The herbal formula HT042 induces longitudinal bone growth in adolescent female rats

The Effects of Natural Product-Derived Extracts for Longitudinal Bone Growth: An Overview of In Vivo Experiments

Approximately 80% of children with short stature are classified as having Idiopathic Short Stature (ISS). While growth hormone (GH) treatment received FDA approval in the United States in 2003, its long-term impact on final height remains debated. Other treatments, like aromatase inhibitors, metformin, and insulin-like growth factor-1 (IGF-1), have been explored, but there is no established standard treatment for ISS. In South Korea and other Asian countries, East Asian Traditional Medicine (EATM) is sometimes employed by parents to potentially enhance their children's height growth, often involving herbal medicines. One such product, Astragalus membranaceus extract mixture HT042, claims to promote height growth in children and has gained approval from the Korean Food and Drug Administration (KFDA). Research suggests that HT042 supplementation can increase height growth in children without skeletal maturation, possibly by elevating serum IGF-1 and IGF-binding protein-3 levels. Preclinical studies also indicate the potential benefits of natural products, including of EATM therapies for ISS. The purpose of this review is to offer an overview of bone growth factors related to ISS and to investigate the potential of natural products, including herbal preparations, as alternative treatments for managing ISS symptoms, based on their known efficacy in in vivo studies.

Hydrolyzed Collagen Tripeptide Promotes Longitudinal Bone Growth in Childhood Rats via Increases in Insulin-Like Growth Factor-1 and Bone Morphogenetic Proteins

Previous studies have reported that collagen tripeptide (CTP) derived from collagen hydrolysate has various beneficial effects on health by protecting against skin aging and improving bone formation and cartilage regeneration. Collagen-Tripep20TM (CTP20), which is a low-molecular-weight CTP derived from fish skin, contains a bioactive CTP, Gly-Pro-Hyp >3.2% with a tripeptide content >20%. Herein, we investigated the osteogenic effects and mechanisms of CTP20 (<500 Da) on MG-63 osteoblast-like cells and SW1353 chondrocytes. And we measured promoting ratio of the longitudinal bone growth in childhood rats. First, CTP20 at 100 μg/mL elevated the proliferation (15.0% and 28.2%), alkaline phosphatase activity (29.3% and 32.0%), collagen synthesis (1.25- and 1.14-fold), and calcium deposition (1.18- and 1.15-fold) in MG-63 cells and SW1353, respectively. In addition, we found that CTP20 could promote the longitudinal growth and height of the growth plate of the tibia in childhood rats. CTP20 enhanced the protein expression of insulin-like growth factor-1 (IGF-1) in MG-63 and SW1353 cells, and in the growth plate of childhood rats, along with Janus Kinase 2, and signal transducer and activator of transcription 5 activation in MG-63 and SW1353 cells. CTP20 also elevated the expression levels of bone morphogenetic proteins (BMPs) in MG-63 and SW1353 cells and in the growth plates of childhood rats. These results indicate that CTP20 may promote the endochondral ossification and longitudinal bone growth, through enhancing of IGF-1 and BMPs. (Clinical Trial Registration number: smecae 19-09-01).

Effects of Astragalus Extract Mixture HT042 on Circulating IGF-1 Level and Growth Hormone Axis in Rats

Astragalus extract mixture HT042 is a standardized functional food granted by the Korean FDA for promoting “Children’s Height Growth”. In this study, we determined whether HT042 affects circulatory Insulin-like growth factor-1 (IGF-1) after administration and investigated whether Growth hormone (GH), Growth hormone-releasing hormone receptor (GHRH-R), and Growth hormone secretagogue receptor (GHS-R) mRNAs are expressed in the pituitary, and whether Growth hormone-releasing hormone (GHRH) and Somatostatin (SST) are expressed in the hypothalamus. We also evaluated the growth effect of HT042 on endochondral bone formation. Male Sprague-Dawley rats in the control and HT042 groups were orally administered a single dose of the control and HT042, respectively, and those in the recombinant human GH (rhGH) group were subcutaneously injected with rhGH. Tetracycline was injected intraperitoneally 72 h prior to sacrifice to decide endochondral bone formation. To determine the endocrine or paracrine/autocrine mechanism, we evaluated the expression of local BMP-2 and IGF-1, an immunohistochemical study after HT042 administration. It was confirmed that the growth-promoting effect of HT042 can be contributed to the increase in serum IGF-1, which can be stimulated by GH secretion. Administration of HT042 modulated the activity of GHRH-R and GHR-S in the pituitary gland and promoted GH secretion, thereby changing longitudinal growth through GH/IGF-1 mediation. Results for GHRH and SST expression demonstrated that the hypothalamus can be influenced and mediated by HT042 through a complex neuroendocrine regulatory system. In addition, it was confirmed by oral administration for 10 days that HT042 increased bone formation in cartilage, which is important for height growth. The effect of HT042 could be owing to upregulation of local Bone morphogenetic protein-2 (BMP-2) and IGF-1 expression in the growth plate, which could be regarded as a GH-dependent autocrine/paracrine pathway, as well as circulatory IGF-1.

