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At least 451 records · Page 25Linked to original sources
PubMed2004

Role of early insulin secretion in postglucose-loading hyperglycaemia and postfat-loading hyperlipidaemia: comparing nateglinide and glibenclamide for acute effects on insulin secretion in OLETF rats.

AIM: The aim of this study was to clarify the role of an early insulin secretion in postprandial hyperglycaemia and hyperlipidaemia; a study using spontaneously type 2 diabetic Otsuka Long-Evans Tokushima Fatty rats with visceral obesity was performed to investigate the acute effect of nateglinide (NAT) vs. glibenclamide (GB) on increases in glucose after glucose loading and on increases in triglyceride (TG) after fat loading. METHODS: Fasting rats were given 50 mg/kg of NAT, 1 mg/kg of GB or 5% methyl cellulose (vehicle) as control and then immediately given oral glucose 1 g/kg. RESULTS: An acute increase in insulin levels in portal blood peaked at 15 min in the NAT group, while insulin levels in the GB group continued to increase significantly after 60 min. Glucose levels in peripheral blood were significantly lower in the NAT group at 30 and 60 min and in the GB group at 120, 180 and 270 min after glucose loading, compared with those in the vehicle group. Subsequently, fasting rats were given NAT, GB or vehicle and then immediately given oral fat emulsion (soy oil 2 g/kg). An acute increase in insulin secretion was seen with NAT, peaking at 30 min, while TG, chylomicron and very low-density lipoprotein levels after fat loading were shown to be significantly lower with NAT than with vehicle. However, the continued insulin secretion observed with GB led to no significant decrease in TG levels after fat loading. In addition, lipoprotein lipase mRNA expression in adipose tissue increased significantly 120 min after NAT administration in comparison with baseline. This increase was not noted with GB administration. CONCLUSION: Abnormalities in early insulin secretion are closely associated with the pathogenesis of various disease conditions that combine to characterize type 2 diabetes, suggesting that normalizing early insulin response in portal blood represents an important treatment not only for postprandial hyperglycaemia but also for postprandial hyperlipidaemia.

Adipose Tissue↗
PubMed1984

C-peptide and insulin secretion. Relationship between peripheral concentrations of C-peptide and insulin and their secretion rates in the dog.

Estimation of the insulin secretory rate from peripheral C-peptide concentrations depends upon the following characteristics of C-peptide kinetics: (a) equimolar secretion of insulin and C-peptide by pancreatic beta cells; (b) negligible hepatic extraction of C-peptide; (c) constant metabolic clearance rate (MCR) of C-peptide over a physiological and pathophysiological range of plasma levels; and (d) proportional changes in the secretion rate of C-peptide and its peripheral concentrations under varying physiological conditions. In the present experiments, the relationship between a variable intraportal infusion of C-peptide and its concentration in the femoral artery was explored in 12 pancreatectomized dogs. As the infusion of C-peptide was rapidly increased, the magnitude of its peripheral concentration initially increased less than the infusion rate by 20-30%. After an equilibration period of approximately 30 min, however, further increases and decreases in the intraportal infusion were accompanied by nearly proportional changes in its peripheral concentration. Estimates of the amount of C-peptide infused during the experiment based on the steady state C-peptide MCR and its peripheral concentration were within 20% of the amount of C-peptide actually infused. These experiments demonstrate that the portal delivery rate of C-peptide can be calculated from its MCR and peripheral concentration in the dog. They also provide a basis for testing the validity of more complicated models of insulin secretion based on peripheral C-peptide concentrations in the dog as well as other species, including man. Finally, we have shown that the hepatic extraction of endogenously secreted C-peptide is negligible in the basal state (3.1 +/- 6.1%), and does not change after oral glucose ingestion. The MCR of exogenous dog C-peptide was similar whether measured by constant peripheral intravenous infusion (12.3 +/- 0.7 ml/kg per min), constant intraportal infusion (13.4 +/- 0.6 ml/kg per min), or analysis of the decay curve after a bolus injection (13.5 +/- 0.7 ml/kg per min).

Animals↗
PubMed2004

Disruption of glucose sensing and insulin secretion by ribozyme Kir6.2-gene targeting in insulin-secreting cells.

