Basal and LH-RH-stimulated gonadotropin secretion in oophorectomized female rats with streptozotocin-induced diabetes

In vitro insulin effect on basal and LH-RH- stimulated gonadotropin secretion in oophorectomized female rats with streptozotocin diabetes administered estradiol as replacing hormone therapy was studied. The results were compared to those obtained after a similar incubation of adenohypophyses of oophorectomized rats and of oophorectomized rats administered estradiol. Estradiol was found to change the type of LH-RH-stimulated gonadotropin secretion in oophorectomized animals. Basal, but not LH-RH-stimulated gonadotropin secretion, was increased in rats with experimental diabetes as against other groups. Insulin inhibited basal and increased LH-RH-stimulated gonadotropin secretion in oophorectomized rat’s with streptozotocin diabetes administered estradiol. A conclusion is made about impaired sensitivity of hypophyseal gonadotrophs to LH-RH in streptozotocin diabetes and about a possible contribution of insulin to regulation of body reproductive system at the level of hypophysis.

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Analysis of hypothalamo-hypophyseo-gonadal relationships in female rats with experimental diabetes

Problems of Endocrinology ◽

10.14341/probl11334 ◽

1994 ◽

Vol 40 (1) ◽

pp. 46-50 ◽

Cited By ~ 2

Author(s):

V N Babichev ◽

Ye L Adamskaya ◽

T A Peryshkova

Keyword(s):

Nuclear Receptors ◽

Sex Hormones ◽

Experimental Diabetes ◽

Streptozotocin Diabetes ◽

Female Rats ◽

Gonadotropin Secretion ◽

Estral Cycle ◽

Lh Rh ◽

Reduced Activity ◽

Intact Rats

Hypothalamo-hypophyseo-gonadal system functional activity was studied in rats with streptozotocin diabetes. In intact rats concentrations of sex hormones nuclear receptors were measured in the hypothalamic preopticoanterior, mediobasal segments and in the adenohypophysis, as were blood serum gonadotropins and sex hormones. Estradiol and progesterone were injected to ovariectomized females and LH-RH levels measured in preopticoanterior segment of the hypothalamus, arcuate nucleus, and median eminence, as well as LH and FSH concentrations in the blood in order to detect disorders in basal and cyclic gonadotropin secretion. Streptozotocin injection to cycling females disordered the estral cycle and was associated with reduction of LH, FSH, and sex hormones basal and cyclic secretion. Estradiol nuclear receptors concentrations reduced in the preopticoanterior hypothalamus and hypophysis, the count of nuclear testosterone-binding sites reduced only in the hypophysis. Gonadotropin wave stimulated with sex steroids in ovariectomized females was reduced in diabetes because of changed activity of LH-RH-producing system. We believe that changes in basal and cyclic secretion of gonadotropins in rat females with experimental diabetes is explained by reduced activity of LH-RH-producing system and receptor binding at the level of the hypothalamo-hypophyseal complex.

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Neuroendocrine control of the pituitary gonadotropic function in experimental diabetes

Problems of Endocrinology ◽

10.14341/probl10395 ◽

2019 ◽

Vol 43 (3) ◽

pp. 43-47

Author(s):

V. N. Babichev ◽

E. I. Adamskaya ◽

T. A. Kuznetsova ◽

I. V. Shishkina

Keyword(s):