Phlomoides umbrosa (Turcz.) Kamelin & Makhm: A review of its traditional uses, botany, phytochemistry, pharmacology and clinical research

ETHNOPHARMACOLOGICAL RELEVANCE

Phlomoides umbrosa (Turcz.) Kamelin & Makhm (P. umbrosa, Lamiaceae) is also known as "Caosu" in China and "Han Sok-Dan" in Korea. It has been used as a traditional medicine for hundreds of years. This plant is not only as a traditional medicine to alleviate diseases such as colds, arthritis, osteoporosis, but also as a food additive.

AIM OF THE STUDY

This review provides up-to-date investigations of this plant, including its botany, traditional uses, pharmacology, phytochemistry, clinical research, cytotoxicity, and safety evaluation. The possible purposes and perspectives for future research of P. umbrosa are also discussed.

MATERIALS AND METHODS

Information on the studies of P. umbrosa is collected from scientific journals and reports via library and electronic data search (PubMed, Baidu Academic, Google Scholar, Science Direct, ACS, Web of Science, and CNKI). Meanwhile, it is also obtained from published works of folk records, ethnopharmacological literature, Ph.D. and Masters Dissertation.

RESULTS

Phytochemical research reveals that this plant contains triterpenoids, iridoids, phenylethanoids, flavonoids, essential oil, microelement, etc. The extract of P. umbrosa exhibits extensive pharmacological activities including anti-osteoporosis, anti-allergic, anti-bacterial, anti-nociceptive, anti-inflammatory, anti-oxidant, anti-cancer. Almost no obvious toxicity or side effects is observed and recorded for P. umbrosa.

CONCLUSIONS

This review summarizes traditional uses, botany, pharmacology, phytochemistry, clinical research, cytotoxicity, and safety evaluation of P. umbrosa, and presents the constituents and their corresponding chemical structures found in P. umbrosa comprehensively for the first time. Meanwhile, modern pharmacological studies also are extensively investigated at present. It is worth mentioning that P. umbrosa promotes children's growth as well as the application of clinical research. Although there are clinical studies on P. umbrosa, its pharmacokinetics needs to be further elucidated. Besides, P. umbrosa is also limited in identifying active compounds and clarifying pharmacological mechanisms. Similarly, modern researches on the traditional application of P. umbrosa should also be urgently confirmed, such as treatment of fractures and hemostasis. It is believed that this review will provide a theoretical basis and valuable data for future in-depth research and application.

Effects of a Mixture of Humulus japonicus on Longitudinal Bone Growth in Hypophysectomized Rats

Previously, we reported that the administration of a mixture of Humulus japonicus (MH) increased the longitudinal bone growth rate in Sprague Dawley rats. In this study, we investigated the effects of the dietary administration of MH on longitudinal bone growth in growth hormone (GH)-deficient hypophysectomized male and female rats to determine whether the effect of MH was similar to that of GH. We measured the nose-to-anus and nose-to-tail length gain, femur and tibia lengths, growth plate zones, and expression of insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) after the dietary administration of MH or the injection of GH into hypophysectomized rats for 4 weeks. Results demonstrated that the dietary administration of MH had no effect on longitudinal bone growth, whereas the injection of GH increased the nose-to-tail length gain and femur and tibia lengths in hypophysectomized rats. In addition, MH did not affect the growth plate, bone mineralization, and expression of IGF-1 and IGFBP-3. These findings indicate that MH does not exert a GH-like effect and that the effects of MH and GH on longitudinal bone growth involve different pathways.

