Biomedical subjects

Ludwik K Malendowicz

Publications and source records attributed to Ludwik K Malendowicz.

67 records · Page 4Linked to original sources

PubMed2002

Simulated microgravity impairs aldosterone secretion in rats: possible involvement of adrenomedullin.

The prolonged exposure to microgravity (MG) or simulated MG (SMG) has been reported to cause hypotension, mainly due to reduced vascular contractility, and dysregulation of fluid and electrolyte balance. However, the mechanism(s) involved in these MG- or SMG-induced effects is not yet completely elucidated. Hence, we investigated in the rat the effect of prolonged (15 day) SMG, in the form of hindlimb unweighting, on the renin-angiotensin-aldosterone system (RAAS), as well as on atrial natriuretic peptide (ANP) and adrenomedullin (ADM), two hypotensive peptides that play a major role in the regulation of RAAS activity by inhibiting adrenal aldosterone secretion. SMG caused a mild hypotension in rats, associated with the blockade of body weight gain. Plasma aldosterone concentration and basal and agonist-stimulated in vitro aldosterone secretion from adrenal slices were decreased, and plasma renin activity was moderately increased. Neither Na(+) and K(+) serum concentrations nor ACTH and corticosterone blood levels were significantly affected. Plasma ANP concentration did not display significant alterations, while ADM blood concentration underwent a marked rise. The administration of the ADM-receptor antagonist ADM-(22-52) during the last 3 days of hindlimb unweighting reversed the SMG-induced hypotension and hypoaldosteronism. Collectively, these findings allow us to suggest that prolonged SMG impairs RAAS activity in rats, through a mechanism probably involving upregulation of the ADM system. Both hypoaldosteronism and increased ADM secretion may contribute to the development of hypotension during prolonged exposure to SMG.

Adrenal Glands↗

PubMed2002

11beta-Hydroxysteroid dehydrogenase types 1 and 2 are up- and downregulated in cortisol-secreting adrenal adenomas.

BACKGROUND: 11beta-Hydroxysteroid dehydrogenase types 1 and 2 (11betaHSD1 and 11betaHSD2) are two isoenzymes that convert inactive glucocorticoids (e.g., cortisone) to their active forms (e.g., cortisol) and vice versa. Abundant evidence indicates that 11betaHSD2 is expressed as mRNA and protein in both adrenal cortex and adrenal tumors. In contrast, 11betaHSD1 has been investigated to a much lesser degree. We therefore studied and compared the expression and activity of the two isoenzymes in the human adrenal cortex (HAC) and cortisol-secreting adenomas (CSAs). METHODS: Six HAC and six CSA specimens were studied. 11betaHSD1 and 11betaHSD2 gene expression was studied by conventional and semiquantitative reverse transcription-polymerase chain reaction. 11betaHSD1 and 11betaHSD2 activity was assayed by measuring the capacity of both microsomal fraction and tissue fragments to convert [3H]cortisone to [3H]cortisol and vice versa. Steroid hormones were separated and purified by high-performance liquid chromatography, and cortisol concentration was measured by radioimmunoassay. RESULTS: Semiquantitative reverse transcription-polymerase chain reaction and enzymatic assay demonstrated higher 11betaHSD1 expression and activity and lower 11betaHSD2 expression and activity in CSAs than in HACs. CSA slices secreted larger amounts of cortisol than did HAC specimens, and the cholesterol side-chain-cleaving enzyme inhibitor aminoglutethimide, by blocking the early step of steroid synthesis, reduced cortisol secretion by approximately 70%. Aminoglutethimide decreased [3H]cortisol production from [3H]cortisone and increased [3H]cortisone production from [3H]cortisol in both tissues, thereby annulling differences in 11betaHSD1 and 11betaHSD2 activity between HACs and CSAs. CONCLUSION: Collectively, our findings indicate that 1) both 11betaHSD isoenzymes are expressed as mRNA and proteins in the HAC and CSA, with 11betaHSD1 upregulated and 1betaHSD2 downregulated in CSAs; and 2) 11betaHSD1 and 11betaHSD2 activity is positively and negatively correlated with the intracellular concentration of steroid hormones. Hence, 11betaHSD isoenzymes could act as amplifiers of the secretagogue effect of agonists and could contribute to the elevated hormonal secretion of CSAs.

