Acquisition of submandibular gland nerve growth factor (SMG‐NGF) responsiveness to thyroxine administration in neonatal mice

Lakshmanan, J.; Beri, U.; Perheentupa, Jaakko; Grueters, Annette; Kim, H.; Macaso, Thelma M.; Fisher, Delbert A.

doi:10.1002/jnr.490120107

Cited by 7 publications

(9 citation statements)

References 23 publications

(6 reference statements)

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“…Moreover, the results suggest that exposure to thyroid hormones prior to 7 days of age is not necessary for induction of accelerated maturation of the SMG using EGF or NGF as the end-point determinant of such maturation. These results, however, differ slightly from those reported by Lakshmanan et al (25) who showed a significant increase in SMG EGF content in 15-day-old mice treated from birth compared to mice treated from day 7. The differences are difficult to reconcile since Lakshmanan et al (25) used essentially the same protocol employed in the present study.…”

Section: Discussioncontrasting

confidence: 99%

“…These results, however, differ slightly from those reported by Lakshmanan et al (25) who showed a significant increase in SMG EGF content in 15-day-old mice treated from birth compared to mice treated from day 7. The differences are difficult to reconcile since Lakshmanan et al (25) used essentially the same protocol employed in the present study.…”

Section: Discussioncontrasting

confidence: 99%

“…This sequence of events would be compatible with initial thyroid hormone responsiveness being localized to granular tubule cell precursor during early neonatal life and thyroxine accelerated appearance of mature granular tubule cells and their biosynthetic products. After completion of these studies, Lakshmanan et al (25) reported that T4 treatment during the first postnatal week increased SMG RNA, protein, and lipid contents but had no significant effects on SMG NGF concentration.…”

Section: Discussionmentioning

confidence: 99%

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Thyroxine Increases Submandibular Gland Nerve Growth Factor and Epidermal Growth Factor Concentrations Precociously in Neonatal Mice: Evidence for Thyroid Hormone-Mediated Growth Factor Synthesis

Walker

1986

Pediatr Res

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ABSTRAm. Thyroxine (T4) administration to adult female mice significantly increases submandibular gland (SMG) nerve growth factor (NGF) and epidermal growth factor (EGF) concentrations and does so in a time-and dose-dependent manner. Postnatal maturation of the SMG can be markedly accelerated by T4 treatment. We, therefore, performed a series of experiments to examine the effect of T4 on SMG NGF and EGF content and concentration as a function of postnatal age in neonatal mice. In experiment 1, male and female neonatal Swiss-Webster mice received daily subcutaneous injections of T4 (0.4 fig/ g body weight) for 6, 13, or 20 days and were sacrificed 24 h after the last injection. Vehicle injected mice served as controls. SMG NGF and EGF content and concentration were measured by specific double antibody radioimmunoassay systems. Pools were made using either female or male SMGs. Since no significant differences were noted for NGF or EGF content using sex of the animal as the determining variable, the values were combined. At 7 days of age, mean SMG NGF and EGF content and concentration of control mice significantly exceeded those of T4-treated animals (p < 0.05). At 14 days of age, mean SMG NGF and EGF content in T4-treated mice significantly exceeded those in control mice by 39-and 22-fold, respectively (p < 0.001). At 21 days of age, these increases were 4100-and 2400-fold, respectively. In order to determine more precisely the time of onset of responsivity of the SMG to thyroid hormones, a second series of experiments was performed. Vehicle and T4 (0.4 fig/g body weight daily) injected mice were sacrificed at 7, 9, 11, and 14 days of age. SMG EGF concentration was measured by radioimmunoassay. T4 treatment was without significant effect at 7 and 9 days of age. At 11 days of age, mean SMG EGF content and concentration in the T4-treated mice exceeded that in control mice by a factor of 2 (p < 0.05). Subsequently, SMG EGF content and concentration increased exponentially. Daily treatment of neonatal mice from birth or from the 7th postnatal day resulted in similar SMG EGF content and concentration when measured at 14 days of age. These data indicate that T4 administration to neo-

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Section: Discussioncontrasting

confidence: 99%

Section: Discussioncontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Thyroxine Increases Submandibular Gland Nerve Growth Factor and Epidermal Growth Factor Concentrations Precociously in Neonatal Mice: Evidence for Thyroid Hormone-Mediated Growth Factor Synthesis

Walker

1986

Pediatr Res

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“…7-15 days of age. Previous studies in this laboratory have indicated that both SMG-NGF and EGF acquire T4 responsiveness during the 2nd wk of life (17,18). Early actions of T4 on SMG include cytodifferentiation and organization (30).…”