Longitudinal Bone Growth Stimulating Effect of Allium macrostemon in Adolescent Female Rats

Allium macrostemon (AM) may affect bone growth by regulating bone formation and resorption. To examine the effect of AM on bone growth, 48 rats were divided into four administration groups in which either distilled water, AM (100 and 300 mg/kg), or recombinant human growth hormone (rhGH; 20 μg/kg) was administered for 10 days. On day 9, all animals were intraperitoneally injected with tetracycline hydrochloride (20 mg/kg), and 48 h after the injection, the rats were sacrificed. Their tibial sections were photographed to measure bone growth. Antigen-specific immunohistochemistry was performed to detect insulin-like growth factor-1 (IGF-1) and bone morphogenetic protein-2 (BMP-2). The food intake of the AM 100 mg/kg group was higher; however, the food intake of the AM 300 mg/kg group was less than that of the control group. The rhGH and AM 100 mg/kg groups showed greater rates of bone growth (359.0 ± 23.7 and 373.1 ± 28.0 μm/day, respectively) compared with the control group. IGF-1 and BMP-2 in the AM and rhGH groups were highly expressed. Indigestion at higher doses of AM led to nonsignificant bone growth in spite of increased IGF-1 and BMP-2 expression. Therefore, a suitable amount of AM could increase bone growth.

Inhibition of cytochrome P450 2B6 by Astragalus extract mixture HT042

Astragalus extract mixture (AEM) HT042 is a functional food approved by the MFDS (Korean FDA) for increasing height. It comprises a mixture of three standardized extracts from Astragalus membranaceus root, Eleutherococcus senticosus stem, and Phlomis umbrosa root. In this study, drug-functional food interaction was analyzed using six major human cytochrome P450 enzymes. The inhibitory effect of AEM HT042 on P450 activities was studied using a P450-NADPH P450 reductase reconstitution system. Among the six P450 enzymes (1A2, 2A6, 2B6, 2D6, 2C9, and 3A4), only P450 2B6 activity was markedly decreased by AEM HT042 addition. The bupropion hydroxylation activity of P450 2B6 was analyzed using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A calculated IC₅₀ value of 10.62 µg/ml was obtained. To identify the inhibitory compounds in the mixture, four active compounds in AEM HT042 were analyzed. Shanzhiside methylester exhibited inhibitory effects on P450 2B6, whereas formononetin, eleutheroside E, and sesamoside did not affect P450 2B6 activity at all. Our results suggest that shanzhiside methylester in AEM HT042 is responsible for the inhibitory effect on P450 2B6 metabolism. Characterization of the inhibitory effect on P450 can help determine the safe administration of functional foods along with many clinical drugs that are metabolized by P450.

Effects of Siwu decoction on chondrocyte proliferation of growth plate in adolescent rats

ETHNOPHARMACOLOGICAL RELEVANCE

According to traditional Korean medicine theory in which children's growth retardation is attributed to blood deficiency, Siwu decoction (SWD), a representative treatment for blood deficiency, was chosen as a sample.

AIM OF THE STUDY

To evaluate the effects of SWD on chondrocyte proliferation of growth plate in adolescent female rats.

MATERIALS AND METHODS

Female adolescent rats were allocated to one of the following four groups; SWD 100 and 300 mg/kg, recombinant human growth hormone, and vehicle for 4 days. Tetracycline was intraperitoneally injected at 48 h before sacrifice to obtain a band exhibiting fluorescence by binding newly formed bone. Bromodeoxyuridine was injected at day 2-4 to mark proliferating chondrocytes. To evaluate possible mechanisms of SWD, expressions of insulin-like growth factor-1 (IGF-1) and bone morphogenetic protein-2 (BMP-2) in the growth plate were examined by immunohistochemistry.

RESULTS

Treatment with SWD significantly increased the number of BrdU-positive chondrocytes and the new bone formation in the proximal growth plate of tibia compared to the vehicle treated control group. SWD also increased the expression of IGF-1 and BMP-2 in the proliferative and hypertrophic zones of the growth plate.

CONCLUSIONS

SWD 300 mg/kg stimulates chondrocyte proliferation and new bone formation in the growth plate. Immunohistochemical studies indicate that the effects of SWD may be due to upregulation of local IGF-1 and BMP-2 expression in the growth plate, which may be considered as a GH-dependent paracrine-autocrine pathway.