11-beta-Hydroxysteroid Dehydrogenase Type 2↗

PubMed2002

Rat thyroid gland expresses the long form of leptin receptors, and leptin stimulates the function of the gland in euthyroid non-fasted animals.

Leptin is an adipose tissue-secreted hormone, which decreases caloric intake and increases energy expenditure. Some effects of leptin on energy balance seem to be mediated by the hypothalamo-pituitary-thyroid axis. The present study was designed to ascertain whether i) rat thyroid gland expresses the long form of leptin receptor (ObRb) and ii) the prolonged leptin administration (daily subcutaneous injections of 24 nmol/kg leptin for 6 consecutive days) affects thyroid-gland function in this species. Coupled RT-PCR, Western blotting and immunocytochemical findings demonstrated the expression of Ob-Rb as mRNA and protein in the thyroid gland of normal rats. Prolonged leptin treatment raised thyroid-gland weight, and morphometry showed that in the enlarged glands the volume of the follicle epithelium was increased, while that of colloid remained unchanged, so that epithelium/colloid ratio was markedly lowered. In leptin-administered rats, the plasma concentration of TSH was decreased, while those of thyroid hormones (free T3 and total T4) were notably raised. Collectively, these findings suggest that systemically administered leptin stimulates growth and secretion of thyroid gland in the rat, through a direct mechanism involving Ob-Rb.

Animals↗

PubMed2002

Effects of prolonged leptin infusion on rat pituitary-adrenocortical function.

Compelling evidence suggests that a regulatory loop between leptin and the hypothalamo-pituitary-adrenal (HPA) axis is operative, where ACTH inhibits leptin secretion by adipose tissue and in turn leptin increases expression and secretion of ACTH. However, conflicting findings have been obtained in vivo on the acute and chronic effects of leptin on the HPA axis. Adult female Wistar rats, kept in metabolic cages, were intraperitoneally infused for 2, 4, 8 or 16 days with leptin (10 nmol/kg. 24 h); control animals were infused with the vehicle only. The rate of body-weight gain was similar in control and leptin-infused rats. At day 16 of treatment relative pituitary weight was higher and relative adrenal weight smaller in leptin-infused than control rats. Pituitary ACTH concentration gradually decreased with the duration of treatment, and the drop was significantly higher in leptin-infused than control rats. During the entire experimental period the blood level of aldosterone was similar in both groups of rats. Conversely, at days 2 and 4 of treatment the blood concentration of corticosterone was lower in leptin-infused than in control rats, which at these times displayed elevated levels of circulating corticosterone. Taken together, these findings allow us to conclude that in the rat the prolonged infusion of low doses of leptin i) primarily depresses pituitary ACTH production, the effect being probably mediated by the hypothalamus; and ii) inhibits corticosterone response to the stress evoked by placing of animals in the metabolic cages.

Adrenocorticotropic Hormone↗

PubMed2002

Adrenomedullin and its receptors are expressed in the zona glomerulosa of human adrenal gland: evidence that ADM enhances proliferation and decreases apoptosis in cultured ZG cells.

Adrenomedullin (ADM) is a hypotensive peptide, that derives from the proteolytic cleavage of pro(p)ADM and acts through two subtypes of receptors, called L1-receptor (L1-R) and calcitonin receptor-like receptor (CRLR). CRLR may function as a calcitonin gene-related peptide or a selective ADM receptor depending on the expression of the subtype 1 or the subtypes 2 and 3 of a family of proteins, named receptor-activity-modifying protein (RAMPs). Reverse transcription (RT)-polymerase chain reaction (PCR) consistently allowed the detection of pADM mRNA in zona glomerulosa (ZG), but not zona fasciculata-reticularis (ZF/R) cells of eight human adrenal cortexes. Despite the rather high level of pADM mRNA, immunocytochemistry and radioimmunoassay showed that the expression of ADM as protein in the ZG was weak. However, ZG cells expressed peptidyl-glycine alpha-amidating monooxigenase, the enzyme converting immature ADM to the mature peptide, thereby suggesting their potential ability to produce active ADM. RT-PCR demonstrated the presence in ZG, but not ZF/R cells of the specific mRNAs of L1-R, CRLR and RAMPs1-3. Semiquantitative PCR showed that L1-R expression was higher than that of CRLR, while the level of expression of the three RAMPs was nearly the same. ADM (10(-8) M) inhibited both angiotensin-II (10(-9) M)- and K(+) (10(-2) M)-stimulated aldosterone secretion from cultured ZG cells, without affecting basal production. ADM (10(-8) M) also increased proliferative activity and lowered apoptotic deletion of cultured cells. All the effect of ADM were reversed by the ADM-receptor antagonist ADM(22-52). In conclusion our study provides evidence that i) human ZG cells express ADM and ADM receptors of both L1 and CRLR/PAMP2,3 subtypes; and ii) through the activation of these receptors, ADM exerts an aldosterone antisecretagogue action and a growth promoting effect on cultured ZG cells, the latter an effect which includes both stimulation of proliferation and inhibition of apoptosis. Taken together, these findings make it likely that endogenous ADM system plays a potentially important role in the paracrine/ autocrine regulation of human adrenal cortex.