The ATP-sensitive K+ (KATP) channel, composed of Kir6.2 and sulfonylurea receptor (SUR1), in pancreatic beta-cells is believed to serve as a metabolic sensor regulating insulin secretion according to glucose levels. Thus, genetic disruption of Kir6.2 expression may impair KATP channel function in glucose sensing and insulin secretion. Here we show evidence obtained from functional genetic assays supporting this hypothesis. To avoid adaptive cellular mechanisms in transgenic preparations, we designed a hammerhead ribozyme that specifically targeted the Kir6.2 mRNA at serine 78. The Kir6.2-ribozyme was constructed in an adenoviral vector and expressed in insulin-secreting RINm5F cells. Both RT-PCR and Northern blot analyses showed that Kir6.2 transcripts were significantly reduced with a Kir6.2-ribozyme treatment. Whole-cell patch-clamp studies indicated that the Kir6.2-ribozyme treatment lowered KATP channel density by 66%. In response to higher glucose challenge, insulin release from the RINm5F cells dropped by approximately 20% in a transfection dose of 0.7 multiplicity of infection, and by 30-40% in a dose of 2.7 multiplicity of infection. These results therefore indicate that KATP channels play an important role in glucose sensing and insulin secretion, and ribozyme Kir6.2-gene targeting is an effective approach for selective inhibition of functional expression of KATP channels.

Adenoviridae↗
PubMed1993

Mass spectrometric analysis of opioid and tachykinin neuropeptides in non-secreting and ACTH-secreting human pituitary adenomas.

In a study to test the hypothesis that defects in the metabolism of neuropeptides might be a contributing factor to human anterior pituitary tumor formation, the proenkephalin A, proopiomelanocortin (POMC), and tachykinin systems, which produce methionine enkephalin (ME), beta-endorphin (BE), and substance P (SP), respectively, were measured in patients who had a wide variety of pituitary tumors. Mass spectrometry was used to optimize the level of molecular specificity of the ME and BE analytical measurements, and radioimmunoassay was used to measure SP-like immunoreactivity (SP-li). Compared to data obtained from pituitaries from post-mortem controls, the non-secreting tumors contained a significantly lower amount of the POMC neuropeptide, BE. The lower ME level was not significant. However, two adrenocorticotrophic hormone (ACTH)-secreting tumors contained ME, BE, and SP-li amounts that were much higher than both the controls and nonsecreting tumors. These data suggest that a hypometabolism of the POMC precursor may be operating in non-secreting tumors, and that a hypermetabolism of the proenkephalin A, POMC, and tachykinin precursors may be operating in two ACTH-secreting tumors. These data demonstrate that mass spectrometry plays a critical role in the study of human pituitary tumors.

Adenoma↗
PubMed1990

Protease secretion by Erwinia chrysanthemi: the specific secretion functions are analogous to those of Escherichia coli alpha-haemolysin.

A 5.5 kb DNA fragment carrying the functions necessary for the specific secretion of the extracellular metalloproteases B and C produced by the Gram-negative phytopathogenic bacterium Erwinia chrysanthemi has been sequenced. The fragment contains four transcribed and translated genes: inh, which codes for a protease inhibitor and is not required for protease secretion, and prtD, prtE and prtF, which share significant homology with the hlyB, hlyD and tolC genes required for alpha-haemolysin secretion in Escherichia coli. Mutations in any of the three prt genes abolish protease secretion. The prtD and prtE products (60 and 50 kd) contain at least one hydrophobic segment and the prtF gene product contains a signal sequence.

Amino Acid Sequence↗
PubMed1983

Effects of furosemide on biliary secretion, pancreatic blood flow, and pancreatic exocrine secretion.

The effects of furosemide on biliary secretion and on pancreatic hemodynamics and exocrine function were studied by quantitative flowmetry and timed collections of biliary and pancreatic exocrine secretion in the anesthetized dog. Biliary flow and the output of its components (Na+, K+, Ca, Mg, 3-OH bile salts, and bilirubin) increased significantly following a furosemide injection of 0.6 mg/kg and rose progressively to 75-150 per cent above basal levels as the furosemide dose was increased to 9.6 mg/kg. Pretreatment with secretin had no influence on furosemide-induced biliary secretion. Furosemide doses of 4.8 and 9.6 mg/kg increased blood flow in the superior pancreaticoduodenal arterial bed by 30-60 per cent but did not alter flow in the inferior pancreaticoduodenal arterial bed or the pancreatic branch of the splenic artery. However, small increases were seen in flow in the latter two arterial beds after furosemide when secretin administration preceded furosemide. Basal pancreatic secretion was not affected by furosemide, but pretreatment with a submaximal sustaining infusion of secretin uncovered a furosemide action to increase pancreatic exocrine flow and the outputs of Na+, K+, Ca, Mg, and enzymes by 25-35 per cent. These data extend previous studies of the gastrointestinal vasodilator effects of furosemide to the pancreatic circulation and previous data demonstrating furosemide-induced ionic transport in nonrenal systems to biliary, pancreatic acinar, and ductular transport in both organs. Whether the augmentation of pancreatic blood flow is secondary to enhanced ion transport in the exocrine pancreas or to an effect on ionic cotransport in vascular smooth muscle is unknown.