Effects of Eleutherococcus Extract Mixture on Endochondral Bone Formation in Rats

Eleutherococcus extract mixture (EEM) is an herbal mixture of dried stem of Eleutherococcus sessiliflorus and germinated barley, which has been highly effective, in previous screening and among the traditional medicines to tonify innate qi and acquired qi, respectively. In this study, we investigate the effects of EEM on endochondral bone formation. Female adolescent rats were given EEM, growth hormone or vehicle for 10 days. Tetracycline was intraperitoneally injected to light the fluorescent band 72 h before sacrifice to determine endochondral bone formation. In order to evaluate endocrine or paracrine/autocrine mechanisms, expressions of insulin-like growth factor 1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3), or bone morphogenetic protein 2 (BMP2) were evaluated after EEM administration in liver or growth plate (GP). EEM oral administration significantly increased endochondral bone formation and proliferative and hypertrophic zonal heights of tibial GP. EEM also upregulated hepatic IGF1 and IGFBP3 mRNA expressions, and IGF1 and BMP2 expressions in GP. Taken together, EEM increases endochondral bone formation through stimulating proliferation and hypertrophy with upregulation of hepatic IGF1 and IGFBP3 expressions. Considering immunohistochemical studies, the effect of EEM may be due to increased local IGF1 and BMP2 expression in GP, which may be considered growth hormone (GH)-dependent endocrine and autocrine/paracrine pathways.

Effects of Huang Bai (Phellodendri Cortex) on bone growth and pubertal development in adolescent female rats

Background

To evaluate the effects of Huang Bai (Phellodendron amurense) on growth and maturation in adolescent female rats.

Methods

Female Sprague-Dawley rats (28 days old; n = 72) were divided into six daily treatment groups: control (distilled water), Huang Bai (100 and 300 mg/kg), recombinant human GH (rhGH; 20 μg/kg), estradiol (1 μg/kg), and triptorelin (100 μg). Body weight, food intake, and vaginal opening were measured daily from postnatal day (PND) 28 to PND 43. Tetracycline (20 mg/kg) was injected on PND 41. After sacrifice on PND 43, the ovaries and uterus were weighed, and the tibias were fixed in 4% paraformaldehyde. Decalcified and dehydrated tibias were sectioned at a thickness of 40 μm, and sectioned tissues were examined with a fluorescence microscope. Insulin-like growth factor (IGF)-1 and bone morphogenetic protein (BMP)-2 were detected using immunohistochemistry.

Results

Relative to controls, body weight was higher in the triptorelin group. Bone growth rate increased in the Huang Bai 100 mg/kg (354.00 ± 31.1 μm/day), rhGH (367.10 ± 27.11 μm/day), and triptorelin (374.50 ± 25.37 μm/day) groups. Expression of IGF-1 and BMP-2 in the hypertrophic zone was higher in all experimental groups. Vaginal opening occurred earlier in the estradiol group (PND 33.58 ± 1.62) than in controls and later in the triptorelin group (PND > 43). Ovarian and uterine weights were lower in the oestradiol and triptorelin groups. However, Huang Bai had nonsignificant effects on vaginal opening and the weights of ovaries and the uterus.

Conclusions

Huang Bai stimulated bone growth by upregulating IGF-1 and BMP-2 in the growth plate. However, it had no effect on pubertal development.

Effects of Astragalus Extract Mixture HT042 on Height Growth in Children with Mild Short Stature: A Multicenter Randomized Controlled Trial

HT042 is a standardized functional food ingredient approved by Korean Food and Drug Administration with a claim 'HT042 can help height growth of children'. We aimed to evaluate the safety and efficacy of HT042 on height growth in children with mild short stature. A multicenter, randomized, double-blind, placebo-controlled parallel study was performed on children aged 6-8 years with height ranked below the 25th percentile. In 129 children, height gain was significantly higher in HT042 group than placebo group after 24 weeks (mean difference, 0.29 cm; 95% CI, 0.01 to 0.57 cm; p = 0.027). The difference was elevated when the efficacy analysis was restricted to children below the 10th percentile (mean difference, 0.45 cm; 95% CI, 0.04 to 0.87 cm; p = 0.031). Because bone age advancement was lower in HT042 group, height standard deviation score gain for bone age was higher in HT042 group and the difference was significant in children below the 10th percentile (mean difference, 0.20 score; 95% CI, 0.00 to 0.39 points; p = 0.045). Serum IGF-1 and IGFBP-3 levels were significantly increased compared with baseline within HT042 group, but group difference was not significant. HT042 supplementation helped to increase height growth in children without skeletal maturation and was more effective in much shorter children. The effects might be mediated by increases in serum IGF-1 and IGFBP-3 levels. Copyright © 2017 John Wiley & Sons, Ltd.