Adrenal Cortex↗

PubMed2002

Pituitary adenylate cyclase-activating polypeptide and PACAP receptor expression and function in the rat adrenal gland.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a basic 38-amino acid peptide, which acts through three main G protein-coupled VIP/PACAP receptor subtypes, called PAC1, VPAC1 and VPAC2. We have investigated the expression and function of PACAP and its receptors in the rat adrenal gland. Reverse transcription (RT)-polymerase chain reaction (PCR) and radioimmune assay (RIA) allowed the detection of PACAP expression as mRNA and protein exclusively in adrenal medulla (AM). RT-PCR and quantitative autoradiography, using [(125)I]PACAP and selective VIP/PACAP receptor ligands, demonstrated the expression of PAC1 only in AM, and VPAC1 and VPAC2 in both AM and zona glomerulosa (ZG), PACAP receptor expression being absent in zona fasciculata/reticularis (ZF/R). PACAP38 concentration-dependently increased aldosterone secretion from dispersed ZG cells and catecholamine secretion from AM tissue, the maximal effective concentration being 10(-7) M. ZF/R cells did not display any secretory response to PACAP38. Aldosterone response of ZG cells to 10(-7) M PACAP38 was unaffected by the PAC1-antagonist (A) PACAP(6-38), and significantly decreased by the VPAC1-A [Ac-His(1),D-Phe(2),Lys(15),Arg(16)]VIP(3-7) GRF(8-27)-NH(2). Catecholamine response of AM tissue to PACAP38 was reduced, but not abolished, by both PAC1-A and VPAC1-A. The VPAC2 agonist (ago) Ro25-1553 elicited sizeable secretory responses from both ZG cells and AM tissue. PACAP38 (10(-7) M) evoked a marked rise in cyclic-AMP (cAMP) and inositol-1,4,5-triphosphate (IP3) production by ZG cells and AM tissue. cAMP response of ZG cells was lowered by VPAC1-A, and that of AM tissue by both PAC1-A and VPAC1-A. IP3 response of ZG cells and AM tissue was unaffected by PAC1-A and decreased by VPAC1-A. VPAC2-ago did not affect cAMP release, but raised IP3 production by both ZG cells and AM tissue. Aldosterone response of ZG cells and catecholamine response of AM tissue to PACAP38 (10(-7) M) were reduced by the adenylate cyclase (AC) and phospholipase-C (PLC) inhibitors (I) SQ-22536 and U-73122, as well as by the protein kinase (PK)A-I H-89 and PKC-I calphostin-C. Conversely, the secretory responses of both ZG and AM preparations to VPAC2-ago were annulled by PLC-I, lowered by PKC-I, and unaffected by either AC-I or PKA-I. Collectively, our findings allow us to conclude that in the rat adrenals: i) PACAP biosynthesis exclusively occurs in the AM; ii) ZG cells are provided with functional VPAC1 and VPAC2 receptors, whose activation by PACAP evokes a moderate aldosterone response; iii) AM cells possess all the subtypes of VIP/PACAP receptors, whose activation by PACAP elicits a marked catecholamine response; and iv) PAC1 receptors are coupled to the AC-dependent cascade, VPAC1 receptors to both the AC- and PLC-dependent cascades, and VPAC2 receptors exclusively to the PLC-dependent cascade.

