Finally, a Desktop solution for publishing your images to Instagram straight out of Lightroom. The solution is a neat little plugin by LR/Instagram which is designed for Windows and Mac and works with Lightroom Version 3.0 and up to Lightroom CC.
The plugin lets you upload images directly from Lightroom with your Caption and Hashtags. Although its an unofficial plugin, it uses Instagram API to publish your images.
Simply install the plugin using Lightroom Plugin Manager and locate it in the Library Module under the Publish Services panel. Click on setup to sign in to Instagram and you are good to go.
Next step is to edit your image and add them to LR/Instagram collection (under the Publish Service). Right click and select Publish Now.