Safety evaluation of Astragalus extract mixture HT042 and its constituent herbs in Sprague-Dawley rats

BACKGROUND

Astragalus extract mixture HT042 is a combination of three standardized extracts from Astragalus membranaceus root, Eleutherococcus senticosus stem, and Phlomis umbrosa root, which has proven to stimulate children's height growth.

PURPOSE

The aim of this study was to demonstrate the safety of HT042 and its three constituent herbs when administered orally.

METHODS

Acute and sub-chronic oral toxicity studies were conducted using male and female Sprague-Dawley rats. In the acute toxicity study, HT042 and each of the herbs was administered at single doses of up to 5000 mg/kg. In the 13-week sub-chronic toxicity study, HT042 was administered at repeated doses of up to 4000 mg/kg/day.

RESULTS

In the acute toxicity study of HT042 and each of the herbs, no deaths occurred and there was no indication of toxicity, on the basis of clinical signs, body weight, and necropsy findings. In the sub-chronic toxicity study of HT042, there were no deaths and no changes in clinical signs or the findings of ophthalmic examinations. Although there were some treatment-related changes in other findings, these alterations were not considered toxicologically significant because they remained within normal ranges or recovered during the recovery period.

CONCLUSION

The oral approximate lethal doses of HT042 and each of the herbs were > 5000 mg/kg, and the no-observed-adverse-effect level of HT042 was 4000 mg/kg/day in male and female rats.

Astragalus Extract Mixture HT042 Increases Longitudinal Bone Growth Rate by Upregulating Circulatory IGF-1 in Rats

Astragalus extract mixture HT042 is a standardized ingredient of health functional food approved by Korean FDA with a claim of “height growth of children.” HT042 stimulates bone growth rate and increases local IGF-1 expression in growth plate of rats which can be considered as direct stimulation of GH and its paracrine/autocrine actions. However, it remains unclear whether HT042 stimulates circulatory IGF-1 which also plays a major role to stimulate bone growth. To determine the effects on circulatory IGF-1, IGF-1 and IGFBP-3 expressions and phosphorylation of JAK2/STAT5 were evaluated in the liver after 10 days of HT042 administration. HT042 upregulated liver IGF-1 and IGFBP-3 mRNA expression, IGF-1 protein expression, and phosphorylation of JAK2/STAT5. HT042 also increased bone growth rate and proliferative zonal height in growth plate. In conclusion, HT042 stimulates bone growth rate via increment of proliferative rate by upregulation of liver IGF-1 and IGFBP-3 mRNA followed by IGF-1 protein expression through phosphorylation of JAK2/STAT5, which can be regarded as normal functioning of GH-dependent endocrine pathway.

Astragalus Extract Mixture HT042 Improves Bone Growth, Mass, and Microarchitecture in Prepubertal Female Rats: A Microcomputed Tomographic Study

Astragalus extract mixture HT042 is a standardized multiherbal mixture comprising Astragalus membranaceus, Eleutherococcus senticosus, and Phlomis umbrosa, which has proven to promote children's height growth. The aim of this study was to investigate the effects of HT042 on longitudinal bone growth, bone mass, and bone microstructure in growing rats using a high-resolution microcomputed tomography system. Four-week-old female rats were fed an HT042-containing diet for 2 weeks. Tibial length was measured at baseline and weekly in vivo. At the end of the study, volumetric bone mineral density (vBMD) and microarchitectural parameters were estimated in the trabecular and cortical bone of the tibia. Tibial length gain was significantly increased by HT042 compared to that reported with the control diet. In the proximal tibial metaphysis, HT042-treated rats had significantly higher trabecular vBMD, bone volume fraction, and trabecular number and lower trabecular separation, trabecular pattern factor, and structure model index values than control rats did. Total cross-sectional area and bone area of the cortical bone in the tibial diaphysis also increased. These findings suggest that HT042 increases longitudinal bone growth rate, improves trabecular bone mass, and enhances the microarchitecture of trabecular and cortical bone during growth.