Adrenal Medulla↗

PubMed2002

Human adrenal cortex and aldosterone secreting adenomas express both 11beta-hydroxysteroid dehydrogenase type 1 and type 2 genes.

11beta-Hydroxysteroid dehydrogenase type 1 and type 2 (11betaHSD1 and 11betaHSD2) isozymes catalize the conversion of inactive glucocorticoids (e.g. cortisone) to their active forms (e.g. cortisol) and vice versa, respectively. Reverse transcription-polymerase chain reaction allowed the detection of 11betaHSD1 and 11betaHSD2 mRNAs in the human adrenal cortex, liver, kidneys, as well as in six aldosterone-secreting adenomas. 11betaHSD1 and 11betaHSD2 activity, as evaluated by the capacity of the microsomal fraction to convert [3H]cortisone to [3H]cortisol and vice versa, was detected in both human adrenal cortex and aldosteronomas, although it was less elevated than in liver and kidneys. Aldosteronomas possessed more intense 11betaHSD1 activity and less intense 11betaHSD2 activity than the normal adrenal cortex. The hypothesis is advanced that the elevated local concentration of steroid-hormone intermediates occurring in aldosteronomas up-regulates 11betaHSD1 and down-regulates 11betaHSD2, thereby contributing to their enhanced steroidogenic function.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗

PubMed2002

Investigation of the effect of different regulatory peptides on adrenocortical cell proliferation in immature rats: evidence that endogenous adrenomedullin exerts a stimulating action.

Compelling evidence indicates that the active growth of immature rat adrenal glands is sustained not only by an increased release of pituitary ACTH, but also by other ancillary mechanisms. We investigated whether vasoactive intestinal peptide (VIP), atrial natriuretic peptide (ANP), adrenomedullin (ADM) and proadrenomedullin N-terminal 20 peptide (PAMP) play a relevant role in these mechanisms. These four regulatory peptides were chosen because previous studies demonstrated that they are expressed in rat adrenals and are able to modulate the secretory activity and growth of zona glomerulosa (ZG), i.e., the adrenal layer. Groups of immature (20-day old) rats were given three subcutaneous injections (28, 16 and 4 h before sacrifice) of 2 nmol/100 g of the four peptides and/or selective antagonists of their receptors (VIP-A, ANP-A, ADM-A and PAMP-A), and 0.1 mg/100 g vincristin 3 h before autopsy. Adrenal glands were collected, processed for light microscopy, and the mitotic index (MI; percentage of metaphase-arrested cells) was evaluated in the subcapsular ZG. Neither VIP nor VIP-A affected MI. Both ANP and ANP-A decreased MI and their effects displayed additivity. ADM and PAMP raised MI and the effect was abolished by ADM-A and PAMP-A, respectively. When administered alone ADM-A, but not PAMP-A, significantly lowered MI. Collectively, our findings suggest that: i) neither VIP nor PAMP are involved in the regulation of immature rat adrenals; ii) ANP exerts a non-receptor-mediated inhibitory action, whose physiological relevance remains to be investigated; and iii) endogenous ADM system plays a relevant role in the mechanisms underlying the maintenance of high growth rate during adrenal maturation.

Adrenal Cortex↗

PubMed2002

Adrenomedullin and its receptors are expressed in the zona glomerulosa of immature and adult rat adrenals: evidences of upregulation of ADM system in immature glands.

Evidence has been provided that adrenomedullin (ADM) stimulates the proliferative activity of adult rat adrenal zona glomerulosa (ZG). However, the selective ADM receptor antagonist ADM(22-52), although being able to block ADM effect, was per se ineffective. In contrast, in the companion paper, we showed that ADM(22-52) depresses the proliferation rate of ZG in 20-day-old rats, suggesting the involvement of endogenous ADM system in adrenal maturation. Hence, we investigated by semiquantitative reverse transcription-polymerase chain reaction and radioimmune assay the expression of ADM system in adult and immature rat ZG. ProADM mRNA and ADM-immunoreactivity were both more elevated in immature- than adult-rat ZG. Plasma ADM concentration did not show significant age-related differences. ADM acts via two subtypes of ADM(22-52)-sensitive receptors: the L1 receptor (L1-R) and the calcitonin-receptor-like-receptor (CRLR), the latter behaves as selective ADM receptor only in the presence of the receptor-activity-modifying proteins (RAMPs)2 and 3. L1-R expression was enhanced in immature rat ZG, while CRLR and RAMP(2,3) expression did not display significant differences. It is concluded that the endogenous ADM system located in the ZG is upregulated in immature rats, and plays an important autocrine-paracrine role in the maintenance of the elevated growth rate during adrenal maturation.