Nuclear Receptors ◽

Experimental Diabetes ◽

Diabetic Rats ◽

Female Rats ◽

Maximal Response ◽

Basal Secretion ◽

Male And Female Rats ◽

Lh Rh ◽

Lh Secretion

The hypothalamo-pituitary-gonadal system was examined in male and female rats with experimental diabetes induced by streptozotocin (STZ). Injection of STZ caused a decrease of testosterone (T) concentration and of T nuclear receptors in the pituitary. The levels of luteinizing and follicle stimulating hormones (LH and FSH) in the blood of diabetic rats did not differ from those in intact animals. In vitro experiments showed that the development of diabetes did not change the basal secretion of LH by the pituitary in males. Maximal response to LH-RH was recorded in control males after 3-hour incubation, whereas the rate of LH secretion in experimental rats did not differ from basal values. Injection of STZ to cycling females disordered the estrous cycle and involved decreases of the basal and cyclic secretion of LH, FSH, and sex hormones. The concentrations of estradiol nuclear receptors in the preoptic anterohypothalamic region and pituitary decreased, whereas the number of T-binding sites decreased only in the pituitary. Sex hormone-stimulated gonadotropin wave in oophorect- omized females was decreased in diabetes, which was due to changed activity of the LH-RH producing system. The authors hypothesize that changes in the mechanism of regulation of the hypothalamo-pituitary-gonadal system in experimental diabetes are related to pituitary disorders in males, whereas changed basal and cyclic secretion of LH and FSH in females is caused by disordered activity of the LH-RH production and receptor binding at the level of the hypothalamo-pituitary complex.

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REGULATION OF THE METABOLISM OF PITUITARY NUCLEIC ACIDS IN FEMALE RATS

Journal of Endocrinology ◽

10.1677/joe.0.0850001 ◽

1980 ◽

Vol 85 (1) ◽

pp. 1-8 ◽

Cited By ~ 12

Author(s):

J. BÍRÓ

Keyword(s):

Nucleic Acids ◽

Intraperitoneal Injection ◽

Anterior Pituitary ◽

Rna Metabolism ◽

Female Rats ◽

Biphasic Effect ◽

Lh Rh ◽

Lh Releasing Hormone

SUMMARY Ovariectomy caused an increase in the metabolism of pituitary nucleic acids. This effect was reversed in vivo by a biphasic action of oestradiol-17β which first facilitated RNA metabolism after 8 h and then inhibited it 16 h after intraperitoneal injection. To analyse the origin of this biphasic effect the roles of LH releasing hormone (LH-RH) and hysterectomy were examined. Incorporation of uridine into the RNA of the anterior pituitary gland of female rats was inhibited both in vivo and in vitro by LH-RH. Hysterectomy augmented the increase in the RNA metabolism caused by ovariectomy whereas steroid-free uterine extracts inhibited the increase significantly. We have concluded that extrapituitary factors may be involved in the effects of oestrogen on the metabolism of pituitary nucleic acids.

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Effect of inhibin-like activity on LH-RH-stimulated release of FSH by pituitary glands from female rats in vitro

Life Sciences ◽

10.1016/0024-3205(83)90114-5 ◽

1983 ◽

Vol 32 (10) ◽

pp. 1091-1098 ◽

Cited By ~ 7

Author(s):

A.A.J. Jenner ◽

J. de Koning ◽

G.P. van Rees

Keyword(s):

Female Rats ◽

Pituitary Glands ◽

Lh Rh

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Altered microvascular reactivity in streptozotocin-induced diabetes in rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1989.257.5.h1438 ◽

1989 ◽

Vol 257 (5) ◽

pp. H1438-H1445 ◽

Cited By ~ 2

Author(s):

M. A. Hill ◽

R. G. Larkins

Keyword(s):

Experimental Diabetes ◽

Ang Ii ◽

Prostaglandin I2 ◽

Short Term ◽

Third Order ◽

Basal Diameter ◽

Microvascular Reactivity ◽

Vasoconstrictor Response ◽

Streptozotocin Induced Diabetes

This study examined the effect of short-term streptozotocin-induced diabetes in rats on the response of cremaster muscle arterioles to angiotensin II (ANG II) and vasodilatory prostaglandins. Topically applied ANG II (10(-10) to 10(-6) M) caused significantly greater vasoconstriction of third-order arterioles in diabetic animals in comparison with controls. For example, in response to 10(-6) M ANG II arterioles of the diabetic animals constricted to 43 +/- 10% of basal diameter compared with controls' 67 +/- 6% (P less than 0.05). Furthermore, the magnitude of the secondary vasodilatation after ANG II-induced constriction was decreased in diabetic animals (108 +/- 4 and 131 +/- 9%, P less than 0.025). Cyclooxygenase inhibition resulted in marked arteriolar constriction, with this effect being less evident in diabetic animals. In response to indomethacin (2.8 x 10(-5) M), arterioles of the diabetic animals constricted to 84 +/- 7% of basal diameter compared with 56 +/- 4% in controls (P less than 0.01). Arterioles of the diabetic animals were less responsive to exogenous prostaglandin I2 (PGI2) and PGE2 (10(-12) to 10(-6) M) despite evidence of increased in vitro PGI2 production. The data demonstrate potentiation of the vasoconstrictor response and a diminution of the secondary vasodilator response to ANG II in experimental diabetes. These alterations may be due, in part, to decreased responsiveness of skeletal muscle arterioles to vasodilatory prostaglandins.