Effect of HT042, herbal formula, on longitudinal bone growth in spontaneous dwarf rats

HT042 is a new herbal prescription consisting of Astragalus membranaceus, Phlomis umbrosa and Eleutherococcus senticosus, which are used in Korean medicine to stimulate growth in children. We investigated the effects of HT042 on the body weight, longitudinal bone growth, and bone length in spontaneous dwarf rats (SDR). Male and female SDRs were divided into three groups: the control group (DW, 10 mL/kg/day), the recombinant human GH group (rhGH; 500 µg/kg/day), and the HT042 (100 mg/kg/day) group. Each group received the respective treatments for 10 days. Body weight was measured on day 10 of treatment. On day 8, tetracycline (20 mg/kg) was injected intraperitoneally into all individuals to form a fluorescent band on the newly synthesized bone. On day 10, femur and tibia lengths were measured using PIXImus. Body weight, longitudinal bone growth, and bone length were not affected in the HT042 group. In contrast, the rhGH group showed significantly increased body weight, longitudinal bone growth, and bone length. In conclusion, HT042 does not act through a GH-like effect to promote longitudinal bone growth.

Amomum villosum induces longitudinal bone growth in adolescent female rats

OBJECTIVE

This study was conducted to evaluate the effect of Amomum villosum on longitudinal bone growth.

METHODS

Adolescent female Sprague-Dawley rats were divided into 3 groups and treated for 4 days: control (distilled water, p.o.), recombinant human growth hormone (rhGH; 100 microg/kg, s.c.), and A. villosum (500 mg/kg, p.o.) groups. On day 3, tetracycline (20 g/kg, i.p.) was injected for growth plate identification. On days 2, and 4, 5-bromo-2'-deoxyuridine (BrdU) (50 mg/kg, i.p.) was injected to label proliferating cells. On day 5, tibias were dissected and fixed in 4% paraformaldehyde, dehydrated, and sectionedfor immunohistochemistry and histomorphometry.

RESULTS

The rate of bone growth in the A. villosum and rhGH groups increased to (410 +/- 44) and (389 +/- 46) microm/day (P<0.01), respectively, as compared with the control (330.7 +/- 34.7) microm/day. The thickness of the growth plates also increased to (591 +/- 37) and (598 +/- 32) microm, respectively, as compared with the control (524 +/- 89) microm (P<0.001). The number of BrdU-positive cells in the chondrocytes of the A. villosum and rhGH groups was also significantly higher (126 +/- 24) and (143 +/- 18) cells/mm2, respectively) than in the control (109 +/- 25) mm2 (P<0.05). Insulin-like growth factor-1 and bone morphogenetic protein-2 in the A. villosum and rhGH groups were highly expressed in the growth plate as compared with the control samples, indicating increased bone formation.

CONCLUSIONS

A. villosum could be used to treat growth retardation during adolescence.

Skeletal growth and IGF levels in rats after HT042 treatment

HT042, a new herbal prescription consisting of Astragalus membranaceus, Phlomis umbrosa and Eleutherococcus senticosus, is used in traditional Korean medicine to stimulate growth in children. This study was conducted to investigate the effects of HT042 on skeletal growth, insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) levels, and oestrogenic activity in female rats. Female Sprague-Dawley rats were divided into control, recombinant human growth hormone (rhGH; 20 µg/kg/day), and HT042 (100 mg/kg/day) groups and treated for 3 weeks. Axial skeletal growth, femur length, and growth plate length were measured every 3 weeks. The serum IGF-1 and IGFBP-3 levels were analysed. Moreover, the oestrogenic activity of the herbal extracts in the immature and ovariectomized rats was tested. The nose-anus, nose-tail, femur and growth-plate lengths were increased significantly in the HT042 group. Both IGF-1 and IGFBP-3 were highly expressed in the hypertrophic zone of the growth plate. The serum IGF-1 levels were increased. Moreover, HT042 had no uterotrophic effects in the rats. Consequently, HT042 promoted longitudinal bone growth by stimulating cell proliferation in the epiphyseal plate and inducing the expression of IGF-1 without an oestrogenic response. HT042 may be helpful in stimulating growth in children with short stature.