Adrenomedullin↗

PubMed2002

Effects of galanin on proliferation and apoptosis of immature rat thymocytes.

Evidence indicates that some regulatory peptides (endothelins, cholecystokinin and VIP) are involved in the control of thymus growth, and we have investigated whether galanin may be included in this group of peptides. In fact, galanin, a 29-amino acid peptide acting through three subtypes of G protein-coupled receptors (GalR1, GalR2 and GalR3), seems to play a role in the control of the immune system. Reverse transcription (RT)-polymerase chain reaction (PCR) allowed the detection of galanin, GalR1 and GalR3 mRNAs in the thymus cortex of immature (20-day-old) rats, while GalR2 expression was very weak or absent. Immature rats were given three subcutaneous injections (28, 16 and 4 h before sacrifice) of 2 nmol/100 g galanin and or the galanin-receptor antagonist (galanin-A) [D-Thr(6),D-Trp(8,9),15-ol]-galanin(1-15), and 0.1 mg/100 g vincristine 3 h before sacrifice. Thymuses were processed for light microscopy and the percentage of metaphase-arrested cells (mitotic index) was evaluated. Galanin-A increased the thymus mitotic index, while galanin was ineffective, thereby suggesting that endogenous galanin exerts a maximal tonic inhibitory effect on the proliferative activity of thymocytes in immature rats. Immature rat thymocytes were cultured in vitro for 12 h in the presence of 10(-6) M galanin and/or galanin-A. Hoechst 33342 and propidium iodide were added to the cultures, and the percentage of apoptotic and necrotic cells was determined under fluorescence microscope. Galanin increased apoptotic index, and the effect was prevented by galanin-A. Neither galanin nor galanin-A altered necrotic index. Collectively, our findings indicate that galanin, probably acting through GalR1 and GalR3, exerts antiproliferative and proapoptotic effects on immature rat thymocytes, which makes it likely that this peptide plays a role in the autocrine/paracrine functional regulation of immune system in the rat.

Animals↗

PubMed2002

Preproglucagon derived peptides and thyrotropin (TSH) secretion in the rat: robust and sustained lowering of blood TSH levels in exendin-4 injected animals.

We have investigated the acute effects of preproglucagon derived peptides (PGDP) - glucagon, glucagon-like peptide-1 (GLP-1), glucagon-like peptide-2 (GLP-2), and exendin-4 (EX4), a GLP-1 receptor agonist, on thyrotropin (TSH) secretion in the rat. Within 120 min after subcutaneous injection, neither glucagon nor GLP-1 or GLP-2 had an effect on blood rTSH concentration in adult female rat. On the contrary, EX4 injection significantly lowered the plasma thyrotropin level. A potent inhibitory effect of EX4 administration on blood rTSH level was seen even 12 h after bolus peptide administration, whereas EX4-induced elevation in blood glucose concentration returned to normal values after 6 h of experiment. EX4 administration in doses from 0.05 to 1.00 nmol/100 g body weight resulted in very similar drop in blood rTSH levels. To check whether EX4-induced lowering in blood rTSH concentrations may be prevented by exendin-(9-39) [EX(9-39)], rats were treated with EX4 and/or EX(9-39). Both the bolus administration and the 3-day treatment with EX(9-39) notably lowered blood rTSH concentration of studied rats. Administration of EX(9-39) did not change blood rTSH response to EX4. Results of our in vivo studies are rather unexpected and raise serious questions on the specificity of EX4 and EX(9-39) action in vivo. Since both the native EX4 molecule as well as its truncated form [EX(9-39)] exerts a similar inhibitory effect on TSH secretion in the rat, it seems legitimate to suggest that this action depends only on 9-39 amino acid sequence of EX4. Moreover, obtained results suggest that both EX4 and EX(9-39)-evoked inhibition of TSH secretion in the rat is not dependent on their interaction with GLP-1 receptor only. Detailed mechanism of such action remains to be elucidated.

