyclo [Pro1DPhe6] LHRH and des 1-3, 10[DAla6] LHRH) or antagonists ([DPhe2DPhe6] LHRH, [DPhe2DPhe(NH2)6] LHRH or cyclo [Pro1DPhe2DPhe6] LHRH). All preparations used stimulated granulosa oxytocin and oestradiol secretion. Vasopressin release was significantly increased after all treatments with LHRH antagonists, but not after LHRH or its agonists.

[The effect of recombinant somatotropin hormone on the secretion of ovarian hormones in sexually mature swine in vivo and in vitro].

The development of recombinant somatotropic hormone (STH) creates a prerequisite for a wide application of exogenous stimulation of meat and milk performance of cows and pigs. Reproduction effect and its mechanism is till now restricted by a lack of complex information though there are several studies of principal character and basic effects of STH on reproduction process are also known. The result of some experimental studies, quoted in scientific literature, was a hypothesis that STH effect is accompanied by increased production of so-called insulin-like growth factors.

The interrelationships between nonapeptide and steroid hormones secretion by bovine granulosa cells in vitro.

The effects of adding oxytocin (OT) and arginine-vasopressin (AVP) on progesterone and estradiol-17 beta secretion by bovine granulosa cells in culture were studied. The influence of these steroids on OT and AVP release was also evaluated. OT (1, 10, 100 or 1000 mIU/ml) stimulates both progesterone and estradiol output.

[Production of progesterone and testosterone in ovarian granulosa cells in sows after administration of nonapeptide hormones in vitro].

In the present paper the effects of nonapeptide hormones and of some of their chemical analogues were investigated on progesterone and testosterone production in granulosa cells of sow ovaries; the experiments were made in vitro. This objective was given by data on potential regulatory roles of nonapeptides at the level of hypothalamus, pituitary and reproductive organs. The goal of this experiment was to analyze the effects of various doses of oxytocin (OT), arginine-8-vasopressin (AVP), arginine-8-vasotocin and of some of their analogues on progesterone and testosterone production in vitro in granulosa cells of sow ovaries.

Effect of FSH, LH, LH-RH and arginine-vasotocin on the production of steroids, nonapeptide hormones and cGMP by rabbits granulosa cells isolated at different stages of reproductive cycle.

Granulosa cells isolated from ovaries of non-cycling, cycling and pregnant rabbits of the same age were cultured in vitro either without or with pFSH (1 micrograms/ml), bLH (1 IU/ml), LH-RH (25 ng/ml) or arginine-8-vasotocin (100 ng/ml). The production of immunoreactive progesterone, estradiol-17 beta, oxytocin, arginine-8-vasopressin and cGMP was analyzed. The gonadotropins did not show any significant effects on the cells isolated from non-cycling and cycling rabbits, but not from these of pregnant ones.

The influence of oxytocin, vasopressin and their analogues on progesterone and testosterone production by porcine granulosa cells in vitro.

Effects of nonapeptide hormones and some of their chemical analogues on progesterone and testosterone production by culture of porcine granulosa cells have been investigated. Oxytocin (0.01-10 IU/ml), arginine-8-vasopressin (0.

Prolactin-like substance secretion by granulosa cells isolated from bovine ovaries.

By the 5-day culture of bovine granulosa cells both in serum-free and in serum-supplemented medium the time-dependent accumulation of PRL immunoreactivity was observed. FSH additions (10-10,000 ng/ml medium) led to a dramatic rise of immunoreactive PRL in a dose-dependent manner. LH stimulated the increase of PRL-like substance only in a great dose (10 IU/ml).

Reciprocal control of oxytocin and cAMP production by porcine granulosa cells in vitro.

Oxytocin and cAMP accumulation in the medium after 4 days incubation of porcine granulosa cells was measured and confirmed the production of these substances by porcine ovaries. Both cAMP analogue dbcAMP (10, 100, 1,000 or 10,000 microM/ml) and 3-isobutyl-1-methyl-xanthine (intracellular cAMP metabolization inhibitor, 0.1, 1, 10 or 100 microM/ml) additions increased granulosa cells oxytocin production in a dose-dependent manner.

[Secretory activity of ovarian granulosa cells in cows in relation to production of prolactin or prolactin-like substances in vitro].

Ovarian functions are regulated by a wide variety of substances of hypothalamic, pituitary and intraovarian origin. In particular, prolactin (PRL) plays an important role in the control of ovaries. The aim of our in-vitro experiments was to prove a possibility of PRL production by bovine granulosa cells and to search into the endocrine regulators of this process.

[Fluctuations in the level of progesterone in the peripheral blood of nutria during pregnancy].

The fluctuations in the concentrations of progesterone in peripheral blood of three intact coypus and three coypus after natural mating were investigated for the period of four months. Immediately after mating the concentrations of progesterone are low (1.5-2.