13-Cis-Retinoic Acid-Induced Hyperglycemia in the Fresh Water Edible Crab, Oziothelphusa Senex Senex is mediated by Triggering Release of Hyperglycemic Hormone from Eyestalks

Sreenivasula Reddy P

doi:10.4172/2155-9546.1000356

Abstract

The present study was aimed to investigate the effect of 13-cis-retinoic acid (13-CRA) on hemolymph glucose levels in the fresh water edible crab, Oziothelphusa senex senex. Injection of 13-CRA significantly increased hemolymph glucose levels in a dose-dependent manner in intact crabs. Bilateral eyestalk ablation (ESX) resulted in significant decrease in hemolymph glucose levels. Injection of 13-CRA in to ESX crabs did not cause any significant changes in hemolymph glucose level as compared to ESX crabs suggesting that the effect of 13-CRA could be on the neuroendocrine system in the eyestalks increasing secretion of hyperglycemic hormone. To test this hypothesis, eyestalks were collected from control and 13-CRA injected crabs, and tested for hyperglycemic effect and also for the hyperglycemic hormone levels. The levels of hyperglycemic hormone and the hyperglycemic effect were significantly low in the eyestalks collected from 13-CRA injected crabs when compared with eyestalks from control crabs. From results, it is hypothesized that 13-CRA-induced hyperglycemia in the crab, O. senex, is mediated by triggering the release of hyperglycemic hormone from the eyestalk.

Highlights

In crustaceans, glucose homeostasis is primarily under the control of an eyestalk hormone, namely crustacean hyperglycemic hormone (CHH)
Retinoic acids (RA) including 9-cis-retinoic acid (9-CRA) and 13-cis-retinoic acid (13-CRA) and all-trans-retinoic acid (ATRA) are the metabolites of the vitamin A. Retinoids render their biological activity by binding to nuclear receptors in vertebrates. cis-retinoic acids like 9-CRA and 13-CRA interacts with both retinoic acid receptors (RARα,β,γ) and retinoid X receptor (RXR), whereas ATRA mainly interacts with the RARs [8]
Injection of 13CRA into intact crabs resulted in significant hyperglycemia in a dose-dependent manner, whereas injection of physiological saline did not cause any significant effect on hemolymph glucose levels (Figure 1)

Summary

Introduction

Glucose homeostasis is primarily under the control of an eyestalk hormone, namely crustacean hyperglycemic hormone (CHH). The action of CHH in inducing hyperglycemia is mainly through mobilization of glucose from the tissue carbohydrate pools [6]. Retinoic acids (RA) including 9-cis-retinoic acid (9-CRA) and 13-cis-retinoic acid (13-CRA) and all-trans-retinoic acid (ATRA) are the metabolites of the vitamin A. Retinoids render their biological activity by binding to nuclear receptors in vertebrates. Cis-retinoic acids like 9-CRA and 13-CRA interacts with both retinoic acid receptors (RARα,β,γ) and retinoid X receptor (RXR), whereas ATRA mainly interacts with the RARs [8]. The antidiabetic effects of retinoids in human skeletal muscle [11] and diabetic rodents [12] are accepted to be the mediated through the RXR/RAR heterodimer, and RXR homodimer

Methods

Results

Discussion

Conclusion