Animals↗

PubMed2002

Evidence for an autocrine-paracrine role of adrenomedullin in the cultured rat adrenal zona glomerulosa cells.

Rat adrenomedullin (ADM) is a 50-amino acid hypotensive and vasodilating peptide, which derives from the posttranslational proteolytic cleavage of pro(p)ADM. ADM acts via at least two subtypes of receptors, named L1-receptor (L1-R) and calcitonin receptor-like receptor (CRLR). CRLR functions as a calcitonin gene-related peptide or a selective ADM receptor depending on the expression of the subtype 1 or the subtypes 2 and 3 of a family of receptor-activity-modifying proteins (RAMPs). Adrenal zona glomerulosa (ZG) is one of the main target tissues of ADM, which has been shown to exert a potent inhibitory effect on aldosterone secretion acting through ADM[22-52]-sensitive receptors. Reverse transcription (RT)-polymerase chain reaction (PCR) consistently allowed the detection of pADM mRNA in the ZG, but not zona fasciculata-reticularis (ZF/R) cells of the rat adrenal cortex. Immunocytochemistry and radioimmune assay showed a weak but sizeable expression of ADM protein in the ZG, but not inner adrenocortical layers. ZG cells expressed peptidyl-glycine alpha-amidating monooxigenase, the enzyme converting immature ADM to the mature peptide, thereby suggesting their potential ability to produce active ADM. RT-PCR demonstrated the presence in ZG, but not ZF/R cells, of the specific mRNAs of L1-R, CRLR and RAMPs (especially RAMP2). ZG cells were cultured in vitro for 24 or 48 h in the presence of ADM (10(-8) M) and/or its receptor antagonist ADM[22-52] (10(-6) M). ADM increased proliferation index and lowered apoptotic index of cultured cells, and the effects were annulled by ADM[22-52]. ADM[22-52] alone was ineffective in 24 h cultures, but moderately decreased proliferation index and raised apoptotic index in 48 h cultures. In conclusion, our study provides evidence that i) rat ZG cells express ADM and ADM receptor of L1 and CRLR/RAMP2 subtypes, which both are sensitive to ADM[22-52]; and ii) endogenous ADM system modulates in an autocrine/paracrine manner ZG growth, by stimulating cell proliferation and reducing cell apoptotic deletion.

Adrenomedullin↗

PubMed2002

Differential expression of adrenomedullin and its receptors in newborn and adult rat thymus.

Adrenomedullin (ADM) is a hypotensive peptide, which derives from the proteolytic cleavage of pro(p)ADM and acts via two main subtypes of receptors, referred to as L1-receptor (L1-R) and calcitonin-receptor-like receptor (CRLR). While L1-R is selective for ADM, CRLR may bind either calcitonin gene-related peptide (CGRP) or ADM depending on the expression of the subtype 1 or the subtypes 2 and 3 of a family of chaperones, named receptor-activity-modifying proteins (RAMPs). There is evidence that ADM, in addition to regulating blood pressure and water and electrolyte balance, may be also involved during embryogenesis in the growth and differentiation of organs and tissues, especially of those where strong mesenchymal-epithelial interactions take place. Thymus is a linfo-epithelial organ, which undergoes a very rapid prenatal and postnatal growth, playing a pivotal role in the development of immunological defense. Hence, it appeared worthwhile to investigate the expression of ADM system in the newborn (3-day-old) rat thymus as compared to adult (3-month-old) animals. Reverse transcription (RT)-polymerase chain reaction (PCR) allowed the detection of the specific mRNAs of pADM and peptidyl-glycine alpha-amidating monooxigenase (PAM), the enzyme which converts immature ADM to the mature peptide, in both newborn and adult rat thymuses. PAM expression was markedly higher in newborn animals, which accords well with the more elevated concentrations of ADM measured by RIA in newborn than adult rat thymuses. L1-R, CRLR, RAMP1 and RAMP2 mRNA were detected in both groups of rats, and with the exception of RAMP1, the expression was markedly higher in newborn than adult rat thymus. RAMP3 mRNA was present only in the thymus of newborn animals. Collectively, the present findings indicate that ADM system is up-regulated in newborn rat thymus, thereby making it likely that ADM may be involved in the thymus growth and in the development of immunological defense mechanisms.

Adrenomedullin↗