Section: Discussionmentioning

confidence: 88%

“…Moreover, little information is available regarding the role of the autonomic nervous system in the growth and maturation of developing SMG (15,16). Recent studies in our laboratory have indicated that both SMG-NGF (17) and EGF (18) are T4 responsive during the second week of life. In view of the fact that T4 in newborn animals has profound effects on the developing nervous system (19,20), we examined the role of the SNS in mediating the T4 effect on developing SMG.…”

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Involvement of Developing Sympathetic Nervous System in Thyroxine-Mediated Submandibular Gland Nerve Growth Factor and Epidermal Growth Factor Responses

et al. 1986

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ABSTRACT. Thyroxine (T4) administration in mice during the 2nd wk of postnatal life elicits a precocious increase in submandibular gland-nerve growth factor (SMG-NGF) and epidermal growth factor (SMG-EGF) levels, but the mechanism(s) of T4 action has not been studied. The present report examines the role of the developing sympathetic nervous system (SNS) in the SMG-NGF and EGF responses to T4. For this purpose newborn mice were injected with T4 and/or 6-hydroxydopamine, a toxic congener of norephinephrine which causes selective destruction of sympathetic nerve terminals. The effectiveness of chemical sympathectomy was assessed by SMG-norepinephrine measurements using a sensitive radioenzymatic assay. The glandular norepinephrine contents were greatly reduced indicating that the dose and duration of 6-OHDA treatment were sufficient to cause a total sympathectomy in SMG tissue. In addition, the 6-OHDA treatment greatly reduced the wet weight and total protein content of the sympathetic superior cervical ganglia which innervate SMG tissue. SMG-NGF and EGF concentrations were measured by specific radioimmunoassays. 6-OHDA treatment alone did not affect the basal SMG-NGF and EGF concentrations. However, the maximal responses of SMG-NGF and EGF to T4 administration were greatly reduced by concurrent treatment with 6-OHDA. In summary, the data demonstrate a critical role for developing sympathetic nervous system in the T4-stimulated increase in SMG-NGF and EGF concentrations. (Pediatr Res 20: 232-236, 1986) Abbreviations T4, thyroxine SMG,-submandibular gland NGF, nerve growth factor EGF, epidermal growth factor SNS, sympathetic nervous system SCG, superior cervical ganglia NE, norepinephrine RIA, radioimmunoassay the autonomic nervous system (3). EGF is a polypeptide which exhibits a potent mitogenic effect on a wide variety of cell types (4). NGF and EGF are synthesized and stored in the CGT of the SMG (5, 6). SMG-NGF and EGF levels are low during the first three weeks of life in the mouse (7), a time when the SMG are grossly immature. Both SMG-NGF and EGF levels undergo exponential increases after weaning (i.e. 2 1 days) when the SMG exhibits rapid and maximal cytodifferentiation. In sexually mature animals the SMG exhibits sexual dimorphism with respect to structure (8) and growth factor content, including both NGF and EGF (9, 10). The factor(s) and the mechanism(s) that regulate these developmental changes are not fully understood.Several hormones are known to influence growth and maturation of mouse SMG (1 1, 12), including thyroxine, testosterone, and corticosterone, and these hormones have been recognized to augment the glandular contents of both NGF and EGF in adult animals (10,13,14). However, the critical time period for the actions of these hormones on SMG-NGF and EGF and their participation in the normal ontogenesis of SMG-NGF and EGF are not clearly understood. Moreover, little information is available regarding the role of the autonomic nervous system in the growth and maturation of developing SMG (1...

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The granular convoluted tubule (GCT) cell of rodent submandibular glands

Gresik¹

1994

Microscopy Res & Technique

175

183

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The granular convoluted tubule (GCT) is a segment of the duct system of all rodents, situated between the striated and intercalated ducts. It has the peculiar property of synthesizing a large variety of biologically active polypeptides whose role in saliva remains unknown. The literature on the fine structure of GCT cells is critically reviewed. Some recent developments on endocrine regulation of the structure and contents of rodent GCT cells are summarized, with emphasis on EGF, NGF, renin, and kallikrein proteases. A survey of the distribution of GCT cells in several vertebrate families is presented.

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Acquisition of submandibular gland nerve growth factor (SMG‐NGF) responsiveness to thyroxine administration in neonatal mice

Cited by 7 publications

References 23 publications

Thyroxine Increases Submandibular Gland Nerve Growth Factor and Epidermal Growth Factor Concentrations Precociously in Neonatal Mice: Evidence for Thyroid Hormone-Mediated Growth Factor Synthesis

Thyroxine Increases Submandibular Gland Nerve Growth Factor and Epidermal Growth Factor Concentrations Precociously in Neonatal Mice: Evidence for Thyroid Hormone-Mediated Growth Factor Synthesis

Involvement of Developing Sympathetic Nervous System in Thyroxine-Mediated Submandibular Gland Nerve Growth Factor and Epidermal Growth Factor Responses

The granular convoluted tubule (GCT) cell of rodent submandibular glands

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