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Comparison between the effects of LH-RH and raised K+ concentration on release of LH from pituitary glands of female rats in vitro

FEBS Letters ◽

10.1016/0014-5793(81)80241-4 ◽

1981 ◽

Vol 126 (2) ◽

pp. 199-202 ◽

Cited By ~ 2

Author(s):

J. De Koning ◽

A.M.I. Tijssen ◽

J.A.M.J. Van Dieten ◽

G.P. Van Rees

Keyword(s):

Female Rats ◽

Pituitary Glands ◽

K Concentration ◽

Lh Rh

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Wen-Jing-Tang, a Traditional Chinese Herbal Medicine Increases Luteinizing Hormone Release In Vitro

The American Journal of Chinese Medicine ◽

10.1142/s0192415x86000259 ◽

1986 ◽

Vol 14 (03n04) ◽

pp. 157-160 ◽

Cited By ~ 5

Author(s):

Akira Miyake ◽

Jin-Woo Lee ◽

Keiichi Tasaka ◽

Shirou Ohtsuka ◽

Toshihiro Aono

Keyword(s):

Herbal Medicine ◽

Luteinizing Hormone ◽

Chinese Herbal Medicine ◽

Female Rats ◽

Normal Female ◽

Traditional Chinese Herbal Medicine ◽

Chinese Herbal ◽

Lh Release ◽

Lh Rh

For examination of the effect on luteinizing hormone (LH) release of Wen-Jing-Tang, a traditional Chinese herbal medicine, the pituitary from normal female rats in diestrus was perifused alone or in sequence with the mediobasal hypothalamus (MBH) in a sequential double-chamber perifusion system. Wen-Jing-Tang at 5 or 500 μg/ml induced significant LH release (60-95 % increase) from the pituitary in series with the MBH, but had no effect on LH release from the pituitary perifused alone. These data suggest that Wen-Jing-Tang induces LH release from the pituitary through hypothalamic LH-RH.

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Effect of streptozotocin diabetes on polysomal aggregation and protein synthesis rate in the liver of pregnant rats and their offspring

Bioscience Reports ◽

10.1007/bf01200211 ◽

1995 ◽

Vol 15 (1) ◽

pp. 15-20 ◽

Cited By ~ 3

Author(s):

M. E. Martin ◽

A. M. Garcia ◽

L. Blanco ◽

E. Herrera ◽

M. Salinas

Keyword(s):

Protein Synthesis ◽

Streptozotocin Diabetes ◽

Diabetic Rats ◽

Female Rats ◽

Synthesis Rate ◽

Protein Synthesis Rate ◽

Pregnant Rats ◽

Free System ◽

Rna Concentration

To study the effect of diabetes on hepatic protein synthesis and polysomal aggregation in pregnant rats, female rats were treated with streptozotocin prior to conception. Some animals were mated, and studied at day 20 of pregnancy, whereas, others were studied in parallel under non pregnant conditions. The protein synthesis rate measured with an “in vitro” cell-free system was higher in pregnant than in virgin control rats. It decreased with diabetes in both groups, although values remained higher in diabetic pregnant rats than in the virgin animals. The fetuses of diabetic rats had a lower protein synthesis rate than those from controls, although they showed a higher protein synthesis rate than either their respective mothers or virgin rats. Liver RNA concentration was higher in control and diabetic, pregnant rats than in virgin rats, and the effect of diabetes decreasing this parameter was only significant for pregnant rats. Liver RNA concentration in fetuses was lower than in their mothers, and did not differ between control and diabetic animals. The decreased protein synthesis found in diabetic animals was accompanied by disaggregation of heavy polysomes into lighter species, indicating an impairment in peptide-chain initiation.

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