Animals↗
PubMed1980

Stimulus secretion coupling: role of cyclic GMP and calcium in the regulation of secretion from rat exocrine pancreas.

In rat pancreatic fragments, stimulation of amylase and labeled protein release by carbachol, caerulein, and ionophore A 23187 results within minutes in a short rise in cyclic GMP levels. Cyclic AMP levels do not change significantly. The secretory response elicited by each secretagogue is not modified when combined in pairs. Under intracellular calcium depleting conditions, both the cyclic GMP and the secretory responses to secretagogues are inhibited in parallel, suggesting a good correlation between both processes. Furthermore, 8-Bromocyclic GMP induces pancreatic secretion, but to a lesser extent, and fails to alter the increase in secretion caused by the various secretagogues. However, other agents such as imidazole, ascorbic acid, phenylhydrazine, and sodium azide also increase cyclic GMP levels but fail to stimulate pancreatic secretion. On the other hand, dibutyryl cyclic AMP also stimulates amylase and labeled protein discharge and potentiates the increase caused by cabachol, caerulein, and ionophore A 23187. These results do not permit conclusions regarding a cause and effect relationship between cyclic GMP and secretion. A role for calcium seems to be the most likely.

Amylases↗
PubMed1993

Protein secretion by the mouse blastocyst: stimulatory effect on secretion into the blastocoel by transforming growth factor-alpha.

We have previously demonstrated that newly synthesized proteins are secreted into the mouse blastocoel [Dardik and Schultz (1991): Biol Reprod 45:328-333]. In the present study we examine the effect of transforming growth factor-alpha (TGF-alpha) on these proteins. We observe that TGF-alpha stimulates secretion of these newly synthesized proteins into the blastocoel and apical medium, which faces the zona pellucida, by about 65%. Although one-dimensional gel electrophoretic analysis does not reveal any marked differences in the patterns of newly synthesized proteins secreted into the blastocoel in response to TGF-alpha, zymography reveals a marked stimulation in the secretion of several gelatinases into the blastocoel and apical medium. These results suggest additional functions for TGF-alpha in mouse preimplantation development.

Animals↗
PubMed2002

The effect of ginseng on bile-pancreatic secretion in the rat. Increase in proteins and inhibition of total lipids and cholesterol secretion.

Ginseng is one of the most popular herbal remedies. Studies were performed in anaesthetized rats to examine the effect of ginseng on bile secretion. Male Sprague-Dawley rats were anaesthetized with intraperitoneal (i.p.) urethane (1.25 g kg(-1)) and equipped with biliary cannulas inserted into the bile duct through the sphincter of Oddi. Rats were treated with a single i.p. injection of ginseng at 25, 50 or 100 mg kg(-1) (1 ml(-1)) 30 min before bile collection; the control group received i.p. saline only at 1 ml(-1)volume. The effect of multiple doses of ginseng on bile volume and biliary composition was also studied. Ginseng was given in the higher dose of 100 mg kg(-1) (1 ml(-1), i.p.) every 12 hours for 2 days. Bile was collected in 15 min fractions for 90 min. Bile flow (bile-pancreatic juice), biliary excretion of total proteins, cholesterol and total lipids were measured. The single administration of different doses (25, 50 and 100 mg kg (-1)) of ginseng reduced basal bile secretion in a dose-dependent manner. Single-dose administration of ginseng at 100 mg kg(-1) caused 32.9% reduction in basal bile flow. Meanwhile, mean basal bile flow was reduced by 15.1% in rats treated with multiple doses of ginseng at 100 mg kg(-1) for two days. Biliary protein concentrations were significantly increased after single- or multiple-dose administration of ginseng, but protein output was only significantly increased (33%) in rats treated with ginseng (100 mg kg(-1)) twice a day for 2 days. Biliary total lipids and cholesterol concentration and outputs were significantly reduced after single or multiple administration of ginseng. In conclusion, administration of ginseng in the rat resulted in a reduction of bile flow and in bile secretion of total lipids and cholesterol, while it increased the secretion of proteins in a dose-dependent manner. The precise mechanisms underlying these effects remain to be elucidated. The findings indicate the need for clinical trials for the effect of this herb on bile composition and flow in man in view of a possible modulatory effect for the herb on gallstone formation.

Animals↗
PubMed1985

Biliary and pancreatic secretions influence experimental duodenal ulcer without affecting gastric secretion in the rat.

The effect of the absence of biliary and/or pancreatic secretions in the duodenum or the enhanced presence of bile at the proximal duodenum on the incidence, severity, number, and location of cysteamine-induced duodenal ulcers was investigated in the rat. Cysteamine produced ulcers on the anterior wall of the duodenum in 75% and on the posterior wall ("kissing ulcers") in 50% of the animals. Diversion of biliary and/or pancreatic secretions from the duodenum increased both the severity and the incidence of the posterior duodenal ulcers. Diversion of bile to the proximal duodenum, on the other hand, decreased the severity as well as the incidence of the anterior duodenal ulcers. Mortality in rats receiving cysteamine correlated with the severity of ulcers. Taurocholic acid at nontoxic doses given subcutaneously or orally to nonoperated rats and rats which had bile diverted to the proximal duodenum aggravated the cysteamine-caused duodenal ulcers. Neither proximal nor distal diversion of bile had a major effect on gastric secretion of acid and pepsin in normal or cysteamine-treated rats. We conclude that both bile and pancreatic secretions may directly influence the development of cysteamine-induced duodenal ulcers in the rat.

Animals↗
PubMedDate not supplied

Insulin decreases the secretion of apoB-100 from hepatic HepG2 cells but does not decrease the secretion of apoB-48 from intestinal CaCo-2 cells.

We compared the acute effect of insulin on the human colonic intestinal epithelial cell line CaCo-2 and the transformed human hepatic cell line HepG2. Over 24 h, 100 nM and 10 microM insulin significantly inhibited the secretion of apolipoprotein (apo) B-100 from HepG2 cells to 63 and 49% of control, respectively. Insulin had no effect on the secretion of apoB-48 from CaCo-2 cells. There was no effect of insulin on the cholesterol ester or free cholesterol concentrations in HepG2 or CaCo-2 cells. HepG2 and CaCo-2 cells bound insulin with high affinity, leading to similar stimulation of insulin receptor protein tyrosine kinase activation. Protein kinase C or mitogen-activated protein kinase activity in the presence or absence of insulin was not correlated with apoB-48 production in CaCo-2 cells. Therefore, insulin acutely decreases the secretion of apoB-100 in hepatic HepG2 cells, but does not acutely modulate the production or secretion of apoB-48 from CaCo-2 intestinal cells.

Apolipoprotein B-100↗
PubMed1981

Effect of topical application of amino acids on gastric pepsin secretion in the rat. Part III: effect of L- and D-isomers of amino acids on gastric secretion in reperfusion system.

This study was undertaken to compare the potency of each L- and D-isomers of 5 amino acids in stimulating gastric acid and pepsin secretion by the intragastric reperfusion preparation in rats. Gastric basal and glycine-stimulated secretions in this preparation were lower than those Ghosh-Lai preparation, but not to a statistically significant extent. All D- and L-isomers of amino acids tested were found to markedly stimulate pepsin secretion, but to only slightly stimulate acid secretion. Pepsin stimulatory response to each D and L-isomer of amino acid was similar. The stimulatory effects of amino acids thus seem to be unrelated to the optical stereoisomeric configuration.

Administration, Topical↗
PubMed1993

Negative feedback regulation of acid secretion: linkage of acid secretion and mucosal defense.

To regulate inappropriate or excessive acid secretion that may be harmful not only to surrounding mucosal cells but also parietal cells themselves, versatile mechanisms operate to control acid secretion. In this article elaborate mechanisms that participate in the control of acid secretion are described with our data and a review of relevant findings in the literature concerning the action or secretion of key regulatory molecules. The analysis of the regulatory mechanisms revealed that appropriate secretory control can be achieved by multiple feedback regulations, which are closely coordinated with mucosal defense. In the feedback circuits, the regulatory factors cannot be simply categorized into either aggressive or defensive factors. Therefore we propose that the mucosal integrity and tissue homeostasis would be better understood by a feedback loop model rather than by a dualistic balance model.

Animals↗
PubMed1991

Follicle stimulating hormone-secreting pituitary adenoma: inappropriate secretion and effect of pulsatile luteinizing hormone releasing hormone analogue (buserelin) administration.

A patient with an FSH secreting pituitary adenoma is reported. Elevated FSH and serum free alpha-subunit (SU) with low levels of LH and testosterone (T) were found. Immunostaining showed the presence of alpha-SU, FSH-beta and LH-beta subunits. LHRH analogue (buserelin) was administered in a pulsatile manner, by portable computerized infusion pump sc for ten days. During the first 24 h of treatment FSH, LH (p less than 0.001) and T (p less than 0.01) rose significantly. Ten days later, the expected desensitization phenomenon did not occur, but further increases of T (8.4 +/- 2.6, mean +/- SD, vs 17.4 +/- 4.1 nmol/l, p less than 0.001) and FSH (58.9 +/- 9.6 vs 70.7 +/- 3.8 mlU/ml, p less than 0.001) were registered. LH decreased (12.5 +/- 2.4 vs 7.1 +/- 0.6 mlU/ml, p less than 0.001) at day 10, but remained higher than basal level (5.0 +/- 0.6, p less than 0.001). Free alpha-SU also rose (2.8 +/- 0.4 vs 4.4 +/- 1.7 mlU/ml, p less than 0.001) after ten days of treatment. The chronic stimulatory effect of analogue on LH with a lack of desensitization suggests tumorous secretion despite a partially preserved negative feedback of testosterone. Low basal LH levels, in some patients with FSH secreting tumors may not be due to tumor mass effect, but rather may be the consequence of altered LH production and/or secretion by the tumor. Although buserelin may not have a therapeutic effect, it is of use in differential diagnosis of hypergonadotropinemia.

Adenoma, Chromophobe↗
PubMed1997

Short stature and failure of pubertal development in thalassaemia major: evidence for hypothalamic neurosecretory dysfunction of growth hormone secretion and defective pituitary gonadotropin secretion.

UNLABELLED: In patients with beta-thalassaemia major, frequent blood transfusions combined with desferrioxamine chelation therapy lead to an improved rate of survival. Endocrine disorders related to secondary haemosiderosis such as short stature, delayed puberty and hypogonadism are major problems in both adolescent and adult patients. A total of 32 patients with beta-thalassaemia major undergoing treatment at the Children's Hospital, University of Göttingen were examined. Fourteen of these were short in stature. Growth hormone (GH) secretion was investigated in 13 patients exhibiting either a short stature or reduced growth rate. The stimulated GH secretion of 10 patients in this subgroup lay within the normal range. Studies of their spontaneous GH secretion during the night revealed that these patients had a markedly reduced mean GH and reduced amplitudes in their GH peaks. Low insulin-like growth factor (IGF)-I levels were seen in the growth-retarded thalassaemic patients. Eight were subjected to an IGF generation test and showed a strong increase in both IGF-I and insulin-like growth factor binding protein (IGFBP)-3 levels indicating intact IGF-I generation by the liver. Hypogonadotropic hypogonadism was found to be present in both the male and female patients with impaired sexual development. After priming with LH-releasing hormone (GnRH) per pump in 2 female and 5 male patients, no change in either their serum oestradiol or testosterone levels or in LH/FSH response to GnRH was observed suggesting that they were suffering from a severe pituitary gonadotropin insufficiency. Three male patients at the age of puberty but exhibiting short stature. low GH, low IGF-I and hypogonadism received low dose long-acting testosterone. After 3 12 months of therapy there was a marked growth spurt, higher nocturnal GH levels and an increase in both IGF-I and IGFBP-3. CONCLUSION: Reduced GH secretion and low IGF-I in thalassaemic patients are related to a neurosecretory dysfunction due to iron overload rather than to liver damage. Hypogonadotropic hypogonadism is caused by the selective loss of pituitary gonadotropin function. In patients with both GH deficiency and hypogonadism, low dose sexual steroid treatment should be considered either as an alternative or an additional treatment before starting GH therapy.

Adolescent↗
PubMed2003

Dual action of neutral sphingomyelinase on rat hepatocytes: activation of cholesteryl ester metabolism and biliary cholesterol secretion and inhibition of VLDL secretion.

To address the role of cell membrane neutral sphingomyelinase (EC 3.1.4.12; SMase) in the regulation of cholesterol metabolism in the liver parenchymal cell, we examined the effect of exogenous neutral SMase on the metabolism of cholesteryl esters and the secretion of VLDL and biliary lipids in isolated rat hepatocytes. We show that treatment of hepatocytes with SMase (20 mU/mL) resulted in the intracellular buildup of cholesteryl esters, increased ACAT (EC 2.3.1.26) activity without affecting the ACAT2 mRNA level, and increased cytosolic and microsomal cholesteryl ester hydrolase (EC 3.1.1.13) activity. This was accompanied by increases in the secretion of biliary bile acid, phospholipid, and cholesterol and in increased cholesterol 7alpha-hydroxylase (EC 1.14.13.17) activity and levels of mRNA, as well as decreased levels of apoB mRNA and a decreased secretion of VLDL apoB (apoB-48, approximately 45%; apoB-100, approximately 32%) and lipids (approximately 55%). Moreover, the VLDL particles secreted had an abnormal size and lipid composition; they were larger than controls, were relatively enriched in cholesteryl ester, and depleted in TG and cholesterol. Cell-permeable ceramides did not replicate any of the reported effects. These findings demonstrate that the increased cholesteryl ester turnover, oversecretion of biliary cholesterol and bile acids, and undersecretion of VLDL cholesterol and particles are concerted responses of the primary hepatocytes to exogenous neutral SMase brought about by regulation at several levels. We suggest that plasma membrane neutral SMase may have a specific, ceramide-independent effect in the regulation of cholesterol output pathways in hepatocytes.

Animals↗
PubMed1976

Role of calcium in exocrine pancreatic secretion. II. Comparison of the effects of carbachol and the inophore A-23187 on enzyme secretion and calcium movements in rabbit pancreas.

1. The secretory effects of carbachol and the ionophore A-23187 on the isolated rabbit pancreas and rabbit pancreas fragments are compared in order to obtain more insight in the involvement of calcium in the stimulus-secretion coupling of pancreatic enzyme secretion. 2. The divalent cation ionophore A-23187 mimicks the effect of carbachol on pancreatic enzyme secretion in both preparations. 3. The action of the ionophore is dependent on the presence of extracellular calcium. The carbachol effect is much less dependent on calcium, as it occurs even in a Ca2+ -free medium containing 10(-4) M ethyleneglycol-bis(beta-aminoethylether)-N,N-tetraacetic acid. 4. Carbachol causes a marked increase in the 45Ca2+ efflux from pre-loaded pancreas fragments in both a normal Krebs-Ringer bicarbonate medium and this Ca2+ -free medium. 5. Although the tissue still contains about 50% of its original 45Ca2+ content, at the time of stimulation, the ionophore has little or no effect on the 45Ca2+ efflux. This indicates that the cytoplasmic 45Ca2+ concentration is very low, and hence that most of the 45Ca2+ must be sequestered in one or more intracellular stores. 6. It is concluded that both substances stimulate pancreatic enzyme secretion by increasing the cytoplasmic calcium concentration, through an increase in the calcium permeability of the plasma membrane in the case of the ionophore, and through a release of Ca2+ from intracellular stores in the case of carbachol.

Animals↗
PubMed1992

Effects of activin A and somatostatin on intact FSH secretion and intracellular Ca2+ concentration in human FSH-secreting pituitary adenoma cells.

Activin A stimulated synthesis and secretion of intact FSH in dispersed human FSH-secreting adenoma cells. Significant stimulation was observed after 24 hr. Activin A caused an increase in Ca2+ concentration ([Ca2+]i). This response occurred soon after the activin A action. These effects were blocked in Ca(2+)-deficient medium and by nitrendipine (5 microM). Somatostatin inhibited the activin A-induced intact FSH secretion and the [Ca2+]i response. These findings indicated that Ca2+ influx through voltage-gated Ca2+ channel was involved in the activin A induced synthesis and secretion of intact FSH.

Activins↗